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<td class='main'><a href='/'>index</a> : <a title='renesas/drm.git' href='/renesas/drm.git/'>renesas/drm.git</a></td><td class='form'><form method='get'>
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<tr><td class='sub'>libdrm, cloned from git://anongit.freedesktop.org/mesa/drm</td><td class='sub right'>Laurent Pinchart</td></tr></table>
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<div class='path'>path: <a href='/renesas/drm.git/log/?h=android&amp;id=6d59bad8e9cab6170e1af3d67597b6f5f145c33f'>root</a>/<a href='/renesas/drm.git/log/linux-core?h=android&amp;id=6d59bad8e9cab6170e1af3d67597b6f5f145c33f'>linux-core</a>/<a href='/renesas/drm.git/log/linux-core/via_map.c?h=android&amp;id=6d59bad8e9cab6170e1af3d67597b6f5f145c33f'>via_map.c</a></div><div class='content'><table class='list nowrap'><tr class='nohover'><th class='left'>Age</th><th class='left'>Commit message (<a href='/renesas/drm.git/log/linux-core/via_map.c?h=android&amp;id=6d59bad8e9cab6170e1af3d67597b6f5f145c33f&amp;showmsg=1'>Expand</a>)</th><th class='left'>Author</th></tr>
<tr><td><span title='2006-12-01 10:37:55 +0100'>2006-12-01</span></td><td><a href='/renesas/drm.git/commit/linux-core/via_map.c?h=android&amp;id=4a0e61d91013f88ca9555a280e2363bed14aec02'>Track linux-core symlinks in git.</a></td><td>Michel Dänzer</td></tr>
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<a id='n362' href='#n362'>362</a>
<a id='n363' href='#n363'>363</a>
<a id='n364' href='#n364'>364</a>
<a id='n365' href='#n365'>365</a>
<a id='n366' href='#n366'>366</a>
<a id='n367' href='#n367'>367</a>
<a id='n368' href='#n368'>368</a>
<a id='n369' href='#n369'>369</a>
<a id='n370' href='#n370'>370</a>
<a id='n371' href='#n371'>371</a>
<a id='n372' href='#n372'>372</a>
<a id='n373' href='#n373'>373</a>
<a id='n374' href='#n374'>374</a>
<a id='n375' href='#n375'>375</a>
<a id='n376' href='#n376'>376</a>
<a id='n377' href='#n377'>377</a>
<a id='n378' href='#n378'>378</a>
<a id='n379' href='#n379'>379</a>
<a id='n380' href='#n380'>380</a>
<a id='n381' href='#n381'>381</a>
<a id='n382' href='#n382'>382</a>
<a id='n383' href='#n383'>383</a>
<a id='n384' href='#n384'>384</a>
<a id='n385' href='#n385'>385</a>
<a id='n386' href='#n386'>386</a>
<a id='n387' href='#n387'>387</a>
<a id='n388' href='#n388'>388</a>
<a id='n389' href='#n389'>389</a>
<a id='n390' href='#n390'>390</a>
<a id='n391' href='#n391'>391</a>
<a id='n392' href='#n392'>392</a>
<a id='n393' href='#n393'>393</a>
<a id='n394' href='#n394'>394</a>
<a id='n395' href='#n395'>395</a>
<a id='n396' href='#n396'>396</a>
<a id='n397' href='#n397'>397</a>
<a id='n398' href='#n398'>398</a>
<a id='n399' href='#n399'>399</a>
<a id='n400' href='#n400'>400</a>
<a id='n401' href='#n401'>401</a>
<a id='n402' href='#n402'>402</a>
<a id='n403' href='#n403'>403</a>
<a id='n404' href='#n404'>404</a>
<a id='n405' href='#n405'>405</a>
<a id='n406' href='#n406'>406</a>
<a id='n407' href='#n407'>407</a>
<a id='n408' href='#n408'>408</a>
<a id='n409' href='#n409'>409</a>
<a id='n410' href='#n410'>410</a>
<a id='n411' href='#n411'>411</a>
<a id='n412' href='#n412'>412</a>
<a id='n413' href='#n413'>413</a>
<a id='n414' href='#n414'>414</a>
<a id='n415' href='#n415'>415</a>
<a id='n416' href='#n416'>416</a>
<a id='n417' href='#n417'>417</a>
<a id='n418' href='#n418'>418</a>
<a id='n419' href='#n419'>419</a>
<a id='n420' href='#n420'>420</a>
<a id='n421' href='#n421'>421</a>
<a id='n422' href='#n422'>422</a>
<a id='n423' href='#n423'>423</a>
<a id='n424' href='#n424'>424</a>
<a id='n425' href='#n425'>425</a>
<a id='n426' href='#n426'>426</a>
<a id='n427' href='#n427'>427</a>
<a id='n428' href='#n428'>428</a>
<a id='n429' href='#n429'>429</a>
<a id='n430' href='#n430'>430</a>
<a id='n431' href='#n431'>431</a>
<a id='n432' href='#n432'>432</a>
<a id='n433' href='#n433'>433</a>
<a id='n434' href='#n434'>434</a>
<a id='n435' href='#n435'>435</a>
<a id='n436' href='#n436'>436</a>
<a id='n437' href='#n437'>437</a>
<a id='n438' href='#n438'>438</a>
<a id='n439' href='#n439'>439</a>
<a id='n440' href='#n440'>440</a>
<a id='n441' href='#n441'>441</a>
<a id='n442' href='#n442'>442</a>
<a id='n443' href='#n443'>443</a>
<a id='n444' href='#n444'>444</a>
<a id='n445' href='#n445'>445</a>
<a id='n446' href='#n446'>446</a>
<a id='n447' href='#n447'>447</a>
<a id='n448' href='#n448'>448</a>
<a id='n449' href='#n449'>449</a>
<a id='n450' href='#n450'>450</a>
<a id='n451' href='#n451'>451</a>
<a id='n452' href='#n452'>452</a>
<a id='n453' href='#n453'>453</a>
<a id='n454' href='#n454'>454</a>
<a id='n455' href='#n455'>455</a>
<a id='n456' href='#n456'>456</a>
<a id='n457' href='#n457'>457</a>
<a id='n458' href='#n458'>458</a>
<a id='n459' href='#n459'>459</a>
<a id='n460' href='#n460'>460</a>
<a id='n461' href='#n461'>461</a>
<a id='n462' href='#n462'>462</a>
<a id='n463' href='#n463'>463</a>
<a id='n464' href='#n464'>464</a>
<a id='n465' href='#n465'>465</a>
<a id='n466' href='#n466'>466</a>
<a id='n467' href='#n467'>467</a>
<a id='n468' href='#n468'>468</a>
<a id='n469' href='#n469'>469</a>
<a id='n470' href='#n470'>470</a>
<a id='n471' href='#n471'>471</a>
<a id='n472' href='#n472'>472</a>
<a id='n473' href='#n473'>473</a>
<a id='n474' href='#n474'>474</a>
<a id='n475' href='#n475'>475</a>
<a id='n476' href='#n476'>476</a>
<a id='n477' href='#n477'>477</a>
<a id='n478' href='#n478'>478</a>
<a id='n479' href='#n479'>479</a>
<a id='n480' href='#n480'>480</a>
<a id='n481' href='#n481'>481</a>
<a id='n482' href='#n482'>482</a>
<a id='n483' href='#n483'>483</a>
<a id='n484' href='#n484'>484</a>
<a id='n485' href='#n485'>485</a>
<a id='n486' href='#n486'>486</a>
<a id='n487' href='#n487'>487</a>
<a id='n488' href='#n488'>488</a>
<a id='n489' href='#n489'>489</a>
<a id='n490' href='#n490'>490</a>
<a id='n491' href='#n491'>491</a>
<a id='n492' href='#n492'>492</a>
<a id='n493' href='#n493'>493</a>
<a id='n494' href='#n494'>494</a>
<a id='n495' href='#n495'>495</a>
<a id='n496' href='#n496'>496</a>
<a id='n497' href='#n497'>497</a>
<a id='n498' href='#n498'>498</a>
<a id='n499' href='#n499'>499</a>
<a id='n500' href='#n500'>500</a>
<a id='n501' href='#n501'>501</a>
<a id='n502' href='#n502'>502</a>
<a id='n503' href='#n503'>503</a>
<a id='n504' href='#n504'>504</a>
<a id='n505' href='#n505'>505</a>
<a id='n506' href='#n506'>506</a>
<a id='n507' href='#n507'>507</a>
<a id='n508' href='#n508'>508</a>
<a id='n509' href='#n509'>509</a>
<a id='n510' href='#n510'>510</a>
<a id='n511' href='#n511'>511</a>
<a id='n512' href='#n512'>512</a>
<a id='n513' href='#n513'>513</a>
<a id='n514' href='#n514'>514</a>
<a id='n515' href='#n515'>515</a>
<a id='n516' href='#n516'>516</a>
<a id='n517' href='#n517'>517</a>
<a id='n518' href='#n518'>518</a>
<a id='n519' href='#n519'>519</a>
<a id='n520' href='#n520'>520</a>
<a id='n521' href='#n521'>521</a>
<a id='n522' href='#n522'>522</a>
<a id='n523' href='#n523'>523</a>
<a id='n524' href='#n524'>524</a>
<a id='n525' href='#n525'>525</a>
<a id='n526' href='#n526'>526</a>
<a id='n527' href='#n527'>527</a>
<a id='n528' href='#n528'>528</a>
<a id='n529' href='#n529'>529</a>
<a id='n530' href='#n530'>530</a>
<a id='n531' href='#n531'>531</a>
<a id='n532' href='#n532'>532</a>
<a id='n533' href='#n533'>533</a>
<a id='n534' href='#n534'>534</a>
<a id='n535' href='#n535'>535</a>
<a id='n536' href='#n536'>536</a>
<a id='n537' href='#n537'>537</a>
<a id='n538' href='#n538'>538</a>
<a id='n539' href='#n539'>539</a>
<a id='n540' href='#n540'>540</a>
<a id='n541' href='#n541'>541</a>
<a id='n542' href='#n542'>542</a>
<a id='n543' href='#n543'>543</a>
<a id='n544' href='#n544'>544</a>
<a id='n545' href='#n545'>545</a>
<a id='n546' href='#n546'>546</a>
<a id='n547' href='#n547'>547</a>
<a id='n548' href='#n548'>548</a>
<a id='n549' href='#n549'>549</a>
<a id='n550' href='#n550'>550</a>
<a id='n551' href='#n551'>551</a>
<a id='n552' href='#n552'>552</a>
<a id='n553' href='#n553'>553</a>
<a id='n554' href='#n554'>554</a>
<a id='n555' href='#n555'>555</a>
<a id='n556' href='#n556'>556</a>
<a id='n557' href='#n557'>557</a>
<a id='n558' href='#n558'>558</a>
<a id='n559' href='#n559'>559</a>
<a id='n560' href='#n560'>560</a>
<a id='n561' href='#n561'>561</a>
<a id='n562' href='#n562'>562</a>
<a id='n563' href='#n563'>563</a>
<a id='n564' href='#n564'>564</a>
<a id='n565' href='#n565'>565</a>
<a id='n566' href='#n566'>566</a>
<a id='n567' href='#n567'>567</a>
<a id='n568' href='#n568'>568</a>
<a id='n569' href='#n569'>569</a>
<a id='n570' href='#n570'>570</a>
<a id='n571' href='#n571'>571</a>
<a id='n572' href='#n572'>572</a>
<a id='n573' href='#n573'>573</a>
<a id='n574' href='#n574'>574</a>
<a id='n575' href='#n575'>575</a>
<a id='n576' href='#n576'>576</a>
<a id='n577' href='#n577'>577</a>
<a id='n578' href='#n578'>578</a>
<a id='n579' href='#n579'>579</a>
<a id='n580' href='#n580'>580</a>
<a id='n581' href='#n581'>581</a>
<a id='n582' href='#n582'>582</a>
<a id='n583' href='#n583'>583</a>
<a id='n584' href='#n584'>584</a>
<a id='n585' href='#n585'>585</a>
<a id='n586' href='#n586'>586</a>
<a id='n587' href='#n587'>587</a>
<a id='n588' href='#n588'>588</a>
<a id='n589' href='#n589'>589</a>
<a id='n590' href='#n590'>590</a>
<a id='n591' href='#n591'>591</a>
<a id='n592' href='#n592'>592</a>
<a id='n593' href='#n593'>593</a>
<a id='n594' href='#n594'>594</a>
<a id='n595' href='#n595'>595</a>
<a id='n596' href='#n596'>596</a>
<a id='n597' href='#n597'>597</a>
<a id='n598' href='#n598'>598</a>
<a id='n599' href='#n599'>599</a>
<a id='n600' href='#n600'>600</a>
<a id='n601' href='#n601'>601</a>
<a id='n602' href='#n602'>602</a>
<a id='n603' href='#n603'>603</a>
<a id='n604' href='#n604'>604</a>
<a id='n605' href='#n605'>605</a>
<a id='n606' href='#n606'>606</a>
<a id='n607' href='#n607'>607</a>
<a id='n608' href='#n608'>608</a>
<a id='n609' href='#n609'>609</a>
<a id='n610' href='#n610'>610</a>
<a id='n611' href='#n611'>611</a>
<a id='n612' href='#n612'>612</a>
<a id='n613' href='#n613'>613</a>
<a id='n614' href='#n614'>614</a>
<a id='n615' href='#n615'>615</a>
<a id='n616' href='#n616'>616</a>
<a id='n617' href='#n617'>617</a>
<a id='n618' href='#n618'>618</a>
<a id='n619' href='#n619'>619</a>
<a id='n620' href='#n620'>620</a>
<a id='n621' href='#n621'>621</a>
<a id='n622' href='#n622'>622</a>
<a id='n623' href='#n623'>623</a>
<a id='n624' href='#n624'>624</a>
<a id='n625' href='#n625'>625</a>
<a id='n626' href='#n626'>626</a>
<a id='n627' href='#n627'>627</a>
<a id='n628' href='#n628'>628</a>
<a id='n629' href='#n629'>629</a>
<a id='n630' href='#n630'>630</a>
<a id='n631' href='#n631'>631</a>
<a id='n632' href='#n632'>632</a>
<a id='n633' href='#n633'>633</a>
<a id='n634' href='#n634'>634</a>
<a id='n635' href='#n635'>635</a>
<a id='n636' href='#n636'>636</a>
<a id='n637' href='#n637'>637</a>
<a id='n638' href='#n638'>638</a>
<a id='n639' href='#n639'>639</a>
<a id='n640' href='#n640'>640</a>
<a id='n641' href='#n641'>641</a>
<a id='n642' href='#n642'>642</a>
<a id='n643' href='#n643'>643</a>
<a id='n644' href='#n644'>644</a>
<a id='n645' href='#n645'>645</a>
<a id='n646' href='#n646'>646</a>
<a id='n647' href='#n647'>647</a>
<a id='n648' href='#n648'>648</a>
<a id='n649' href='#n649'>649</a>
<a id='n650' href='#n650'>650</a>
<a id='n651' href='#n651'>651</a>
<a id='n652' href='#n652'>652</a>
<a id='n653' href='#n653'>653</a>
<a id='n654' href='#n654'>654</a>
<a id='n655' href='#n655'>655</a>
<a id='n656' href='#n656'>656</a>
<a id='n657' href='#n657'>657</a>
<a id='n658' href='#n658'>658</a>
<a id='n659' href='#n659'>659</a>
<a id='n660' href='#n660'>660</a>
<a id='n661' href='#n661'>661</a>
<a id='n662' href='#n662'>662</a>
<a id='n663' href='#n663'>663</a>
<a id='n664' href='#n664'>664</a>
<a id='n665' href='#n665'>665</a>
<a id='n666' href='#n666'>666</a>
<a id='n667' href='#n667'>667</a>
<a id='n668' href='#n668'>668</a>
<a id='n669' href='#n669'>669</a>
<a id='n670' href='#n670'>670</a>
<a id='n671' href='#n671'>671</a>
<a id='n672' href='#n672'>672</a>
<a id='n673' href='#n673'>673</a>
<a id='n674' href='#n674'>674</a>
<a id='n675' href='#n675'>675</a>
<a id='n676' href='#n676'>676</a>
<a id='n677' href='#n677'>677</a>
<a id='n678' href='#n678'>678</a>
<a id='n679' href='#n679'>679</a>
<a id='n680' href='#n680'>680</a>
<a id='n681' href='#n681'>681</a>
<a id='n682' href='#n682'>682</a>
<a id='n683' href='#n683'>683</a>
<a id='n684' href='#n684'>684</a>
<a id='n685' href='#n685'>685</a>
<a id='n686' href='#n686'>686</a>
<a id='n687' href='#n687'>687</a>
<a id='n688' href='#n688'>688</a>
<a id='n689' href='#n689'>689</a>
<a id='n690' href='#n690'>690</a>
<a id='n691' href='#n691'>691</a>
<a id='n692' href='#n692'>692</a>
<a id='n693' href='#n693'>693</a>
<a id='n694' href='#n694'>694</a>
<a id='n695' href='#n695'>695</a>
<a id='n696' href='#n696'>696</a>
<a id='n697' href='#n697'>697</a>
<a id='n698' href='#n698'>698</a>
<a id='n699' href='#n699'>699</a>
<a id='n700' href='#n700'>700</a>
<a id='n701' href='#n701'>701</a>
<a id='n702' href='#n702'>702</a>
<a id='n703' href='#n703'>703</a>
<a id='n704' href='#n704'>704</a>
<a id='n705' href='#n705'>705</a>
<a id='n706' href='#n706'>706</a>
<a id='n707' href='#n707'>707</a>
<a id='n708' href='#n708'>708</a>
<a id='n709' href='#n709'>709</a>
<a id='n710' href='#n710'>710</a>
<a id='n711' href='#n711'>711</a>
<a id='n712' href='#n712'>712</a>
<a id='n713' href='#n713'>713</a>
<a id='n714' href='#n714'>714</a>
<a id='n715' href='#n715'>715</a>
<a id='n716' href='#n716'>716</a>
<a id='n717' href='#n717'>717</a>
<a id='n718' href='#n718'>718</a>
<a id='n719' href='#n719'>719</a>
<a id='n720' href='#n720'>720</a>
<a id='n721' href='#n721'>721</a>
<a id='n722' href='#n722'>722</a>
<a id='n723' href='#n723'>723</a>
<a id='n724' href='#n724'>724</a>
<a id='n725' href='#n725'>725</a>
<a id='n726' href='#n726'>726</a>
<a id='n727' href='#n727'>727</a>
<a id='n728' href='#n728'>728</a>
<a id='n729' href='#n729'>729</a>
<a id='n730' href='#n730'>730</a>
<a id='n731' href='#n731'>731</a>
<a id='n732' href='#n732'>732</a>
<a id='n733' href='#n733'>733</a>
<a id='n734' href='#n734'>734</a>
<a id='n735' href='#n735'>735</a>
<a id='n736' href='#n736'>736</a>
<a id='n737' href='#n737'>737</a>
<a id='n738' href='#n738'>738</a>
<a id='n739' href='#n739'>739</a>
<a id='n740' href='#n740'>740</a>
<a id='n741' href='#n741'>741</a>
<a id='n742' href='#n742'>742</a>
<a id='n743' href='#n743'>743</a>
<a id='n744' href='#n744'>744</a>
<a id='n745' href='#n745'>745</a>
<a id='n746' href='#n746'>746</a>
<a id='n747' href='#n747'>747</a>
<a id='n748' href='#n748'>748</a>
<a id='n749' href='#n749'>749</a>
<a id='n750' href='#n750'>750</a>
<a id='n751' href='#n751'>751</a>
<a id='n752' href='#n752'>752</a>
<a id='n753' href='#n753'>753</a>
<a id='n754' href='#n754'>754</a>
<a id='n755' href='#n755'>755</a>
<a id='n756' href='#n756'>756</a>
<a id='n757' href='#n757'>757</a>
<a id='n758' href='#n758'>758</a>
<a id='n759' href='#n759'>759</a>
<a id='n760' href='#n760'>760</a>
<a id='n761' href='#n761'>761</a>
<a id='n762' href='#n762'>762</a>
<a id='n763' href='#n763'>763</a>
<a id='n764' href='#n764'>764</a>
<a id='n765' href='#n765'>765</a>
<a id='n766' href='#n766'>766</a>
<a id='n767' href='#n767'>767</a>
<a id='n768' href='#n768'>768</a>
<a id='n769' href='#n769'>769</a>
<a id='n770' href='#n770'>770</a>
<a id='n771' href='#n771'>771</a>
<a id='n772' href='#n772'>772</a>
<a id='n773' href='#n773'>773</a>
<a id='n774' href='#n774'>774</a>
<a id='n775' href='#n775'>775</a>
<a id='n776' href='#n776'>776</a>
<a id='n777' href='#n777'>777</a>
<a id='n778' href='#n778'>778</a>
<a id='n779' href='#n779'>779</a>
<a id='n780' href='#n780'>780</a>
<a id='n781' href='#n781'>781</a>
<a id='n782' href='#n782'>782</a>
<a id='n783' href='#n783'>783</a>
<a id='n784' href='#n784'>784</a>
<a id='n785' href='#n785'>785</a>
<a id='n786' href='#n786'>786</a>
<a id='n787' href='#n787'>787</a>
<a id='n788' href='#n788'>788</a>
<a id='n789' href='#n789'>789</a>
<a id='n790' href='#n790'>790</a>
<a id='n791' href='#n791'>791</a>
<a id='n792' href='#n792'>792</a>
<a id='n793' href='#n793'>793</a>
<a id='n794' href='#n794'>794</a>
<a id='n795' href='#n795'>795</a>
<a id='n796' href='#n796'>796</a>
<a id='n797' href='#n797'>797</a>
<a id='n798' href='#n798'>798</a>
<a id='n799' href='#n799'>799</a>
<a id='n800' href='#n800'>800</a>
<a id='n801' href='#n801'>801</a>
<a id='n802' href='#n802'>802</a>
<a id='n803' href='#n803'>803</a>
<a id='n804' href='#n804'>804</a>
<a id='n805' href='#n805'>805</a>
<a id='n806' href='#n806'>806</a>
<a id='n807' href='#n807'>807</a>
<a id='n808' href='#n808'>808</a>
<a id='n809' href='#n809'>809</a>
<a id='n810' href='#n810'>810</a>
<a id='n811' href='#n811'>811</a>
<a id='n812' href='#n812'>812</a>
<a id='n813' href='#n813'>813</a>
<a id='n814' href='#n814'>814</a>
<a id='n815' href='#n815'>815</a>
<a id='n816' href='#n816'>816</a>
<a id='n817' href='#n817'>817</a>
<a id='n818' href='#n818'>818</a>
<a id='n819' href='#n819'>819</a>
<a id='n820' href='#n820'>820</a>
<a id='n821' href='#n821'>821</a>
<a id='n822' href='#n822'>822</a>
<a id='n823' href='#n823'>823</a>
<a id='n824' href='#n824'>824</a>
<a id='n825' href='#n825'>825</a>
<a id='n826' href='#n826'>826</a>
<a id='n827' href='#n827'>827</a>
<a id='n828' href='#n828'>828</a>
<a id='n829' href='#n829'>829</a>
<a id='n830' href='#n830'>830</a>
<a id='n831' href='#n831'>831</a>
<a id='n832' href='#n832'>832</a>
<a id='n833' href='#n833'>833</a>
<a id='n834' href='#n834'>834</a>
<a id='n835' href='#n835'>835</a>
<a id='n836' href='#n836'>836</a>
<a id='n837' href='#n837'>837</a>
<a id='n838' href='#n838'>838</a>
<a id='n839' href='#n839'>839</a>
<a id='n840' href='#n840'>840</a>
<a id='n841' href='#n841'>841</a>
<a id='n842' href='#n842'>842</a>
<a id='n843' href='#n843'>843</a>
<a id='n844' href='#n844'>844</a>
<a id='n845' href='#n845'>845</a>
<a id='n846' href='#n846'>846</a>
<a id='n847' href='#n847'>847</a>
<a id='n848' href='#n848'>848</a>
<a id='n849' href='#n849'>849</a>
<a id='n850' href='#n850'>850</a>
<a id='n851' href='#n851'>851</a>
<a id='n852' href='#n852'>852</a>
<a id='n853' href='#n853'>853</a>
<a id='n854' href='#n854'>854</a>
<a id='n855' href='#n855'>855</a>
<a id='n856' href='#n856'>856</a>
<a id='n857' href='#n857'>857</a>
<a id='n858' href='#n858'>858</a>
<a id='n859' href='#n859'>859</a>
<a id='n860' href='#n860'>860</a>
<a id='n861' href='#n861'>861</a>
<a id='n862' href='#n862'>862</a>
<a id='n863' href='#n863'>863</a>
<a id='n864' href='#n864'>864</a>
<a id='n865' href='#n865'>865</a>
<a id='n866' href='#n866'>866</a>
<a id='n867' href='#n867'>867</a>
<a id='n868' href='#n868'>868</a>
<a id='n869' href='#n869'>869</a>
<a id='n870' href='#n870'>870</a>
<a id='n871' href='#n871'>871</a>
<a id='n872' href='#n872'>872</a>
<a id='n873' href='#n873'>873</a>
<a id='n874' href='#n874'>874</a>
<a id='n875' href='#n875'>875</a>
<a id='n876' href='#n876'>876</a>
<a id='n877' href='#n877'>877</a>
<a id='n878' href='#n878'>878</a>
<a id='n879' href='#n879'>879</a>
<a id='n880' href='#n880'>880</a>
<a id='n881' href='#n881'>881</a>
<a id='n882' href='#n882'>882</a>
<a id='n883' href='#n883'>883</a>
<a id='n884' href='#n884'>884</a>
<a id='n885' href='#n885'>885</a>
<a id='n886' href='#n886'>886</a>
<a id='n887' href='#n887'>887</a>
<a id='n888' href='#n888'>888</a>
<a id='n889' href='#n889'>889</a>
<a id='n890' href='#n890'>890</a>
<a id='n891' href='#n891'>891</a>
<a id='n892' href='#n892'>892</a>
<a id='n893' href='#n893'>893</a>
<a id='n894' href='#n894'>894</a>
<a id='n895' href='#n895'>895</a>
<a id='n896' href='#n896'>896</a>
<a id='n897' href='#n897'>897</a>
<a id='n898' href='#n898'>898</a>
<a id='n899' href='#n899'>899</a>
<a id='n900' href='#n900'>900</a>
<a id='n901' href='#n901'>901</a>
<a id='n902' href='#n902'>902</a>
<a id='n903' href='#n903'>903</a>
<a id='n904' href='#n904'>904</a>
<a id='n905' href='#n905'>905</a>
<a id='n906' href='#n906'>906</a>
<a id='n907' href='#n907'>907</a>
<a id='n908' href='#n908'>908</a>
<a id='n909' href='#n909'>909</a>
<a id='n910' href='#n910'>910</a>
<a id='n911' href='#n911'>911</a>
<a id='n912' href='#n912'>912</a>
<a id='n913' href='#n913'>913</a>
<a id='n914' href='#n914'>914</a>
<a id='n915' href='#n915'>915</a>
<a id='n916' href='#n916'>916</a>
<a id='n917' href='#n917'>917</a>
<a id='n918' href='#n918'>918</a>
<a id='n919' href='#n919'>919</a>
<a id='n920' href='#n920'>920</a>
<a id='n921' href='#n921'>921</a>
<a id='n922' href='#n922'>922</a>
<a id='n923' href='#n923'>923</a>
<a id='n924' href='#n924'>924</a>
<a id='n925' href='#n925'>925</a>
<a id='n926' href='#n926'>926</a>
<a id='n927' href='#n927'>927</a>
<a id='n928' href='#n928'>928</a>
<a id='n929' href='#n929'>929</a>
<a id='n930' href='#n930'>930</a>
<a id='n931' href='#n931'>931</a>
<a id='n932' href='#n932'>932</a>
<a id='n933' href='#n933'>933</a>
<a id='n934' href='#n934'>934</a>
<a id='n935' href='#n935'>935</a>
<a id='n936' href='#n936'>936</a>
<a id='n937' href='#n937'>937</a>
<a id='n938' href='#n938'>938</a>
<a id='n939' href='#n939'>939</a>
<a id='n940' href='#n940'>940</a>
<a id='n941' href='#n941'>941</a>
<a id='n942' href='#n942'>942</a>
<a id='n943' href='#n943'>943</a>
<a id='n944' href='#n944'>944</a>
<a id='n945' href='#n945'>945</a>
<a id='n946' href='#n946'>946</a>
<a id='n947' href='#n947'>947</a>
<a id='n948' href='#n948'>948</a>
<a id='n949' href='#n949'>949</a>
<a id='n950' href='#n950'>950</a>
<a id='n951' href='#n951'>951</a>
<a id='n952' href='#n952'>952</a>
<a id='n953' href='#n953'>953</a>
<a id='n954' href='#n954'>954</a>
<a id='n955' href='#n955'>955</a>
<a id='n956' href='#n956'>956</a>
<a id='n957' href='#n957'>957</a>
<a id='n958' href='#n958'>958</a>
<a id='n959' href='#n959'>959</a>
<a id='n960' href='#n960'>960</a>
<a id='n961' href='#n961'>961</a>
<a id='n962' href='#n962'>962</a>
<a id='n963' href='#n963'>963</a>
<a id='n964' href='#n964'>964</a>
<a id='n965' href='#n965'>965</a>
<a id='n966' href='#n966'>966</a>
<a id='n967' href='#n967'>967</a>
<a id='n968' href='#n968'>968</a>
<a id='n969' href='#n969'>969</a>
<a id='n970' href='#n970'>970</a>
<a id='n971' href='#n971'>971</a>
<a id='n972' href='#n972'>972</a>
<a id='n973' href='#n973'>973</a>
<a id='n974' href='#n974'>974</a>
<a id='n975' href='#n975'>975</a>
<a id='n976' href='#n976'>976</a>
<a id='n977' href='#n977'>977</a>
<a id='n978' href='#n978'>978</a>
<a id='n979' href='#n979'>979</a>
<a id='n980' href='#n980'>980</a>
<a id='n981' href='#n981'>981</a>
<a id='n982' href='#n982'>982</a>
<a id='n983' href='#n983'>983</a>
<a id='n984' href='#n984'>984</a>
<a id='n985' href='#n985'>985</a>
<a id='n986' href='#n986'>986</a>
<a id='n987' href='#n987'>987</a>
<a id='n988' href='#n988'>988</a>
<a id='n989' href='#n989'>989</a>
<a id='n990' href='#n990'>990</a>
<a id='n991' href='#n991'>991</a>
<a id='n992' href='#n992'>992</a>
<a id='n993' href='#n993'>993</a>
<a id='n994' href='#n994'>994</a>
<a id='n995' href='#n995'>995</a>
<a id='n996' href='#n996'>996</a>
<a id='n997' href='#n997'>997</a>
<a id='n998' href='#n998'>998</a>
<a id='n999' href='#n999'>999</a>
<a id='n1000' href='#n1000'>1000</a>
<a id='n1001' href='#n1001'>1001</a>
<a id='n1002' href='#n1002'>1002</a>
<a id='n1003' href='#n1003'>1003</a>
<a id='n1004' href='#n1004'>1004</a>
<a id='n1005' href='#n1005'>1005</a>
<a id='n1006' href='#n1006'>1006</a>
<a id='n1007' href='#n1007'>1007</a>
<a id='n1008' href='#n1008'>1008</a>
<a id='n1009' href='#n1009'>1009</a>
<a id='n1010' href='#n1010'>1010</a>
<a id='n1011' href='#n1011'>1011</a>
<a id='n1012' href='#n1012'>1012</a>
<a id='n1013' href='#n1013'>1013</a>
<a id='n1014' href='#n1014'>1014</a>
<a id='n1015' href='#n1015'>1015</a>
<a id='n1016' href='#n1016'>1016</a>
<a id='n1017' href='#n1017'>1017</a>
<a id='n1018' href='#n1018'>1018</a>
<a id='n1019' href='#n1019'>1019</a>
<a id='n1020' href='#n1020'>1020</a>
<a id='n1021' href='#n1021'>1021</a>
<a id='n1022' href='#n1022'>1022</a>
<a id='n1023' href='#n1023'>1023</a>
<a id='n1024' href='#n1024'>1024</a>
<a id='n1025' href='#n1025'>1025</a>
<a id='n1026' href='#n1026'>1026</a>
<a id='n1027' href='#n1027'>1027</a>
<a id='n1028' href='#n1028'>1028</a>
<a id='n1029' href='#n1029'>1029</a>
<a id='n1030' href='#n1030'>1030</a>
<a id='n1031' href='#n1031'>1031</a>
<a id='n1032' href='#n1032'>1032</a>
<a id='n1033' href='#n1033'>1033</a>
<a id='n1034' href='#n1034'>1034</a>
<a id='n1035' href='#n1035'>1035</a>
<a id='n1036' href='#n1036'>1036</a>
<a id='n1037' href='#n1037'>1037</a>
<a id='n1038' href='#n1038'>1038</a>
<a id='n1039' href='#n1039'>1039</a>
<a id='n1040' href='#n1040'>1040</a>
<a id='n1041' href='#n1041'>1041</a>
<a id='n1042' href='#n1042'>1042</a>
<a id='n1043' href='#n1043'>1043</a>
<a id='n1044' href='#n1044'>1044</a>
<a id='n1045' href='#n1045'>1045</a>
<a id='n1046' href='#n1046'>1046</a>
<a id='n1047' href='#n1047'>1047</a>
<a id='n1048' href='#n1048'>1048</a>
<a id='n1049' href='#n1049'>1049</a>
<a id='n1050' href='#n1050'>1050</a>
<a id='n1051' href='#n1051'>1051</a>
<a id='n1052' href='#n1052'>1052</a>
<a id='n1053' href='#n1053'>1053</a>
<a id='n1054' href='#n1054'>1054</a>
<a id='n1055' href='#n1055'>1055</a>
<a id='n1056' href='#n1056'>1056</a>
<a id='n1057' href='#n1057'>1057</a>
<a id='n1058' href='#n1058'>1058</a>
<a id='n1059' href='#n1059'>1059</a>
<a id='n1060' href='#n1060'>1060</a>
<a id='n1061' href='#n1061'>1061</a>
<a id='n1062' href='#n1062'>1062</a>
<a id='n1063' href='#n1063'>1063</a>
<a id='n1064' href='#n1064'>1064</a>
<a id='n1065' href='#n1065'>1065</a>
<a id='n1066' href='#n1066'>1066</a>
<a id='n1067' href='#n1067'>1067</a>
<a id='n1068' href='#n1068'>1068</a>
<a id='n1069' href='#n1069'>1069</a>
<a id='n1070' href='#n1070'>1070</a>
<a id='n1071' href='#n1071'>1071</a>
<a id='n1072' href='#n1072'>1072</a>
<a id='n1073' href='#n1073'>1073</a>
<a id='n1074' href='#n1074'>1074</a>
<a id='n1075' href='#n1075'>1075</a>
<a id='n1076' href='#n1076'>1076</a>
<a id='n1077' href='#n1077'>1077</a>
<a id='n1078' href='#n1078'>1078</a>
<a id='n1079' href='#n1079'>1079</a>
<a id='n1080' href='#n1080'>1080</a>
<a id='n1081' href='#n1081'>1081</a>
<a id='n1082' href='#n1082'>1082</a>
<a id='n1083' href='#n1083'>1083</a>
<a id='n1084' href='#n1084'>1084</a>
<a id='n1085' href='#n1085'>1085</a>
<a id='n1086' href='#n1086'>1086</a>
<a id='n1087' href='#n1087'>1087</a>
<a id='n1088' href='#n1088'>1088</a>
<a id='n1089' href='#n1089'>1089</a>
<a id='n1090' href='#n1090'>1090</a>
<a id='n1091' href='#n1091'>1091</a>
<a id='n1092' href='#n1092'>1092</a>
<a id='n1093' href='#n1093'>1093</a>
<a id='n1094' href='#n1094'>1094</a>
<a id='n1095' href='#n1095'>1095</a>
<a id='n1096' href='#n1096'>1096</a>
<a id='n1097' href='#n1097'>1097</a>
<a id='n1098' href='#n1098'>1098</a>
<a id='n1099' href='#n1099'>1099</a>
<a id='n1100' href='#n1100'>1100</a>
<a id='n1101' href='#n1101'>1101</a>
<a id='n1102' href='#n1102'>1102</a>
<a id='n1103' href='#n1103'>1103</a>
<a id='n1104' href='#n1104'>1104</a>
<a id='n1105' href='#n1105'>1105</a>
<a id='n1106' href='#n1106'>1106</a>
<a id='n1107' href='#n1107'>1107</a>
<a id='n1108' href='#n1108'>1108</a>
<a id='n1109' href='#n1109'>1109</a>
<a id='n1110' href='#n1110'>1110</a>
<a id='n1111' href='#n1111'>1111</a>
<a id='n1112' href='#n1112'>1112</a>
<a id='n1113' href='#n1113'>1113</a>
<a id='n1114' href='#n1114'>1114</a>
<a id='n1115' href='#n1115'>1115</a>
<a id='n1116' href='#n1116'>1116</a>
<a id='n1117' href='#n1117'>1117</a>
<a id='n1118' href='#n1118'>1118</a>
<a id='n1119' href='#n1119'>1119</a>
<a id='n1120' href='#n1120'>1120</a>
<a id='n1121' href='#n1121'>1121</a>
<a id='n1122' href='#n1122'>1122</a>
<a id='n1123' href='#n1123'>1123</a>
<a id='n1124' href='#n1124'>1124</a>
<a id='n1125' href='#n1125'>1125</a>
<a id='n1126' href='#n1126'>1126</a>
<a id='n1127' href='#n1127'>1127</a>
<a id='n1128' href='#n1128'>1128</a>
<a id='n1129' href='#n1129'>1129</a>
<a id='n1130' href='#n1130'>1130</a>
<a id='n1131' href='#n1131'>1131</a>
<a id='n1132' href='#n1132'>1132</a>
<a id='n1133' href='#n1133'>1133</a>
<a id='n1134' href='#n1134'>1134</a>
<a id='n1135' href='#n1135'>1135</a>
<a id='n1136' href='#n1136'>1136</a>
<a id='n1137' href='#n1137'>1137</a>
<a id='n1138' href='#n1138'>1138</a>
<a id='n1139' href='#n1139'>1139</a>
<a id='n1140' href='#n1140'>1140</a>
<a id='n1141' href='#n1141'>1141</a>
<a id='n1142' href='#n1142'>1142</a>
<a id='n1143' href='#n1143'>1143</a>
<a id='n1144' href='#n1144'>1144</a>
<a id='n1145' href='#n1145'>1145</a>
<a id='n1146' href='#n1146'>1146</a>
<a id='n1147' href='#n1147'>1147</a>
<a id='n1148' href='#n1148'>1148</a>
<a id='n1149' href='#n1149'>1149</a>
<a id='n1150' href='#n1150'>1150</a>
<a id='n1151' href='#n1151'>1151</a>
<a id='n1152' href='#n1152'>1152</a>
<a id='n1153' href='#n1153'>1153</a>
<a id='n1154' href='#n1154'>1154</a>
<a id='n1155' href='#n1155'>1155</a>
<a id='n1156' href='#n1156'>1156</a>
<a id='n1157' href='#n1157'>1157</a>
<a id='n1158' href='#n1158'>1158</a>
<a id='n1159' href='#n1159'>1159</a>
<a id='n1160' href='#n1160'>1160</a>
<a id='n1161' href='#n1161'>1161</a>
<a id='n1162' href='#n1162'>1162</a>
<a id='n1163' href='#n1163'>1163</a>
<a id='n1164' href='#n1164'>1164</a>
<a id='n1165' href='#n1165'>1165</a>
<a id='n1166' href='#n1166'>1166</a>
<a id='n1167' href='#n1167'>1167</a>
<a id='n1168' href='#n1168'>1168</a>
<a id='n1169' href='#n1169'>1169</a>
<a id='n1170' href='#n1170'>1170</a>
<a id='n1171' href='#n1171'>1171</a>
<a id='n1172' href='#n1172'>1172</a>
<a id='n1173' href='#n1173'>1173</a>
<a id='n1174' href='#n1174'>1174</a>
<a id='n1175' href='#n1175'>1175</a>
<a id='n1176' href='#n1176'>1176</a>
<a id='n1177' href='#n1177'>1177</a>
<a id='n1178' href='#n1178'>1178</a>
<a id='n1179' href='#n1179'>1179</a>
<a id='n1180' href='#n1180'>1180</a>
<a id='n1181' href='#n1181'>1181</a>
<a id='n1182' href='#n1182'>1182</a>
<a id='n1183' href='#n1183'>1183</a>
<a id='n1184' href='#n1184'>1184</a>
<a id='n1185' href='#n1185'>1185</a>
<a id='n1186' href='#n1186'>1186</a>
<a id='n1187' href='#n1187'>1187</a>
<a id='n1188' href='#n1188'>1188</a>
<a id='n1189' href='#n1189'>1189</a>
<a id='n1190' href='#n1190'>1190</a>
<a id='n1191' href='#n1191'>1191</a>
<a id='n1192' href='#n1192'>1192</a>
<a id='n1193' href='#n1193'>1193</a>
<a id='n1194' href='#n1194'>1194</a>
<a id='n1195' href='#n1195'>1195</a>
<a id='n1196' href='#n1196'>1196</a>
<a id='n1197' href='#n1197'>1197</a>
<a id='n1198' href='#n1198'>1198</a>
<a id='n1199' href='#n1199'>1199</a>
<a id='n1200' href='#n1200'>1200</a>
<a id='n1201' href='#n1201'>1201</a>
<a id='n1202' href='#n1202'>1202</a>
<a id='n1203' href='#n1203'>1203</a>
<a id='n1204' href='#n1204'>1204</a>
<a id='n1205' href='#n1205'>1205</a>
<a id='n1206' href='#n1206'>1206</a>
<a id='n1207' href='#n1207'>1207</a>
<a id='n1208' href='#n1208'>1208</a>
<a id='n1209' href='#n1209'>1209</a>
<a id='n1210' href='#n1210'>1210</a>
<a id='n1211' href='#n1211'>1211</a>
<a id='n1212' href='#n1212'>1212</a>
<a id='n1213' href='#n1213'>1213</a>
<a id='n1214' href='#n1214'>1214</a>
<a id='n1215' href='#n1215'>1215</a>
<a id='n1216' href='#n1216'>1216</a>
<a id='n1217' href='#n1217'>1217</a>
<a id='n1218' href='#n1218'>1218</a>
<a id='n1219' href='#n1219'>1219</a>
<a id='n1220' href='#n1220'>1220</a>
<a id='n1221' href='#n1221'>1221</a>
<a id='n1222' href='#n1222'>1222</a>
<a id='n1223' href='#n1223'>1223</a>
<a id='n1224' href='#n1224'>1224</a>
<a id='n1225' href='#n1225'>1225</a>
<a id='n1226' href='#n1226'>1226</a>
<a id='n1227' href='#n1227'>1227</a>
<a id='n1228' href='#n1228'>1228</a>
<a id='n1229' href='#n1229'>1229</a>
<a id='n1230' href='#n1230'>1230</a>
<a id='n1231' href='#n1231'>1231</a>
<a id='n1232' href='#n1232'>1232</a>
<a id='n1233' href='#n1233'>1233</a>
<a id='n1234' href='#n1234'>1234</a>
<a id='n1235' href='#n1235'>1235</a>
<a id='n1236' href='#n1236'>1236</a>
<a id='n1237' href='#n1237'>1237</a>
<a id='n1238' href='#n1238'>1238</a>
<a id='n1239' href='#n1239'>1239</a>
<a id='n1240' href='#n1240'>1240</a>
<a id='n1241' href='#n1241'>1241</a>
<a id='n1242' href='#n1242'>1242</a>
<a id='n1243' href='#n1243'>1243</a>
<a id='n1244' href='#n1244'>1244</a>
<a id='n1245' href='#n1245'>1245</a>
<a id='n1246' href='#n1246'>1246</a>
<a id='n1247' href='#n1247'>1247</a>
<a id='n1248' href='#n1248'>1248</a>
<a id='n1249' href='#n1249'>1249</a>
<a id='n1250' href='#n1250'>1250</a>
<a id='n1251' href='#n1251'>1251</a>
<a id='n1252' href='#n1252'>1252</a>
<a id='n1253' href='#n1253'>1253</a>
<a id='n1254' href='#n1254'>1254</a>
<a id='n1255' href='#n1255'>1255</a>
<a id='n1256' href='#n1256'>1256</a>
<a id='n1257' href='#n1257'>1257</a>
<a id='n1258' href='#n1258'>1258</a>
<a id='n1259' href='#n1259'>1259</a>
<a id='n1260' href='#n1260'>1260</a>
<a id='n1261' href='#n1261'>1261</a>
<a id='n1262' href='#n1262'>1262</a>
<a id='n1263' href='#n1263'>1263</a>
<a id='n1264' href='#n1264'>1264</a>
<a id='n1265' href='#n1265'>1265</a>
<a id='n1266' href='#n1266'>1266</a>
<a id='n1267' href='#n1267'>1267</a>
<a id='n1268' href='#n1268'>1268</a>
<a id='n1269' href='#n1269'>1269</a>
<a id='n1270' href='#n1270'>1270</a>
<a id='n1271' href='#n1271'>1271</a>
<a id='n1272' href='#n1272'>1272</a>
<a id='n1273' href='#n1273'>1273</a>
<a id='n1274' href='#n1274'>1274</a>
<a id='n1275' href='#n1275'>1275</a>
<a id='n1276' href='#n1276'>1276</a>
<a id='n1277' href='#n1277'>1277</a>
<a id='n1278' href='#n1278'>1278</a>
<a id='n1279' href='#n1279'>1279</a>
<a id='n1280' href='#n1280'>1280</a>
<a id='n1281' href='#n1281'>1281</a>
<a id='n1282' href='#n1282'>1282</a>
<a id='n1283' href='#n1283'>1283</a>
<a id='n1284' href='#n1284'>1284</a>
<a id='n1285' href='#n1285'>1285</a>
<a id='n1286' href='#n1286'>1286</a>
<a id='n1287' href='#n1287'>1287</a>
<a id='n1288' href='#n1288'>1288</a>
<a id='n1289' href='#n1289'>1289</a>
<a id='n1290' href='#n1290'>1290</a>
<a id='n1291' href='#n1291'>1291</a>
<a id='n1292' href='#n1292'>1292</a>
<a id='n1293' href='#n1293'>1293</a>
<a id='n1294' href='#n1294'>1294</a>
<a id='n1295' href='#n1295'>1295</a>
<a id='n1296' href='#n1296'>1296</a>
<a id='n1297' href='#n1297'>1297</a>
<a id='n1298' href='#n1298'>1298</a>
<a id='n1299' href='#n1299'>1299</a>
<a id='n1300' href='#n1300'>1300</a>
<a id='n1301' href='#n1301'>1301</a>
<a id='n1302' href='#n1302'>1302</a>
<a id='n1303' href='#n1303'>1303</a>
<a id='n1304' href='#n1304'>1304</a>
<a id='n1305' href='#n1305'>1305</a>
<a id='n1306' href='#n1306'>1306</a>
<a id='n1307' href='#n1307'>1307</a>
<a id='n1308' href='#n1308'>1308</a>
<a id='n1309' href='#n1309'>1309</a>
<a id='n1310' href='#n1310'>1310</a>
<a id='n1311' href='#n1311'>1311</a>
<a id='n1312' href='#n1312'>1312</a>
<a id='n1313' href='#n1313'>1313</a>
<a id='n1314' href='#n1314'>1314</a>
<a id='n1315' href='#n1315'>1315</a>
<a id='n1316' href='#n1316'>1316</a>
<a id='n1317' href='#n1317'>1317</a>
<a id='n1318' href='#n1318'>1318</a>
<a id='n1319' href='#n1319'>1319</a>
<a id='n1320' href='#n1320'>1320</a>
<a id='n1321' href='#n1321'>1321</a>
<a id='n1322' href='#n1322'>1322</a>
<a id='n1323' href='#n1323'>1323</a>
<a id='n1324' href='#n1324'>1324</a>
<a id='n1325' href='#n1325'>1325</a>
<a id='n1326' href='#n1326'>1326</a>
<a id='n1327' href='#n1327'>1327</a>
<a id='n1328' href='#n1328'>1328</a>
<a id='n1329' href='#n1329'>1329</a>
<a id='n1330' href='#n1330'>1330</a>
<a id='n1331' href='#n1331'>1331</a>
<a id='n1332' href='#n1332'>1332</a>
<a id='n1333' href='#n1333'>1333</a>
<a id='n1334' href='#n1334'>1334</a>
<a id='n1335' href='#n1335'>1335</a>
<a id='n1336' href='#n1336'>1336</a>
<a id='n1337' href='#n1337'>1337</a>
<a id='n1338' href='#n1338'>1338</a>
<a id='n1339' href='#n1339'>1339</a>
<a id='n1340' href='#n1340'>1340</a>
<a id='n1341' href='#n1341'>1341</a>
<a id='n1342' href='#n1342'>1342</a>
<a id='n1343' href='#n1343'>1343</a>
<a id='n1344' href='#n1344'>1344</a>
<a id='n1345' href='#n1345'>1345</a>
<a id='n1346' href='#n1346'>1346</a>
<a id='n1347' href='#n1347'>1347</a>
<a id='n1348' href='#n1348'>1348</a>
<a id='n1349' href='#n1349'>1349</a>
<a id='n1350' href='#n1350'>1350</a>
<a id='n1351' href='#n1351'>1351</a>
<a id='n1352' href='#n1352'>1352</a>
<a id='n1353' href='#n1353'>1353</a>
<a id='n1354' href='#n1354'>1354</a>
<a id='n1355' href='#n1355'>1355</a>
<a id='n1356' href='#n1356'>1356</a>
<a id='n1357' href='#n1357'>1357</a>
<a id='n1358' href='#n1358'>1358</a>
<a id='n1359' href='#n1359'>1359</a>
<a id='n1360' href='#n1360'>1360</a>
<a id='n1361' href='#n1361'>1361</a>
<a id='n1362' href='#n1362'>1362</a>
<a id='n1363' href='#n1363'>1363</a>
<a id='n1364' href='#n1364'>1364</a>
<a id='n1365' href='#n1365'>1365</a>
<a id='n1366' href='#n1366'>1366</a>
<a id='n1367' href='#n1367'>1367</a>
<a id='n1368' href='#n1368'>1368</a>
<a id='n1369' href='#n1369'>1369</a>
<a id='n1370' href='#n1370'>1370</a>
<a id='n1371' href='#n1371'>1371</a>
<a id='n1372' href='#n1372'>1372</a>
<a id='n1373' href='#n1373'>1373</a>
<a id='n1374' href='#n1374'>1374</a>
<a id='n1375' href='#n1375'>1375</a>
<a id='n1376' href='#n1376'>1376</a>
<a id='n1377' href='#n1377'>1377</a>
<a id='n1378' href='#n1378'>1378</a>
<a id='n1379' href='#n1379'>1379</a>
<a id='n1380' href='#n1380'>1380</a>
<a id='n1381' href='#n1381'>1381</a>
<a id='n1382' href='#n1382'>1382</a>
<a id='n1383' href='#n1383'>1383</a>
<a id='n1384' href='#n1384'>1384</a>
<a id='n1385' href='#n1385'>1385</a>
<a id='n1386' href='#n1386'>1386</a>
<a id='n1387' href='#n1387'>1387</a>
<a id='n1388' href='#n1388'>1388</a>
<a id='n1389' href='#n1389'>1389</a>
<a id='n1390' href='#n1390'>1390</a>
<a id='n1391' href='#n1391'>1391</a>
<a id='n1392' href='#n1392'>1392</a>
<a id='n1393' href='#n1393'>1393</a>
<a id='n1394' href='#n1394'>1394</a>
<a id='n1395' href='#n1395'>1395</a>
<a id='n1396' href='#n1396'>1396</a>
<a id='n1397' href='#n1397'>1397</a>
<a id='n1398' href='#n1398'>1398</a>
<a id='n1399' href='#n1399'>1399</a>
<a id='n1400' href='#n1400'>1400</a>
<a id='n1401' href='#n1401'>1401</a>
<a id='n1402' href='#n1402'>1402</a>
<a id='n1403' href='#n1403'>1403</a>
<a id='n1404' href='#n1404'>1404</a>
<a id='n1405' href='#n1405'>1405</a>
<a id='n1406' href='#n1406'>1406</a>
<a id='n1407' href='#n1407'>1407</a>
<a id='n1408' href='#n1408'>1408</a>
<a id='n1409' href='#n1409'>1409</a>
<a id='n1410' href='#n1410'>1410</a>
<a id='n1411' href='#n1411'>1411</a>
<a id='n1412' href='#n1412'>1412</a>
<a id='n1413' href='#n1413'>1413</a>
<a id='n1414' href='#n1414'>1414</a>
<a id='n1415' href='#n1415'>1415</a>
<a id='n1416' href='#n1416'>1416</a>
<a id='n1417' href='#n1417'>1417</a>
<a id='n1418' href='#n1418'>1418</a>
<a id='n1419' href='#n1419'>1419</a>
<a id='n1420' href='#n1420'>1420</a>
<a id='n1421' href='#n1421'>1421</a>
<a id='n1422' href='#n1422'>1422</a>
<a id='n1423' href='#n1423'>1423</a>
<a id='n1424' href='#n1424'>1424</a>
<a id='n1425' href='#n1425'>1425</a>
<a id='n1426' href='#n1426'>1426</a>
<a id='n1427' href='#n1427'>1427</a>
<a id='n1428' href='#n1428'>1428</a>
<a id='n1429' href='#n1429'>1429</a>
<a id='n1430' href='#n1430'>1430</a>
<a id='n1431' href='#n1431'>1431</a>
<a id='n1432' href='#n1432'>1432</a>
<a id='n1433' href='#n1433'>1433</a>
<a id='n1434' href='#n1434'>1434</a>
<a id='n1435' href='#n1435'>1435</a>
<a id='n1436' href='#n1436'>1436</a>
<a id='n1437' href='#n1437'>1437</a>
<a id='n1438' href='#n1438'>1438</a>
<a id='n1439' href='#n1439'>1439</a>
<a id='n1440' href='#n1440'>1440</a>
<a id='n1441' href='#n1441'>1441</a>
<a id='n1442' href='#n1442'>1442</a>
<a id='n1443' href='#n1443'>1443</a>
<a id='n1444' href='#n1444'>1444</a>
<a id='n1445' href='#n1445'>1445</a>
<a id='n1446' href='#n1446'>1446</a>
<a id='n1447' href='#n1447'>1447</a>
<a id='n1448' href='#n1448'>1448</a>
<a id='n1449' href='#n1449'>1449</a>
<a id='n1450' href='#n1450'>1450</a>
<a id='n1451' href='#n1451'>1451</a>
<a id='n1452' href='#n1452'>1452</a>
<a id='n1453' href='#n1453'>1453</a>
<a id='n1454' href='#n1454'>1454</a>
<a id='n1455' href='#n1455'>1455</a>
<a id='n1456' href='#n1456'>1456</a>
<a id='n1457' href='#n1457'>1457</a>
<a id='n1458' href='#n1458'>1458</a>
<a id='n1459' href='#n1459'>1459</a>
<a id='n1460' href='#n1460'>1460</a>
<a id='n1461' href='#n1461'>1461</a>
<a id='n1462' href='#n1462'>1462</a>
<a id='n1463' href='#n1463'>1463</a>
<a id='n1464' href='#n1464'>1464</a>
<a id='n1465' href='#n1465'>1465</a>
<a id='n1466' href='#n1466'>1466</a>
<a id='n1467' href='#n1467'>1467</a>
<a id='n1468' href='#n1468'>1468</a>
<a id='n1469' href='#n1469'>1469</a>
<a id='n1470' href='#n1470'>1470</a>
<a id='n1471' href='#n1471'>1471</a>
<a id='n1472' href='#n1472'>1472</a>
<a id='n1473' href='#n1473'>1473</a>
<a id='n1474' href='#n1474'>1474</a>
<a id='n1475' href='#n1475'>1475</a>
<a id='n1476' href='#n1476'>1476</a>
<a id='n1477' href='#n1477'>1477</a>
<a id='n1478' href='#n1478'>1478</a>
<a id='n1479' href='#n1479'>1479</a>
<a id='n1480' href='#n1480'>1480</a>
<a id='n1481' href='#n1481'>1481</a>
<a id='n1482' href='#n1482'>1482</a>
<a id='n1483' href='#n1483'>1483</a>
<a id='n1484' href='#n1484'>1484</a>
<a id='n1485' href='#n1485'>1485</a>
<a id='n1486' href='#n1486'>1486</a>
<a id='n1487' href='#n1487'>1487</a>
<a id='n1488' href='#n1488'>1488</a>
<a id='n1489' href='#n1489'>1489</a>
<a id='n1490' href='#n1490'>1490</a>
<a id='n1491' href='#n1491'>1491</a>
<a id='n1492' href='#n1492'>1492</a>
<a id='n1493' href='#n1493'>1493</a>
<a id='n1494' href='#n1494'>1494</a>
<a id='n1495' href='#n1495'>1495</a>
<a id='n1496' href='#n1496'>1496</a>
<a id='n1497' href='#n1497'>1497</a>
<a id='n1498' href='#n1498'>1498</a>
<a id='n1499' href='#n1499'>1499</a>
<a id='n1500' href='#n1500'>1500</a>
<a id='n1501' href='#n1501'>1501</a>
<a id='n1502' href='#n1502'>1502</a>
<a id='n1503' href='#n1503'>1503</a>
<a id='n1504' href='#n1504'>1504</a>
<a id='n1505' href='#n1505'>1505</a>
<a id='n1506' href='#n1506'>1506</a>
<a id='n1507' href='#n1507'>1507</a>
<a id='n1508' href='#n1508'>1508</a>
<a id='n1509' href='#n1509'>1509</a>
<a id='n1510' href='#n1510'>1510</a>
<a id='n1511' href='#n1511'>1511</a>
<a id='n1512' href='#n1512'>1512</a>
<a id='n1513' href='#n1513'>1513</a>
<a id='n1514' href='#n1514'>1514</a>
<a id='n1515' href='#n1515'>1515</a>
<a id='n1516' href='#n1516'>1516</a>
<a id='n1517' href='#n1517'>1517</a>
<a id='n1518' href='#n1518'>1518</a>
<a id='n1519' href='#n1519'>1519</a>
<a id='n1520' href='#n1520'>1520</a>
<a id='n1521' href='#n1521'>1521</a>
<a id='n1522' href='#n1522'>1522</a>
<a id='n1523' href='#n1523'>1523</a>
<a id='n1524' href='#n1524'>1524</a>
<a id='n1525' href='#n1525'>1525</a>
<a id='n1526' href='#n1526'>1526</a>
<a id='n1527' href='#n1527'>1527</a>
<a id='n1528' href='#n1528'>1528</a>
<a id='n1529' href='#n1529'>1529</a>
<a id='n1530' href='#n1530'>1530</a>
<a id='n1531' href='#n1531'>1531</a>
<a id='n1532' href='#n1532'>1532</a>
<a id='n1533' href='#n1533'>1533</a>
<a id='n1534' href='#n1534'>1534</a>
<a id='n1535' href='#n1535'>1535</a>
<a id='n1536' href='#n1536'>1536</a>
<a id='n1537' href='#n1537'>1537</a>
<a id='n1538' href='#n1538'>1538</a>
<a id='n1539' href='#n1539'>1539</a>
<a id='n1540' href='#n1540'>1540</a>
<a id='n1541' href='#n1541'>1541</a>
<a id='n1542' href='#n1542'>1542</a>
<a id='n1543' href='#n1543'>1543</a>
<a id='n1544' href='#n1544'>1544</a>
<a id='n1545' href='#n1545'>1545</a>
<a id='n1546' href='#n1546'>1546</a>
<a id='n1547' href='#n1547'>1547</a>
<a id='n1548' href='#n1548'>1548</a>
<a id='n1549' href='#n1549'>1549</a>
<a id='n1550' href='#n1550'>1550</a>
<a id='n1551' href='#n1551'>1551</a>
<a id='n1552' href='#n1552'>1552</a>
<a id='n1553' href='#n1553'>1553</a>
<a id='n1554' href='#n1554'>1554</a>
<a id='n1555' href='#n1555'>1555</a>
<a id='n1556' href='#n1556'>1556</a>
<a id='n1557' href='#n1557'>1557</a>
<a id='n1558' href='#n1558'>1558</a>
<a id='n1559' href='#n1559'>1559</a>
<a id='n1560' href='#n1560'>1560</a>
<a id='n1561' href='#n1561'>1561</a>
<a id='n1562' href='#n1562'>1562</a>
<a id='n1563' href='#n1563'>1563</a>
<a id='n1564' href='#n1564'>1564</a>
<a id='n1565' href='#n1565'>1565</a>
<a id='n1566' href='#n1566'>1566</a>
<a id='n1567' href='#n1567'>1567</a>
<a id='n1568' href='#n1568'>1568</a>
<a id='n1569' href='#n1569'>1569</a>
<a id='n1570' href='#n1570'>1570</a>
<a id='n1571' href='#n1571'>1571</a>
<a id='n1572' href='#n1572'>1572</a>
<a id='n1573' href='#n1573'>1573</a>
<a id='n1574' href='#n1574'>1574</a>
<a id='n1575' href='#n1575'>1575</a>
<a id='n1576' href='#n1576'>1576</a>
<a id='n1577' href='#n1577'>1577</a>
<a id='n1578' href='#n1578'>1578</a>
<a id='n1579' href='#n1579'>1579</a>
<a id='n1580' href='#n1580'>1580</a>
<a id='n1581' href='#n1581'>1581</a>
<a id='n1582' href='#n1582'>1582</a>
<a id='n1583' href='#n1583'>1583</a>
<a id='n1584' href='#n1584'>1584</a>
<a id='n1585' href='#n1585'>1585</a>
<a id='n1586' href='#n1586'>1586</a>
<a id='n1587' href='#n1587'>1587</a>
<a id='n1588' href='#n1588'>1588</a>
<a id='n1589' href='#n1589'>1589</a>
<a id='n1590' href='#n1590'>1590</a>
<a id='n1591' href='#n1591'>1591</a>
<a id='n1592' href='#n1592'>1592</a>
<a id='n1593' href='#n1593'>1593</a>
<a id='n1594' href='#n1594'>1594</a>
<a id='n1595' href='#n1595'>1595</a>
<a id='n1596' href='#n1596'>1596</a>
<a id='n1597' href='#n1597'>1597</a>
<a id='n1598' href='#n1598'>1598</a>
<a id='n1599' href='#n1599'>1599</a>
<a id='n1600' href='#n1600'>1600</a>
<a id='n1601' href='#n1601'>1601</a>
<a id='n1602' href='#n1602'>1602</a>
<a id='n1603' href='#n1603'>1603</a>
<a id='n1604' href='#n1604'>1604</a>
<a id='n1605' href='#n1605'>1605</a>
<a id='n1606' href='#n1606'>1606</a>
<a id='n1607' href='#n1607'>1607</a>
<a id='n1608' href='#n1608'>1608</a>
<a id='n1609' href='#n1609'>1609</a>
<a id='n1610' href='#n1610'>1610</a>
<a id='n1611' href='#n1611'>1611</a>
<a id='n1612' href='#n1612'>1612</a>
<a id='n1613' href='#n1613'>1613</a>
<a id='n1614' href='#n1614'>1614</a>
<a id='n1615' href='#n1615'>1615</a>
<a id='n1616' href='#n1616'>1616</a>
<a id='n1617' href='#n1617'>1617</a>
<a id='n1618' href='#n1618'>1618</a>
<a id='n1619' href='#n1619'>1619</a>
<a id='n1620' href='#n1620'>1620</a>
<a id='n1621' href='#n1621'>1621</a>
<a id='n1622' href='#n1622'>1622</a>
<a id='n1623' href='#n1623'>1623</a>
<a id='n1624' href='#n1624'>1624</a>
<a id='n1625' href='#n1625'>1625</a>
<a id='n1626' href='#n1626'>1626</a>
<a id='n1627' href='#n1627'>1627</a>
<a id='n1628' href='#n1628'>1628</a>
<a id='n1629' href='#n1629'>1629</a>
<a id='n1630' href='#n1630'>1630</a>
<a id='n1631' href='#n1631'>1631</a>
<a id='n1632' href='#n1632'>1632</a>
<a id='n1633' href='#n1633'>1633</a>
<a id='n1634' href='#n1634'>1634</a>
<a id='n1635' href='#n1635'>1635</a>
<a id='n1636' href='#n1636'>1636</a>
<a id='n1637' href='#n1637'>1637</a>
<a id='n1638' href='#n1638'>1638</a>
<a id='n1639' href='#n1639'>1639</a>
<a id='n1640' href='#n1640'>1640</a>
<a id='n1641' href='#n1641'>1641</a>
<a id='n1642' href='#n1642'>1642</a>
<a id='n1643' href='#n1643'>1643</a>
<a id='n1644' href='#n1644'>1644</a>
<a id='n1645' href='#n1645'>1645</a>
<a id='n1646' href='#n1646'>1646</a>
<a id='n1647' href='#n1647'>1647</a>
<a id='n1648' href='#n1648'>1648</a>
<a id='n1649' href='#n1649'>1649</a>
<a id='n1650' href='#n1650'>1650</a>
<a id='n1651' href='#n1651'>1651</a>
<a id='n1652' href='#n1652'>1652</a>
<a id='n1653' href='#n1653'>1653</a>
<a id='n1654' href='#n1654'>1654</a>
<a id='n1655' href='#n1655'>1655</a>
<a id='n1656' href='#n1656'>1656</a>
<a id='n1657' href='#n1657'>1657</a>
<a id='n1658' href='#n1658'>1658</a>
<a id='n1659' href='#n1659'>1659</a>
<a id='n1660' href='#n1660'>1660</a>
<a id='n1661' href='#n1661'>1661</a>
<a id='n1662' href='#n1662'>1662</a>
<a id='n1663' href='#n1663'>1663</a>
<a id='n1664' href='#n1664'>1664</a>
<a id='n1665' href='#n1665'>1665</a>
<a id='n1666' href='#n1666'>1666</a>
<a id='n1667' href='#n1667'>1667</a>
<a id='n1668' href='#n1668'>1668</a>
<a id='n1669' href='#n1669'>1669</a>
<a id='n1670' href='#n1670'>1670</a>
<a id='n1671' href='#n1671'>1671</a>
<a id='n1672' href='#n1672'>1672</a>
<a id='n1673' href='#n1673'>1673</a>
<a id='n1674' href='#n1674'>1674</a>
<a id='n1675' href='#n1675'>1675</a>
<a id='n1676' href='#n1676'>1676</a>
<a id='n1677' href='#n1677'>1677</a>
<a id='n1678' href='#n1678'>1678</a>
<a id='n1679' href='#n1679'>1679</a>
<a id='n1680' href='#n1680'>1680</a>
<a id='n1681' href='#n1681'>1681</a>
<a id='n1682' href='#n1682'>1682</a>
<a id='n1683' href='#n1683'>1683</a>
<a id='n1684' href='#n1684'>1684</a>
<a id='n1685' href='#n1685'>1685</a>
<a id='n1686' href='#n1686'>1686</a>
<a id='n1687' href='#n1687'>1687</a>
<a id='n1688' href='#n1688'>1688</a>
<a id='n1689' href='#n1689'>1689</a>
<a id='n1690' href='#n1690'>1690</a>
<a id='n1691' href='#n1691'>1691</a>
<a id='n1692' href='#n1692'>1692</a>
<a id='n1693' href='#n1693'>1693</a>
<a id='n1694' href='#n1694'>1694</a>
<a id='n1695' href='#n1695'>1695</a>
<a id='n1696' href='#n1696'>1696</a>
<a id='n1697' href='#n1697'>1697</a>
<a id='n1698' href='#n1698'>1698</a>
<a id='n1699' href='#n1699'>1699</a>
<a id='n1700' href='#n1700'>1700</a>
<a id='n1701' href='#n1701'>1701</a>
<a id='n1702' href='#n1702'>1702</a>
<a id='n1703' href='#n1703'>1703</a>
<a id='n1704' href='#n1704'>1704</a>
<a id='n1705' href='#n1705'>1705</a>
<a id='n1706' href='#n1706'>1706</a>
<a id='n1707' href='#n1707'>1707</a>
<a id='n1708' href='#n1708'>1708</a>
<a id='n1709' href='#n1709'>1709</a>
<a id='n1710' href='#n1710'>1710</a>
<a id='n1711' href='#n1711'>1711</a>
<a id='n1712' href='#n1712'>1712</a>
<a id='n1713' href='#n1713'>1713</a>
<a id='n1714' href='#n1714'>1714</a>
<a id='n1715' href='#n1715'>1715</a>
<a id='n1716' href='#n1716'>1716</a>
<a id='n1717' href='#n1717'>1717</a>
<a id='n1718' href='#n1718'>1718</a>
<a id='n1719' href='#n1719'>1719</a>
<a id='n1720' href='#n1720'>1720</a>
<a id='n1721' href='#n1721'>1721</a>
<a id='n1722' href='#n1722'>1722</a>
<a id='n1723' href='#n1723'>1723</a>
<a id='n1724' href='#n1724'>1724</a>
<a id='n1725' href='#n1725'>1725</a>
<a id='n1726' href='#n1726'>1726</a>
<a id='n1727' href='#n1727'>1727</a>
<a id='n1728' href='#n1728'>1728</a>
<a id='n1729' href='#n1729'>1729</a>
<a id='n1730' href='#n1730'>1730</a>
<a id='n1731' href='#n1731'>1731</a>
<a id='n1732' href='#n1732'>1732</a>
<a id='n1733' href='#n1733'>1733</a>
<a id='n1734' href='#n1734'>1734</a>
<a id='n1735' href='#n1735'>1735</a>
<a id='n1736' href='#n1736'>1736</a>
<a id='n1737' href='#n1737'>1737</a>
<a id='n1738' href='#n1738'>1738</a>
<a id='n1739' href='#n1739'>1739</a>
<a id='n1740' href='#n1740'>1740</a>
<a id='n1741' href='#n1741'>1741</a>
<a id='n1742' href='#n1742'>1742</a>
<a id='n1743' href='#n1743'>1743</a>
<a id='n1744' href='#n1744'>1744</a>
<a id='n1745' href='#n1745'>1745</a>
<a id='n1746' href='#n1746'>1746</a>
<a id='n1747' href='#n1747'>1747</a>
<a id='n1748' href='#n1748'>1748</a>
<a id='n1749' href='#n1749'>1749</a>
<a id='n1750' href='#n1750'>1750</a>
<a id='n1751' href='#n1751'>1751</a>
<a id='n1752' href='#n1752'>1752</a>
<a id='n1753' href='#n1753'>1753</a>
<a id='n1754' href='#n1754'>1754</a>
<a id='n1755' href='#n1755'>1755</a>
<a id='n1756' href='#n1756'>1756</a>
<a id='n1757' href='#n1757'>1757</a>
<a id='n1758' href='#n1758'>1758</a>
<a id='n1759' href='#n1759'>1759</a>
<a id='n1760' href='#n1760'>1760</a>
<a id='n1761' href='#n1761'>1761</a>
<a id='n1762' href='#n1762'>1762</a>
<a id='n1763' href='#n1763'>1763</a>
<a id='n1764' href='#n1764'>1764</a>
<a id='n1765' href='#n1765'>1765</a>
<a id='n1766' href='#n1766'>1766</a>
<a id='n1767' href='#n1767'>1767</a>
<a id='n1768' href='#n1768'>1768</a>
<a id='n1769' href='#n1769'>1769</a>
<a id='n1770' href='#n1770'>1770</a>
<a id='n1771' href='#n1771'>1771</a>
<a id='n1772' href='#n1772'>1772</a>
<a id='n1773' href='#n1773'>1773</a>
<a id='n1774' href='#n1774'>1774</a>
<a id='n1775' href='#n1775'>1775</a>
<a id='n1776' href='#n1776'>1776</a>
<a id='n1777' href='#n1777'>1777</a>
<a id='n1778' href='#n1778'>1778</a>
<a id='n1779' href='#n1779'>1779</a>
<a id='n1780' href='#n1780'>1780</a>
<a id='n1781' href='#n1781'>1781</a>
<a id='n1782' href='#n1782'>1782</a>
<a id='n1783' href='#n1783'>1783</a>
<a id='n1784' href='#n1784'>1784</a>
<a id='n1785' href='#n1785'>1785</a>
<a id='n1786' href='#n1786'>1786</a>
<a id='n1787' href='#n1787'>1787</a>
<a id='n1788' href='#n1788'>1788</a>
<a id='n1789' href='#n1789'>1789</a>
<a id='n1790' href='#n1790'>1790</a>
<a id='n1791' href='#n1791'>1791</a>
<a id='n1792' href='#n1792'>1792</a>
<a id='n1793' href='#n1793'>1793</a>
<a id='n1794' href='#n1794'>1794</a>
<a id='n1795' href='#n1795'>1795</a>
<a id='n1796' href='#n1796'>1796</a>
<a id='n1797' href='#n1797'>1797</a>
<a id='n1798' href='#n1798'>1798</a>
<a id='n1799' href='#n1799'>1799</a>
<a id='n1800' href='#n1800'>1800</a>
<a id='n1801' href='#n1801'>1801</a>
<a id='n1802' href='#n1802'>1802</a>
<a id='n1803' href='#n1803'>1803</a>
<a id='n1804' href='#n1804'>1804</a>
<a id='n1805' href='#n1805'>1805</a>
<a id='n1806' href='#n1806'>1806</a>
<a id='n1807' href='#n1807'>1807</a>
<a id='n1808' href='#n1808'>1808</a>
<a id='n1809' href='#n1809'>1809</a>
<a id='n1810' href='#n1810'>1810</a>
<a id='n1811' href='#n1811'>1811</a>
<a id='n1812' href='#n1812'>1812</a>
<a id='n1813' href='#n1813'>1813</a>
<a id='n1814' href='#n1814'>1814</a>
<a id='n1815' href='#n1815'>1815</a>
<a id='n1816' href='#n1816'>1816</a>
<a id='n1817' href='#n1817'>1817</a>
<a id='n1818' href='#n1818'>1818</a>
<a id='n1819' href='#n1819'>1819</a>
<a id='n1820' href='#n1820'>1820</a>
<a id='n1821' href='#n1821'>1821</a>
<a id='n1822' href='#n1822'>1822</a>
<a id='n1823' href='#n1823'>1823</a>
<a id='n1824' href='#n1824'>1824</a>
<a id='n1825' href='#n1825'>1825</a>
<a id='n1826' href='#n1826'>1826</a>
<a id='n1827' href='#n1827'>1827</a>
<a id='n1828' href='#n1828'>1828</a>
<a id='n1829' href='#n1829'>1829</a>
<a id='n1830' href='#n1830'>1830</a>
<a id='n1831' href='#n1831'>1831</a>
<a id='n1832' href='#n1832'>1832</a>
<a id='n1833' href='#n1833'>1833</a>
<a id='n1834' href='#n1834'>1834</a>
<a id='n1835' href='#n1835'>1835</a>
<a id='n1836' href='#n1836'>1836</a>
<a id='n1837' href='#n1837'>1837</a>
<a id='n1838' href='#n1838'>1838</a>
<a id='n1839' href='#n1839'>1839</a>
<a id='n1840' href='#n1840'>1840</a>
<a id='n1841' href='#n1841'>1841</a>
<a id='n1842' href='#n1842'>1842</a>
<a id='n1843' href='#n1843'>1843</a>
<a id='n1844' href='#n1844'>1844</a>
<a id='n1845' href='#n1845'>1845</a>
<a id='n1846' href='#n1846'>1846</a>
<a id='n1847' href='#n1847'>1847</a>
<a id='n1848' href='#n1848'>1848</a>
<a id='n1849' href='#n1849'>1849</a>
<a id='n1850' href='#n1850'>1850</a>
<a id='n1851' href='#n1851'>1851</a>
<a id='n1852' href='#n1852'>1852</a>
<a id='n1853' href='#n1853'>1853</a>
<a id='n1854' href='#n1854'>1854</a>
<a id='n1855' href='#n1855'>1855</a>
<a id='n1856' href='#n1856'>1856</a>
<a id='n1857' href='#n1857'>1857</a>
<a id='n1858' href='#n1858'>1858</a>
<a id='n1859' href='#n1859'>1859</a>
<a id='n1860' href='#n1860'>1860</a>
<a id='n1861' href='#n1861'>1861</a>
<a id='n1862' href='#n1862'>1862</a>
<a id='n1863' href='#n1863'>1863</a>
<a id='n1864' href='#n1864'>1864</a>
<a id='n1865' href='#n1865'>1865</a>
<a id='n1866' href='#n1866'>1866</a>
<a id='n1867' href='#n1867'>1867</a>
<a id='n1868' href='#n1868'>1868</a>
<a id='n1869' href='#n1869'>1869</a>
<a id='n1870' href='#n1870'>1870</a>
<a id='n1871' href='#n1871'>1871</a>
<a id='n1872' href='#n1872'>1872</a>
<a id='n1873' href='#n1873'>1873</a>
<a id='n1874' href='#n1874'>1874</a>
<a id='n1875' href='#n1875'>1875</a>
<a id='n1876' href='#n1876'>1876</a>
<a id='n1877' href='#n1877'>1877</a>
<a id='n1878' href='#n1878'>1878</a>
<a id='n1879' href='#n1879'>1879</a>
<a id='n1880' href='#n1880'>1880</a>
<a id='n1881' href='#n1881'>1881</a>
<a id='n1882' href='#n1882'>1882</a>
<a id='n1883' href='#n1883'>1883</a>
<a id='n1884' href='#n1884'>1884</a>
<a id='n1885' href='#n1885'>1885</a>
<a id='n1886' href='#n1886'>1886</a>
<a id='n1887' href='#n1887'>1887</a>
<a id='n1888' href='#n1888'>1888</a>
<a id='n1889' href='#n1889'>1889</a>
<a id='n1890' href='#n1890'>1890</a>
<a id='n1891' href='#n1891'>1891</a>
<a id='n1892' href='#n1892'>1892</a>
<a id='n1893' href='#n1893'>1893</a>
<a id='n1894' href='#n1894'>1894</a>
<a id='n1895' href='#n1895'>1895</a>
<a id='n1896' href='#n1896'>1896</a>
<a id='n1897' href='#n1897'>1897</a>
<a id='n1898' href='#n1898'>1898</a>
<a id='n1899' href='#n1899'>1899</a>
<a id='n1900' href='#n1900'>1900</a>
<a id='n1901' href='#n1901'>1901</a>
<a id='n1902' href='#n1902'>1902</a>
<a id='n1903' href='#n1903'>1903</a>
<a id='n1904' href='#n1904'>1904</a>
<a id='n1905' href='#n1905'>1905</a>
<a id='n1906' href='#n1906'>1906</a>
<a id='n1907' href='#n1907'>1907</a>
<a id='n1908' href='#n1908'>1908</a>
<a id='n1909' href='#n1909'>1909</a>
<a id='n1910' href='#n1910'>1910</a>
<a id='n1911' href='#n1911'>1911</a>
<a id='n1912' href='#n1912'>1912</a>
<a id='n1913' href='#n1913'>1913</a>
<a id='n1914' href='#n1914'>1914</a>
<a id='n1915' href='#n1915'>1915</a>
<a id='n1916' href='#n1916'>1916</a>
<a id='n1917' href='#n1917'>1917</a>
<a id='n1918' href='#n1918'>1918</a>
<a id='n1919' href='#n1919'>1919</a>
<a id='n1920' href='#n1920'>1920</a>
<a id='n1921' href='#n1921'>1921</a>
<a id='n1922' href='#n1922'>1922</a>
<a id='n1923' href='#n1923'>1923</a>
<a id='n1924' href='#n1924'>1924</a>
<a id='n1925' href='#n1925'>1925</a>
<a id='n1926' href='#n1926'>1926</a>
<a id='n1927' href='#n1927'>1927</a>
<a id='n1928' href='#n1928'>1928</a>
<a id='n1929' href='#n1929'>1929</a>
<a id='n1930' href='#n1930'>1930</a>
<a id='n1931' href='#n1931'>1931</a>
<a id='n1932' href='#n1932'>1932</a>
<a id='n1933' href='#n1933'>1933</a>
<a id='n1934' href='#n1934'>1934</a>
<a id='n1935' href='#n1935'>1935</a>
<a id='n1936' href='#n1936'>1936</a>
<a id='n1937' href='#n1937'>1937</a>
<a id='n1938' href='#n1938'>1938</a>
<a id='n1939' href='#n1939'>1939</a>
<a id='n1940' href='#n1940'>1940</a>
<a id='n1941' href='#n1941'>1941</a>
<a id='n1942' href='#n1942'>1942</a>
<a id='n1943' href='#n1943'>1943</a>
<a id='n1944' href='#n1944'>1944</a>
<a id='n1945' href='#n1945'>1945</a>
<a id='n1946' href='#n1946'>1946</a>
<a id='n1947' href='#n1947'>1947</a>
<a id='n1948' href='#n1948'>1948</a>
<a id='n1949' href='#n1949'>1949</a>
<a id='n1950' href='#n1950'>1950</a>
<a id='n1951' href='#n1951'>1951</a>
<a id='n1952' href='#n1952'>1952</a>
<a id='n1953' href='#n1953'>1953</a>
<a id='n1954' href='#n1954'>1954</a>
<a id='n1955' href='#n1955'>1955</a>
<a id='n1956' href='#n1956'>1956</a>
<a id='n1957' href='#n1957'>1957</a>
<a id='n1958' href='#n1958'>1958</a>
<a id='n1959' href='#n1959'>1959</a>
<a id='n1960' href='#n1960'>1960</a>
<a id='n1961' href='#n1961'>1961</a>
<a id='n1962' href='#n1962'>1962</a>
<a id='n1963' href='#n1963'>1963</a>
<a id='n1964' href='#n1964'>1964</a>
<a id='n1965' href='#n1965'>1965</a>
<a id='n1966' href='#n1966'>1966</a>
<a id='n1967' href='#n1967'>1967</a>
<a id='n1968' href='#n1968'>1968</a>
<a id='n1969' href='#n1969'>1969</a>
<a id='n1970' href='#n1970'>1970</a>
<a id='n1971' href='#n1971'>1971</a>
<a id='n1972' href='#n1972'>1972</a>
<a id='n1973' href='#n1973'>1973</a>
<a id='n1974' href='#n1974'>1974</a>
<a id='n1975' href='#n1975'>1975</a>
<a id='n1976' href='#n1976'>1976</a>
<a id='n1977' href='#n1977'>1977</a>
<a id='n1978' href='#n1978'>1978</a>
<a id='n1979' href='#n1979'>1979</a>
<a id='n1980' href='#n1980'>1980</a>
<a id='n1981' href='#n1981'>1981</a>
<a id='n1982' href='#n1982'>1982</a>
<a id='n1983' href='#n1983'>1983</a>
<a id='n1984' href='#n1984'>1984</a>
<a id='n1985' href='#n1985'>1985</a>
<a id='n1986' href='#n1986'>1986</a>
<a id='n1987' href='#n1987'>1987</a>
<a id='n1988' href='#n1988'>1988</a>
<a id='n1989' href='#n1989'>1989</a>
<a id='n1990' href='#n1990'>1990</a>
<a id='n1991' href='#n1991'>1991</a>
<a id='n1992' href='#n1992'>1992</a>
<a id='n1993' href='#n1993'>1993</a>
<a id='n1994' href='#n1994'>1994</a>
<a id='n1995' href='#n1995'>1995</a>
<a id='n1996' href='#n1996'>1996</a>
<a id='n1997' href='#n1997'>1997</a>
<a id='n1998' href='#n1998'>1998</a>
<a id='n1999' href='#n1999'>1999</a>
<a id='n2000' href='#n2000'>2000</a>
<a id='n2001' href='#n2001'>2001</a>
<a id='n2002' href='#n2002'>2002</a>
<a id='n2003' href='#n2003'>2003</a>
<a id='n2004' href='#n2004'>2004</a>
<a id='n2005' href='#n2005'>2005</a>
<a id='n2006' href='#n2006'>2006</a>
<a id='n2007' href='#n2007'>2007</a>
<a id='n2008' href='#n2008'>2008</a>
<a id='n2009' href='#n2009'>2009</a>
<a id='n2010' href='#n2010'>2010</a>
<a id='n2011' href='#n2011'>2011</a>
<a id='n2012' href='#n2012'>2012</a>
<a id='n2013' href='#n2013'>2013</a>
<a id='n2014' href='#n2014'>2014</a>
<a id='n2015' href='#n2015'>2015</a>
<a id='n2016' href='#n2016'>2016</a>
<a id='n2017' href='#n2017'>2017</a>
<a id='n2018' href='#n2018'>2018</a>
<a id='n2019' href='#n2019'>2019</a>
<a id='n2020' href='#n2020'>2020</a>
<a id='n2021' href='#n2021'>2021</a>
<a id='n2022' href='#n2022'>2022</a>
<a id='n2023' href='#n2023'>2023</a>
<a id='n2024' href='#n2024'>2024</a>
<a id='n2025' href='#n2025'>2025</a>
<a id='n2026' href='#n2026'>2026</a>
<a id='n2027' href='#n2027'>2027</a>
<a id='n2028' href='#n2028'>2028</a>
<a id='n2029' href='#n2029'>2029</a>
<a id='n2030' href='#n2030'>2030</a>
<a id='n2031' href='#n2031'>2031</a>
<a id='n2032' href='#n2032'>2032</a>
<a id='n2033' href='#n2033'>2033</a>
<a id='n2034' href='#n2034'>2034</a>
<a id='n2035' href='#n2035'>2035</a>
<a id='n2036' href='#n2036'>2036</a>
<a id='n2037' href='#n2037'>2037</a>
<a id='n2038' href='#n2038'>2038</a>
<a id='n2039' href='#n2039'>2039</a>
<a id='n2040' href='#n2040'>2040</a>
<a id='n2041' href='#n2041'>2041</a>
<a id='n2042' href='#n2042'>2042</a>
<a id='n2043' href='#n2043'>2043</a>
<a id='n2044' href='#n2044'>2044</a>
<a id='n2045' href='#n2045'>2045</a>
<a id='n2046' href='#n2046'>2046</a>
<a id='n2047' href='#n2047'>2047</a>
<a id='n2048' href='#n2048'>2048</a>
<a id='n2049' href='#n2049'>2049</a>
<a id='n2050' href='#n2050'>2050</a>
<a id='n2051' href='#n2051'>2051</a>
<a id='n2052' href='#n2052'>2052</a>
<a id='n2053' href='#n2053'>2053</a>
<a id='n2054' href='#n2054'>2054</a>
<a id='n2055' href='#n2055'>2055</a>
<a id='n2056' href='#n2056'>2056</a>
<a id='n2057' href='#n2057'>2057</a>
<a id='n2058' href='#n2058'>2058</a>
<a id='n2059' href='#n2059'>2059</a>
<a id='n2060' href='#n2060'>2060</a>
<a id='n2061' href='#n2061'>2061</a>
<a id='n2062' href='#n2062'>2062</a>
<a id='n2063' href='#n2063'>2063</a>
<a id='n2064' href='#n2064'>2064</a>
<a id='n2065' href='#n2065'>2065</a>
<a id='n2066' href='#n2066'>2066</a>
<a id='n2067' href='#n2067'>2067</a>
<a id='n2068' href='#n2068'>2068</a>
<a id='n2069' href='#n2069'>2069</a>
<a id='n2070' href='#n2070'>2070</a>
<a id='n2071' href='#n2071'>2071</a>
<a id='n2072' href='#n2072'>2072</a>
<a id='n2073' href='#n2073'>2073</a>
<a id='n2074' href='#n2074'>2074</a>
<a id='n2075' href='#n2075'>2075</a>
<a id='n2076' href='#n2076'>2076</a>
<a id='n2077' href='#n2077'>2077</a>
<a id='n2078' href='#n2078'>2078</a>
<a id='n2079' href='#n2079'>2079</a>
<a id='n2080' href='#n2080'>2080</a>
<a id='n2081' href='#n2081'>2081</a>
<a id='n2082' href='#n2082'>2082</a>
<a id='n2083' href='#n2083'>2083</a>
<a id='n2084' href='#n2084'>2084</a>
<a id='n2085' href='#n2085'>2085</a>
<a id='n2086' href='#n2086'>2086</a>
<a id='n2087' href='#n2087'>2087</a>
<a id='n2088' href='#n2088'>2088</a>
<a id='n2089' href='#n2089'>2089</a>
<a id='n2090' href='#n2090'>2090</a>
<a id='n2091' href='#n2091'>2091</a>
<a id='n2092' href='#n2092'>2092</a>
<a id='n2093' href='#n2093'>2093</a>
<a id='n2094' href='#n2094'>2094</a>
<a id='n2095' href='#n2095'>2095</a>
<a id='n2096' href='#n2096'>2096</a>
<a id='n2097' href='#n2097'>2097</a>
<a id='n2098' href='#n2098'>2098</a>
<a id='n2099' href='#n2099'>2099</a>
<a id='n2100' href='#n2100'>2100</a>
<a id='n2101' href='#n2101'>2101</a>
<a id='n2102' href='#n2102'>2102</a>
<a id='n2103' href='#n2103'>2103</a>
<a id='n2104' href='#n2104'>2104</a>
<a id='n2105' href='#n2105'>2105</a>
<a id='n2106' href='#n2106'>2106</a>
<a id='n2107' href='#n2107'>2107</a>
<a id='n2108' href='#n2108'>2108</a>
<a id='n2109' href='#n2109'>2109</a>
<a id='n2110' href='#n2110'>2110</a>
<a id='n2111' href='#n2111'>2111</a>
<a id='n2112' href='#n2112'>2112</a>
<a id='n2113' href='#n2113'>2113</a>
<a id='n2114' href='#n2114'>2114</a>
<a id='n2115' href='#n2115'>2115</a>
<a id='n2116' href='#n2116'>2116</a>
<a id='n2117' href='#n2117'>2117</a>
<a id='n2118' href='#n2118'>2118</a>
<a id='n2119' href='#n2119'>2119</a>
<a id='n2120' href='#n2120'>2120</a>
<a id='n2121' href='#n2121'>2121</a>
<a id='n2122' href='#n2122'>2122</a>
<a id='n2123' href='#n2123'>2123</a>
<a id='n2124' href='#n2124'>2124</a>
<a id='n2125' href='#n2125'>2125</a>
<a id='n2126' href='#n2126'>2126</a>
<a id='n2127' href='#n2127'>2127</a>
<a id='n2128' href='#n2128'>2128</a>
<a id='n2129' href='#n2129'>2129</a>
<a id='n2130' href='#n2130'>2130</a>
<a id='n2131' href='#n2131'>2131</a>
<a id='n2132' href='#n2132'>2132</a>
<a id='n2133' href='#n2133'>2133</a>
<a id='n2134' href='#n2134'>2134</a>
<a id='n2135' href='#n2135'>2135</a>
<a id='n2136' href='#n2136'>2136</a>
<a id='n2137' href='#n2137'>2137</a>
<a id='n2138' href='#n2138'>2138</a>
<a id='n2139' href='#n2139'>2139</a>
<a id='n2140' href='#n2140'>2140</a>
<a id='n2141' href='#n2141'>2141</a>
<a id='n2142' href='#n2142'>2142</a>
<a id='n2143' href='#n2143'>2143</a>
<a id='n2144' href='#n2144'>2144</a>
<a id='n2145' href='#n2145'>2145</a>
<a id='n2146' href='#n2146'>2146</a>
<a id='n2147' href='#n2147'>2147</a>
<a id='n2148' href='#n2148'>2148</a>
<a id='n2149' href='#n2149'>2149</a>
<a id='n2150' href='#n2150'>2150</a>
<a id='n2151' href='#n2151'>2151</a>
<a id='n2152' href='#n2152'>2152</a>
<a id='n2153' href='#n2153'>2153</a>
<a id='n2154' href='#n2154'>2154</a>
<a id='n2155' href='#n2155'>2155</a>
<a id='n2156' href='#n2156'>2156</a>
<a id='n2157' href='#n2157'>2157</a>
<a id='n2158' href='#n2158'>2158</a>
<a id='n2159' href='#n2159'>2159</a>
<a id='n2160' href='#n2160'>2160</a>
<a id='n2161' href='#n2161'>2161</a>
<a id='n2162' href='#n2162'>2162</a>
<a id='n2163' href='#n2163'>2163</a>
<a id='n2164' href='#n2164'>2164</a>
<a id='n2165' href='#n2165'>2165</a>
<a id='n2166' href='#n2166'>2166</a>
<a id='n2167' href='#n2167'>2167</a>
<a id='n2168' href='#n2168'>2168</a>
<a id='n2169' href='#n2169'>2169</a>
<a id='n2170' href='#n2170'>2170</a>
<a id='n2171' href='#n2171'>2171</a>
<a id='n2172' href='#n2172'>2172</a>
<a id='n2173' href='#n2173'>2173</a>
<a id='n2174' href='#n2174'>2174</a>
<a id='n2175' href='#n2175'>2175</a>
<a id='n2176' href='#n2176'>2176</a>
<a id='n2177' href='#n2177'>2177</a>
<a id='n2178' href='#n2178'>2178</a>
<a id='n2179' href='#n2179'>2179</a>
<a id='n2180' href='#n2180'>2180</a>
<a id='n2181' href='#n2181'>2181</a>
<a id='n2182' href='#n2182'>2182</a>
<a id='n2183' href='#n2183'>2183</a>
<a id='n2184' href='#n2184'>2184</a>
<a id='n2185' href='#n2185'>2185</a>
<a id='n2186' href='#n2186'>2186</a>
<a id='n2187' href='#n2187'>2187</a>
<a id='n2188' href='#n2188'>2188</a>
<a id='n2189' href='#n2189'>2189</a>
<a id='n2190' href='#n2190'>2190</a>
<a id='n2191' href='#n2191'>2191</a>
<a id='n2192' href='#n2192'>2192</a>
<a id='n2193' href='#n2193'>2193</a>
<a id='n2194' href='#n2194'>2194</a>
<a id='n2195' href='#n2195'>2195</a>
<a id='n2196' href='#n2196'>2196</a>
<a id='n2197' href='#n2197'>2197</a>
<a id='n2198' href='#n2198'>2198</a>
<a id='n2199' href='#n2199'>2199</a>
<a id='n2200' href='#n2200'>2200</a>
<a id='n2201' href='#n2201'>2201</a>
<a id='n2202' href='#n2202'>2202</a>
<a id='n2203' href='#n2203'>2203</a>
<a id='n2204' href='#n2204'>2204</a>
<a id='n2205' href='#n2205'>2205</a>
<a id='n2206' href='#n2206'>2206</a>
<a id='n2207' href='#n2207'>2207</a>
<a id='n2208' href='#n2208'>2208</a>
<a id='n2209' href='#n2209'>2209</a>
<a id='n2210' href='#n2210'>2210</a>
<a id='n2211' href='#n2211'>2211</a>
<a id='n2212' href='#n2212'>2212</a>
<a id='n2213' href='#n2213'>2213</a>
<a id='n2214' href='#n2214'>2214</a>
<a id='n2215' href='#n2215'>2215</a>
<a id='n2216' href='#n2216'>2216</a>
<a id='n2217' href='#n2217'>2217</a>
<a id='n2218' href='#n2218'>2218</a>
<a id='n2219' href='#n2219'>2219</a>
<a id='n2220' href='#n2220'>2220</a>
<a id='n2221' href='#n2221'>2221</a>
<a id='n2222' href='#n2222'>2222</a>
<a id='n2223' href='#n2223'>2223</a>
<a id='n2224' href='#n2224'>2224</a>
<a id='n2225' href='#n2225'>2225</a>
<a id='n2226' href='#n2226'>2226</a>
<a id='n2227' href='#n2227'>2227</a>
<a id='n2228' href='#n2228'>2228</a>
<a id='n2229' href='#n2229'>2229</a>
<a id='n2230' href='#n2230'>2230</a>
<a id='n2231' href='#n2231'>2231</a>
<a id='n2232' href='#n2232'>2232</a>
<a id='n2233' href='#n2233'>2233</a>
<a id='n2234' href='#n2234'>2234</a>
<a id='n2235' href='#n2235'>2235</a>
<a id='n2236' href='#n2236'>2236</a>
<a id='n2237' href='#n2237'>2237</a>
<a id='n2238' href='#n2238'>2238</a>
<a id='n2239' href='#n2239'>2239</a>
<a id='n2240' href='#n2240'>2240</a>
<a id='n2241' href='#n2241'>2241</a>
<a id='n2242' href='#n2242'>2242</a>
<a id='n2243' href='#n2243'>2243</a>
<a id='n2244' href='#n2244'>2244</a>
<a id='n2245' href='#n2245'>2245</a>
<a id='n2246' href='#n2246'>2246</a>
<a id='n2247' href='#n2247'>2247</a>
<a id='n2248' href='#n2248'>2248</a>
<a id='n2249' href='#n2249'>2249</a>
<a id='n2250' href='#n2250'>2250</a>
<a id='n2251' href='#n2251'>2251</a>
<a id='n2252' href='#n2252'>2252</a>
<a id='n2253' href='#n2253'>2253</a>
<a id='n2254' href='#n2254'>2254</a>
<a id='n2255' href='#n2255'>2255</a>
<a id='n2256' href='#n2256'>2256</a>
<a id='n2257' href='#n2257'>2257</a>
<a id='n2258' href='#n2258'>2258</a>
<a id='n2259' href='#n2259'>2259</a>
<a id='n2260' href='#n2260'>2260</a>
<a id='n2261' href='#n2261'>2261</a>
<a id='n2262' href='#n2262'>2262</a>
<a id='n2263' href='#n2263'>2263</a>
<a id='n2264' href='#n2264'>2264</a>
<a id='n2265' href='#n2265'>2265</a>
<a id='n2266' href='#n2266'>2266</a>
<a id='n2267' href='#n2267'>2267</a>
<a id='n2268' href='#n2268'>2268</a>
<a id='n2269' href='#n2269'>2269</a>
<a id='n2270' href='#n2270'>2270</a>
<a id='n2271' href='#n2271'>2271</a>
<a id='n2272' href='#n2272'>2272</a>
<a id='n2273' href='#n2273'>2273</a>
<a id='n2274' href='#n2274'>2274</a>
<a id='n2275' href='#n2275'>2275</a>
<a id='n2276' href='#n2276'>2276</a>
<a id='n2277' href='#n2277'>2277</a>
<a id='n2278' href='#n2278'>2278</a>
<a id='n2279' href='#n2279'>2279</a>
<a id='n2280' href='#n2280'>2280</a>
<a id='n2281' href='#n2281'>2281</a>
<a id='n2282' href='#n2282'>2282</a>
<a id='n2283' href='#n2283'>2283</a>
<a id='n2284' href='#n2284'>2284</a>
<a id='n2285' href='#n2285'>2285</a>
<a id='n2286' href='#n2286'>2286</a>
<a id='n2287' href='#n2287'>2287</a>
<a id='n2288' href='#n2288'>2288</a>
<a id='n2289' href='#n2289'>2289</a>
<a id='n2290' href='#n2290'>2290</a>
<a id='n2291' href='#n2291'>2291</a>
<a id='n2292' href='#n2292'>2292</a>
<a id='n2293' href='#n2293'>2293</a>
<a id='n2294' href='#n2294'>2294</a>
<a id='n2295' href='#n2295'>2295</a>
<a id='n2296' href='#n2296'>2296</a>
<a id='n2297' href='#n2297'>2297</a>
<a id='n2298' href='#n2298'>2298</a>
<a id='n2299' href='#n2299'>2299</a>
<a id='n2300' href='#n2300'>2300</a>
<a id='n2301' href='#n2301'>2301</a>
<a id='n2302' href='#n2302'>2302</a>
<a id='n2303' href='#n2303'>2303</a>
<a id='n2304' href='#n2304'>2304</a>
<a id='n2305' href='#n2305'>2305</a>
<a id='n2306' href='#n2306'>2306</a>
<a id='n2307' href='#n2307'>2307</a>
<a id='n2308' href='#n2308'>2308</a>
<a id='n2309' href='#n2309'>2309</a>
<a id='n2310' href='#n2310'>2310</a>
<a id='n2311' href='#n2311'>2311</a>
<a id='n2312' href='#n2312'>2312</a>
<a id='n2313' href='#n2313'>2313</a>
<a id='n2314' href='#n2314'>2314</a>
<a id='n2315' href='#n2315'>2315</a>
<a id='n2316' href='#n2316'>2316</a>
<a id='n2317' href='#n2317'>2317</a>
<a id='n2318' href='#n2318'>2318</a>
<a id='n2319' href='#n2319'>2319</a>
<a id='n2320' href='#n2320'>2320</a>
<a id='n2321' href='#n2321'>2321</a>
<a id='n2322' href='#n2322'>2322</a>
<a id='n2323' href='#n2323'>2323</a>
<a id='n2324' href='#n2324'>2324</a>
<a id='n2325' href='#n2325'>2325</a>
<a id='n2326' href='#n2326'>2326</a>
<a id='n2327' href='#n2327'>2327</a>
<a id='n2328' href='#n2328'>2328</a>
<a id='n2329' href='#n2329'>2329</a>
<a id='n2330' href='#n2330'>2330</a>
<a id='n2331' href='#n2331'>2331</a>
<a id='n2332' href='#n2332'>2332</a>
<a id='n2333' href='#n2333'>2333</a>
<a id='n2334' href='#n2334'>2334</a>
<a id='n2335' href='#n2335'>2335</a>
<a id='n2336' href='#n2336'>2336</a>
<a id='n2337' href='#n2337'>2337</a>
<a id='n2338' href='#n2338'>2338</a>
<a id='n2339' href='#n2339'>2339</a>
<a id='n2340' href='#n2340'>2340</a>
<a id='n2341' href='#n2341'>2341</a>
<a id='n2342' href='#n2342'>2342</a>
<a id='n2343' href='#n2343'>2343</a>
<a id='n2344' href='#n2344'>2344</a>
<a id='n2345' href='#n2345'>2345</a>
<a id='n2346' href='#n2346'>2346</a>
<a id='n2347' href='#n2347'>2347</a>
<a id='n2348' href='#n2348'>2348</a>
<a id='n2349' href='#n2349'>2349</a>
<a id='n2350' href='#n2350'>2350</a>
<a id='n2351' href='#n2351'>2351</a>
<a id='n2352' href='#n2352'>2352</a>
<a id='n2353' href='#n2353'>2353</a>
<a id='n2354' href='#n2354'>2354</a>
<a id='n2355' href='#n2355'>2355</a>
<a id='n2356' href='#n2356'>2356</a>
<a id='n2357' href='#n2357'>2357</a>
<a id='n2358' href='#n2358'>2358</a>
<a id='n2359' href='#n2359'>2359</a>
<a id='n2360' href='#n2360'>2360</a>
<a id='n2361' href='#n2361'>2361</a>
<a id='n2362' href='#n2362'>2362</a>
<a id='n2363' href='#n2363'>2363</a>
<a id='n2364' href='#n2364'>2364</a>
<a id='n2365' href='#n2365'>2365</a>
<a id='n2366' href='#n2366'>2366</a>
<a id='n2367' href='#n2367'>2367</a>
<a id='n2368' href='#n2368'>2368</a>
<a id='n2369' href='#n2369'>2369</a>
<a id='n2370' href='#n2370'>2370</a>
<a id='n2371' href='#n2371'>2371</a>
<a id='n2372' href='#n2372'>2372</a>
<a id='n2373' href='#n2373'>2373</a>
<a id='n2374' href='#n2374'>2374</a>
<a id='n2375' href='#n2375'>2375</a>
<a id='n2376' href='#n2376'>2376</a>
<a id='n2377' href='#n2377'>2377</a>
<a id='n2378' href='#n2378'>2378</a>
<a id='n2379' href='#n2379'>2379</a>
<a id='n2380' href='#n2380'>2380</a>
<a id='n2381' href='#n2381'>2381</a>
<a id='n2382' href='#n2382'>2382</a>
<a id='n2383' href='#n2383'>2383</a>
<a id='n2384' href='#n2384'>2384</a>
<a id='n2385' href='#n2385'>2385</a>
<a id='n2386' href='#n2386'>2386</a>
<a id='n2387' href='#n2387'>2387</a>
<a id='n2388' href='#n2388'>2388</a>
<a id='n2389' href='#n2389'>2389</a>
<a id='n2390' href='#n2390'>2390</a>
<a id='n2391' href='#n2391'>2391</a>
<a id='n2392' href='#n2392'>2392</a>
<a id='n2393' href='#n2393'>2393</a>
<a id='n2394' href='#n2394'>2394</a>
<a id='n2395' href='#n2395'>2395</a>
<a id='n2396' href='#n2396'>2396</a>
<a id='n2397' href='#n2397'>2397</a>
<a id='n2398' href='#n2398'>2398</a>
<a id='n2399' href='#n2399'>2399</a>
<a id='n2400' href='#n2400'>2400</a>
<a id='n2401' href='#n2401'>2401</a>
<a id='n2402' href='#n2402'>2402</a>
<a id='n2403' href='#n2403'>2403</a>
<a id='n2404' href='#n2404'>2404</a>
<a id='n2405' href='#n2405'>2405</a>
<a id='n2406' href='#n2406'>2406</a>
<a id='n2407' href='#n2407'>2407</a>
<a id='n2408' href='#n2408'>2408</a>
<a id='n2409' href='#n2409'>2409</a>
<a id='n2410' href='#n2410'>2410</a>
<a id='n2411' href='#n2411'>2411</a>
<a id='n2412' href='#n2412'>2412</a>
<a id='n2413' href='#n2413'>2413</a>
<a id='n2414' href='#n2414'>2414</a>
<a id='n2415' href='#n2415'>2415</a>
<a id='n2416' href='#n2416'>2416</a>
<a id='n2417' href='#n2417'>2417</a>
<a id='n2418' href='#n2418'>2418</a>
<a id='n2419' href='#n2419'>2419</a>
<a id='n2420' href='#n2420'>2420</a>
<a id='n2421' href='#n2421'>2421</a>
<a id='n2422' href='#n2422'>2422</a>
<a id='n2423' href='#n2423'>2423</a>
<a id='n2424' href='#n2424'>2424</a>
<a id='n2425' href='#n2425'>2425</a>
<a id='n2426' href='#n2426'>2426</a>
<a id='n2427' href='#n2427'>2427</a>
<a id='n2428' href='#n2428'>2428</a>
<a id='n2429' href='#n2429'>2429</a>
<a id='n2430' href='#n2430'>2430</a>
<a id='n2431' href='#n2431'>2431</a>
<a id='n2432' href='#n2432'>2432</a>
<a id='n2433' href='#n2433'>2433</a>
<a id='n2434' href='#n2434'>2434</a>
<a id='n2435' href='#n2435'>2435</a>
<a id='n2436' href='#n2436'>2436</a>
<a id='n2437' href='#n2437'>2437</a>
<a id='n2438' href='#n2438'>2438</a>
<a id='n2439' href='#n2439'>2439</a>
<a id='n2440' href='#n2440'>2440</a>
<a id='n2441' href='#n2441'>2441</a>
<a id='n2442' href='#n2442'>2442</a>
<a id='n2443' href='#n2443'>2443</a>
<a id='n2444' href='#n2444'>2444</a>
<a id='n2445' href='#n2445'>2445</a>
<a id='n2446' href='#n2446'>2446</a>
<a id='n2447' href='#n2447'>2447</a>
<a id='n2448' href='#n2448'>2448</a>
<a id='n2449' href='#n2449'>2449</a>
<a id='n2450' href='#n2450'>2450</a>
<a id='n2451' href='#n2451'>2451</a>
<a id='n2452' href='#n2452'>2452</a>
<a id='n2453' href='#n2453'>2453</a>
<a id='n2454' href='#n2454'>2454</a>
<a id='n2455' href='#n2455'>2455</a>
<a id='n2456' href='#n2456'>2456</a>
<a id='n2457' href='#n2457'>2457</a>
<a id='n2458' href='#n2458'>2458</a>
<a id='n2459' href='#n2459'>2459</a>
<a id='n2460' href='#n2460'>2460</a>
<a id='n2461' href='#n2461'>2461</a>
<a id='n2462' href='#n2462'>2462</a>
<a id='n2463' href='#n2463'>2463</a>
<a id='n2464' href='#n2464'>2464</a>
<a id='n2465' href='#n2465'>2465</a>
<a id='n2466' href='#n2466'>2466</a>
<a id='n2467' href='#n2467'>2467</a>
<a id='n2468' href='#n2468'>2468</a>
<a id='n2469' href='#n2469'>2469</a>
<a id='n2470' href='#n2470'>2470</a>
<a id='n2471' href='#n2471'>2471</a>
<a id='n2472' href='#n2472'>2472</a>
<a id='n2473' href='#n2473'>2473</a>
<a id='n2474' href='#n2474'>2474</a>
<a id='n2475' href='#n2475'>2475</a>
<a id='n2476' href='#n2476'>2476</a>
<a id='n2477' href='#n2477'>2477</a>
<a id='n2478' href='#n2478'>2478</a>
<a id='n2479' href='#n2479'>2479</a>
<a id='n2480' href='#n2480'>2480</a>
<a id='n2481' href='#n2481'>2481</a>
<a id='n2482' href='#n2482'>2482</a>
<a id='n2483' href='#n2483'>2483</a>
<a id='n2484' href='#n2484'>2484</a>
<a id='n2485' href='#n2485'>2485</a>
<a id='n2486' href='#n2486'>2486</a>
<a id='n2487' href='#n2487'>2487</a>
<a id='n2488' href='#n2488'>2488</a>
<a id='n2489' href='#n2489'>2489</a>
<a id='n2490' href='#n2490'>2490</a>
<a id='n2491' href='#n2491'>2491</a>
<a id='n2492' href='#n2492'>2492</a>
<a id='n2493' href='#n2493'>2493</a>
<a id='n2494' href='#n2494'>2494</a>
<a id='n2495' href='#n2495'>2495</a>
<a id='n2496' href='#n2496'>2496</a>
<a id='n2497' href='#n2497'>2497</a>
<a id='n2498' href='#n2498'>2498</a>
<a id='n2499' href='#n2499'>2499</a>
<a id='n2500' href='#n2500'>2500</a>
<a id='n2501' href='#n2501'>2501</a>
<a id='n2502' href='#n2502'>2502</a>
<a id='n2503' href='#n2503'>2503</a>
<a id='n2504' href='#n2504'>2504</a>
<a id='n2505' href='#n2505'>2505</a>
<a id='n2506' href='#n2506'>2506</a>
<a id='n2507' href='#n2507'>2507</a>
<a id='n2508' href='#n2508'>2508</a>
<a id='n2509' href='#n2509'>2509</a>
<a id='n2510' href='#n2510'>2510</a>
<a id='n2511' href='#n2511'>2511</a>
<a id='n2512' href='#n2512'>2512</a>
<a id='n2513' href='#n2513'>2513</a>
<a id='n2514' href='#n2514'>2514</a>
<a id='n2515' href='#n2515'>2515</a>
<a id='n2516' href='#n2516'>2516</a>
<a id='n2517' href='#n2517'>2517</a>
<a id='n2518' href='#n2518'>2518</a>
<a id='n2519' href='#n2519'>2519</a>
<a id='n2520' href='#n2520'>2520</a>
<a id='n2521' href='#n2521'>2521</a>
<a id='n2522' href='#n2522'>2522</a>
<a id='n2523' href='#n2523'>2523</a>
<a id='n2524' href='#n2524'>2524</a>
<a id='n2525' href='#n2525'>2525</a>
<a id='n2526' href='#n2526'>2526</a>
<a id='n2527' href='#n2527'>2527</a>
<a id='n2528' href='#n2528'>2528</a>
<a id='n2529' href='#n2529'>2529</a>
<a id='n2530' href='#n2530'>2530</a>
<a id='n2531' href='#n2531'>2531</a>
<a id='n2532' href='#n2532'>2532</a>
<a id='n2533' href='#n2533'>2533</a>
<a id='n2534' href='#n2534'>2534</a>
<a id='n2535' href='#n2535'>2535</a>
<a id='n2536' href='#n2536'>2536</a>
<a id='n2537' href='#n2537'>2537</a>
<a id='n2538' href='#n2538'>2538</a>
<a id='n2539' href='#n2539'>2539</a>
<a id='n2540' href='#n2540'>2540</a>
<a id='n2541' href='#n2541'>2541</a>
<a id='n2542' href='#n2542'>2542</a>
<a id='n2543' href='#n2543'>2543</a>
<a id='n2544' href='#n2544'>2544</a>
<a id='n2545' href='#n2545'>2545</a>
<a id='n2546' href='#n2546'>2546</a>
<a id='n2547' href='#n2547'>2547</a>
<a id='n2548' href='#n2548'>2548</a>
<a id='n2549' href='#n2549'>2549</a>
<a id='n2550' href='#n2550'>2550</a>
<a id='n2551' href='#n2551'>2551</a>
<a id='n2552' href='#n2552'>2552</a>
<a id='n2553' href='#n2553'>2553</a>
<a id='n2554' href='#n2554'>2554</a>
<a id='n2555' href='#n2555'>2555</a>
<a id='n2556' href='#n2556'>2556</a>
<a id='n2557' href='#n2557'>2557</a>
<a id='n2558' href='#n2558'>2558</a>
<a id='n2559' href='#n2559'>2559</a>
<a id='n2560' href='#n2560'>2560</a>
<a id='n2561' href='#n2561'>2561</a>
<a id='n2562' href='#n2562'>2562</a>
<a id='n2563' href='#n2563'>2563</a>
<a id='n2564' href='#n2564'>2564</a>
<a id='n2565' href='#n2565'>2565</a>
<a id='n2566' href='#n2566'>2566</a>
<a id='n2567' href='#n2567'>2567</a>
<a id='n2568' href='#n2568'>2568</a>
<a id='n2569' href='#n2569'>2569</a>
<a id='n2570' href='#n2570'>2570</a>
<a id='n2571' href='#n2571'>2571</a>
<a id='n2572' href='#n2572'>2572</a>
<a id='n2573' href='#n2573'>2573</a>
<a id='n2574' href='#n2574'>2574</a>
<a id='n2575' href='#n2575'>2575</a>
<a id='n2576' href='#n2576'>2576</a>
<a id='n2577' href='#n2577'>2577</a>
<a id='n2578' href='#n2578'>2578</a>
<a id='n2579' href='#n2579'>2579</a>
<a id='n2580' href='#n2580'>2580</a>
<a id='n2581' href='#n2581'>2581</a>
<a id='n2582' href='#n2582'>2582</a>
<a id='n2583' href='#n2583'>2583</a>
<a id='n2584' href='#n2584'>2584</a>
<a id='n2585' href='#n2585'>2585</a>
<a id='n2586' href='#n2586'>2586</a>
<a id='n2587' href='#n2587'>2587</a>
<a id='n2588' href='#n2588'>2588</a>
<a id='n2589' href='#n2589'>2589</a>
<a id='n2590' href='#n2590'>2590</a>
<a id='n2591' href='#n2591'>2591</a>
<a id='n2592' href='#n2592'>2592</a>
<a id='n2593' href='#n2593'>2593</a>
<a id='n2594' href='#n2594'>2594</a>
<a id='n2595' href='#n2595'>2595</a>
<a id='n2596' href='#n2596'>2596</a>
<a id='n2597' href='#n2597'>2597</a>
<a id='n2598' href='#n2598'>2598</a>
<a id='n2599' href='#n2599'>2599</a>
<a id='n2600' href='#n2600'>2600</a>
<a id='n2601' href='#n2601'>2601</a>
<a id='n2602' href='#n2602'>2602</a>
<a id='n2603' href='#n2603'>2603</a>
<a id='n2604' href='#n2604'>2604</a>
<a id='n2605' href='#n2605'>2605</a>
<a id='n2606' href='#n2606'>2606</a>
<a id='n2607' href='#n2607'>2607</a>
<a id='n2608' href='#n2608'>2608</a>
<a id='n2609' href='#n2609'>2609</a>
<a id='n2610' href='#n2610'>2610</a>
<a id='n2611' href='#n2611'>2611</a>
<a id='n2612' href='#n2612'>2612</a>
<a id='n2613' href='#n2613'>2613</a>
<a id='n2614' href='#n2614'>2614</a>
<a id='n2615' href='#n2615'>2615</a>
<a id='n2616' href='#n2616'>2616</a>
<a id='n2617' href='#n2617'>2617</a>
<a id='n2618' href='#n2618'>2618</a>
<a id='n2619' href='#n2619'>2619</a>
<a id='n2620' href='#n2620'>2620</a>
<a id='n2621' href='#n2621'>2621</a>
<a id='n2622' href='#n2622'>2622</a>
<a id='n2623' href='#n2623'>2623</a>
<a id='n2624' href='#n2624'>2624</a>
<a id='n2625' href='#n2625'>2625</a>
<a id='n2626' href='#n2626'>2626</a>
<a id='n2627' href='#n2627'>2627</a>
<a id='n2628' href='#n2628'>2628</a>
<a id='n2629' href='#n2629'>2629</a>
<a id='n2630' href='#n2630'>2630</a>
<a id='n2631' href='#n2631'>2631</a>
<a id='n2632' href='#n2632'>2632</a>
<a id='n2633' href='#n2633'>2633</a>
<a id='n2634' href='#n2634'>2634</a>
<a id='n2635' href='#n2635'>2635</a>
<a id='n2636' href='#n2636'>2636</a>
<a id='n2637' href='#n2637'>2637</a>
<a id='n2638' href='#n2638'>2638</a>
<a id='n2639' href='#n2639'>2639</a>
<a id='n2640' href='#n2640'>2640</a>
<a id='n2641' href='#n2641'>2641</a>
<a id='n2642' href='#n2642'>2642</a>
<a id='n2643' href='#n2643'>2643</a>
<a id='n2644' href='#n2644'>2644</a>
<a id='n2645' href='#n2645'>2645</a>
<a id='n2646' href='#n2646'>2646</a>
<a id='n2647' href='#n2647'>2647</a>
<a id='n2648' href='#n2648'>2648</a>
<a id='n2649' href='#n2649'>2649</a>
<a id='n2650' href='#n2650'>2650</a>
<a id='n2651' href='#n2651'>2651</a>
<a id='n2652' href='#n2652'>2652</a>
<a id='n2653' href='#n2653'>2653</a>
<a id='n2654' href='#n2654'>2654</a>
<a id='n2655' href='#n2655'>2655</a>
<a id='n2656' href='#n2656'>2656</a>
<a id='n2657' href='#n2657'>2657</a>
<a id='n2658' href='#n2658'>2658</a>
<a id='n2659' href='#n2659'>2659</a>
<a id='n2660' href='#n2660'>2660</a>
<a id='n2661' href='#n2661'>2661</a>
<a id='n2662' href='#n2662'>2662</a>
<a id='n2663' href='#n2663'>2663</a>
<a id='n2664' href='#n2664'>2664</a>
<a id='n2665' href='#n2665'>2665</a>
<a id='n2666' href='#n2666'>2666</a>
<a id='n2667' href='#n2667'>2667</a>
<a id='n2668' href='#n2668'>2668</a>
<a id='n2669' href='#n2669'>2669</a>
<a id='n2670' href='#n2670'>2670</a>
<a id='n2671' href='#n2671'>2671</a>
<a id='n2672' href='#n2672'>2672</a>
<a id='n2673' href='#n2673'>2673</a>
<a id='n2674' href='#n2674'>2674</a>
<a id='n2675' href='#n2675'>2675</a>
<a id='n2676' href='#n2676'>2676</a>
<a id='n2677' href='#n2677'>2677</a>
<a id='n2678' href='#n2678'>2678</a>
<a id='n2679' href='#n2679'>2679</a>
<a id='n2680' href='#n2680'>2680</a>
<a id='n2681' href='#n2681'>2681</a>
<a id='n2682' href='#n2682'>2682</a>
<a id='n2683' href='#n2683'>2683</a>
<a id='n2684' href='#n2684'>2684</a>
<a id='n2685' href='#n2685'>2685</a>
<a id='n2686' href='#n2686'>2686</a>
<a id='n2687' href='#n2687'>2687</a>
<a id='n2688' href='#n2688'>2688</a>
<a id='n2689' href='#n2689'>2689</a>
<a id='n2690' href='#n2690'>2690</a>
<a id='n2691' href='#n2691'>2691</a>
<a id='n2692' href='#n2692'>2692</a>
<a id='n2693' href='#n2693'>2693</a>
<a id='n2694' href='#n2694'>2694</a>
<a id='n2695' href='#n2695'>2695</a>
<a id='n2696' href='#n2696'>2696</a>
<a id='n2697' href='#n2697'>2697</a>
<a id='n2698' href='#n2698'>2698</a>
<a id='n2699' href='#n2699'>2699</a>
<a id='n2700' href='#n2700'>2700</a>
<a id='n2701' href='#n2701'>2701</a>
<a id='n2702' href='#n2702'>2702</a>
<a id='n2703' href='#n2703'>2703</a>
<a id='n2704' href='#n2704'>2704</a>
<a id='n2705' href='#n2705'>2705</a>
<a id='n2706' href='#n2706'>2706</a>
<a id='n2707' href='#n2707'>2707</a>
<a id='n2708' href='#n2708'>2708</a>
<a id='n2709' href='#n2709'>2709</a>
<a id='n2710' href='#n2710'>2710</a>
<a id='n2711' href='#n2711'>2711</a>
<a id='n2712' href='#n2712'>2712</a>
<a id='n2713' href='#n2713'>2713</a>
<a id='n2714' href='#n2714'>2714</a>
<a id='n2715' href='#n2715'>2715</a>
<a id='n2716' href='#n2716'>2716</a>
<a id='n2717' href='#n2717'>2717</a>
<a id='n2718' href='#n2718'>2718</a>
<a id='n2719' href='#n2719'>2719</a>
<a id='n2720' href='#n2720'>2720</a>
<a id='n2721' href='#n2721'>2721</a>
<a id='n2722' href='#n2722'>2722</a>
<a id='n2723' href='#n2723'>2723</a>
<a id='n2724' href='#n2724'>2724</a>
<a id='n2725' href='#n2725'>2725</a>
<a id='n2726' href='#n2726'>2726</a>
<a id='n2727' href='#n2727'>2727</a>
<a id='n2728' href='#n2728'>2728</a>
<a id='n2729' href='#n2729'>2729</a>
<a id='n2730' href='#n2730'>2730</a>
<a id='n2731' href='#n2731'>2731</a>
<a id='n2732' href='#n2732'>2732</a>
<a id='n2733' href='#n2733'>2733</a>
<a id='n2734' href='#n2734'>2734</a>
<a id='n2735' href='#n2735'>2735</a>
<a id='n2736' href='#n2736'>2736</a>
<a id='n2737' href='#n2737'>2737</a>
<a id='n2738' href='#n2738'>2738</a>
<a id='n2739' href='#n2739'>2739</a>
<a id='n2740' href='#n2740'>2740</a>
<a id='n2741' href='#n2741'>2741</a>
<a id='n2742' href='#n2742'>2742</a>
<a id='n2743' href='#n2743'>2743</a>
<a id='n2744' href='#n2744'>2744</a>
<a id='n2745' href='#n2745'>2745</a>
<a id='n2746' href='#n2746'>2746</a>
<a id='n2747' href='#n2747'>2747</a>
<a id='n2748' href='#n2748'>2748</a>
<a id='n2749' href='#n2749'>2749</a>
<a id='n2750' href='#n2750'>2750</a>
<a id='n2751' href='#n2751'>2751</a>
<a id='n2752' href='#n2752'>2752</a>
<a id='n2753' href='#n2753'>2753</a>
<a id='n2754' href='#n2754'>2754</a>
<a id='n2755' href='#n2755'>2755</a>
<a id='n2756' href='#n2756'>2756</a>
<a id='n2757' href='#n2757'>2757</a>
<a id='n2758' href='#n2758'>2758</a>
<a id='n2759' href='#n2759'>2759</a>
<a id='n2760' href='#n2760'>2760</a>
<a id='n2761' href='#n2761'>2761</a>
<a id='n2762' href='#n2762'>2762</a>
<a id='n2763' href='#n2763'>2763</a>
<a id='n2764' href='#n2764'>2764</a>
<a id='n2765' href='#n2765'>2765</a>
<a id='n2766' href='#n2766'>2766</a>
<a id='n2767' href='#n2767'>2767</a>
<a id='n2768' href='#n2768'>2768</a>
<a id='n2769' href='#n2769'>2769</a>
<a id='n2770' href='#n2770'>2770</a>
<a id='n2771' href='#n2771'>2771</a>
<a id='n2772' href='#n2772'>2772</a>
<a id='n2773' href='#n2773'>2773</a>
<a id='n2774' href='#n2774'>2774</a>
<a id='n2775' href='#n2775'>2775</a>
<a id='n2776' href='#n2776'>2776</a>
<a id='n2777' href='#n2777'>2777</a>
<a id='n2778' href='#n2778'>2778</a>
<a id='n2779' href='#n2779'>2779</a>
<a id='n2780' href='#n2780'>2780</a>
<a id='n2781' href='#n2781'>2781</a>
<a id='n2782' href='#n2782'>2782</a>
<a id='n2783' href='#n2783'>2783</a>
<a id='n2784' href='#n2784'>2784</a>
<a id='n2785' href='#n2785'>2785</a>
<a id='n2786' href='#n2786'>2786</a>
<a id='n2787' href='#n2787'>2787</a>
<a id='n2788' href='#n2788'>2788</a>
<a id='n2789' href='#n2789'>2789</a>
<a id='n2790' href='#n2790'>2790</a>
<a id='n2791' href='#n2791'>2791</a>
<a id='n2792' href='#n2792'>2792</a>
<a id='n2793' href='#n2793'>2793</a>
<a id='n2794' href='#n2794'>2794</a>
<a id='n2795' href='#n2795'>2795</a>
<a id='n2796' href='#n2796'>2796</a>
<a id='n2797' href='#n2797'>2797</a>
<a id='n2798' href='#n2798'>2798</a>
<a id='n2799' href='#n2799'>2799</a>
<a id='n2800' href='#n2800'>2800</a>
<a id='n2801' href='#n2801'>2801</a>
<a id='n2802' href='#n2802'>2802</a>
<a id='n2803' href='#n2803'>2803</a>
<a id='n2804' href='#n2804'>2804</a>
<a id='n2805' href='#n2805'>2805</a>
<a id='n2806' href='#n2806'>2806</a>
<a id='n2807' href='#n2807'>2807</a>
<a id='n2808' href='#n2808'>2808</a>
<a id='n2809' href='#n2809'>2809</a>
<a id='n2810' href='#n2810'>2810</a>
<a id='n2811' href='#n2811'>2811</a>
<a id='n2812' href='#n2812'>2812</a>
<a id='n2813' href='#n2813'>2813</a>
<a id='n2814' href='#n2814'>2814</a>
<a id='n2815' href='#n2815'>2815</a>
<a id='n2816' href='#n2816'>2816</a>
<a id='n2817' href='#n2817'>2817</a>
<a id='n2818' href='#n2818'>2818</a>
<a id='n2819' href='#n2819'>2819</a>
<a id='n2820' href='#n2820'>2820</a>
<a id='n2821' href='#n2821'>2821</a>
<a id='n2822' href='#n2822'>2822</a>
<a id='n2823' href='#n2823'>2823</a>
<a id='n2824' href='#n2824'>2824</a>
<a id='n2825' href='#n2825'>2825</a>
<a id='n2826' href='#n2826'>2826</a>
<a id='n2827' href='#n2827'>2827</a>
<a id='n2828' href='#n2828'>2828</a>
<a id='n2829' href='#n2829'>2829</a>
<a id='n2830' href='#n2830'>2830</a>
<a id='n2831' href='#n2831'>2831</a>
<a id='n2832' href='#n2832'>2832</a>
<a id='n2833' href='#n2833'>2833</a>
<a id='n2834' href='#n2834'>2834</a>
<a id='n2835' href='#n2835'>2835</a>
<a id='n2836' href='#n2836'>2836</a>
<a id='n2837' href='#n2837'>2837</a>
<a id='n2838' href='#n2838'>2838</a>
<a id='n2839' href='#n2839'>2839</a>
<a id='n2840' href='#n2840'>2840</a>
<a id='n2841' href='#n2841'>2841</a>
<a id='n2842' href='#n2842'>2842</a>
<a id='n2843' href='#n2843'>2843</a>
<a id='n2844' href='#n2844'>2844</a>
<a id='n2845' href='#n2845'>2845</a>
<a id='n2846' href='#n2846'>2846</a>
<a id='n2847' href='#n2847'>2847</a>
<a id='n2848' href='#n2848'>2848</a>
<a id='n2849' href='#n2849'>2849</a>
<a id='n2850' href='#n2850'>2850</a>
<a id='n2851' href='#n2851'>2851</a>
<a id='n2852' href='#n2852'>2852</a>
<a id='n2853' href='#n2853'>2853</a>
<a id='n2854' href='#n2854'>2854</a>
<a id='n2855' href='#n2855'>2855</a>
<a id='n2856' href='#n2856'>2856</a>
<a id='n2857' href='#n2857'>2857</a>
<a id='n2858' href='#n2858'>2858</a>
<a id='n2859' href='#n2859'>2859</a>
<a id='n2860' href='#n2860'>2860</a>
<a id='n2861' href='#n2861'>2861</a>
<a id='n2862' href='#n2862'>2862</a>
<a id='n2863' href='#n2863'>2863</a>
<a id='n2864' href='#n2864'>2864</a>
<a id='n2865' href='#n2865'>2865</a>
<a id='n2866' href='#n2866'>2866</a>
<a id='n2867' href='#n2867'>2867</a>
<a id='n2868' href='#n2868'>2868</a>
<a id='n2869' href='#n2869'>2869</a>
<a id='n2870' href='#n2870'>2870</a>
<a id='n2871' href='#n2871'>2871</a>
<a id='n2872' href='#n2872'>2872</a>
<a id='n2873' href='#n2873'>2873</a>
<a id='n2874' href='#n2874'>2874</a>
<a id='n2875' href='#n2875'>2875</a>
<a id='n2876' href='#n2876'>2876</a>
<a id='n2877' href='#n2877'>2877</a>
<a id='n2878' href='#n2878'>2878</a>
<a id='n2879' href='#n2879'>2879</a>
<a id='n2880' href='#n2880'>2880</a>
<a id='n2881' href='#n2881'>2881</a>
<a id='n2882' href='#n2882'>2882</a>
<a id='n2883' href='#n2883'>2883</a>
<a id='n2884' href='#n2884'>2884</a>
<a id='n2885' href='#n2885'>2885</a>
<a id='n2886' href='#n2886'>2886</a>
<a id='n2887' href='#n2887'>2887</a>
<a id='n2888' href='#n2888'>2888</a>
<a id='n2889' href='#n2889'>2889</a>
<a id='n2890' href='#n2890'>2890</a>
<a id='n2891' href='#n2891'>2891</a>
<a id='n2892' href='#n2892'>2892</a>
<a id='n2893' href='#n2893'>2893</a>
<a id='n2894' href='#n2894'>2894</a>
<a id='n2895' href='#n2895'>2895</a>
<a id='n2896' href='#n2896'>2896</a>
<a id='n2897' href='#n2897'>2897</a>
<a id='n2898' href='#n2898'>2898</a>
<a id='n2899' href='#n2899'>2899</a>
<a id='n2900' href='#n2900'>2900</a>
<a id='n2901' href='#n2901'>2901</a>
<a id='n2902' href='#n2902'>2902</a>
<a id='n2903' href='#n2903'>2903</a>
<a id='n2904' href='#n2904'>2904</a>
<a id='n2905' href='#n2905'>2905</a>
<a id='n2906' href='#n2906'>2906</a>
<a id='n2907' href='#n2907'>2907</a>
<a id='n2908' href='#n2908'>2908</a>
<a id='n2909' href='#n2909'>2909</a>
<a id='n2910' href='#n2910'>2910</a>
<a id='n2911' href='#n2911'>2911</a>
<a id='n2912' href='#n2912'>2912</a>
<a id='n2913' href='#n2913'>2913</a>
<a id='n2914' href='#n2914'>2914</a>
<a id='n2915' href='#n2915'>2915</a>
<a id='n2916' href='#n2916'>2916</a>
<a id='n2917' href='#n2917'>2917</a>
<a id='n2918' href='#n2918'>2918</a>
<a id='n2919' href='#n2919'>2919</a>
<a id='n2920' href='#n2920'>2920</a>
<a id='n2921' href='#n2921'>2921</a>
<a id='n2922' href='#n2922'>2922</a>
<a id='n2923' href='#n2923'>2923</a>
<a id='n2924' href='#n2924'>2924</a>
<a id='n2925' href='#n2925'>2925</a>
<a id='n2926' href='#n2926'>2926</a>
<a id='n2927' href='#n2927'>2927</a>
<a id='n2928' href='#n2928'>2928</a>
<a id='n2929' href='#n2929'>2929</a>
<a id='n2930' href='#n2930'>2930</a>
<a id='n2931' href='#n2931'>2931</a>
<a id='n2932' href='#n2932'>2932</a>
<a id='n2933' href='#n2933'>2933</a>
<a id='n2934' href='#n2934'>2934</a>
<a id='n2935' href='#n2935'>2935</a>
<a id='n2936' href='#n2936'>2936</a>
<a id='n2937' href='#n2937'>2937</a>
<a id='n2938' href='#n2938'>2938</a>
<a id='n2939' href='#n2939'>2939</a>
<a id='n2940' href='#n2940'>2940</a>
<a id='n2941' href='#n2941'>2941</a>
<a id='n2942' href='#n2942'>2942</a>
<a id='n2943' href='#n2943'>2943</a>
<a id='n2944' href='#n2944'>2944</a>
<a id='n2945' href='#n2945'>2945</a>
<a id='n2946' href='#n2946'>2946</a>
<a id='n2947' href='#n2947'>2947</a>
<a id='n2948' href='#n2948'>2948</a>
<a id='n2949' href='#n2949'>2949</a>
<a id='n2950' href='#n2950'>2950</a>
<a id='n2951' href='#n2951'>2951</a>
<a id='n2952' href='#n2952'>2952</a>
<a id='n2953' href='#n2953'>2953</a>
<a id='n2954' href='#n2954'>2954</a>
<a id='n2955' href='#n2955'>2955</a>
<a id='n2956' href='#n2956'>2956</a>
<a id='n2957' href='#n2957'>2957</a>
<a id='n2958' href='#n2958'>2958</a>
<a id='n2959' href='#n2959'>2959</a>
<a id='n2960' href='#n2960'>2960</a>
<a id='n2961' href='#n2961'>2961</a>
<a id='n2962' href='#n2962'>2962</a>
<a id='n2963' href='#n2963'>2963</a>
<a id='n2964' href='#n2964'>2964</a>
<a id='n2965' href='#n2965'>2965</a>
<a id='n2966' href='#n2966'>2966</a>
<a id='n2967' href='#n2967'>2967</a>
<a id='n2968' href='#n2968'>2968</a>
<a id='n2969' href='#n2969'>2969</a>
<a id='n2970' href='#n2970'>2970</a>
<a id='n2971' href='#n2971'>2971</a>
<a id='n2972' href='#n2972'>2972</a>
<a id='n2973' href='#n2973'>2973</a>
<a id='n2974' href='#n2974'>2974</a>
<a id='n2975' href='#n2975'>2975</a>
<a id='n2976' href='#n2976'>2976</a>
<a id='n2977' href='#n2977'>2977</a>
<a id='n2978' href='#n2978'>2978</a>
<a id='n2979' href='#n2979'>2979</a>
<a id='n2980' href='#n2980'>2980</a>
<a id='n2981' href='#n2981'>2981</a>
<a id='n2982' href='#n2982'>2982</a>
<a id='n2983' href='#n2983'>2983</a>
<a id='n2984' href='#n2984'>2984</a>
<a id='n2985' href='#n2985'>2985</a>
<a id='n2986' href='#n2986'>2986</a>
<a id='n2987' href='#n2987'>2987</a>
<a id='n2988' href='#n2988'>2988</a>
<a id='n2989' href='#n2989'>2989</a>
<a id='n2990' href='#n2990'>2990</a>
<a id='n2991' href='#n2991'>2991</a>
<a id='n2992' href='#n2992'>2992</a>
<a id='n2993' href='#n2993'>2993</a>
<a id='n2994' href='#n2994'>2994</a>
<a id='n2995' href='#n2995'>2995</a>
<a id='n2996' href='#n2996'>2996</a>
<a id='n2997' href='#n2997'>2997</a>
<a id='n2998' href='#n2998'>2998</a>
<a id='n2999' href='#n2999'>2999</a>
<a id='n3000' href='#n3000'>3000</a>
<a id='n3001' href='#n3001'>3001</a>
<a id='n3002' href='#n3002'>3002</a>
<a id='n3003' href='#n3003'>3003</a>
<a id='n3004' href='#n3004'>3004</a>
<a id='n3005' href='#n3005'>3005</a>
<a id='n3006' href='#n3006'>3006</a>
<a id='n3007' href='#n3007'>3007</a>
<a id='n3008' href='#n3008'>3008</a>
<a id='n3009' href='#n3009'>3009</a>
<a id='n3010' href='#n3010'>3010</a>
<a id='n3011' href='#n3011'>3011</a>
<a id='n3012' href='#n3012'>3012</a>
<a id='n3013' href='#n3013'>3013</a>
<a id='n3014' href='#n3014'>3014</a>
<a id='n3015' href='#n3015'>3015</a>
<a id='n3016' href='#n3016'>3016</a>
<a id='n3017' href='#n3017'>3017</a>
<a id='n3018' href='#n3018'>3018</a>
<a id='n3019' href='#n3019'>3019</a>
<a id='n3020' href='#n3020'>3020</a>
<a id='n3021' href='#n3021'>3021</a>
<a id='n3022' href='#n3022'>3022</a>
<a id='n3023' href='#n3023'>3023</a>
<a id='n3024' href='#n3024'>3024</a>
<a id='n3025' href='#n3025'>3025</a>
<a id='n3026' href='#n3026'>3026</a>
<a id='n3027' href='#n3027'>3027</a>
<a id='n3028' href='#n3028'>3028</a>
<a id='n3029' href='#n3029'>3029</a>
<a id='n3030' href='#n3030'>3030</a>
<a id='n3031' href='#n3031'>3031</a>
<a id='n3032' href='#n3032'>3032</a>
<a id='n3033' href='#n3033'>3033</a>
<a id='n3034' href='#n3034'>3034</a>
<a id='n3035' href='#n3035'>3035</a>
<a id='n3036' href='#n3036'>3036</a>
<a id='n3037' href='#n3037'>3037</a>
<a id='n3038' href='#n3038'>3038</a>
<a id='n3039' href='#n3039'>3039</a>
<a id='n3040' href='#n3040'>3040</a>
<a id='n3041' href='#n3041'>3041</a>
<a id='n3042' href='#n3042'>3042</a>
<a id='n3043' href='#n3043'>3043</a>
<a id='n3044' href='#n3044'>3044</a>
<a id='n3045' href='#n3045'>3045</a>
<a id='n3046' href='#n3046'>3046</a>
<a id='n3047' href='#n3047'>3047</a>
<a id='n3048' href='#n3048'>3048</a>
<a id='n3049' href='#n3049'>3049</a>
<a id='n3050' href='#n3050'>3050</a>
<a id='n3051' href='#n3051'>3051</a>
<a id='n3052' href='#n3052'>3052</a>
<a id='n3053' href='#n3053'>3053</a>
<a id='n3054' href='#n3054'>3054</a>
<a id='n3055' href='#n3055'>3055</a>
<a id='n3056' href='#n3056'>3056</a>
<a id='n3057' href='#n3057'>3057</a>
<a id='n3058' href='#n3058'>3058</a>
<a id='n3059' href='#n3059'>3059</a>
<a id='n3060' href='#n3060'>3060</a>
<a id='n3061' href='#n3061'>3061</a>
<a id='n3062' href='#n3062'>3062</a>
<a id='n3063' href='#n3063'>3063</a>
<a id='n3064' href='#n3064'>3064</a>
<a id='n3065' href='#n3065'>3065</a>
<a id='n3066' href='#n3066'>3066</a>
<a id='n3067' href='#n3067'>3067</a>
<a id='n3068' href='#n3068'>3068</a>
<a id='n3069' href='#n3069'>3069</a>
<a id='n3070' href='#n3070'>3070</a>
<a id='n3071' href='#n3071'>3071</a>
<a id='n3072' href='#n3072'>3072</a>
<a id='n3073' href='#n3073'>3073</a>
<a id='n3074' href='#n3074'>3074</a>
<a id='n3075' href='#n3075'>3075</a>
<a id='n3076' href='#n3076'>3076</a>
<a id='n3077' href='#n3077'>3077</a>
<a id='n3078' href='#n3078'>3078</a>
<a id='n3079' href='#n3079'>3079</a>
<a id='n3080' href='#n3080'>3080</a>
<a id='n3081' href='#n3081'>3081</a>
<a id='n3082' href='#n3082'>3082</a>
<a id='n3083' href='#n3083'>3083</a>
<a id='n3084' href='#n3084'>3084</a>
<a id='n3085' href='#n3085'>3085</a>
<a id='n3086' href='#n3086'>3086</a>
<a id='n3087' href='#n3087'>3087</a>
<a id='n3088' href='#n3088'>3088</a>
<a id='n3089' href='#n3089'>3089</a>
<a id='n3090' href='#n3090'>3090</a>
<a id='n3091' href='#n3091'>3091</a>
<a id='n3092' href='#n3092'>3092</a>
<a id='n3093' href='#n3093'>3093</a>
<a id='n3094' href='#n3094'>3094</a>
<a id='n3095' href='#n3095'>3095</a>
<a id='n3096' href='#n3096'>3096</a>
<a id='n3097' href='#n3097'>3097</a>
<a id='n3098' href='#n3098'>3098</a>
<a id='n3099' href='#n3099'>3099</a>
<a id='n3100' href='#n3100'>3100</a>
<a id='n3101' href='#n3101'>3101</a>
<a id='n3102' href='#n3102'>3102</a>
<a id='n3103' href='#n3103'>3103</a>
<a id='n3104' href='#n3104'>3104</a>
<a id='n3105' href='#n3105'>3105</a>
<a id='n3106' href='#n3106'>3106</a>
<a id='n3107' href='#n3107'>3107</a>
<a id='n3108' href='#n3108'>3108</a>
<a id='n3109' href='#n3109'>3109</a>
<a id='n3110' href='#n3110'>3110</a>
<a id='n3111' href='#n3111'>3111</a>
<a id='n3112' href='#n3112'>3112</a>
<a id='n3113' href='#n3113'>3113</a>
<a id='n3114' href='#n3114'>3114</a>
<a id='n3115' href='#n3115'>3115</a>
<a id='n3116' href='#n3116'>3116</a>
<a id='n3117' href='#n3117'>3117</a>
<a id='n3118' href='#n3118'>3118</a>
<a id='n3119' href='#n3119'>3119</a>
<a id='n3120' href='#n3120'>3120</a>
<a id='n3121' href='#n3121'>3121</a>
<a id='n3122' href='#n3122'>3122</a>
<a id='n3123' href='#n3123'>3123</a>
<a id='n3124' href='#n3124'>3124</a>
<a id='n3125' href='#n3125'>3125</a>
<a id='n3126' href='#n3126'>3126</a>
<a id='n3127' href='#n3127'>3127</a>
<a id='n3128' href='#n3128'>3128</a>
<a id='n3129' href='#n3129'>3129</a>
<a id='n3130' href='#n3130'>3130</a>
<a id='n3131' href='#n3131'>3131</a>
<a id='n3132' href='#n3132'>3132</a>
<a id='n3133' href='#n3133'>3133</a>
<a id='n3134' href='#n3134'>3134</a>
<a id='n3135' href='#n3135'>3135</a>
<a id='n3136' href='#n3136'>3136</a>
<a id='n3137' href='#n3137'>3137</a>
<a id='n3138' href='#n3138'>3138</a>
<a id='n3139' href='#n3139'>3139</a>
<a id='n3140' href='#n3140'>3140</a>
<a id='n3141' href='#n3141'>3141</a>
<a id='n3142' href='#n3142'>3142</a>
<a id='n3143' href='#n3143'>3143</a>
<a id='n3144' href='#n3144'>3144</a>
<a id='n3145' href='#n3145'>3145</a>
<a id='n3146' href='#n3146'>3146</a>
<a id='n3147' href='#n3147'>3147</a>
<a id='n3148' href='#n3148'>3148</a>
<a id='n3149' href='#n3149'>3149</a>
<a id='n3150' href='#n3150'>3150</a>
<a id='n3151' href='#n3151'>3151</a>
<a id='n3152' href='#n3152'>3152</a>
<a id='n3153' href='#n3153'>3153</a>
<a id='n3154' href='#n3154'>3154</a>
<a id='n3155' href='#n3155'>3155</a>
<a id='n3156' href='#n3156'>3156</a>
<a id='n3157' href='#n3157'>3157</a>
<a id='n3158' href='#n3158'>3158</a>
<a id='n3159' href='#n3159'>3159</a>
<a id='n3160' href='#n3160'>3160</a>
<a id='n3161' href='#n3161'>3161</a>
<a id='n3162' href='#n3162'>3162</a>
<a id='n3163' href='#n3163'>3163</a>
<a id='n3164' href='#n3164'>3164</a>
<a id='n3165' href='#n3165'>3165</a>
<a id='n3166' href='#n3166'>3166</a>
<a id='n3167' href='#n3167'>3167</a>
<a id='n3168' href='#n3168'>3168</a>
<a id='n3169' href='#n3169'>3169</a>
<a id='n3170' href='#n3170'>3170</a>
<a id='n3171' href='#n3171'>3171</a>
<a id='n3172' href='#n3172'>3172</a>
<a id='n3173' href='#n3173'>3173</a>
<a id='n3174' href='#n3174'>3174</a>
<a id='n3175' href='#n3175'>3175</a>
<a id='n3176' href='#n3176'>3176</a>
<a id='n3177' href='#n3177'>3177</a>
<a id='n3178' href='#n3178'>3178</a>
<a id='n3179' href='#n3179'>3179</a>
<a id='n3180' href='#n3180'>3180</a>
<a id='n3181' href='#n3181'>3181</a>
<a id='n3182' href='#n3182'>3182</a>
<a id='n3183' href='#n3183'>3183</a>
<a id='n3184' href='#n3184'>3184</a>
<a id='n3185' href='#n3185'>3185</a>
<a id='n3186' href='#n3186'>3186</a>
<a id='n3187' href='#n3187'>3187</a>
<a id='n3188' href='#n3188'>3188</a>
<a id='n3189' href='#n3189'>3189</a>
<a id='n3190' href='#n3190'>3190</a>
<a id='n3191' href='#n3191'>3191</a>
<a id='n3192' href='#n3192'>3192</a>
<a id='n3193' href='#n3193'>3193</a>
<a id='n3194' href='#n3194'>3194</a>
<a id='n3195' href='#n3195'>3195</a>
<a id='n3196' href='#n3196'>3196</a>
<a id='n3197' href='#n3197'>3197</a>
<a id='n3198' href='#n3198'>3198</a>
<a id='n3199' href='#n3199'>3199</a>
<a id='n3200' href='#n3200'>3200</a>
<a id='n3201' href='#n3201'>3201</a>
<a id='n3202' href='#n3202'>3202</a>
<a id='n3203' href='#n3203'>3203</a>
<a id='n3204' href='#n3204'>3204</a>
<a id='n3205' href='#n3205'>3205</a>
<a id='n3206' href='#n3206'>3206</a>
<a id='n3207' href='#n3207'>3207</a>
<a id='n3208' href='#n3208'>3208</a>
<a id='n3209' href='#n3209'>3209</a>
<a id='n3210' href='#n3210'>3210</a>
<a id='n3211' href='#n3211'>3211</a>
<a id='n3212' href='#n3212'>3212</a>
<a id='n3213' href='#n3213'>3213</a>
<a id='n3214' href='#n3214'>3214</a>
<a id='n3215' href='#n3215'>3215</a>
<a id='n3216' href='#n3216'>3216</a>
<a id='n3217' href='#n3217'>3217</a>
<a id='n3218' href='#n3218'>3218</a>
<a id='n3219' href='#n3219'>3219</a>
<a id='n3220' href='#n3220'>3220</a>
<a id='n3221' href='#n3221'>3221</a>
<a id='n3222' href='#n3222'>3222</a>
<a id='n3223' href='#n3223'>3223</a>
<a id='n3224' href='#n3224'>3224</a>
<a id='n3225' href='#n3225'>3225</a>
<a id='n3226' href='#n3226'>3226</a>
<a id='n3227' href='#n3227'>3227</a>
<a id='n3228' href='#n3228'>3228</a>
<a id='n3229' href='#n3229'>3229</a>
<a id='n3230' href='#n3230'>3230</a>
<a id='n3231' href='#n3231'>3231</a>
<a id='n3232' href='#n3232'>3232</a>
<a id='n3233' href='#n3233'>3233</a>
<a id='n3234' href='#n3234'>3234</a>
<a id='n3235' href='#n3235'>3235</a>
<a id='n3236' href='#n3236'>3236</a>
<a id='n3237' href='#n3237'>3237</a>
<a id='n3238' href='#n3238'>3238</a>
<a id='n3239' href='#n3239'>3239</a>
<a id='n3240' href='#n3240'>3240</a>
<a id='n3241' href='#n3241'>3241</a>
<a id='n3242' href='#n3242'>3242</a>
<a id='n3243' href='#n3243'>3243</a>
<a id='n3244' href='#n3244'>3244</a>
<a id='n3245' href='#n3245'>3245</a>
<a id='n3246' href='#n3246'>3246</a>
<a id='n3247' href='#n3247'>3247</a>
<a id='n3248' href='#n3248'>3248</a>
<a id='n3249' href='#n3249'>3249</a>
<a id='n3250' href='#n3250'>3250</a>
<a id='n3251' href='#n3251'>3251</a>
<a id='n3252' href='#n3252'>3252</a>
<a id='n3253' href='#n3253'>3253</a>
<a id='n3254' href='#n3254'>3254</a>
<a id='n3255' href='#n3255'>3255</a>
<a id='n3256' href='#n3256'>3256</a>
<a id='n3257' href='#n3257'>3257</a>
<a id='n3258' href='#n3258'>3258</a>
<a id='n3259' href='#n3259'>3259</a>
<a id='n3260' href='#n3260'>3260</a>
<a id='n3261' href='#n3261'>3261</a>
<a id='n3262' href='#n3262'>3262</a>
<a id='n3263' href='#n3263'>3263</a>
<a id='n3264' href='#n3264'>3264</a>
<a id='n3265' href='#n3265'>3265</a>
<a id='n3266' href='#n3266'>3266</a>
<a id='n3267' href='#n3267'>3267</a>
<a id='n3268' href='#n3268'>3268</a>
<a id='n3269' href='#n3269'>3269</a>
<a id='n3270' href='#n3270'>3270</a>
<a id='n3271' href='#n3271'>3271</a>
<a id='n3272' href='#n3272'>3272</a>
<a id='n3273' href='#n3273'>3273</a>
<a id='n3274' href='#n3274'>3274</a>
<a id='n3275' href='#n3275'>3275</a>
<a id='n3276' href='#n3276'>3276</a>
<a id='n3277' href='#n3277'>3277</a>
<a id='n3278' href='#n3278'>3278</a>
<a id='n3279' href='#n3279'>3279</a>
<a id='n3280' href='#n3280'>3280</a>
<a id='n3281' href='#n3281'>3281</a>
<a id='n3282' href='#n3282'>3282</a>
<a id='n3283' href='#n3283'>3283</a>
<a id='n3284' href='#n3284'>3284</a>
<a id='n3285' href='#n3285'>3285</a>
<a id='n3286' href='#n3286'>3286</a>
<a id='n3287' href='#n3287'>3287</a>
<a id='n3288' href='#n3288'>3288</a>
<a id='n3289' href='#n3289'>3289</a>
<a id='n3290' href='#n3290'>3290</a>
<a id='n3291' href='#n3291'>3291</a>
<a id='n3292' href='#n3292'>3292</a>
<a id='n3293' href='#n3293'>3293</a>
<a id='n3294' href='#n3294'>3294</a>
<a id='n3295' href='#n3295'>3295</a>
<a id='n3296' href='#n3296'>3296</a>
<a id='n3297' href='#n3297'>3297</a>
<a id='n3298' href='#n3298'>3298</a>
<a id='n3299' href='#n3299'>3299</a>
<a id='n3300' href='#n3300'>3300</a>
<a id='n3301' href='#n3301'>3301</a>
<a id='n3302' href='#n3302'>3302</a>
<a id='n3303' href='#n3303'>3303</a>
<a id='n3304' href='#n3304'>3304</a>
<a id='n3305' href='#n3305'>3305</a>
<a id='n3306' href='#n3306'>3306</a>
<a id='n3307' href='#n3307'>3307</a>
<a id='n3308' href='#n3308'>3308</a>
<a id='n3309' href='#n3309'>3309</a>
<a id='n3310' href='#n3310'>3310</a>
<a id='n3311' href='#n3311'>3311</a>
<a id='n3312' href='#n3312'>3312</a>
<a id='n3313' href='#n3313'>3313</a>
<a id='n3314' href='#n3314'>3314</a>
<a id='n3315' href='#n3315'>3315</a>
<a id='n3316' href='#n3316'>3316</a>
<a id='n3317' href='#n3317'>3317</a>
<a id='n3318' href='#n3318'>3318</a>
<a id='n3319' href='#n3319'>3319</a>
<a id='n3320' href='#n3320'>3320</a>
<a id='n3321' href='#n3321'>3321</a>
<a id='n3322' href='#n3322'>3322</a>
<a id='n3323' href='#n3323'>3323</a>
<a id='n3324' href='#n3324'>3324</a>
<a id='n3325' href='#n3325'>3325</a>
<a id='n3326' href='#n3326'>3326</a>
<a id='n3327' href='#n3327'>3327</a>
<a id='n3328' href='#n3328'>3328</a>
<a id='n3329' href='#n3329'>3329</a>
<a id='n3330' href='#n3330'>3330</a>
<a id='n3331' href='#n3331'>3331</a>
<a id='n3332' href='#n3332'>3332</a>
<a id='n3333' href='#n3333'>3333</a>
<a id='n3334' href='#n3334'>3334</a>
<a id='n3335' href='#n3335'>3335</a>
<a id='n3336' href='#n3336'>3336</a>
<a id='n3337' href='#n3337'>3337</a>
<a id='n3338' href='#n3338'>3338</a>
<a id='n3339' href='#n3339'>3339</a>
<a id='n3340' href='#n3340'>3340</a>
<a id='n3341' href='#n3341'>3341</a>
<a id='n3342' href='#n3342'>3342</a>
<a id='n3343' href='#n3343'>3343</a>
<a id='n3344' href='#n3344'>3344</a>
<a id='n3345' href='#n3345'>3345</a>
<a id='n3346' href='#n3346'>3346</a>
<a id='n3347' href='#n3347'>3347</a>
<a id='n3348' href='#n3348'>3348</a>
<a id='n3349' href='#n3349'>3349</a>
<a id='n3350' href='#n3350'>3350</a>
<a id='n3351' href='#n3351'>3351</a>
<a id='n3352' href='#n3352'>3352</a>
<a id='n3353' href='#n3353'>3353</a>
<a id='n3354' href='#n3354'>3354</a>
<a id='n3355' href='#n3355'>3355</a>
<a id='n3356' href='#n3356'>3356</a>
<a id='n3357' href='#n3357'>3357</a>
<a id='n3358' href='#n3358'>3358</a>
<a id='n3359' href='#n3359'>3359</a>
<a id='n3360' href='#n3360'>3360</a>
<a id='n3361' href='#n3361'>3361</a>
<a id='n3362' href='#n3362'>3362</a>
<a id='n3363' href='#n3363'>3363</a>
<a id='n3364' href='#n3364'>3364</a>
<a id='n3365' href='#n3365'>3365</a>
<a id='n3366' href='#n3366'>3366</a>
<a id='n3367' href='#n3367'>3367</a>
<a id='n3368' href='#n3368'>3368</a>
<a id='n3369' href='#n3369'>3369</a>
<a id='n3370' href='#n3370'>3370</a>
<a id='n3371' href='#n3371'>3371</a>
<a id='n3372' href='#n3372'>3372</a>
<a id='n3373' href='#n3373'>3373</a>
<a id='n3374' href='#n3374'>3374</a>
<a id='n3375' href='#n3375'>3375</a>
<a id='n3376' href='#n3376'>3376</a>
<a id='n3377' href='#n3377'>3377</a>
<a id='n3378' href='#n3378'>3378</a>
<a id='n3379' href='#n3379'>3379</a>
<a id='n3380' href='#n3380'>3380</a>
<a id='n3381' href='#n3381'>3381</a>
<a id='n3382' href='#n3382'>3382</a>
<a id='n3383' href='#n3383'>3383</a>
<a id='n3384' href='#n3384'>3384</a>
<a id='n3385' href='#n3385'>3385</a>
<a id='n3386' href='#n3386'>3386</a>
<a id='n3387' href='#n3387'>3387</a>
<a id='n3388' href='#n3388'>3388</a>
<a id='n3389' href='#n3389'>3389</a>
<a id='n3390' href='#n3390'>3390</a>
<a id='n3391' href='#n3391'>3391</a>
<a id='n3392' href='#n3392'>3392</a>
<a id='n3393' href='#n3393'>3393</a>
<a id='n3394' href='#n3394'>3394</a>
<a id='n3395' href='#n3395'>3395</a>
<a id='n3396' href='#n3396'>3396</a>
<a id='n3397' href='#n3397'>3397</a>
<a id='n3398' href='#n3398'>3398</a>
<a id='n3399' href='#n3399'>3399</a>
<a id='n3400' href='#n3400'>3400</a>
<a id='n3401' href='#n3401'>3401</a>
<a id='n3402' href='#n3402'>3402</a>
<a id='n3403' href='#n3403'>3403</a>
<a id='n3404' href='#n3404'>3404</a>
<a id='n3405' href='#n3405'>3405</a>
<a id='n3406' href='#n3406'>3406</a>
<a id='n3407' href='#n3407'>3407</a>
<a id='n3408' href='#n3408'>3408</a>
<a id='n3409' href='#n3409'>3409</a>
<a id='n3410' href='#n3410'>3410</a>
<a id='n3411' href='#n3411'>3411</a>
<a id='n3412' href='#n3412'>3412</a>
<a id='n3413' href='#n3413'>3413</a>
<a id='n3414' href='#n3414'>3414</a>
<a id='n3415' href='#n3415'>3415</a>
<a id='n3416' href='#n3416'>3416</a>
<a id='n3417' href='#n3417'>3417</a>
<a id='n3418' href='#n3418'>3418</a>
<a id='n3419' href='#n3419'>3419</a>
<a id='n3420' href='#n3420'>3420</a>
<a id='n3421' href='#n3421'>3421</a>
<a id='n3422' href='#n3422'>3422</a>
<a id='n3423' href='#n3423'>3423</a>
<a id='n3424' href='#n3424'>3424</a>
<a id='n3425' href='#n3425'>3425</a>
<a id='n3426' href='#n3426'>3426</a>
<a id='n3427' href='#n3427'>3427</a>
<a id='n3428' href='#n3428'>3428</a>
<a id='n3429' href='#n3429'>3429</a>
<a id='n3430' href='#n3430'>3430</a>
<a id='n3431' href='#n3431'>3431</a>
<a id='n3432' href='#n3432'>3432</a>
<a id='n3433' href='#n3433'>3433</a>
<a id='n3434' href='#n3434'>3434</a>
<a id='n3435' href='#n3435'>3435</a>
<a id='n3436' href='#n3436'>3436</a>
<a id='n3437' href='#n3437'>3437</a>
<a id='n3438' href='#n3438'>3438</a>
<a id='n3439' href='#n3439'>3439</a>
<a id='n3440' href='#n3440'>3440</a>
<a id='n3441' href='#n3441'>3441</a>
<a id='n3442' href='#n3442'>3442</a>
<a id='n3443' href='#n3443'>3443</a>
<a id='n3444' href='#n3444'>3444</a>
<a id='n3445' href='#n3445'>3445</a>
<a id='n3446' href='#n3446'>3446</a>
<a id='n3447' href='#n3447'>3447</a>
<a id='n3448' href='#n3448'>3448</a>
<a id='n3449' href='#n3449'>3449</a>
<a id='n3450' href='#n3450'>3450</a>
<a id='n3451' href='#n3451'>3451</a>
<a id='n3452' href='#n3452'>3452</a>
<a id='n3453' href='#n3453'>3453</a>
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<a id='n3457' href='#n3457'>3457</a>
<a id='n3458' href='#n3458'>3458</a>
<a id='n3459' href='#n3459'>3459</a>
<a id='n3460' href='#n3460'>3460</a>
<a id='n3461' href='#n3461'>3461</a>
<a id='n3462' href='#n3462'>3462</a>
<a id='n3463' href='#n3463'>3463</a>
<a id='n3464' href='#n3464'>3464</a>
<a id='n3465' href='#n3465'>3465</a>
<a id='n3466' href='#n3466'>3466</a>
<a id='n3467' href='#n3467'>3467</a>
<a id='n3468' href='#n3468'>3468</a>
<a id='n3469' href='#n3469'>3469</a>
<a id='n3470' href='#n3470'>3470</a>
<a id='n3471' href='#n3471'>3471</a>
<a id='n3472' href='#n3472'>3472</a>
<a id='n3473' href='#n3473'>3473</a>
<a id='n3474' href='#n3474'>3474</a>
<a id='n3475' href='#n3475'>3475</a>
<a id='n3476' href='#n3476'>3476</a>
<a id='n3477' href='#n3477'>3477</a>
<a id='n3478' href='#n3478'>3478</a>
<a id='n3479' href='#n3479'>3479</a>
<a id='n3480' href='#n3480'>3480</a>
<a id='n3481' href='#n3481'>3481</a>
<a id='n3482' href='#n3482'>3482</a>
<a id='n3483' href='#n3483'>3483</a>
<a id='n3484' href='#n3484'>3484</a>
<a id='n3485' href='#n3485'>3485</a>
<a id='n3486' href='#n3486'>3486</a>
<a id='n3487' href='#n3487'>3487</a>
<a id='n3488' href='#n3488'>3488</a>
<a id='n3489' href='#n3489'>3489</a>
<a id='n3490' href='#n3490'>3490</a>
<a id='n3491' href='#n3491'>3491</a>
<a id='n3492' href='#n3492'>3492</a>
<a id='n3493' href='#n3493'>3493</a>
<a id='n3494' href='#n3494'>3494</a>
<a id='n3495' href='#n3495'>3495</a>
<a id='n3496' href='#n3496'>3496</a>
<a id='n3497' href='#n3497'>3497</a>
<a id='n3498' href='#n3498'>3498</a>
<a id='n3499' href='#n3499'>3499</a>
<a id='n3500' href='#n3500'>3500</a>
<a id='n3501' href='#n3501'>3501</a>
<a id='n3502' href='#n3502'>3502</a>
<a id='n3503' href='#n3503'>3503</a>
<a id='n3504' href='#n3504'>3504</a>
<a id='n3505' href='#n3505'>3505</a>
<a id='n3506' href='#n3506'>3506</a>
<a id='n3507' href='#n3507'>3507</a>
<a id='n3508' href='#n3508'>3508</a>
<a id='n3509' href='#n3509'>3509</a>
<a id='n3510' href='#n3510'>3510</a>
<a id='n3511' href='#n3511'>3511</a>
<a id='n3512' href='#n3512'>3512</a>
<a id='n3513' href='#n3513'>3513</a>
<a id='n3514' href='#n3514'>3514</a>
<a id='n3515' href='#n3515'>3515</a>
<a id='n3516' href='#n3516'>3516</a>
<a id='n3517' href='#n3517'>3517</a>
<a id='n3518' href='#n3518'>3518</a>
<a id='n3519' href='#n3519'>3519</a>
<a id='n3520' href='#n3520'>3520</a>
<a id='n3521' href='#n3521'>3521</a>
<a id='n3522' href='#n3522'>3522</a>
<a id='n3523' href='#n3523'>3523</a>
<a id='n3524' href='#n3524'>3524</a>
<a id='n3525' href='#n3525'>3525</a>
<a id='n3526' href='#n3526'>3526</a>
<a id='n3527' href='#n3527'>3527</a>
<a id='n3528' href='#n3528'>3528</a>
<a id='n3529' href='#n3529'>3529</a>
<a id='n3530' href='#n3530'>3530</a>
<a id='n3531' href='#n3531'>3531</a>
<a id='n3532' href='#n3532'>3532</a>
<a id='n3533' href='#n3533'>3533</a>
<a id='n3534' href='#n3534'>3534</a>
<a id='n3535' href='#n3535'>3535</a>
<a id='n3536' href='#n3536'>3536</a>
<a id='n3537' href='#n3537'>3537</a>
<a id='n3538' href='#n3538'>3538</a>
<a id='n3539' href='#n3539'>3539</a>
<a id='n3540' href='#n3540'>3540</a>
<a id='n3541' href='#n3541'>3541</a>
<a id='n3542' href='#n3542'>3542</a>
<a id='n3543' href='#n3543'>3543</a>
<a id='n3544' href='#n3544'>3544</a>
<a id='n3545' href='#n3545'>3545</a>
<a id='n3546' href='#n3546'>3546</a>
<a id='n3547' href='#n3547'>3547</a>
<a id='n3548' href='#n3548'>3548</a>
<a id='n3549' href='#n3549'>3549</a>
<a id='n3550' href='#n3550'>3550</a>
<a id='n3551' href='#n3551'>3551</a>
<a id='n3552' href='#n3552'>3552</a>
<a id='n3553' href='#n3553'>3553</a>
<a id='n3554' href='#n3554'>3554</a>
<a id='n3555' href='#n3555'>3555</a>
<a id='n3556' href='#n3556'>3556</a>
<a id='n3557' href='#n3557'>3557</a>
<a id='n3558' href='#n3558'>3558</a>
<a id='n3559' href='#n3559'>3559</a>
<a id='n3560' href='#n3560'>3560</a>
<a id='n3561' href='#n3561'>3561</a>
<a id='n3562' href='#n3562'>3562</a>
<a id='n3563' href='#n3563'>3563</a>
<a id='n3564' href='#n3564'>3564</a>
<a id='n3565' href='#n3565'>3565</a>
<a id='n3566' href='#n3566'>3566</a>
<a id='n3567' href='#n3567'>3567</a>
<a id='n3568' href='#n3568'>3568</a>
<a id='n3569' href='#n3569'>3569</a>
<a id='n3570' href='#n3570'>3570</a>
<a id='n3571' href='#n3571'>3571</a>
<a id='n3572' href='#n3572'>3572</a>
<a id='n3573' href='#n3573'>3573</a>
<a id='n3574' href='#n3574'>3574</a>
<a id='n3575' href='#n3575'>3575</a>
<a id='n3576' href='#n3576'>3576</a>
<a id='n3577' href='#n3577'>3577</a>
<a id='n3578' href='#n3578'>3578</a>
<a id='n3579' href='#n3579'>3579</a>
<a id='n3580' href='#n3580'>3580</a>
<a id='n3581' href='#n3581'>3581</a>
<a id='n3582' href='#n3582'>3582</a>
<a id='n3583' href='#n3583'>3583</a>
<a id='n3584' href='#n3584'>3584</a>
<a id='n3585' href='#n3585'>3585</a>
<a id='n3586' href='#n3586'>3586</a>
<a id='n3587' href='#n3587'>3587</a>
<a id='n3588' href='#n3588'>3588</a>
<a id='n3589' href='#n3589'>3589</a>
<a id='n3590' href='#n3590'>3590</a>
<a id='n3591' href='#n3591'>3591</a>
<a id='n3592' href='#n3592'>3592</a>
<a id='n3593' href='#n3593'>3593</a>
<a id='n3594' href='#n3594'>3594</a>
<a id='n3595' href='#n3595'>3595</a>
<a id='n3596' href='#n3596'>3596</a>
<a id='n3597' href='#n3597'>3597</a>
<a id='n3598' href='#n3598'>3598</a>
<a id='n3599' href='#n3599'>3599</a>
<a id='n3600' href='#n3600'>3600</a>
<a id='n3601' href='#n3601'>3601</a>
<a id='n3602' href='#n3602'>3602</a>
<a id='n3603' href='#n3603'>3603</a>
<a id='n3604' href='#n3604'>3604</a>
<a id='n3605' href='#n3605'>3605</a>
<a id='n3606' href='#n3606'>3606</a>
<a id='n3607' href='#n3607'>3607</a>
<a id='n3608' href='#n3608'>3608</a>
<a id='n3609' href='#n3609'>3609</a>
<a id='n3610' href='#n3610'>3610</a>
<a id='n3611' href='#n3611'>3611</a>
<a id='n3612' href='#n3612'>3612</a>
<a id='n3613' href='#n3613'>3613</a>
<a id='n3614' href='#n3614'>3614</a>
<a id='n3615' href='#n3615'>3615</a>
<a id='n3616' href='#n3616'>3616</a>
<a id='n3617' href='#n3617'>3617</a>
<a id='n3618' href='#n3618'>3618</a>
<a id='n3619' href='#n3619'>3619</a>
<a id='n3620' href='#n3620'>3620</a>
<a id='n3621' href='#n3621'>3621</a>
<a id='n3622' href='#n3622'>3622</a>
<a id='n3623' href='#n3623'>3623</a>
<a id='n3624' href='#n3624'>3624</a>
<a id='n3625' href='#n3625'>3625</a>
<a id='n3626' href='#n3626'>3626</a>
<a id='n3627' href='#n3627'>3627</a>
<a id='n3628' href='#n3628'>3628</a>
<a id='n3629' href='#n3629'>3629</a>
<a id='n3630' href='#n3630'>3630</a>
<a id='n3631' href='#n3631'>3631</a>
<a id='n3632' href='#n3632'>3632</a>
<a id='n3633' href='#n3633'>3633</a>
<a id='n3634' href='#n3634'>3634</a>
<a id='n3635' href='#n3635'>3635</a>
<a id='n3636' href='#n3636'>3636</a>
<a id='n3637' href='#n3637'>3637</a>
<a id='n3638' href='#n3638'>3638</a>
<a id='n3639' href='#n3639'>3639</a>
<a id='n3640' href='#n3640'>3640</a>
<a id='n3641' href='#n3641'>3641</a>
<a id='n3642' href='#n3642'>3642</a>
<a id='n3643' href='#n3643'>3643</a>
<a id='n3644' href='#n3644'>3644</a>
<a id='n3645' href='#n3645'>3645</a>
<a id='n3646' href='#n3646'>3646</a>
<a id='n3647' href='#n3647'>3647</a>
<a id='n3648' href='#n3648'>3648</a>
<a id='n3649' href='#n3649'>3649</a>
<a id='n3650' href='#n3650'>3650</a>
<a id='n3651' href='#n3651'>3651</a>
<a id='n3652' href='#n3652'>3652</a>
<a id='n3653' href='#n3653'>3653</a>
<a id='n3654' href='#n3654'>3654</a>
<a id='n3655' href='#n3655'>3655</a>
<a id='n3656' href='#n3656'>3656</a>
<a id='n3657' href='#n3657'>3657</a>
<a id='n3658' href='#n3658'>3658</a>
<a id='n3659' href='#n3659'>3659</a>
<a id='n3660' href='#n3660'>3660</a>
<a id='n3661' href='#n3661'>3661</a>
<a id='n3662' href='#n3662'>3662</a>
<a id='n3663' href='#n3663'>3663</a>
<a id='n3664' href='#n3664'>3664</a>
<a id='n3665' href='#n3665'>3665</a>
<a id='n3666' href='#n3666'>3666</a>
<a id='n3667' href='#n3667'>3667</a>
<a id='n3668' href='#n3668'>3668</a>
<a id='n3669' href='#n3669'>3669</a>
<a id='n3670' href='#n3670'>3670</a>
<a id='n3671' href='#n3671'>3671</a>
<a id='n3672' href='#n3672'>3672</a>
<a id='n3673' href='#n3673'>3673</a>
<a id='n3674' href='#n3674'>3674</a>
<a id='n3675' href='#n3675'>3675</a>
<a id='n3676' href='#n3676'>3676</a>
<a id='n3677' href='#n3677'>3677</a>
<a id='n3678' href='#n3678'>3678</a>
<a id='n3679' href='#n3679'>3679</a>
<a id='n3680' href='#n3680'>3680</a>
<a id='n3681' href='#n3681'>3681</a>
<a id='n3682' href='#n3682'>3682</a>
<a id='n3683' href='#n3683'>3683</a>
<a id='n3684' href='#n3684'>3684</a>
<a id='n3685' href='#n3685'>3685</a>
<a id='n3686' href='#n3686'>3686</a>
<a id='n3687' href='#n3687'>3687</a>
<a id='n3688' href='#n3688'>3688</a>
<a id='n3689' href='#n3689'>3689</a>
<a id='n3690' href='#n3690'>3690</a>
<a id='n3691' href='#n3691'>3691</a>
<a id='n3692' href='#n3692'>3692</a>
<a id='n3693' href='#n3693'>3693</a>
<a id='n3694' href='#n3694'>3694</a>
<a id='n3695' href='#n3695'>3695</a>
<a id='n3696' href='#n3696'>3696</a>
<a id='n3697' href='#n3697'>3697</a>
<a id='n3698' href='#n3698'>3698</a>
<a id='n3699' href='#n3699'>3699</a>
<a id='n3700' href='#n3700'>3700</a>
<a id='n3701' href='#n3701'>3701</a>
<a id='n3702' href='#n3702'>3702</a>
<a id='n3703' href='#n3703'>3703</a>
<a id='n3704' href='#n3704'>3704</a>
<a id='n3705' href='#n3705'>3705</a>
<a id='n3706' href='#n3706'>3706</a>
<a id='n3707' href='#n3707'>3707</a>
<a id='n3708' href='#n3708'>3708</a>
<a id='n3709' href='#n3709'>3709</a>
<a id='n3710' href='#n3710'>3710</a>
<a id='n3711' href='#n3711'>3711</a>
<a id='n3712' href='#n3712'>3712</a>
<a id='n3713' href='#n3713'>3713</a>
<a id='n3714' href='#n3714'>3714</a>
<a id='n3715' href='#n3715'>3715</a>
<a id='n3716' href='#n3716'>3716</a>
<a id='n3717' href='#n3717'>3717</a>
<a id='n3718' href='#n3718'>3718</a>
<a id='n3719' href='#n3719'>3719</a>
<a id='n3720' href='#n3720'>3720</a>
<a id='n3721' href='#n3721'>3721</a>
<a id='n3722' href='#n3722'>3722</a>
<a id='n3723' href='#n3723'>3723</a>
<a id='n3724' href='#n3724'>3724</a>
<a id='n3725' href='#n3725'>3725</a>
<a id='n3726' href='#n3726'>3726</a>
<a id='n3727' href='#n3727'>3727</a>
<a id='n3728' href='#n3728'>3728</a>
<a id='n3729' href='#n3729'>3729</a>
<a id='n3730' href='#n3730'>3730</a>
<a id='n3731' href='#n3731'>3731</a>
<a id='n3732' href='#n3732'>3732</a>
<a id='n3733' href='#n3733'>3733</a>
<a id='n3734' href='#n3734'>3734</a>
<a id='n3735' href='#n3735'>3735</a>
<a id='n3736' href='#n3736'>3736</a>
<a id='n3737' href='#n3737'>3737</a>
<a id='n3738' href='#n3738'>3738</a>
<a id='n3739' href='#n3739'>3739</a>
<a id='n3740' href='#n3740'>3740</a>
<a id='n3741' href='#n3741'>3741</a>
<a id='n3742' href='#n3742'>3742</a>
<a id='n3743' href='#n3743'>3743</a>
<a id='n3744' href='#n3744'>3744</a>
<a id='n3745' href='#n3745'>3745</a>
<a id='n3746' href='#n3746'>3746</a>
<a id='n3747' href='#n3747'>3747</a>
<a id='n3748' href='#n3748'>3748</a>
<a id='n3749' href='#n3749'>3749</a>
<a id='n3750' href='#n3750'>3750</a>
<a id='n3751' href='#n3751'>3751</a>
<a id='n3752' href='#n3752'>3752</a>
<a id='n3753' href='#n3753'>3753</a>
<a id='n3754' href='#n3754'>3754</a>
<a id='n3755' href='#n3755'>3755</a>
<a id='n3756' href='#n3756'>3756</a>
<a id='n3757' href='#n3757'>3757</a>
<a id='n3758' href='#n3758'>3758</a>
<a id='n3759' href='#n3759'>3759</a>
<a id='n3760' href='#n3760'>3760</a>
<a id='n3761' href='#n3761'>3761</a>
<a id='n3762' href='#n3762'>3762</a>
<a id='n3763' href='#n3763'>3763</a>
<a id='n3764' href='#n3764'>3764</a>
<a id='n3765' href='#n3765'>3765</a>
<a id='n3766' href='#n3766'>3766</a>
<a id='n3767' href='#n3767'>3767</a>
<a id='n3768' href='#n3768'>3768</a>
<a id='n3769' href='#n3769'>3769</a>
<a id='n3770' href='#n3770'>3770</a>
<a id='n3771' href='#n3771'>3771</a>
<a id='n3772' href='#n3772'>3772</a>
<a id='n3773' href='#n3773'>3773</a>
<a id='n3774' href='#n3774'>3774</a>
<a id='n3775' href='#n3775'>3775</a>
<a id='n3776' href='#n3776'>3776</a>
<a id='n3777' href='#n3777'>3777</a>
<a id='n3778' href='#n3778'>3778</a>
<a id='n3779' href='#n3779'>3779</a>
<a id='n3780' href='#n3780'>3780</a>
<a id='n3781' href='#n3781'>3781</a>
<a id='n3782' href='#n3782'>3782</a>
<a id='n3783' href='#n3783'>3783</a>
<a id='n3784' href='#n3784'>3784</a>
<a id='n3785' href='#n3785'>3785</a>
<a id='n3786' href='#n3786'>3786</a>
<a id='n3787' href='#n3787'>3787</a>
<a id='n3788' href='#n3788'>3788</a>
<a id='n3789' href='#n3789'>3789</a>
<a id='n3790' href='#n3790'>3790</a>
<a id='n3791' href='#n3791'>3791</a>
<a id='n3792' href='#n3792'>3792</a>
<a id='n3793' href='#n3793'>3793</a>
<a id='n3794' href='#n3794'>3794</a>
<a id='n3795' href='#n3795'>3795</a>
<a id='n3796' href='#n3796'>3796</a>
<a id='n3797' href='#n3797'>3797</a>
<a id='n3798' href='#n3798'>3798</a>
<a id='n3799' href='#n3799'>3799</a>
<a id='n3800' href='#n3800'>3800</a>
<a id='n3801' href='#n3801'>3801</a>
<a id='n3802' href='#n3802'>3802</a>
<a id='n3803' href='#n3803'>3803</a>
<a id='n3804' href='#n3804'>3804</a>
<a id='n3805' href='#n3805'>3805</a>
<a id='n3806' href='#n3806'>3806</a>
<a id='n3807' href='#n3807'>3807</a>
<a id='n3808' href='#n3808'>3808</a>
<a id='n3809' href='#n3809'>3809</a>
<a id='n3810' href='#n3810'>3810</a>
<a id='n3811' href='#n3811'>3811</a>
<a id='n3812' href='#n3812'>3812</a>
<a id='n3813' href='#n3813'>3813</a>
<a id='n3814' href='#n3814'>3814</a>
<a id='n3815' href='#n3815'>3815</a>
<a id='n3816' href='#n3816'>3816</a>
<a id='n3817' href='#n3817'>3817</a>
<a id='n3818' href='#n3818'>3818</a>
<a id='n3819' href='#n3819'>3819</a>
<a id='n3820' href='#n3820'>3820</a>
<a id='n3821' href='#n3821'>3821</a>
<a id='n3822' href='#n3822'>3822</a>
<a id='n3823' href='#n3823'>3823</a>
<a id='n3824' href='#n3824'>3824</a>
<a id='n3825' href='#n3825'>3825</a>
<a id='n3826' href='#n3826'>3826</a>
<a id='n3827' href='#n3827'>3827</a>
<a id='n3828' href='#n3828'>3828</a>
<a id='n3829' href='#n3829'>3829</a>
<a id='n3830' href='#n3830'>3830</a>
<a id='n3831' href='#n3831'>3831</a>
<a id='n3832' href='#n3832'>3832</a>
<a id='n3833' href='#n3833'>3833</a>
<a id='n3834' href='#n3834'>3834</a>
<a id='n3835' href='#n3835'>3835</a>
<a id='n3836' href='#n3836'>3836</a>
<a id='n3837' href='#n3837'>3837</a>
<a id='n3838' href='#n3838'>3838</a>
<a id='n3839' href='#n3839'>3839</a>
<a id='n3840' href='#n3840'>3840</a>
<a id='n3841' href='#n3841'>3841</a>
<a id='n3842' href='#n3842'>3842</a>
<a id='n3843' href='#n3843'>3843</a>
<a id='n3844' href='#n3844'>3844</a>
<a id='n3845' href='#n3845'>3845</a>
<a id='n3846' href='#n3846'>3846</a>
<a id='n3847' href='#n3847'>3847</a>
<a id='n3848' href='#n3848'>3848</a>
<a id='n3849' href='#n3849'>3849</a>
<a id='n3850' href='#n3850'>3850</a>
<a id='n3851' href='#n3851'>3851</a>
<a id='n3852' href='#n3852'>3852</a>
<a id='n3853' href='#n3853'>3853</a>
<a id='n3854' href='#n3854'>3854</a>
<a id='n3855' href='#n3855'>3855</a>
<a id='n3856' href='#n3856'>3856</a>
<a id='n3857' href='#n3857'>3857</a>
<a id='n3858' href='#n3858'>3858</a>
<a id='n3859' href='#n3859'>3859</a>
<a id='n3860' href='#n3860'>3860</a>
<a id='n3861' href='#n3861'>3861</a>
<a id='n3862' href='#n3862'>3862</a>
<a id='n3863' href='#n3863'>3863</a>
<a id='n3864' href='#n3864'>3864</a>
<a id='n3865' href='#n3865'>3865</a>
<a id='n3866' href='#n3866'>3866</a>
<a id='n3867' href='#n3867'>3867</a>
<a id='n3868' href='#n3868'>3868</a>
<a id='n3869' href='#n3869'>3869</a>
<a id='n3870' href='#n3870'>3870</a>
<a id='n3871' href='#n3871'>3871</a>
<a id='n3872' href='#n3872'>3872</a>
<a id='n3873' href='#n3873'>3873</a>
<a id='n3874' href='#n3874'>3874</a>
<a id='n3875' href='#n3875'>3875</a>
<a id='n3876' href='#n3876'>3876</a>
<a id='n3877' href='#n3877'>3877</a>
<a id='n3878' href='#n3878'>3878</a>
<a id='n3879' href='#n3879'>3879</a>
<a id='n3880' href='#n3880'>3880</a>
<a id='n3881' href='#n3881'>3881</a>
<a id='n3882' href='#n3882'>3882</a>
<a id='n3883' href='#n3883'>3883</a>
<a id='n3884' href='#n3884'>3884</a>
<a id='n3885' href='#n3885'>3885</a>
<a id='n3886' href='#n3886'>3886</a>
<a id='n3887' href='#n3887'>3887</a>
<a id='n3888' href='#n3888'>3888</a>
<a id='n3889' href='#n3889'>3889</a>
<a id='n3890' href='#n3890'>3890</a>
<a id='n3891' href='#n3891'>3891</a>
<a id='n3892' href='#n3892'>3892</a>
<a id='n3893' href='#n3893'>3893</a>
<a id='n3894' href='#n3894'>3894</a>
<a id='n3895' href='#n3895'>3895</a>
<a id='n3896' href='#n3896'>3896</a>
<a id='n3897' href='#n3897'>3897</a>
<a id='n3898' href='#n3898'>3898</a>
<a id='n3899' href='#n3899'>3899</a>
<a id='n3900' href='#n3900'>3900</a>
<a id='n3901' href='#n3901'>3901</a>
<a id='n3902' href='#n3902'>3902</a>
<a id='n3903' href='#n3903'>3903</a>
<a id='n3904' href='#n3904'>3904</a>
<a id='n3905' href='#n3905'>3905</a>
<a id='n3906' href='#n3906'>3906</a>
<a id='n3907' href='#n3907'>3907</a>
<a id='n3908' href='#n3908'>3908</a>
<a id='n3909' href='#n3909'>3909</a>
<a id='n3910' href='#n3910'>3910</a>
<a id='n3911' href='#n3911'>3911</a>
<a id='n3912' href='#n3912'>3912</a>
<a id='n3913' href='#n3913'>3913</a>
<a id='n3914' href='#n3914'>3914</a>
<a id='n3915' href='#n3915'>3915</a>
<a id='n3916' href='#n3916'>3916</a>
<a id='n3917' href='#n3917'>3917</a>
<a id='n3918' href='#n3918'>3918</a>
<a id='n3919' href='#n3919'>3919</a>
<a id='n3920' href='#n3920'>3920</a>
<a id='n3921' href='#n3921'>3921</a>
<a id='n3922' href='#n3922'>3922</a>
<a id='n3923' href='#n3923'>3923</a>
<a id='n3924' href='#n3924'>3924</a>
<a id='n3925' href='#n3925'>3925</a>
<a id='n3926' href='#n3926'>3926</a>
<a id='n3927' href='#n3927'>3927</a>
<a id='n3928' href='#n3928'>3928</a>
<a id='n3929' href='#n3929'>3929</a>
<a id='n3930' href='#n3930'>3930</a>
<a id='n3931' href='#n3931'>3931</a>
<a id='n3932' href='#n3932'>3932</a>
<a id='n3933' href='#n3933'>3933</a>
<a id='n3934' href='#n3934'>3934</a>
<a id='n3935' href='#n3935'>3935</a>
<a id='n3936' href='#n3936'>3936</a>
<a id='n3937' href='#n3937'>3937</a>
<a id='n3938' href='#n3938'>3938</a>
<a id='n3939' href='#n3939'>3939</a>
<a id='n3940' href='#n3940'>3940</a>
<a id='n3941' href='#n3941'>3941</a>
<a id='n3942' href='#n3942'>3942</a>
<a id='n3943' href='#n3943'>3943</a>
<a id='n3944' href='#n3944'>3944</a>
<a id='n3945' href='#n3945'>3945</a>
<a id='n3946' href='#n3946'>3946</a>
<a id='n3947' href='#n3947'>3947</a>
<a id='n3948' href='#n3948'>3948</a>
<a id='n3949' href='#n3949'>3949</a>
<a id='n3950' href='#n3950'>3950</a>
<a id='n3951' href='#n3951'>3951</a>
<a id='n3952' href='#n3952'>3952</a>
<a id='n3953' href='#n3953'>3953</a>
<a id='n3954' href='#n3954'>3954</a>
<a id='n3955' href='#n3955'>3955</a>
<a id='n3956' href='#n3956'>3956</a>
<a id='n3957' href='#n3957'>3957</a>
<a id='n3958' href='#n3958'>3958</a>
<a id='n3959' href='#n3959'>3959</a>
<a id='n3960' href='#n3960'>3960</a>
<a id='n3961' href='#n3961'>3961</a>
<a id='n3962' href='#n3962'>3962</a>
<a id='n3963' href='#n3963'>3963</a>
<a id='n3964' href='#n3964'>3964</a>
<a id='n3965' href='#n3965'>3965</a>
<a id='n3966' href='#n3966'>3966</a>
<a id='n3967' href='#n3967'>3967</a>
<a id='n3968' href='#n3968'>3968</a>
<a id='n3969' href='#n3969'>3969</a>
<a id='n3970' href='#n3970'>3970</a>
<a id='n3971' href='#n3971'>3971</a>
<a id='n3972' href='#n3972'>3972</a>
<a id='n3973' href='#n3973'>3973</a>
<a id='n3974' href='#n3974'>3974</a>
<a id='n3975' href='#n3975'>3975</a>
<a id='n3976' href='#n3976'>3976</a>
<a id='n3977' href='#n3977'>3977</a>
<a id='n3978' href='#n3978'>3978</a>
<a id='n3979' href='#n3979'>3979</a>
<a id='n3980' href='#n3980'>3980</a>
<a id='n3981' href='#n3981'>3981</a>
<a id='n3982' href='#n3982'>3982</a>
<a id='n3983' href='#n3983'>3983</a>
<a id='n3984' href='#n3984'>3984</a>
<a id='n3985' href='#n3985'>3985</a>
<a id='n3986' href='#n3986'>3986</a>
<a id='n3987' href='#n3987'>3987</a>
<a id='n3988' href='#n3988'>3988</a>
<a id='n3989' href='#n3989'>3989</a>
<a id='n3990' href='#n3990'>3990</a>
<a id='n3991' href='#n3991'>3991</a>
<a id='n3992' href='#n3992'>3992</a>
<a id='n3993' href='#n3993'>3993</a>
<a id='n3994' href='#n3994'>3994</a>
<a id='n3995' href='#n3995'>3995</a>
<a id='n3996' href='#n3996'>3996</a>
<a id='n3997' href='#n3997'>3997</a>
<a id='n3998' href='#n3998'>3998</a>
<a id='n3999' href='#n3999'>3999</a>
<a id='n4000' href='#n4000'>4000</a>
<a id='n4001' href='#n4001'>4001</a>
<a id='n4002' href='#n4002'>4002</a>
<a id='n4003' href='#n4003'>4003</a>
<a id='n4004' href='#n4004'>4004</a>
<a id='n4005' href='#n4005'>4005</a>
<a id='n4006' href='#n4006'>4006</a>
<a id='n4007' href='#n4007'>4007</a>
<a id='n4008' href='#n4008'>4008</a>
<a id='n4009' href='#n4009'>4009</a>
<a id='n4010' href='#n4010'>4010</a>
<a id='n4011' href='#n4011'>4011</a>
<a id='n4012' href='#n4012'>4012</a>
<a id='n4013' href='#n4013'>4013</a>
<a id='n4014' href='#n4014'>4014</a>
<a id='n4015' href='#n4015'>4015</a>
<a id='n4016' href='#n4016'>4016</a>
<a id='n4017' href='#n4017'>4017</a>
<a id='n4018' href='#n4018'>4018</a>
<a id='n4019' href='#n4019'>4019</a>
<a id='n4020' href='#n4020'>4020</a>
<a id='n4021' href='#n4021'>4021</a>
<a id='n4022' href='#n4022'>4022</a>
<a id='n4023' href='#n4023'>4023</a>
<a id='n4024' href='#n4024'>4024</a>
<a id='n4025' href='#n4025'>4025</a>
<a id='n4026' href='#n4026'>4026</a>
<a id='n4027' href='#n4027'>4027</a>
<a id='n4028' href='#n4028'>4028</a>
<a id='n4029' href='#n4029'>4029</a>
<a id='n4030' href='#n4030'>4030</a>
<a id='n4031' href='#n4031'>4031</a>
<a id='n4032' href='#n4032'>4032</a>
<a id='n4033' href='#n4033'>4033</a>
<a id='n4034' href='#n4034'>4034</a>
<a id='n4035' href='#n4035'>4035</a>
<a id='n4036' href='#n4036'>4036</a>
<a id='n4037' href='#n4037'>4037</a>
<a id='n4038' href='#n4038'>4038</a>
<a id='n4039' href='#n4039'>4039</a>
<a id='n4040' href='#n4040'>4040</a>
<a id='n4041' href='#n4041'>4041</a>
<a id='n4042' href='#n4042'>4042</a>
<a id='n4043' href='#n4043'>4043</a>
<a id='n4044' href='#n4044'>4044</a>
<a id='n4045' href='#n4045'>4045</a>
<a id='n4046' href='#n4046'>4046</a>
<a id='n4047' href='#n4047'>4047</a>
<a id='n4048' href='#n4048'>4048</a>
<a id='n4049' href='#n4049'>4049</a>
<a id='n4050' href='#n4050'>4050</a>
<a id='n4051' href='#n4051'>4051</a>
<a id='n4052' href='#n4052'>4052</a>
<a id='n4053' href='#n4053'>4053</a>
<a id='n4054' href='#n4054'>4054</a>
<a id='n4055' href='#n4055'>4055</a>
<a id='n4056' href='#n4056'>4056</a>
<a id='n4057' href='#n4057'>4057</a>
<a id='n4058' href='#n4058'>4058</a>
<a id='n4059' href='#n4059'>4059</a>
<a id='n4060' href='#n4060'>4060</a>
<a id='n4061' href='#n4061'>4061</a>
<a id='n4062' href='#n4062'>4062</a>
<a id='n4063' href='#n4063'>4063</a>
<a id='n4064' href='#n4064'>4064</a>
<a id='n4065' href='#n4065'>4065</a>
<a id='n4066' href='#n4066'>4066</a>
<a id='n4067' href='#n4067'>4067</a>
<a id='n4068' href='#n4068'>4068</a>
<a id='n4069' href='#n4069'>4069</a>
<a id='n4070' href='#n4070'>4070</a>
<a id='n4071' href='#n4071'>4071</a>
<a id='n4072' href='#n4072'>4072</a>
<a id='n4073' href='#n4073'>4073</a>
<a id='n4074' href='#n4074'>4074</a>
<a id='n4075' href='#n4075'>4075</a>
<a id='n4076' href='#n4076'>4076</a>
<a id='n4077' href='#n4077'>4077</a>
<a id='n4078' href='#n4078'>4078</a>
<a id='n4079' href='#n4079'>4079</a>
<a id='n4080' href='#n4080'>4080</a>
<a id='n4081' href='#n4081'>4081</a>
<a id='n4082' href='#n4082'>4082</a>
<a id='n4083' href='#n4083'>4083</a>
<a id='n4084' href='#n4084'>4084</a>
<a id='n4085' href='#n4085'>4085</a>
<a id='n4086' href='#n4086'>4086</a>
<a id='n4087' href='#n4087'>4087</a>
<a id='n4088' href='#n4088'>4088</a>
<a id='n4089' href='#n4089'>4089</a>
<a id='n4090' href='#n4090'>4090</a>
<a id='n4091' href='#n4091'>4091</a>
<a id='n4092' href='#n4092'>4092</a>
<a id='n4093' href='#n4093'>4093</a>
<a id='n4094' href='#n4094'>4094</a>
<a id='n4095' href='#n4095'>4095</a>
<a id='n4096' href='#n4096'>4096</a>
<a id='n4097' href='#n4097'>4097</a>
<a id='n4098' href='#n4098'>4098</a>
<a id='n4099' href='#n4099'>4099</a>
<a id='n4100' href='#n4100'>4100</a>
<a id='n4101' href='#n4101'>4101</a>
<a id='n4102' href='#n4102'>4102</a>
<a id='n4103' href='#n4103'>4103</a>
<a id='n4104' href='#n4104'>4104</a>
<a id='n4105' href='#n4105'>4105</a>
<a id='n4106' href='#n4106'>4106</a>
<a id='n4107' href='#n4107'>4107</a>
<a id='n4108' href='#n4108'>4108</a>
<a id='n4109' href='#n4109'>4109</a>
<a id='n4110' href='#n4110'>4110</a>
<a id='n4111' href='#n4111'>4111</a>
<a id='n4112' href='#n4112'>4112</a>
<a id='n4113' href='#n4113'>4113</a>
<a id='n4114' href='#n4114'>4114</a>
<a id='n4115' href='#n4115'>4115</a>
<a id='n4116' href='#n4116'>4116</a>
<a id='n4117' href='#n4117'>4117</a>
<a id='n4118' href='#n4118'>4118</a>
<a id='n4119' href='#n4119'>4119</a>
<a id='n4120' href='#n4120'>4120</a>
<a id='n4121' href='#n4121'>4121</a>
<a id='n4122' href='#n4122'>4122</a>
<a id='n4123' href='#n4123'>4123</a>
<a id='n4124' href='#n4124'>4124</a>
<a id='n4125' href='#n4125'>4125</a>
<a id='n4126' href='#n4126'>4126</a>
<a id='n4127' href='#n4127'>4127</a>
<a id='n4128' href='#n4128'>4128</a>
<a id='n4129' href='#n4129'>4129</a>
<a id='n4130' href='#n4130'>4130</a>
<a id='n4131' href='#n4131'>4131</a>
<a id='n4132' href='#n4132'>4132</a>
<a id='n4133' href='#n4133'>4133</a>
<a id='n4134' href='#n4134'>4134</a>
<a id='n4135' href='#n4135'>4135</a>
<a id='n4136' href='#n4136'>4136</a>
<a id='n4137' href='#n4137'>4137</a>
<a id='n4138' href='#n4138'>4138</a>
<a id='n4139' href='#n4139'>4139</a>
<a id='n4140' href='#n4140'>4140</a>
<a id='n4141' href='#n4141'>4141</a>
<a id='n4142' href='#n4142'>4142</a>
<a id='n4143' href='#n4143'>4143</a>
<a id='n4144' href='#n4144'>4144</a>
<a id='n4145' href='#n4145'>4145</a>
<a id='n4146' href='#n4146'>4146</a>
<a id='n4147' href='#n4147'>4147</a>
<a id='n4148' href='#n4148'>4148</a>
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</pre></td>
<td class='lines'><pre><code><span class="hl kwa">\chapter</span><span class="hl opt">{</span>Basic Facilities of a Virtio Device<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device<span class="hl opt">}</span>

A virtio device is discovered and identified by a bus-specific method
(see the bus specific sections: <span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over PCI Bus<span class="hl opt">}</span>~<span class="hl kwa">\nameref</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over PCI Bus<span class="hl opt">}</span>,
<span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over MMIO<span class="hl opt">}</span>~<span class="hl kwa">\nameref</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over MMIO<span class="hl opt">}</span> and <span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over Channel I/O<span class="hl opt">}</span>~<span class="hl kwa">\nameref</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over Channel I/O<span class="hl opt">}</span>).  Each
device consists of the following parts:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>
<span class="hl kwa">\item</span> Device status field
<span class="hl kwa">\item</span> Feature bits
<span class="hl kwa">\item</span> Device Configuration space
<span class="hl kwa">\item</span> One or more virtqueues
<span class="hl kwa">\end</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>

<span class="hl kwa">\section</span><span class="hl opt">{</span><span class="hl kwa">\field</span><span class="hl opt">{</span>Device Status<span class="hl opt">}</span> Field<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Device Status Field<span class="hl opt">}</span>

The driver MUST update the <span class="hl kwa">\field</span><span class="hl opt">{</span>device status<span class="hl opt">}</span> field in the order below to
indicate its progress. This provides a simple low-level diagnostic:
it&apos;s most useful to imagine them hooked up to traffic lights on the
console indicating the status of each device.  The driver MUST NOT
clear a <span class="hl kwa">\field</span><span class="hl opt">{</span>device status<span class="hl opt">}</span> bit.

<span class="hl kwa">\field</span><span class="hl opt">{</span>device status<span class="hl opt">}</span> is <span class="hl num">0</span> upon reset, otherwise at least one bit should be set:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>description<span class="hl opt">}</span>
<span class="hl kwa">\item</span><span class="hl opt">[</span>ACKNOWLEDGE (<span class="hl num">1</span>)<span class="hl opt">]</span> Indicates that the guest OS has found the
  device and recognized it as a valid virtio device.

<span class="hl kwa">\item</span><span class="hl opt">[</span>DRIVER (<span class="hl num">2</span>)<span class="hl opt">]</span> Indicates that the guest OS knows how to drive the
  device. Under Linux, drivers can be loadable modules so there
  may be a significant (or infinite) delay before setting this
  bit.

<span class="hl kwa">\item</span><span class="hl opt">[</span>FEATURES_OK (<span class="hl num">8</span>)<span class="hl opt">]</span> Indicates that the driver has acknowledged all the
  features it understands, and feature negotiation is complete.

<span class="hl kwa">\item</span><span class="hl opt">[</span>DRIVER_OK (<span class="hl num">4</span>)<span class="hl opt">]</span> Indicates that the driver is set up and ready to
  drive the device.

<span class="hl kwa">\item</span><span class="hl opt">[</span>FAILED (<span class="hl num">128</span>)<span class="hl opt">]</span> Indicates that something went wrong in the guest,
  and it has given up on the device. This could be an internal
  error, or the driver didn&apos;t like the device for some reason, or
  even a fatal error during device operation. The driver MUST
  reset the device before attempting to re-initialize.
<span class="hl kwa">\end</span><span class="hl opt">{</span>description<span class="hl opt">}</span>

<span class="hl kwa">\section</span><span class="hl opt">{</span>Feature Bits<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Feature Bits<span class="hl opt">}</span>

Each virtio device offers all the features it understands.  During
device initialization, the driver reads this and tells the device the
subset that it accepts.  The only way to renegotiate is to reset
the device.

This allows for forwards and backwards compatibility: if the device is
enhanced with a new feature bit, older drivers will not write that
feature bit back to the device and it SHOULD go into backwards
compatibility mode. Similarly, if a driver is enhanced with a feature
that the device doesn&apos;t support, it see the new feature is not offered
and SHOULD go into backwards compatibility mode (or, for poor
implementations it MAY set the FAILED Device Status bit).

The driver MUST NOT accept a feature which the device did not offer,
and MUST NOT accept a feature which requires another feature which was
not accepted.

The device MUST NOT offer a feature which requires another feature
which was not offered.

Feature bits are allocated as follows:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>description<span class="hl opt">}</span>
<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl num">0</span> to <span class="hl num">23</span><span class="hl opt">]</span> Feature bits for the specific device type

<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl num">24</span> to <span class="hl num">32</span><span class="hl opt">]</span> Feature bits reserved for extensions to the queue and
  feature negotiation mechanisms

<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl num">33</span> and above<span class="hl opt">]</span> Feature bits reserved for future extensions.
<span class="hl kwa">\end</span><span class="hl opt">{</span>description<span class="hl opt">}</span>

For example, feature bit <span class="hl num">0</span> for a network device (i.e. Subsystem
Device ID <span class="hl num">1</span>) indicates that the device supports checksumming of
packets.

In particular, new fields in the device configuration space are
indicated by offering a feature bit, so the driver MUST check that the
feature is offered before accessing that part of the configuration
space.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Legacy Interface: A Note on transitions from earlier drafts<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Feature Bits / Legacy Interface: A Note on transitions from earlier drafts<span class="hl opt">}</span>

Earlier drafts of this specification (up to <span class="hl num">0.9</span>.X) defined a similar, but
different interface between the hypervisor and the guest.
Since these are widely deployed, this specification
accommodates optional features to simplify transition
from these earlier draft interfaces. Specifically:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>description<span class="hl opt">}</span>
<span class="hl kwa">\item</span><span class="hl opt">[</span>Legacy Interface<span class="hl opt">]</span>
        is an interface specified by an earlier draft of this specification
        (up to <span class="hl num">0.9</span>.X)
<span class="hl kwa">\item</span><span class="hl opt">[</span>Legacy Device<span class="hl opt">]</span>
        is a device implemented before this specification was released,
        and implementing a legacy interface on the host side
<span class="hl kwa">\item</span><span class="hl opt">[</span>Legacy Driver<span class="hl opt">]</span>
        is a driver implemented before this specification was released,
        and implementing a legacy interface on the guest side
<span class="hl kwa">\end</span><span class="hl opt">{</span>description<span class="hl opt">}</span>

Legacy devices and legacy drivers are not compliant with this
specification.

To simplify transition from these earlier draft interfaces,
it is possible to implement:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>description<span class="hl opt">}</span>
<span class="hl kwa">\item</span><span class="hl opt">[</span>Transitional Device<span class="hl opt">]</span>
        a device supporting both drivers conforming to this
        specification, and allowing legacy drivers.

<span class="hl kwa">\item</span><span class="hl opt">[</span>Transitional Driver<span class="hl opt">]</span>
        a driver supporting both devices conforming to this
        specification, and legacy devices.
<span class="hl kwa">\end</span><span class="hl opt">{</span>description<span class="hl opt">}</span>

Transitional devices and transitional drivers can be compliant with
this specification (ie. when not operating in legacy mode).

Devices or drivers with no legacy compatibility are referred to as
non-transitional devices and drivers, respectively.

Transitional Drivers can detect Legacy Devices by detecting that
the feature bit VIRTIO_F_VERSION_1 is not offered.
Transitional devices can detect Legacy drivers by detecting that
VIRTIO_F_VERSION_1 has not been acknowledged by the driver.
In this case device is used through the legacy interface.

To make them easier to locate, specification sections documenting
these transitional features are explicitly marked with &apos;Legacy
Interface&apos; in the section title.

<span class="hl kwa">\section</span><span class="hl opt">{</span>Device Configuration Space<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Device Configuration Space<span class="hl opt">}</span>

Device configuration space is generally used for rarely-changing or
initialization-time parameters.  Drivers MUST NOT assume reads from
fields greater than <span class="hl num">32</span> bits wide are atomic, nor reads from
multiple fields.

Each transport provides a generation count for the device configuration
space, which must change whenever there is a possibility that two
accesses to the device configuration space can see different versions of that
space.

Thus drivers SHOULD read device configuration space fields like so:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
u32 before, after;
do <span class="hl opt">{</span>
        before = get_config_generation(device);
        // read config entry/entries.
        after = get_config_generation(device);
<span class="hl opt">}</span> while (after != before);
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

Note that device configuration space uses the little-endian format
for multi-byte fields.

Note that future versions of this specification will likely
extend the device configuration space for devices by adding extra fields
at the tail end of some structures in device configuration space.

To allow forward compatibility with such extensions, drivers MUST
NOT limit structure size and device configuration space size.  Instead,
drivers SHOULD only check that device configuration space is *large enough* to
contain the fields required for device operation.

For example, if the specification states that device configuration
space &apos;includes a single <span class="hl num">8</span>-bit field&apos; drivers should understand this to mean that
the device configuration space might also include an arbitrary amount of
tail padding, and accept any device configuration space size equal to or
greater than the specified <span class="hl num">8</span>-bit size.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Legacy Interface: A Note on Device Configuration Space endian-ness<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Device Configuration Space / Legacy Interface: A Note on Configuration Space endian-ness<span class="hl opt">}</span>

Note that for legacy interfaces, device configuration space is generally the
guest&apos;s native endian, rather than PCI&apos;s little-endian.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Legacy Interface: Device Configuration Space<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Device Configuration Space / Legacy Interface: Device Configuration Space<span class="hl opt">}</span>

Legacy devices did not have a configuration generation field, thus are
susceptible to race conditions if configuration is updated.  This
effects the block capacity and network mac fields; best practice is to
read these fields multiple times until two reads generate a consistent
result.

<span class="hl kwa">\section</span><span class="hl opt">{</span>Virtqueues<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Virtqueues<span class="hl opt">}</span>

The mechanism for bulk data transport on virtio devices is
pretentiously called a virtqueue. Each device can have zero or more
virtqueues: for example, the simplest network device has one for
transmit and one for receive.  Each queue has a <span class="hl num">16</span>-bit queue size
parameter, which sets the number of entries and implies the total size
of the queue.

Each virtqueue consists of three parts:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>
<span class="hl kwa">\item</span> Descriptor Table
<span class="hl kwa">\item</span> Available Ring
<span class="hl kwa">\item</span> Used Ring
<span class="hl kwa">\end</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>

where each part is physically-contiguous in guest memory,
and has different alignment requirements.

The memory aligment and size requirements, in bytes, of each part of the
virtqueue are summarized in the following table:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>tabular<span class="hl opt">}{</span>|l|l|l|<span class="hl opt">}</span>
<span class="hl kwa">\hline</span>
Virtqueue Part    &amp; Alignment &amp; Size \\
<span class="hl kwa">\hline \hline</span>
Descriptor Table  &amp; <span class="hl num">16</span>        &amp; $<span class="hl num">16</span> * $(Queue Size) \\
<span class="hl kwa">\hline</span>
Available Ring    &amp; <span class="hl num">2</span>         &amp; $<span class="hl num">6</span> + <span class="hl num">2</span> * $(Queue Size) \\
 <span class="hl kwa">\hline</span>
Used Ring         &amp; <span class="hl num">4</span>         &amp; $<span class="hl num">6</span> + <span class="hl num">4</span> * $(Queue Size) \\
 <span class="hl kwa">\hline</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>tabular<span class="hl opt">}</span>

The Alignment column gives the miminum alignment: for each part
of the virtqueue, the physical address of the first byte
MUST be a multiple of the specified alignment value.

The Size column gives the total number of bytes required for each
part of the virtqueue.

Queue Size corresponds to the maximum number of buffers in the
virtqueue.  For example, if Queue Size is <span class="hl num">4</span> then at most <span class="hl num">4</span> buffers
can be queued at any given time.  Queue Size value is always a
power of <span class="hl num">2</span>.  The maximum Queue Size value is <span class="hl num">32768</span>.  This value
is specified in a bus-specific way.

When the driver wants to send a buffer to the device, it fills in
a slot in the descriptor table (or chains several together), and
writes the descriptor index into the available ring.  It then
notifies the device. When the device has finished a buffer, it
writes the descriptor index into the used ring, and sends an interrupt.


<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Legacy Interfaces: A Note on Virtqueue Layout<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Virtqueues / Legacy Interfaces: A Note on Virtqueue Layout<span class="hl opt">}</span>

For Legacy Interfaces, several additional
restrictions are placed on the virtqueue layout:

Each virtqueue occupies two or more physically-contiguous pages
(usually defined as <span class="hl num">4096</span> bytes, but depending on the transport)
and consists of three parts:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>tabular<span class="hl opt">}{</span>|l|l|l|<span class="hl opt">}</span>
<span class="hl kwa">\hline</span>
Descriptor Table &amp; Available Ring (<span class="hl kwa">\ldots</span> padding<span class="hl kwa">\ldots</span>) &amp; Used Ring \\
<span class="hl kwa">\hline</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>tabular<span class="hl opt">}</span>

The bus-specific Queue Size field controls the total number of bytes
required for the virtqueue according to the following formula:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
#define ALIGN(x) (((x) + PAGE_SIZE) &amp; ~PAGE_SIZE)
static inline unsigned vring_size(unsigned int qsz)
<span class="hl opt">{</span>
     return ALIGN(sizeof(struct vring_desc)*qsz + sizeof(u16)*(<span class="hl num">3</span> + qsz))
          + ALIGN(sizeof(u16)*<span class="hl num">3</span> + sizeof(struct vring_used_elem)*qsz);
<span class="hl opt">}</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

This wastes some space with padding.
The legacy virtqueue layout structure therefore looks like this:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
struct vring <span class="hl opt">{</span>
        // The actual descriptors (<span class="hl num">16</span> bytes each)
        struct vring_desc desc<span class="hl opt">[</span> Queue Size <span class="hl opt">]</span>;

        // A ring of available descriptor heads with free-running index.
        struct vring_avail avail;

        // Padding to the next PAGE_SIZE boundary.
        u8 pad<span class="hl opt">[</span> Padding <span class="hl opt">]</span>;

        // A ring of used descriptor heads with free-running index.
        struct vring_used used;
<span class="hl opt">}</span>;
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Legacy Interfaces: A Note on Virtqueue Endianness<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Virtqueues / Legacy Interfaces: A Note on Virtqueue Endianness<span class="hl opt">}</span>

Note that the endian of fields and in the virtqueue is the native
endian of the guest, not little-endian as specified by this standard.
It is assumed that the host is already aware of the guest endian.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Message Framing<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Virtqueues / Message Framing<span class="hl opt">}</span>
The device MUST NOT make assumptions about the particular arrangement
of descriptors: the message framing is
independent of the contents of the buffers. For example, a network
transmit buffer consists of a <span class="hl num">12</span> byte header followed by the network
packet. This could be most simply placed in the descriptor table as a
<span class="hl num">12</span> byte output descriptor followed by a <span class="hl num">1514</span> byte output descriptor,
but it could also consist of a single <span class="hl num">1526</span> byte output descriptor in
the case where the header and packet are adjacent, or even three or
more descriptors (possibly with loss of efficiency in that case).

Note that, some implementations may have large-but-reasonable
restrictions on total descriptor size (such as based on IOV_MAX in the
host OS). This has not been a problem in practice: little sympathy
will be given to drivers which create unreasonably-sized descriptors
such as by dividing a network packet into <span class="hl num">1500</span> single-byte
descriptors!

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Legacy Interface: Message Framing<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Virtqueues / Message Framing / Legacy Interface: Message Framing<span class="hl opt">}</span>

Regrettably, initial driver implementations used simple layouts, and
devices came to rely on it, despite this specification wording.  In
addition, the specification for virtio_blk SCSI commands required
intuiting field lengths from frame boundaries (see
 <span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:Device Types / Block Device / Device Operation / Legacy Interface: Device Operation<span class="hl opt">}</span>~<span class="hl kwa">\nameref</span><span class="hl opt">{</span>sec:Device Types / Block Device / Device Operation / Legacy Interface: Device Operation<span class="hl opt">}</span>)

It is thus recommended that when using legacy interfaces, transitional
drivers be conservative in their assumptions, unless the
VIRTIO_F_ANY_LAYOUT feature is accepted.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>The Virtqueue Descriptor Table<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Virtqueues / The Virtqueue Descriptor Table<span class="hl opt">}</span>

The descriptor table refers to the buffers the driver is using for
the device. <span class="hl kwa">\field</span><span class="hl opt">{</span>addr<span class="hl opt">}</span> is a physical address, and the buffers
can be chained via <span class="hl kwa">\field</span><span class="hl opt">{</span>next<span class="hl opt">}</span>. Each descriptor describes a
buffer which is read-only for the device (``device-readable&apos;&apos;) or write-only for the device (``device-writable&apos;&apos;), but a chain of
descriptors can contain both device-readable and device-writable buffers.
A device MUST NOT write to a device-readable buffer, and a device SHOULD NOT
read a device-writable buffer (it might do so for debugging or diagnostic
purposes).

The actual contents of the memory offered to the device depends on the
device type.  Most common is to begin the data with a header
(containing little-endian fields) for the device to read, and postfix
it with a status tailer for the device to write.

Drivers MUST NOT add a descriptor chain over than $<span class="hl num">2</span>^<span class="hl opt">{</span><span class="hl num">32</span><span class="hl opt">}</span>$ bytes long in total;
this implies that loops in the descriptor chain are forbidden!

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
/* Note: LEGACY version was not little endian! */
struct vring_desc <span class="hl opt">{</span>
        /* Address (guest-physical). */
        le64 addr;
        /* Length. */
        le32 len;

/* This marks a buffer as continuing via the next field. */
#define VRING_DESC_F_NEXT   <span class="hl num">1</span>
/* This marks a buffer as device write-only (otherwise device read-only). */
#define VRING_DESC_F_WRITE     <span class="hl num">2</span>
/* This means the buffer contains a list of buffer descriptors. */
#define VRING_DESC_F_INDIRECT   <span class="hl num">4</span>
        /* The flags as indicated above. */
        le16 flags;
        /* Next field if flags &amp; NEXT */
        le16 next;
<span class="hl opt">}</span>;
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

The number of descriptors in the table is defined by the queue size
for this virtqueue.

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Indirect Descriptors<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Virtqueues / The Virtqueue Descriptor Table / Indirect Descriptors<span class="hl opt">}</span>

Some devices benefit by concurrently dispatching a large number
of large requests. The VIRTIO_RING_F_INDIRECT_DESC feature allows this (see <span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:virtio-ring.h<span class="hl opt">}</span>~<span class="hl kwa">\nameref</span><span class="hl opt">{</span>sec:virtio-ring.h<span class="hl opt">}</span>). To increase
ring capacity the driver can store a table of indirect
descriptors anywhere in memory, and insert a descriptor in main
virtqueue (with <span class="hl kwa">\field</span><span class="hl opt">{</span>flags<span class="hl opt">}</span>\&amp;VRING_DESC_F_INDIRECT on) that refers to memory buffer
containing this indirect descriptor table; <span class="hl kwa">\field</span><span class="hl opt">{</span>addr<span class="hl opt">}</span> and <span class="hl kwa">\field</span><span class="hl opt">{</span>len<span class="hl opt">}</span>
refer to the indirect table address and length in bytes,
respectively.

The driver MUST NOT set the VRING_DESC_F_INDIRECT flag unless the
VIRTIO_RING_F_INDIRECT_DESC feature was negotiated.

The indirect table layout structure looks like this
(<span class="hl kwa">\field</span><span class="hl opt">{</span>len<span class="hl opt">}</span> is the length of the descriptor that refers to this table,
which is a variable, so this code won&apos;t compile):

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
struct indirect_descriptor_table <span class="hl opt">{</span>
        /* The actual descriptors (<span class="hl num">16</span> bytes each) */
        struct vring_desc desc<span class="hl opt">[</span>len / <span class="hl num">16</span><span class="hl opt">]</span>;
<span class="hl opt">}</span>;
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

The first indirect descriptor is located at start of the indirect
descriptor table (index <span class="hl num">0</span>), additional indirect descriptors are
chained by <span class="hl kwa">\field</span><span class="hl opt">{</span>next<span class="hl opt">}</span>. An indirect descriptor without a valid <span class="hl kwa">\field</span><span class="hl opt">{</span>next<span class="hl opt">}</span>
(with <span class="hl kwa">\field</span><span class="hl opt">{</span>flags<span class="hl opt">}</span>\&amp;VRING_DESC_F_NEXT off) signals the end of the descriptor.
An
indirect descriptor can not refer to another indirect descriptor
table (<span class="hl kwa">\field</span><span class="hl opt">{</span>flags<span class="hl opt">}</span>\&amp;VRING_DESC_F_INDIRECT MUST be off). A single indirect descriptor
table can include both device-readable and device-writable descriptors;
the device MUST ignore the write-only flag (<span class="hl kwa">\field</span><span class="hl opt">{</span>flags<span class="hl opt">}</span>\&amp;VRING_DESC_F_WRITE) in the descriptor that refers to it.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>The Virtqueue Available Ring<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Virtqueues / The Virtqueue Available Ring<span class="hl opt">}</span>

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
/* Note: LEGACY version was not little endian! */
struct vring_avail <span class="hl opt">{</span>
#define VRING_AVAIL_F_NO_INTERRUPT      <span class="hl num">1</span>
        le16 flags;
        le16 idx;
        le16 ring<span class="hl opt">[</span> /* Queue Size */ <span class="hl opt">]</span>;
        le16 used_event; /* Only if VIRTIO_RING_F_EVENT_IDX */
<span class="hl opt">}</span>;
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

The driver uses the available ring to offer buffers to the
device: each ring entry refers to the head of a descriptor chain.  It is only
written by the driver and read by the device.

<span class="hl kwa">\field</span><span class="hl opt">{</span>idx<span class="hl opt">}</span> field indicates where the driver would put the next descriptor
entry in the ring (modulo the queue size). This starts at <span class="hl num">0</span>, and increases.

If the VIRTIO_RING_F_EVENT_IDX feature bit is not negotiated,
<span class="hl kwa">\field</span><span class="hl opt">{</span>flags<span class="hl opt">}</span> field offers a crude interrupt control mechanism.  The driver
MUST set this to <span class="hl num">0</span> or <span class="hl num">1</span>: <span class="hl num">1</span> indicates that the device SHOULD NOT send
an interrupt when it consumes a descriptor chain from the available
ring.  The device MUST ignore the <span class="hl kwa">\field</span><span class="hl opt">{</span>used_event<span class="hl opt">}</span> value in this case.

Otherwise, if the VIRTIO_RING_F_EVENT_IDX feature bit is negotiated,
the driver MUST set <span class="hl kwa">\field</span><span class="hl opt">{</span>flags<span class="hl opt">}</span> to <span class="hl num">0</span>, and use <span class="hl kwa">\field</span><span class="hl opt">{</span>used_event<span class="hl opt">}</span>
in the used ring instead.  The driver can ask the device to delay interrupts
until an entry with an index specified by <span class="hl kwa">\field</span><span class="hl opt">{</span>used_event<span class="hl opt">}</span> is
written in the used ring (equivalently, until <span class="hl kwa">\field</span><span class="hl opt">{</span>idx<span class="hl opt">}</span> in the
used ring will reach the value <span class="hl kwa">\field</span><span class="hl opt">{</span>used_event<span class="hl opt">}</span> + <span class="hl num">1</span>).

The driver MUST handle spurious interrupts: either form of interrupt
suppression is merely an optimization; it may not suppress interrupts
entirely.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>The Virtqueue Used Ring<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Virtqueues / The Virtqueue Used Ring<span class="hl opt">}</span>

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
/* Note: LEGACY version was not little endian! */
struct vring_used <span class="hl opt">{</span>
#define VRING_USED_F_NO_NOTIFY  <span class="hl num">1</span>
        le16 flags;
        le16 idx;
        struct vring_used_elem ring<span class="hl opt">[</span> /* Queue Size */<span class="hl opt">]</span>;
        le16 avail_event; /* Only if VIRTIO_RING_F_EVENT_IDX */
<span class="hl opt">}</span>;

/* Note: LEGACY version was not little endian! */
/* le32 is used here for ids for padding reasons. */
struct vring_used_elem <span class="hl opt">{</span>
        /* Index of start of used descriptor chain. */
        le32 id;
        /* Total length of the descriptor chain which was used (written to) */
        le32 len;
<span class="hl opt">}</span>;
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

The used ring is where the device returns buffers once it is done with
them: it is only written to by the device, and read by the driver.

Each entry in the ring is a pair: <span class="hl kwa">\field</span><span class="hl opt">{</span>id<span class="hl opt">}</span> indicates the head entry of the
descriptor chain describing the buffer (this matches an entry
placed in the available ring by the guest earlier), and <span class="hl kwa">\field</span><span class="hl opt">{</span>len<span class="hl opt">}</span> the total
of bytes written into the buffer. The latter is extremely useful
for drivers using untrusted buffers: if you do not know exactly
how much has been written by the device, you usually have to zero
the buffer to ensure no data leakage occurs.

If the VIRTIO_RING_F_EVENT_IDX feature bit is not negotiated,
<span class="hl kwa">\field</span><span class="hl opt">{</span>flags<span class="hl opt">}</span> offers a crude interrupt control mechanism.  The driver
MUST initialize this to <span class="hl num">0</span>, the device MUST set this to <span class="hl num">0</span> or <span class="hl num">1</span>: <span class="hl num">1</span>
indicates that the driver SHOULD NOT send an notification when it adds
a descriptor chain to the available ring.  The driver MUST ignore the
<span class="hl kwa">\field</span><span class="hl opt">{</span>used_event<span class="hl opt">}</span> value in this case.

Otherwise, if the VIRTIO_RING_F_EVENT_IDX feature bit is negotiated,
the device MUST leave <span class="hl kwa">\field</span><span class="hl opt">{</span>flags<span class="hl opt">}</span> at <span class="hl num">0</span>, and use
<span class="hl kwa">\field</span><span class="hl opt">{</span>avail_event<span class="hl opt">}</span> in the used ring instead.  The device can ask the
driver to delay notifications until an entry with an index specified
by <span class="hl kwa">\field</span><span class="hl opt">{</span>avail_event<span class="hl opt">}</span> is written in the available ring (equivalently,
until <span class="hl kwa">\field</span><span class="hl opt">{</span>idx<span class="hl opt">}</span> in the used ring will reach the value <span class="hl kwa">\field</span><span class="hl opt">{</span>avail_event<span class="hl opt">}</span> +
<span class="hl num">1</span>).

The device MUST handle spurious notification: either form of
notification suppression is merely an optimization; it may not
suppress them entirely.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Helpers for Operating Virtqueues<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Virtqueues / Helpers for Operating Virtqueues<span class="hl opt">}</span>

The Linux Kernel Source code contains the definitions above and
helper routines in a more usable form, in
include/linux/virtio_ring.h. This was explicitly licensed by IBM
and Red Hat under the (<span class="hl num">3</span>-clause) BSD license so that it can be
freely used by all other projects, and is reproduced (with slight
variation to remove Linux assumptions) in <span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:virtio-ring.h<span class="hl opt">}</span>~<span class="hl kwa">\nameref</span><span class="hl opt">{</span>sec:virtio-ring.h<span class="hl opt">}</span>.

<span class="hl kwa">\chapter</span><span class="hl opt">{</span>General Initialization And Device Operation<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:General Initialization And Device Operation<span class="hl opt">}</span>

We start with an overview of device initialization, then expand on the
details of the device and how each step is preformed.  This section
should be read along with the bus-specific section which describes
how to communicate with the specific device.

<span class="hl kwa">\section</span><span class="hl opt">{</span>Device Initialization<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:General Initialization And Device Operation / Device Initialization<span class="hl opt">}</span>

The driver MUST follow this sequence to initialize a device:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>
<span class="hl kwa">\item</span> Reset the device.

<span class="hl kwa">\item</span> Set the ACKNOWLEDGE status bit: the guest OS has notice the device.

<span class="hl kwa">\item</span> Set the DRIVER status bit: the guest OS knows how to drive the device.

<span class="hl kwa">\item</span> Read device feature bits, and write the subset of feature bits
   understood by the OS and driver to the device.  During this step the
   driver MAY read (but MUST NOT write) the device-specific configuration fields to check that it can support the device before accepting it.
   The device MUST allow reading of any device-specific configuration field
   before FEATURES_OK is set.  This includes fields which are conditional
   on feature bits, as long as those feature bits are offered by the device.

<span class="hl kwa">\item\label</span><span class="hl opt">{</span>itm:General Initialization And Device Operation / Device Initialization / Set FEATURES-OK<span class="hl opt">}</span> Set the FEATURES_OK status bit.  The driver MUST not accept
   new feature bits after this step.

<span class="hl kwa">\item\label</span><span class="hl opt">{</span>itm:General Initialization And Device Operation / Device Initialization / Re-read FEATURES-OK<span class="hl opt">}</span> Re-read <span class="hl kwa">\field</span><span class="hl opt">{</span>device status<span class="hl opt">}</span> to ensure the FEATURES_OK bit is still
   set: otherwise, the device does not support our subset of features
   and the device is unusable.

<span class="hl kwa">\item\label</span><span class="hl opt">{</span>itm:General Initialization And Device Operation / Device Initialization / Device-specific Setup<span class="hl opt">}</span> Perform device-specific setup, including discovery of virtqueues for the
   device, optional per-bus setup, reading and possibly writing the
   device&apos;s virtio configuration space, and population of virtqueues.

<span class="hl kwa">\item\label</span><span class="hl opt">{</span>itm:General Initialization And Device Operation / Device Initialization / Set DRIVER-OK<span class="hl opt">}</span> Set the DRIVER_OK status bit.  At this point the device is
   &quot;live&quot;.
<span class="hl kwa">\end</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>

If any of these steps go irrecoverably wrong, the driver SHOULD
set the FAILED status bit to indicate that it has given up on the
device (it can reset the device later to restart if desired).  The
driver MUST NOT continue initialization in that case.

The device MUST NOT consume buffers or notify the driver before DRIVER_OK, and the driver
MUST NOT notify the device before it sets DRIVER_OK.

Devices SHOULD support all valid combinations of features, but we know
that implementations may well make assuptions that they will only be
used by fully-optimized drivers.  The resetting of the FEATURES_OK flag
provides a semi-graceful failure mode for this case.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Legacy Interface: Device Initialization<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:General Initialization And Device Operation / Device Initialization / Legacy Interface: Device Initialization<span class="hl opt">}</span>
Legacy devices do not support the FEATURES_OK status bit, and thus did
not have a graceful way for the device to indicate unsupported feature
combinations.  It also did not provide a clear mechanism to end
feature negotiation, which meant that devices finalized features on
first-use, and no features could be introduced which radically changed
the initial operation of the device.

Legacy device implementations often used the device before setting the
DRIVER_OK bit.

The result was the steps <span class="hl kwa">\ref</span><span class="hl opt">{</span>itm:General Initialization And Device Operation / Device Initialization / Set FEATURES-OK<span class="hl opt">}</span> and <span class="hl kwa">\ref</span><span class="hl opt">{</span>itm:General Initialization And Device Operation / Device Initialization / Re-read FEATURES-OK<span class="hl opt">}</span> were omitted, and steps <span class="hl kwa">\ref</span><span class="hl opt">{</span>itm:General Initialization And Device Operation / Device Initialization / Device-specific Setup<span class="hl opt">}</span> and <span class="hl kwa">\ref</span><span class="hl opt">{</span>itm:General Initialization And Device Operation / Device Initialization / Set DRIVER-OK<span class="hl opt">}</span>
were conflated.

<span class="hl kwa">\section</span><span class="hl opt">{</span>Device Operation<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:General Initialization And Device Operation / Device Operation<span class="hl opt">}</span>

There are two parts to device operation: supplying new buffers to
the device, and processing used buffers from the device. As an
example, the simplest virtio network device has two virtqueues: the
transmit virtqueue and the receive virtqueue. The driver adds
outgoing (device-readable) packets to the transmit virtqueue, and then
frees them after they are used. Similarly, incoming (device-writable)
buffers are added to the receive virtqueue, and processed after
they are used.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Supplying Buffers to The Device<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:General Initialization And Device Operation / Device Operation / Supplying Buffers to The Device<span class="hl opt">}</span>

The driver offers buffers to one of the device&apos;s virtqueues as follows:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>
<span class="hl kwa">\item\label</span><span class="hl opt">{</span>itm:General Initialization And Device Operation / Device Operation / Supplying Buffers to The Device / Place Buffers<span class="hl opt">}</span> The driver places the buffer into free descriptor(s) in the
   descriptor table, chaining as necessary (see <span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Virtqueues / The Virtqueue Descriptor Table<span class="hl opt">}</span>~<span class="hl kwa">\nameref</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Virtqueues / The Virtqueue Descriptor Table<span class="hl opt">}</span>).

<span class="hl kwa">\item\label</span><span class="hl opt">{</span>itm:General Initialization And Device Operation / Device Operation / Supplying Buffers to The Device / Place Index<span class="hl opt">}</span> The driver places the index of the head of the descriptor chain
   into the next ring entry of the available ring.

<span class="hl kwa">\item</span> Steps <span class="hl kwa">\ref</span><span class="hl opt">{</span>itm:General Initialization And Device Operation / Device Operation / Supplying Buffers to The Device / Place Buffers<span class="hl opt">}</span> and <span class="hl kwa">\ref</span><span class="hl opt">{</span>itm:General Initialization And Device Operation / Device Operation / Supplying Buffers to The Device / Place Index<span class="hl opt">}</span> may be performed repeatedly if batching
  is possible.

<span class="hl kwa">\item</span> The driver MUST perform suitable a memory barrier to ensure the device sees
  the updated descriptor table and available ring before the next
  step.

<span class="hl kwa">\item</span> The available <span class="hl kwa">\field</span><span class="hl opt">{</span>idx<span class="hl opt">}</span> is increased by the number of
  descriptor chain heads added to the available ring.

<span class="hl kwa">\item</span> The driver MUST perform a suitable memory barrier to ensure that it updates
  the <span class="hl kwa">\field</span><span class="hl opt">{</span>idx<span class="hl opt">}</span> field before checking for notification suppression.

<span class="hl kwa">\item</span> If notifications are not suppressed, the driver MUST notify the device
    of the new available buffers.
<span class="hl kwa">\end</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>

Note that the above code does not take precautions against the
available ring buffer wrapping around: this is not possible since
the ring buffer is the same size as the descriptor table, so step
(<span class="hl num">1</span>) will prevent such a condition.

In addition, the maximum queue size is <span class="hl num">32768</span> (it must be a power
of <span class="hl num">2</span> which fits in <span class="hl num">16</span> bits), so the <span class="hl num">16</span>-bit <span class="hl kwa">\field</span><span class="hl opt">{</span>idx<span class="hl opt">}</span> value can always
distinguish between a full and empty buffer.

Here is a description of each stage in more detail.

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Placing Buffers Into The Descriptor Table<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:General Initialization And Device Operation / Device Operation / Supplying Buffers to The Device / Placing Buffers Into The Descriptor Table<span class="hl opt">}</span>

A buffer consists of zero or more device-readable physically-contiguous
elements followed by zero or more physically-contiguous
device-writable elements (it must have at least one element). This
algorithm maps it into the descriptor table to form a descriptor
chain:

for each buffer element, b:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>
<span class="hl kwa">\item</span> Get the next free descriptor table entry, d
<span class="hl kwa">\item</span> Set <span class="hl kwa">\field</span><span class="hl opt">{</span>d.addr<span class="hl opt">}</span> to the physical address of the start of b
<span class="hl kwa">\item</span> Set <span class="hl kwa">\field</span><span class="hl opt">{</span>d.len<span class="hl opt">}</span> to the length of b.
<span class="hl kwa">\item</span> If b is device-writable, set <span class="hl kwa">\field</span><span class="hl opt">{</span>d.flags<span class="hl opt">}</span> to VRING_DESC_F_WRITE,
    otherwise <span class="hl num">0</span>.
<span class="hl kwa">\item</span> If there is a buffer element after this:
    <span class="hl kwa">\begin</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>
    <span class="hl kwa">\item</span> Set <span class="hl kwa">\field</span><span class="hl opt">{</span>d.next<span class="hl opt">}</span> to the index of the next free descriptor
      element.
    <span class="hl kwa">\item</span> Set the VRING_DESC_F_NEXT bit in <span class="hl kwa">\field</span><span class="hl opt">{</span>d.flags<span class="hl opt">}</span>.
    <span class="hl kwa">\end</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>

In practice, <span class="hl kwa">\field</span><span class="hl opt">{</span>d.next<span class="hl opt">}</span> is usually used to chain free
descriptors, and a separate count kept to check there are enough
free descriptors before beginning the mappings.

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Updating The Available Ring<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:General Initialization And Device Operation / Device Operation / Supplying Buffers to The Device / Updating The Available Ring<span class="hl opt">}</span>

The descriptor chain head is the first d in the algorithm
above, ie. the index of the descriptor table entry referring to the first
part of the buffer.  A naive implementation would do the following (with the
appropriate conversion to-and-from little-endian assumed):

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
avail-&gt;ring<span class="hl opt">[</span>avail-&gt;idx <span class="hl slc">% qsz] = head;</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

However, in general the driver can add many descriptor chains before it updates
<span class="hl kwa">\field</span><span class="hl opt">{</span>idx<span class="hl opt">}</span> (at which point they become visible to the
device), so it is common to keep a counter of how many the driver has added:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
avail-&gt;ring<span class="hl opt">[</span>(avail-&gt;idx + added++) <span class="hl slc">% qsz] = head;</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Updating <span class="hl kwa">\field</span><span class="hl opt">{</span>idx<span class="hl opt">}}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:General Initialization And Device Operation / Device Operation / Supplying Buffers to The Device / Updating idx<span class="hl opt">}</span>

Once <span class="hl kwa">\field</span><span class="hl opt">{</span>idx<span class="hl opt">}</span> is updated, the device will
be able to access the descriptor chains the driver created and the
memory they refer to. This is why a memory barrier is generally
used before the <span class="hl kwa">\field</span><span class="hl opt">{</span>idx<span class="hl opt">}</span> update, to ensure it sees the most up-to-date
copy.

<span class="hl kwa">\field</span><span class="hl opt">{</span>idx<span class="hl opt">}</span> always increments, and the driver can let it wrap naturally at
<span class="hl num">65536</span>:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
avail-&gt;idx += added;
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Notifying The Device<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:General Initialization And Device Operation / Device Operation / Supplying Buffers to The Device / Notifying The Device<span class="hl opt">}</span>

The actual method of device notification is bus-specific, but generally
it can be expensive.  So the device MAY suppress such notifications if it
doesn&apos;t need them.  The driver has to be careful to expose the new <span class="hl kwa">\field</span><span class="hl opt">{</span>idx<span class="hl opt">}</span>
value before checking if notifications are suppressed: the driver MAY notify
gratuitously, but MUST NOT to omit a required notification. So again,
the driver SHOULD use a memory barrier here before reading <span class="hl kwa">\field</span><span class="hl opt">{</span>flags<span class="hl opt">}</span> or
<span class="hl kwa">\field</span><span class="hl opt">{</span>avail_event<span class="hl opt">}</span>.

If the VIRTIO_F_RING_EVENT_IDX feature is not negotiated, and if the
VRING_USED_F_NOTIFY flag is not set, the driver SHOULD notify the
device.

If the VIRTIO_F_RING_EVENT_IDX feature is negotiated, the driver reads
<span class="hl kwa">\field</span><span class="hl opt">{</span>avail_event<span class="hl opt">}</span> in the available ring structure. If the
available <span class="hl kwa">\field</span><span class="hl opt">{</span>idx<span class="hl opt">}</span> crossed <span class="hl kwa">\field</span><span class="hl opt">{</span>avail_event<span class="hl opt">}</span> value since the
last notification, the driver SHOULD notify the device.  <span class="hl kwa">\field</span><span class="hl opt">{</span>avail_event<span class="hl opt">}</span> wraps naturally at <span class="hl num">65536</span> as well,
giving the following algorithm for calculating whether a device needs
notification:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
(u16)(new_idx - avail_event - <span class="hl num">1</span>) &lt; (u16)(new_idx - old_idx)
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Receiving Used Buffers From The Device<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:General Initialization And Device Operation / Device Operation / Receiving Used Buffers From The Device<span class="hl opt">}</span>

Once the device has used buffers referred to by a descriptor (read from or written to them, or
parts of both, depending on the nature of the virtqueue and the
device), it SHOULD send an interrupt, following an algorithm very
similar to the algorithm used for the driver to send the device a
buffer:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>
<span class="hl kwa">\item</span> Write the head descriptor number to the next entry in the used
  ring.

<span class="hl kwa">\item</span> Update the used ring <span class="hl kwa">\field</span><span class="hl opt">{</span>idx<span class="hl opt">}</span>.

<span class="hl kwa">\item</span> Deliver an interrupt if necessary:

  <span class="hl kwa">\begin</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>
  <span class="hl kwa">\item</span> If the VIRTIO_F_RING_EVENT_IDX feature is not negotiated:
    check if the VRING_AVAIL_F_NO_INTERRUPT flag is not set in
    <span class="hl kwa">\field</span><span class="hl opt">{</span>flags<span class="hl opt">}</span> in the available structure.

  <span class="hl kwa">\item</span> If the VIRTIO_F_RING_EVENT_IDX feature is negotiated: check
    whether the used <span class="hl kwa">\field</span><span class="hl opt">{</span>idx<span class="hl opt">}</span> crossed the <span class="hl kwa">\field</span><span class="hl opt">{</span>used_event<span class="hl opt">}</span> value
    since the last update. <span class="hl kwa">\field</span><span class="hl opt">{</span>used_event<span class="hl opt">}</span> wraps naturally
    at <span class="hl num">65536</span> as well:
<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
(u16)(new_idx - used_event - <span class="hl num">1</span>) &lt; (u16)(new_idx - old_idx)
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
  <span class="hl kwa">\end</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>

For each ring, the driver MAY then disable interrupts by writing
VRING_AVAIL_F_NO_INTERRUPT to <span class="hl kwa">\field</span><span class="hl opt">{</span>flags<span class="hl opt">}</span> in available structure, if required.
Once it has processed the ring entries, it SHOULD re-enable
interrupts by clearing VRING_AVAIL_F_NO_INTERRUPT in <span class="hl kwa">\field</span><span class="hl opt">{</span>flags<span class="hl opt">}</span> or updating
<span class="hl kwa">\field</span><span class="hl opt">{</span>event_idx<span class="hl opt">}</span> in the available structure.  The driver SHOULD then
execute a memory barrier, and then recheck the ring empty
condition. This is necessary to handle the case where after the
last check and before enabling interrupts, an interrupt has been
suppressed by the device:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
vring_disable_interrupts(vq);

for (;;) <span class="hl opt">{</span>
        if (vq-&gt;last_seen_used != le16_to_cpu(vring-&gt;used.idx)) <span class="hl opt">{</span>
                vring_enable_interrupts(vq);
                mb();

                if (vq-&gt;last_seen_used != le16_to_cpu(vring-&gt;used.idx))
                        break;

                vring_disable_interrupts(vq);
        <span class="hl opt">}</span>

        struct vring_used_elem *e = vring.used-&gt;ring<span class="hl opt">[</span>vq-&gt;last_seen_used<span class="hl slc">%vsz];</span>
        process_buffer(e);
        vq-&gt;last_seen_used++;
<span class="hl opt">}</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Notification of Device Configuration Changes<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:General Initialization And Device Operation / Device Operation / Notification of Device Configuration Changes<span class="hl opt">}</span>

For devices where the device-specific configuration information can be changed, an
interrupt is delivered when a device-specific configuration change occurs.

<span class="hl kwa">\section</span><span class="hl opt">{</span>Device Cleanup<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:General Initialization And Device Operation / Device Cleanup<span class="hl opt">}</span>

Once the driver has set the DRIVER_OK status bit, all the configured
virtqueue of the device are considered live.  None of the virtqueues
of a device are live once the device has been reset.

A driver MUST NOT alter descriptor table entries which have been
exposed in the available ring (and not marked consumed by the device
in the used ring) of a live virtqueue.

A driver MUST NOT decrement the available <span class="hl kwa">\field</span><span class="hl opt">{</span>idx<span class="hl opt">}</span> on a live virtqueue (ie.
there is no way to &quot;unexpose&quot; buffers).

Thus a driver MUST ensure a virtqueue isn&apos;t live (by device reset) before removing exposed buffers.

<span class="hl kwa">\chapter</span><span class="hl opt">{</span>Virtio Transport Options<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options<span class="hl opt">}</span>

Virtio can use various different busses, thus the standard is split
into virtio general and bus-specific sections.

<span class="hl kwa">\section</span><span class="hl opt">{</span>Virtio Over PCI Bus<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over PCI Bus<span class="hl opt">}</span>

Virtio devices are commonly implemented as PCI devices.

A Virtio device can be implemented as any kind of PCI device:
a Conventional PCI device or a PCI Express
device.  A Virtio device using Virtio Over PCI Bus MUST expose to
guest an interface that meets the specification requirements of
the appropriate PCI specification: <span class="hl kwa">\hyperref</span><span class="hl opt">[</span>intro:PCI<span class="hl opt">]{[</span>PCI<span class="hl opt">]}</span>
and <span class="hl kwa">\hyperref</span><span class="hl opt">[</span>intro:PCIe<span class="hl opt">]{[</span>PCIe<span class="hl opt">]}</span>
respectively.  To assure designs meet the latest level
requirements, designers of Virtio Over PCI devices must refer to
the PCI-SIG home page at <span class="hl kwa">\url</span><span class="hl opt">{</span>http://www.pcisig.com<span class="hl opt">}</span> for any
approved changes.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>PCI Device Discovery<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Discovery<span class="hl opt">}</span>

Any PCI device with Vendor ID <span class="hl num">0x1AF4</span>, and Device ID <span class="hl num">0x1000</span> through
<span class="hl num">0x103F</span> inclusive is a virtio device<span class="hl kwa">\footnote</span><span class="hl opt">{</span>The actual value within this range is ignored
<span class="hl opt">}</span>.

The Subsystem Device ID indicates which virtio device is
supported by the device. The Subsystem Vendor ID SHOULD reflect
the PCI Vendor ID of the environment (it&apos;s currently only used
for informational purposes by the driver).

All drivers MUST match devices with any Revision ID, this
is to allow devices to be versioned without breaking drivers.

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Legacy Interfaces: A Note on PCI Device Discovery<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Discovery / Legacy Interfaces: A Note on PCI Device Discovery<span class="hl opt">}</span>
Transitional devices MUST have a Revision ID of <span class="hl num">0</span> to match
legacy drivers.

Non-transitional devices MUST have a Revision ID of <span class="hl num">1</span> or higher.

Both transitional and non-transitional drivers MUST match
any Revision ID value.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>PCI Device Layout<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout<span class="hl opt">}</span>

The device is configured via I/O and/or memory regions (though see
<span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout / PCI configuration access capability<span class="hl opt">}</span>
for access via the PCI configuration space).

These regions contain the virtio header registers, the notification register, the
ISR status register and device specific registers, as specified by Virtio
Structure PCI Capabilities.

There may be different widths of accesses to the I/O region; the driver
MUST access each field using the “natural” access method (i.e. <span class="hl num">32</span>-bit accesses for <span class="hl num">32</span>-bit fields, etc).  All multi-byte fields are little-endian.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Virtio Structure PCI Capabilities<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over PCI Bus / Virtio Structure PCI Capabilities<span class="hl opt">}</span>

The virtio device configuration layout includes several structures:
<span class="hl kwa">\begin</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>
<span class="hl kwa">\item</span> Common configuration
<span class="hl kwa">\item</span> Notifications
<span class="hl kwa">\item</span> ISR Status
<span class="hl kwa">\item</span> Device-specific configuration (optional)
<span class="hl kwa">\end</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>

Each structure can be mapped by a Base Address register (BAR) belonging to
the function, or accessed via the special VIRTIO_PCI_CAP_PCI_CFG field in the PCI configuration space.

The location of each structure is specified using a vendor-specific PCI capability located
on the capability list in PCI configuration space of the device.
This virtio structure capability uses little-endian format; all fields are
read-only for the driver unless stated otherwise:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
struct virtio_pci_cap <span class="hl opt">{</span>
        u8 cap_vndr;    /* Generic PCI field: PCI_CAP_ID_VNDR */
        u8 cap_next;    /* Generic PCI field: next ptr. */
        u8 cap_len;     /* Generic PCI field: capability length */
        u8 cfg_type;    /* Identifies the structure. */
        u8 bar;         /* Where to find it. */
        u8 padding<span class="hl opt">[</span><span class="hl num">3</span><span class="hl opt">]</span>;  /* Pad to full dword. */
        le32 offset;    /* Offset within bar. */
        le32 length;    /* Length of the structure, in bytes. */
<span class="hl opt">}</span>;
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

This structure can be followed by extra data, depending on
<span class="hl kwa">\field</span><span class="hl opt">{</span>cfg_type<span class="hl opt">}</span>, as documented below.  In this case device MUST include
this extra data (from the beginning of the <span class="hl kwa">\field</span><span class="hl opt">{</span>cap_vndr<span class="hl opt">}</span> field
through end of the extra data fields if any)
in the capability length as specified by <span class="hl kwa">\field</span><span class="hl opt">{</span>cap_len<span class="hl opt">}</span>.
The device MAY append extra data
or padding to any structure beyond that; the driver MUST accept a <span class="hl kwa">\field</span><span class="hl opt">{</span>cap_len<span class="hl opt">}</span> value
which is larger than specified here.

The fields are interpreted as follows:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>description<span class="hl opt">}</span>
<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\field</span><span class="hl opt">{</span>cap_vndr<span class="hl opt">}]</span>
        <span class="hl num">0x09</span>; Identifies a vendor-specific capability.

<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\field</span><span class="hl opt">{</span>cap_next<span class="hl opt">}]</span>
        Link to next capability in the capability list in the PCI configuration space.

<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\field</span><span class="hl opt">{</span>cap_len<span class="hl opt">}]</span>
        Length of this capability structure, including the whole of
        struct virtio_pci_cap, and extra data if any.
        This length MAY include padding, or fields unused by the driver.

<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\field</span><span class="hl opt">{</span>cfg_type<span class="hl opt">}]</span>
        identifies the structure, according to the following table:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
/* Common configuration */
#define VIRTIO_PCI_CAP_COMMON_CFG        <span class="hl num">1</span>
/* Notifications */
#define VIRTIO_PCI_CAP_NOTIFY_CFG        <span class="hl num">2</span>
/* ISR Status */
#define VIRTIO_PCI_CAP_ISR_CFG           <span class="hl num">3</span>
/* Device specific configuration */
#define VIRTIO_PCI_CAP_DEVICE_CFG        <span class="hl num">4</span>
/* PCI configuration access */
#define VIRTIO_PCI_CAP_PCI_CFG           <span class="hl num">5</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

        Any other value - reserved for future use. Drivers MUST
        ignore any vendor-specific capability structure which has
        a reserved <span class="hl kwa">\field</span><span class="hl opt">{</span>cfg_type<span class="hl opt">}</span> value.

        The device MAY offer more than one structure of any type - this makes it
        possible for the device to expose multiple interfaces to drivers.  The order of
        the capabilities in the capability list specifies the order of preference
        suggested by the device; drivers SHOULD use the first interface that they can
        support.  For example, on some hypervisors, notifications using IO accesses are
        faster than memory accesses. In this case, the device would expose two
        capabilities with <span class="hl kwa">\field</span><span class="hl opt">{</span>cfg_type<span class="hl opt">}</span> set to VIRTIO_PCI_CAP_NOTIFY_CFG:
        the first one addressing an I/O BAR, the second one addressing a memory BAR.
        In this example, the driver SHOULD use the I/O BAR if I/O resources are available, and fall back on
        memory BAR when I/O resources are unavailable.

        Each structure is detailed individually below.

<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\field</span><span class="hl opt">{</span>bar<span class="hl opt">}]</span>
        values <span class="hl num">0x0</span> to <span class="hl num">0x5</span> specify a Base Address register (BAR) belonging to
        the function located beginning at <span class="hl num">10</span>h in PCI Configuration Space
        and used to map the structure into Memory or I/O Space.
        The BAR is permitted to be either <span class="hl num">32</span>-bit or <span class="hl num">64</span>-bit, it can map Memory Space
        or I/O Space.

        Any other value is reserved for future use. Drivers MUST
        ignore any vendor-specific capability structure which has
        a reserved <span class="hl kwa">\field</span><span class="hl opt">{</span>bar<span class="hl opt">}</span> value.

<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\field</span><span class="hl opt">{</span>offset<span class="hl opt">}]</span>
        indicates where the structure begins relative to the base address associated
        with the BAR.  The alignment requirement of <span class="hl kwa">\field</span><span class="hl opt">{</span>offset<span class="hl opt">}</span> are indicated
        in each structure-specific section below.

<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\field</span><span class="hl opt">{</span>length<span class="hl opt">}]</span>
        indicates the length of the structure.

        <span class="hl kwa">\field</span><span class="hl opt">{</span>length<span class="hl opt">}</span> MAY include padding, or fields unused by the driver, or
        future extensions.

        Drivers SHOULD only map part of configuration structure
        large enough for device operation.  Drivers MUST handle
        an unexpectedly large <span class="hl kwa">\field</span><span class="hl opt">{</span>length<span class="hl opt">}</span>, but MAY check that <span class="hl kwa">\field</span><span class="hl opt">{</span>length<span class="hl opt">}</span>
        is large enough for device operation.

        For example, a future device might present a large structure size of several
        MBytes.
        As current devices never utilize structures larger than <span class="hl num">4</span>KBytes in size,
        driver MAY limit the mapped structure size to e.g.
        <span class="hl num">4</span>KBytes (thus ignoring parts of structure after the first
        <span class="hl num">4</span>KBytes) to allow forward compatibility with such devices without loss of
        functionality and without wasting resources.
<span class="hl kwa">\end</span><span class="hl opt">{</span>description<span class="hl opt">}</span>

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Common configuration structure layout<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout / Common configuration structure layout<span class="hl opt">}</span>

The common configuration structure is found at the <span class="hl kwa">\field</span><span class="hl opt">{</span>bar<span class="hl opt">}</span> and <span class="hl kwa">\field</span><span class="hl opt">{</span>offset<span class="hl opt">}</span> within the VIRTIO_PCI_CAP_COMMON_CFG capability; its layout is below.
<span class="hl kwa">\field</span><span class="hl opt">{</span>offset<span class="hl opt">}</span> must be <span class="hl num">4</span>-byte aligned.

The device MUST present at least one common configuration capability.

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
struct virtio_pci_common_cfg <span class="hl opt">{</span>
        /* About the whole device. */
        le32 device_feature_select;     /* read-write */
        le32 device_feature;            /* read-only for driver */
        le32 driver_feature_select;     /* read-write */
        le32 driver_feature;            /* read-write */
        le16 msix_config;               /* read-write */
        le16 num_queues;                /* read-only for driver */
        u8 device_status;               /* read-write */
        u8 config_generation;           /* read-only for driver */

        /* About a specific virtqueue. */
        le16 queue_select;              /* read-write */
        le16 queue_size;                /* read-write, power of <span class="hl num">2</span>, or <span class="hl num">0</span>. */
        le16 queue_msix_vector;         /* read-write */
        le16 queue_enable;              /* read-write */
        le16 queue_notify_off;          /* read-only for driver */
        le64 queue_desc;                /* read-write */
        le64 queue_avail;               /* read-write */
        le64 queue_used;                /* read-write */
<span class="hl opt">}</span>;
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

<span class="hl kwa">\begin</span><span class="hl opt">{</span>description<span class="hl opt">}</span>
<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\field</span><span class="hl opt">{</span>device_feature_select<span class="hl opt">}]</span>
        The driver uses this to select which feature bits <span class="hl kwa">\field</span><span class="hl opt">{</span>device_feature<span class="hl opt">}</span> shows.
        Value <span class="hl num">0x0</span> selects Feature Bits <span class="hl num">0</span> to <span class="hl num">31</span>, <span class="hl num">0x1</span> selects Feature Bits <span class="hl num">32</span> to <span class="hl num">63</span>.
        The device MUST present <span class="hl num">0</span> on <span class="hl kwa">\field</span><span class="hl opt">{</span>device_feature<span class="hl opt">}</span> for any other value.

<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\field</span><span class="hl opt">{</span>device_feature<span class="hl opt">}]</span>
        The device uses this to <span class="hl kwb">report</span> which feature bits it is
        offering to the driver: the driver writes to
        <span class="hl kwa">\field</span><span class="hl opt">{</span>device_feature_select<span class="hl opt">}</span> to select which feature bits are presented.

<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\field</span><span class="hl opt">{</span>driver_feature_select<span class="hl opt">}]</span>
        The driver uses this to select which feature bits <span class="hl kwa">\field</span><span class="hl opt">{</span>driver_feature<span class="hl opt">}</span> shows.
        Value <span class="hl num">0x0</span> selects Feature Bits <span class="hl num">0</span> to <span class="hl num">31</span>, <span class="hl num">0x1</span> selects Feature Bits <span class="hl num">32</span> to <span class="hl num">63</span>.
        When set to any other value:
	<span class="hl kwa">\begin</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>
	<span class="hl kwa">\item</span> the device MUST return <span class="hl num">0</span> on reads from <span class="hl kwa">\field</span><span class="hl opt">{</span>driver_feature<span class="hl opt">}</span>
	<span class="hl kwa">\item</span> the device MUST ignore writing of <span class="hl num">0</span> into <span class="hl kwa">\field</span><span class="hl opt">{</span>driver_feature<span class="hl opt">}</span>
	<span class="hl kwa">\item</span> the driver MUST NOT write any non <span class="hl num">0</span> value into <span class="hl kwa">\field</span><span class="hl opt">{</span>driver_feature<span class="hl opt">}</span> (a corollary of
        the rule that the driver can only write a subset of device features).
	<span class="hl kwa">\end</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>

<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\field</span><span class="hl opt">{</span>driver_feature<span class="hl opt">}]</span>
        The driver writes this to accept feature bits offered by the device.
        Driver Feature Bits selected by <span class="hl kwa">\field</span><span class="hl opt">{</span>driver_feature_select<span class="hl opt">}</span>.

<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\field</span><span class="hl opt">{</span>config_msix_vector<span class="hl opt">}]</span>
        The driver sets the Configuration Vector for MSI-X.

<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\field</span><span class="hl opt">{</span>num_queues<span class="hl opt">}]</span>
        The device specifies the maximum number of virtqueues supported here.

<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\field</span><span class="hl opt">{</span>device_status<span class="hl opt">}]</span>
        The driver writes the device status here (see <span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Device Status Field<span class="hl opt">}</span>). Writing <span class="hl num">0</span> into this
        field resets the device.

<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\field</span><span class="hl opt">{</span>config_generation<span class="hl opt">}]</span>
        Configuration atomicity value.  The device changes this every time the
        configuration noticeably changes.  This means the device may
        only change the value after a configuration read operation,
        but MUST change it if there is any risk of a driver seeing an
        inconsistent configuration state.

<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\field</span><span class="hl opt">{</span>queue_select<span class="hl opt">}]</span>
        Queue Select. The driver selects which virtqueue the following
        fields refer to.

<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\field</span><span class="hl opt">{</span>queue_size<span class="hl opt">}]</span>
        Queue Size.  On reset, specifies the maximum queue size supported by
        the hypervisor. This can be modified by driver to reduce memory requirements.
        The device MUST set this to <span class="hl num">0</span> if this virtqueue is unavailable.

<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\field</span><span class="hl opt">{</span>queue_msix_vector<span class="hl opt">}]</span>
        The driver uses this to specify the queue vector for MSI-X.

<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\field</span><span class="hl opt">{</span>queue_enable<span class="hl opt">}]</span>
        The driver uses this to selectively prevent the device from executing requests from this virtqueue.
        <span class="hl num">1</span> - enabled; <span class="hl num">0</span> - disabled.

        The driver MUST configure the other virtqueue fields before enabling
        the virtqueue.

<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\field</span><span class="hl opt">{</span>queue_notify_off<span class="hl opt">}]</span>
        The driver reads this to calculate the offset from start of Notification structure at
        which this virtqueue is located.
        Note: this is <span class="hl kwa">\em</span><span class="hl opt">{</span>not<span class="hl opt">}</span> an offset in bytes.
        See <span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout / Notification capability<span class="hl opt">}</span> below.

<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\field</span><span class="hl opt">{</span>queue_desc<span class="hl opt">}]</span>
        The driver writes the physical address of Descriptor Table here.  See section <span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Virtqueues<span class="hl opt">}</span>.

<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\field</span><span class="hl opt">{</span>queue_avail<span class="hl opt">}]</span>
        The driver writes the physical address of Available Ring here.  See section <span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Virtqueues<span class="hl opt">}</span>.

<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\field</span><span class="hl opt">{</span>queue_used<span class="hl opt">}]</span>
        The driver writes the physical address of Used Ring here.  See section <span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Virtqueues<span class="hl opt">}</span>.
<span class="hl kwa">\end</span><span class="hl opt">{</span>description<span class="hl opt">}</span>

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Notification structure layout<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout / Notification capability<span class="hl opt">}</span>

The device MUST present at least one notification capability.

The notification location is found using the VIRTIO_PCI_CAP_NOTIFY_CFG
capability.  The <span class="hl kwa">\field</span><span class="hl opt">{</span>offset<span class="hl opt">}</span> must be <span class="hl num">2</span>-byte aligned.  This capability is immediately followed by an additional
field, like so:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
struct virtio_pci_notify_cap <span class="hl opt">{</span>
        struct virtio_pci_cap cap;
        le32 notify_off_multiplier; /* Multiplier for queue_notify_off. */
<span class="hl opt">}</span>;
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

The device MUST either present <span class="hl kwa">\field</span><span class="hl opt">{</span>notify_off_multiplier<span class="hl opt">}</span> as an even power of <span class="hl num">2</span>,
or present <span class="hl kwa">\field</span><span class="hl opt">{</span>notify_off_multiplier<span class="hl opt">}</span> as <span class="hl num">0</span>.

<span class="hl kwa">\field</span><span class="hl opt">{</span>notify_off_multiplier<span class="hl opt">}</span> field is combined with the <span class="hl kwa">\field</span><span class="hl opt">{</span>queue_notify_off<span class="hl opt">}</span> to
derive the Queue Notify address within a BAR for a specific queue:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
        cap.offset + queue_notify_off * notify_off_multiplier
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

The BAR, <span class="hl kwa">\field</span><span class="hl opt">{</span>offset<span class="hl opt">}</span> and <span class="hl kwa">\field</span><span class="hl opt">{</span>notify_off_multiplier<span class="hl opt">}</span> are taken from the
notification capability structure above, and the <span class="hl kwa">\field</span><span class="hl opt">{</span>queue_notify_off<span class="hl opt">}</span> is
taken from the common configuration structure.

For example, if <span class="hl kwa">\field</span><span class="hl opt">{</span>notifier_off_multiplier<span class="hl opt">}</span> is <span class="hl num">0</span>, the device uses
the same Queue Notify address for all queues.

The value <span class="hl kwa">\field</span><span class="hl opt">{</span>cap.length<span class="hl opt">}</span> presented by the device MUST be at least <span class="hl num">2</span>
and MUST be large enough to support queue notification offsets
for all supported queues in all possible configurations.
For all queues, the value <span class="hl kwa">\field</span><span class="hl opt">{</span>cap.length<span class="hl opt">}</span> presented by the device MUST satisfy:
<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
cap.length &gt;= queue_notify_off * notify_off_multiplier + <span class="hl num">2</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>ISR status capability<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout / ISR status capability<span class="hl opt">}</span>

The device MUST present at least one VIRTIO_PCI_CAP_ISR_CFG capability.  This
refers to at least a single byte, which contains the <span class="hl num">8</span>-bit ISR status field:
<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
#define VIRTIO_PCI_ISR_VQ       <span class="hl num">0x1</span>
#define VIRTIO_PCI_ISR_CONFIG   <span class="hl num">0x2</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

See sections <span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over PCI Bus / PCI-specific Initialization And Device Operation / Virtqueue Interrupts From The Device<span class="hl opt">}</span> and <span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over PCI Bus / PCI-specific Initialization And Device Operation / Notification of Device Configuration Changes<span class="hl opt">}</span> for how this is used.

The <span class="hl kwa">\field</span><span class="hl opt">{</span>offset<span class="hl opt">}</span> for the ISR status has no specific alignment requirements.

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Device specific structure<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout / Device specific structure<span class="hl opt">}</span>

The device MAY present at least one VIRTIO_PCI_CAP_DEVICE_CFG capability (some
devices may not have any device specific structure).

The <span class="hl kwa">\field</span><span class="hl opt">{</span>offset<span class="hl opt">}</span> for the device specific structure must be <span class="hl num">4</span>-byte aligned.

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>PCI configuration access capability<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout / PCI configuration access capability<span class="hl opt">}</span>

The device MUST present at least one VIRTIO_PCI_CAP_PCI_CFG.  This
creates an alternative (and likely suboptimal) access method to the
common configuration, notification, ISR and device-specific regions.

The capability is immediately followed by an additional field like so:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
struct virtio_pci_cfg_cap <span class="hl opt">{</span>
        struct virtio_pci_cap cap;
        u8 pci_cfg_data<span class="hl opt">[</span><span class="hl num">4</span><span class="hl opt">]</span>; /* Data for BAR access. */
<span class="hl opt">}</span>;
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

The fields <span class="hl kwa">\field</span><span class="hl opt">{</span>cap.bar<span class="hl opt">}</span>, <span class="hl kwa">\field</span><span class="hl opt">{</span>cap.length<span class="hl opt">}</span>, <span class="hl kwa">\field</span><span class="hl opt">{</span>cap.offset<span class="hl opt">}</span> and <span class="hl kwa">\field</span><span class="hl opt">{</span>pci_cfg_data<span class="hl opt">}</span>
are read-write (RW).

To access to a device region, the driver writes into the capability
structure (ie. within the PCI configuration space) as follows:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>
<span class="hl kwa">\item</span> The driver sets the BAR to access by writing to <span class="hl kwa">\field</span><span class="hl opt">{</span>cap.bar<span class="hl opt">}</span>.

<span class="hl kwa">\item</span> The driver sets the size of the access by writing <span class="hl num">1</span>, <span class="hl num">2</span> or <span class="hl num">4</span> to
  <span class="hl kwa">\field</span><span class="hl opt">{</span>cap.length<span class="hl opt">}</span>.

<span class="hl kwa">\item</span> The driver sets the offset within the BAR by writing to
  <span class="hl kwa">\field</span><span class="hl opt">{</span>cap.offset<span class="hl opt">}</span>.  The driver MUST NOT write an offset which is not
  a multiple of <span class="hl kwa">\field</span><span class="hl opt">{</span>cap.length<span class="hl opt">}</span> (ie. all accesses must be aligned).
<span class="hl kwa">\end</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>

At that point, <span class="hl kwa">\field</span><span class="hl opt">{</span>pci_cfg_data<span class="hl opt">}</span> will provide a window of size
<span class="hl kwa">\field</span><span class="hl opt">{</span>cap.length<span class="hl opt">}</span> into the given <span class="hl kwa">\field</span><span class="hl opt">{</span>cap.bar<span class="hl opt">}</span> at offset <span class="hl kwa">\field</span><span class="hl opt">{</span>cap.offset<span class="hl opt">}</span>.

Upon detecting driver write access
to <span class="hl kwa">\field</span><span class="hl opt">{</span>pci_cfg_data<span class="hl opt">}</span>, the device MUST execute a write access
at offset <span class="hl kwa">\field</span><span class="hl opt">{</span>cap.offset<span class="hl opt">}</span> at BAR selected by <span class="hl kwa">\field</span><span class="hl opt">{</span>cap.bar<span class="hl opt">}</span> using the first <span class="hl kwa">\field</span><span class="hl opt">{</span>cap.length<span class="hl opt">}</span>
bytes from <span class="hl kwa">\field</span><span class="hl opt">{</span>pci_cfg_data<span class="hl opt">}</span>.

Upon detecting driver read access
to <span class="hl kwa">\field</span><span class="hl opt">{</span>pci_cfg_data<span class="hl opt">}</span>, the device MUST
execute a read access of length cap.length at offset <span class="hl kwa">\field</span><span class="hl opt">{</span>cap.offset<span class="hl opt">}</span>
at BAR selected by <span class="hl kwa">\field</span><span class="hl opt">{</span>cap.bar<span class="hl opt">}</span> and store the first <span class="hl kwa">\field</span><span class="hl opt">{</span>cap.length<span class="hl opt">}</span> bytes in
<span class="hl kwa">\field</span><span class="hl opt">{</span>pci_cfg_data<span class="hl opt">}</span>.

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Legacy Interfaces: A Note on PCI Device Layout<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout / Legacy Interfaces: A Note on PCI Device Layout<span class="hl opt">}</span>

Transitional devices should present part of configuration
registers in a legacy configuration structure in BAR0 in the first I/O
region of the PCI device, as documented below.

There may be different widths of accesses to the I/O region; the
“natural” access method for each field in the virtio common configuration structure must be
used (i.e. <span class="hl num">32</span>-bit accesses for <span class="hl num">32</span>-bit fields, etc), but 
when accessed through the legacy interface the
device-specific region can be accessed using any width accesses, and
should obtain the same results.

Note that this is possible because while the virtio common configuration structure is PCI
(i.e. little) endian, when using the legacy interface the device-specific
region is encoded in the native endian of the guest (where such distinction is
applicable).

When used through the legacy interface, the virtio common configuration structure looks as follows:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>tabularx<span class="hl opt">}{</span><span class="hl kwa">\textwidth</span><span class="hl opt">}{</span> |X||X|X|X|X|X|X|X|X| <span class="hl opt">}</span>
<span class="hl kwa">\hline</span>
 Bits &amp; <span class="hl num">32</span> &amp; <span class="hl num">32</span> &amp; <span class="hl num">32</span> &amp; <span class="hl num">16</span> &amp; <span class="hl num">16</span> &amp; <span class="hl num">16</span> &amp; <span class="hl num">8</span> &amp; <span class="hl num">8</span> \\
<span class="hl kwa">\hline</span>
 Read / Write &amp; R &amp; R+W &amp; R+W &amp; R &amp; R+W &amp; R+W &amp; R+W &amp; R \\
<span class="hl kwa">\hline</span>
 Purpose &amp; Device Features bits <span class="hl num">0</span>:<span class="hl num">31</span> &amp; Driver Features bits <span class="hl num">0</span>:<span class="hl num">31</span> &amp;
  Queue Address &amp; <span class="hl kwa">\field</span><span class="hl opt">{</span>queue_size<span class="hl opt">}</span> &amp; <span class="hl kwa">\field</span><span class="hl opt">{</span>queue_select<span class="hl opt">}</span> &amp; Queue Notify &amp;
  Device Status &amp; ISR <span class="hl kwa">\newline</span> Status \\
<span class="hl kwa">\hline</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>tabularx<span class="hl opt">}</span>

If MSI-X is enabled for the device, two additional fields
immediately follow this header:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>tabular<span class="hl opt">}{</span> |l||l|l| <span class="hl opt">}</span>
<span class="hl kwa">\hline</span>
Bits       &amp; <span class="hl num">16</span>             &amp; <span class="hl num">16</span>     \\
<span class="hl kwa">\hline</span>
Read/Write &amp; R+W            &amp; R+W    \\
<span class="hl kwa">\hline</span>
Purpose (MSI-X) &amp; <span class="hl kwa">\field</span><span class="hl opt">{</span>config_msix_vector<span class="hl opt">}</span>  &amp; <span class="hl kwa">\field</span><span class="hl opt">{</span>queue_msix_vector<span class="hl opt">}</span> \\
<span class="hl kwa">\hline</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>tabular<span class="hl opt">}</span>

Note: When MSI-X capability is enabled, device specific configuration starts at
byte offset <span class="hl num">24</span> in virtio common configuration structure structure. When MSI-X capability is not
enabled, device specific configuration starts at byte offset <span class="hl num">20</span> in virtio
header.  ie. once you enable MSI-X on the device, the other fields move.
If you turn it off again, they move back!

Immediately following these general headers, there may be
device-specific headers:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>tabular<span class="hl opt">}{</span>|l||l|l|<span class="hl opt">}</span>
<span class="hl kwa">\hline</span>
Bits &amp; Device Specific &amp; <span class="hl kwa">\multirow</span><span class="hl opt">{</span><span class="hl num">3</span><span class="hl opt">}{</span>*<span class="hl opt">}{</span>...<span class="hl opt">}</span> \\
<span class="hl kwa">\cline</span><span class="hl opt">{</span><span class="hl num">1</span>-<span class="hl num">2</span><span class="hl opt">}</span>
Read / Write &amp; Device Specific &amp; \\
<span class="hl kwa">\cline</span><span class="hl opt">{</span><span class="hl num">1</span>-<span class="hl num">2</span><span class="hl opt">}</span>
Purpose &amp; Device Specific &amp; \\
<span class="hl kwa">\hline</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>tabular<span class="hl opt">}</span>

Note that only Feature Bits <span class="hl num">0</span> to <span class="hl num">31</span> are accessible through the
Legacy Interface. When used through the Legacy Interface,
Transitional Devices must assume that Feature Bits <span class="hl num">32</span> to <span class="hl num">63</span>
are not acknowledged by Driver.

As legacy devices had no <span class="hl kwa">\field</span><span class="hl opt">{</span>config_generation<span class="hl opt">}</span> field,
see <span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Device
Configuration Space / Legacy Interface: Device Configuration
Space<span class="hl opt">}</span>~<span class="hl kwa">\nameref</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Device Configuration Space / Legacy Interface: Device Configuration Space<span class="hl opt">}</span> for workarounds.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>PCI-specific Initialization And Device Operation<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over PCI Bus / PCI-specific Initialization And Device Operation<span class="hl opt">}</span>

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Device Initialization<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over PCI Bus / PCI-specific Initialization And Device Operation / Device Initialization<span class="hl opt">}</span>

This documents PCI-specific steps executed during Device Initialization.
As the first step, driver must detect device configuration layout
to locate configuration fields in memory, I/O or PCI configuration space of the
device.

<span class="hl kwa">\paragraph</span><span class="hl opt">{</span>Virtio Device Configuration Layout Detection<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over PCI Bus / PCI-specific Initialization And Device Operation / Device Initialization / Virtio Device Configuration Layout Detection<span class="hl opt">}</span>

As a prerequisite to device initialization, the driver scans the
PCI capability list, detecting virtio configuration layout using Virtio
Structure PCI capabilities.

<span class="hl kwa">\subparagraph</span><span class="hl opt">{</span>Legacy Interface: A Note on Device Layout Detection<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over PCI Bus / PCI-specific Initialization And Device Operation / Device Initialization / Virtio Device Configuration Layout Detection / Legacy Interface: A Note on Device Layout Detection<span class="hl opt">}</span>

Legacy drivers skipped the Device Layout Detection step, assuming legacy
device configuration space in BAR0 in I/O space unconditionally.

Legacy devices did not have the Virtio PCI Capability in their
capability list.

Therefore:

Transitional devices should expose the Legacy Interface in I/O
space in BAR0.

Transitional drivers should look for the Virtio PCI
Capabilities on the capability list.
If these are not present, driver should assume a legacy device.

Non-transitional drivers should look for the Virtio PCI
Capabilities on the capability list.
If these are not present, driver should assume a legacy device,
and fail gracefully.

Non-transitional devices, on a platform where a legacy driver for
a legacy device with the same ID might have previously existed,
MUST take the following steps to fail gracefully when a legacy
driver attempts to drive them:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>
<span class="hl kwa">\item</span> Present an I/O BAR in BAR0, and
<span class="hl kwa">\item</span> Respond to a single-byte zero write to offset <span class="hl num">18</span>
   (corresponding to Device Status register in the legacy layout)
   of BAR0 by presenting zeroes on every BAR and ignoring writes.
<span class="hl kwa">\end</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>

<span class="hl kwa">\paragraph</span><span class="hl opt">{</span>Queue Vector Configuration<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over PCI Bus / PCI-specific Initialization And Device Operation / Device Initialization / Queue Vector Configuration<span class="hl opt">}</span>

When MSI-X capability is present and enabled in the device
(through standard PCI configuration space) <span class="hl kwa">\field</span><span class="hl opt">{</span>config_msix_vector<span class="hl opt">}</span> and <span class="hl kwa">\field</span><span class="hl opt">{</span>queue_msix_vector<span class="hl opt">}</span> are used to map configuration change and queue
interrupts to MSI-X vectors. In this case, the ISR Status is unused.

Writing a valid MSI-X Table entry number, <span class="hl num">0</span> to <span class="hl num">0x7FF</span>, to
<span class="hl kwa">\field</span><span class="hl opt">{</span>config_msix_vector<span class="hl opt">}</span>/<span class="hl kwa">\field</span><span class="hl opt">{</span>queue_msix_vector<span class="hl opt">}</span> maps interrupts triggered
by the configuration change/selected queue events respectively to
the corresponding MSI-X vector. To disable interrupts for a
specific event type, unmap it by writing a special NO_VECTOR
value:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
/* Vector value used to disable MSI for queue */
#define VIRTIO_MSI_NO_VECTOR            <span class="hl num">0xffff</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

Reading these registers returns vector mapped to a given event,
or NO_VECTOR if unmapped. All queue and configuration change
events are unmapped by default.

Note that mapping an event to vector might require allocating
internal device resources, and might fail. Devices MUST <span class="hl kwb">report</span> such
failures by returning the NO_VECTOR value when the relevant
Vector field is read. After mapping an event to vector, the
driver MUST verify success by reading the Vector field value: on
success, the previously written value is returned, and on
failure, NO_VECTOR is returned. If a mapping failure is detected,
the driver can retry mapping with fewer vectors, or disable MSI-X.

<span class="hl kwa">\paragraph</span><span class="hl opt">{</span>Virtqueue Configuration<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over PCI Bus / PCI-specific Initialization And Device Operation / Device Initialization / Virtqueue Configuration<span class="hl opt">}</span>

As a device can have zero or more virtqueues for bulk data
transport (for example, the simplest network device has two), the driver
needs to configure them as part of the device-specific
configuration.

The driver does this as follows, for each virtqueue a device has:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>
<span class="hl kwa">\item</span> Write the virtqueue index (first queue is <span class="hl num">0</span>) to <span class="hl kwa">\field</span><span class="hl opt">{</span>queue_select<span class="hl opt">}</span>.

<span class="hl kwa">\item</span> Read the virtqueue size from <span class="hl kwa">\field</span><span class="hl opt">{</span>queue_size<span class="hl opt">}</span>, which MUST
   be a power of <span class="hl num">2</span>. This controls how big the virtqueue is
  (see <span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Virtqueues<span class="hl opt">}</span>~<span class="hl kwa">\nameref</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Virtqueues<span class="hl opt">}</span>). If this field is <span class="hl num">0</span>, the virtqueue does not exist.

<span class="hl kwa">\item</span> Optionally, select a smaller virtqueue size and write it to <span class="hl kwa">\field</span><span class="hl opt">{</span>queue_size<span class="hl opt">}</span>.

<span class="hl kwa">\item</span> Allocate and zero Descriptor Table, Available and Used rings for the
   virtqueue in contiguous physical memory.

<span class="hl kwa">\item</span> Optionally, if MSI-X capability is present and enabled on the
  device, select a vector to use to request interrupts triggered
  by virtqueue events. Write the MSI-X Table entry number
  corresponding to this vector into <span class="hl kwa">\field</span><span class="hl opt">{</span>queue_msix_vector<span class="hl opt">}</span>. Read
  <span class="hl kwa">\field</span><span class="hl opt">{</span>queue_msix_vector<span class="hl opt">}</span>: on success, previously written value is
  returned; on failure, NO_VECTOR value is returned.
<span class="hl kwa">\end</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>

<span class="hl kwa">\subparagraph</span><span class="hl opt">{</span>Legacy Interface: A Note on Virtqueue Configuration<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over PCI Bus / PCI-specific Initialization And Device Operation / Device Initialization / Virtqueue Configuration / Legacy Interface: A Note on Virtqueue Configuration<span class="hl opt">}</span>
When using the legacy interface, the page size for a virtqueue on a PCI virtio
device is defined as <span class="hl num">4096</span> bytes.  Driver writes the physical address, divided
by <span class="hl num">4096</span> to the Queue Address field<span class="hl kwa">\footnote</span><span class="hl opt">{</span>The <span class="hl num">4096</span> is based on the x86 page size, but it&apos;s also large
enough to ensure that the separate parts of the virtqueue are on
separate cache lines.
<span class="hl opt">}</span>.  There was no mechanism to negotiate the queue size.

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Notifying The Device<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over PCI Bus / PCI-specific Initialization And Device Operation / Notifying The Device<span class="hl opt">}</span>

The driver notifies the device by writing the <span class="hl num">16</span>-bit virtqueue index
of this virtqueue to the Queue Notify address.  See <span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over PCI Bus / PCI Device Layout / Notification capability<span class="hl opt">}</span> for how to calculate this address.

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Virtqueue Interrupts From The Device<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over PCI Bus / PCI-specific Initialization And Device Operation / Virtqueue Interrupts From The Device<span class="hl opt">}</span>

If an interrupt is necessary for a virtqueue, the device SHOULD:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>
  <span class="hl kwa">\item</span> If MSI-X capability is disabled:
    <span class="hl kwa">\begin</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>
    <span class="hl kwa">\item</span> Set the lower bit of the ISR Status field for the device.

    <span class="hl kwa">\item</span> Send the appropriate PCI interrupt for the device.
    <span class="hl kwa">\end</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>

  <span class="hl kwa">\item</span> If MSI-X capability is enabled:
    <span class="hl kwa">\begin</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>
    <span class="hl kwa">\item</span> Request the appropriate MSI-X interrupt message for the
      device, <span class="hl kwa">\field</span><span class="hl opt">{</span>queue_msix_vector<span class="hl opt">}</span> sets the MSI-X Table entry
      number.

    <span class="hl kwa">\item</span> If the vector field value is NO_VECTOR, no interrupt
      message is requested for this event, so the device MUST NOT
      deliver an interrupt.
    <span class="hl kwa">\end</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>

The driver interrupt handler SHOULD:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>
  <span class="hl kwa">\item</span> If MSI-X capability is disabled: read the ISR Status field,
  which will reset it to zero. If the lower bit is zero, the
  interrupt was not for this device. Otherwise, the driver
  SHOULD look through the used rings of all virtqueues for the
  device, to see if any progress has been made by the device
  which requires servicing.

  <span class="hl kwa">\item</span> If MSI-X capability is enabled: look through the used rings of
  all virtqueues mapped to the specific MSI-X vector for the
  device, to see if any progress has been made by the device
  which requires servicing.
<span class="hl kwa">\end</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Notification of Device Configuration Changes<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over PCI Bus / PCI-specific Initialization And Device Operation / Notification of Device Configuration Changes<span class="hl opt">}</span>

Some devices can change the device configuration space. In this case:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>
  <span class="hl kwa">\item</span> If MSI-X capability is disabled: an interrupt is delivered and
  the second lowest bit is set in the ISR Status field to
  indicate that the driver should re-examine the configuration
  space.  Note that a single interrupt can indicate both that one
  or more virtqueue has been used and that the configuration
  space has changed: even if the config bit is set, virtqueues
  MUST be scanned.

  <span class="hl kwa">\item</span> If MSI-X capability is enabled: an interrupt message is
  requested. <span class="hl kwa">\field</span><span class="hl opt">{</span>config_msix_vector<span class="hl opt">}</span> sets the MSI-X Table
  entry number to use. If <span class="hl kwa">\field</span><span class="hl opt">{</span>config_msix_vector<span class="hl opt">}</span> is
  NO_VECTOR, no interrupt message is requested for this event and
  the device MUST NOT deliver an interrupt.
<span class="hl kwa">\end</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>

<span class="hl kwa">\section</span><span class="hl opt">{</span>Virtio Over MMIO<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over MMIO<span class="hl opt">}</span>

Virtual environments without PCI support (a common situation in
embedded devices models) might use simple memory mapped device
(&quot;virtio-mmio&quot;) instead of the PCI device.

The memory mapped virtio device behaviour is based on the PCI
device specification. Therefore most of operations like device
initialization, queues configuration and buffer transfers are
nearly identical. Existing differences are described in the
following sections.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>MMIO Device Discovery<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over MMIO / MMIO Device Discovery<span class="hl opt">}</span>

Unlike PCI, MMIO provides no generic device discovery.  For each
device, the guest OS will need to know the location of the registers
and interrupt(s) used.  The suggested binding for systems using
flattened device trees is shown in this example:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
// EXAMPLE: virtio_block device taking <span class="hl num">256</span> bytes at <span class="hl num">0x1e000</span>, interrupt <span class="hl num">42</span>.
virtio_block&#64;<span class="hl num">1</span>e000 <span class="hl opt">{</span>
        compatible = &quot;virtio,mmio&quot;;
        reg = &lt;<span class="hl num">0x1e000 0x100</span>&gt;;
        interrupts = &lt;<span class="hl num">42</span>&gt;;
<span class="hl opt">}</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>MMIO Device Register Layout<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over MMIO / MMIO Device Register Layout<span class="hl opt">}</span>

MMIO virtio devices provides a set of memory mapped control
registers followed by a device-specific configuration space,
described in the table~<span class="hl kwa">\ref</span><span class="hl opt">{</span>tab:Virtio Trasport Options / Virtio Over MMIO / MMIO Device Register Layout<span class="hl opt">}</span>.
Driver MUST NOT access memory locations not explicitly described in the
table (or, in case of the configuration space, described in the device specification),
MUST NOT write to the read-only registers (direction R) and
MUST NOT read from the write-only registers (direction W).

All register values are organized as Little Endian.


<span class="hl kwa">\newcommand</span><span class="hl opt">{</span><span class="hl kwa">\mmioreg</span><span class="hl opt">}[</span><span class="hl num">5</span><span class="hl opt">]{</span><span class="hl slc">% Name Function Offset Direction Description</span>
  <span class="hl opt">{</span><span class="hl kwa">\field</span><span class="hl opt">{</span><span class="hl kwc">#1</span><span class="hl opt">}}</span> <span class="hl kwa">\newline</span> <span class="hl kwc">#3</span> <span class="hl kwa">\newline</span> <span class="hl kwc">#4</span> &amp; <span class="hl opt">{</span><span class="hl kwa">\bf</span><span class="hl kwc">#2</span><span class="hl opt">}</span> <span class="hl kwa">\newline</span> <span class="hl kwc">#5</span> \\
<span class="hl opt">}</span>

<span class="hl kwa">\newcommand</span><span class="hl opt">{</span><span class="hl kwa">\mmiodreg</span><span class="hl opt">}[</span><span class="hl num">7</span><span class="hl opt">]{</span><span class="hl slc">% NameHigh NameLow Function OffsetHigh OffsetLow Direction Description</span>
  <span class="hl opt">{</span><span class="hl kwa">\bf</span><span class="hl kwc">#1</span><span class="hl opt">}</span> <span class="hl kwa">\newline</span> <span class="hl kwc">#4</span> <span class="hl kwa">\newline</span> <span class="hl opt">{</span><span class="hl kwa">\bf</span><span class="hl kwc">#2</span><span class="hl opt">}</span> <span class="hl kwa">\newline</span> <span class="hl kwc">#5</span> <span class="hl kwa">\newline</span> <span class="hl kwc">#6</span> &amp; <span class="hl opt">{</span><span class="hl kwa">\bf</span><span class="hl kwc">#3</span><span class="hl opt">}</span> <span class="hl kwa">\newline</span> <span class="hl kwc">#7</span> \\
<span class="hl opt">}</span>

<span class="hl kwa">\begin</span><span class="hl opt">{</span>longtable<span class="hl opt">}{</span>p<span class="hl opt">{</span><span class="hl num">0.2</span><span class="hl kwa">\textwidth</span><span class="hl opt">}</span>p<span class="hl opt">{</span><span class="hl num">0.7</span><span class="hl kwa">\textwidth</span><span class="hl opt">}}</span>
  <span class="hl kwa">\caption</span> <span class="hl opt">{</span>MMIO Device Register Layout<span class="hl opt">}</span>
  <span class="hl kwa">\label</span><span class="hl opt">{</span>tab:Virtio Trasport Options / Virtio Over MMIO / MMIO Device Register Layout<span class="hl opt">}</span> \\
  <span class="hl kwa">\hline</span>
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>Name<span class="hl opt">}{</span>Function<span class="hl opt">}{</span>Offset from base<span class="hl opt">}{</span>Direction<span class="hl opt">}{</span>Description<span class="hl opt">}</span> 
  <span class="hl kwa">\hline</span> 
  <span class="hl kwa">\hline</span> 
  <span class="hl kwa">\endfirsthead</span>
  <span class="hl kwa">\hline</span>
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>Name<span class="hl opt">}{</span>Function<span class="hl opt">}{</span>Offset from the base<span class="hl opt">}{</span>Direction<span class="hl opt">}{</span>Description<span class="hl opt">}</span> 
  <span class="hl kwa">\hline</span> 
  <span class="hl kwa">\hline</span> 
  <span class="hl kwa">\endhead</span>
  <span class="hl kwa">\endfoot</span>
  <span class="hl kwa">\endlastfoot</span>
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>MagicValue<span class="hl opt">}{</span>Magic value<span class="hl opt">}{</span><span class="hl num">0x000</span><span class="hl opt">}{</span>R<span class="hl opt">}{</span><span class="hl slc">%</span>
    Device MUST return value <span class="hl num">0x74726976</span>
    (a Little Endian equivalent of the &quot;virt&quot; string).
    Driver MUST ignore device returning other values,
    although it MAY <span class="hl kwb">report</span> an error.
  <span class="hl opt">}</span> 
  <span class="hl kwa">\hline</span>
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>Version<span class="hl opt">}{</span>Device version number<span class="hl opt">}{</span><span class="hl num">0x004</span><span class="hl opt">}{</span>R<span class="hl opt">}{</span><span class="hl slc">%</span>
    Devices compliant with this specification MUST return value <span class="hl num">0x2</span>.
    Legacy device (see <span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over MMIO / Legacy interface<span class="hl opt">}</span>~<span class="hl kwa">\nameref</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over MMIO / Legacy interface<span class="hl opt">}</span>) MAY return value <span class="hl num">0x1</span>.
    Driver MUST ignore device returning other values,
    although it MAY <span class="hl kwb">report</span> an error.
  <span class="hl opt">}</span>
  <span class="hl kwa">\hline</span> 
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>DeviceID<span class="hl opt">}{</span>Virtio Subsystem Device ID<span class="hl opt">}{</span><span class="hl num">0x008</span><span class="hl opt">}{</span>R<span class="hl opt">}{</span><span class="hl slc">%</span>
    See <span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:Device Types<span class="hl opt">}</span>~<span class="hl kwa">\nameref</span><span class="hl opt">{</span>sec:Device Types<span class="hl opt">}</span> for possible values.
    Value zero (<span class="hl num">0x0</span>) is invalid and driver MUST ignore such device
    but MUST NOT <span class="hl kwb">report</span> any error. This behaviour can be used to
    define a system memory map with placeholder devices at static,
    well known addresses, assigning functions to them depending
    on user&apos;s needs.
  <span class="hl opt">}</span>
  <span class="hl kwa">\hline</span> 
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>VendorID<span class="hl opt">}{</span>Virtio Subsystem Vendor ID<span class="hl opt">}{</span><span class="hl num">0x00c</span><span class="hl opt">}{</span>R<span class="hl opt">}{}</span>
  <span class="hl kwa">\hline</span> 
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>DeviceFeatures<span class="hl opt">}{</span>Flags representing features the device supports<span class="hl opt">}{</span><span class="hl num">0x010</span><span class="hl opt">}{</span>R<span class="hl opt">}{</span><span class="hl slc">%</span>
    Reading from this register returns <span class="hl num">32</span> consecutive flag bits,
    first bit depending on the last value written to
    <span class="hl kwa">\field</span><span class="hl opt">{</span>DeviceFeaturesSel<span class="hl opt">}</span>. Access to this register returns
    bits $<span class="hl kwa">\field</span><span class="hl opt">{</span>DeviceFeaturesSel<span class="hl opt">}</span>*<span class="hl num">32</span>$ to $(<span class="hl kwa">\field</span><span class="hl opt">{</span>DeviceFeaturesSel<span class="hl opt">}</span>*<span class="hl num">32</span>)+<span class="hl num">31</span>$, eg.
    feature bits <span class="hl num">0</span> to <span class="hl num">31</span> if <span class="hl kwa">\field</span><span class="hl opt">{</span>DeviceFeaturesSel<span class="hl opt">}</span> is set to <span class="hl num">0</span> and
    features bits <span class="hl num">32</span> to <span class="hl num">63</span> if <span class="hl kwa">\field</span><span class="hl opt">{</span>DeviceFeaturesSel<span class="hl opt">}</span> is set to <span class="hl num">1</span>.
    Also see <span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Feature Bits<span class="hl opt">}</span>~<span class="hl kwa">\nameref</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Feature Bits<span class="hl opt">}</span>.
  <span class="hl opt">}</span>
  <span class="hl kwa">\hline</span> 
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>DeviceFeaturesSel<span class="hl opt">}{</span>Device (host) features word selection.<span class="hl opt">}{</span><span class="hl num">0x014</span><span class="hl opt">}{</span>W<span class="hl opt">}{</span><span class="hl slc">%</span>
    Writing to this register selects a set of <span class="hl num">32</span> device feature bits
    accessible by reading from <span class="hl kwa">\field</span><span class="hl opt">{</span>DeviceFeatures<span class="hl opt">}</span>. The driver
    MUST write a value to <span class="hl kwa">\field</span><span class="hl opt">{</span>DeviceFeaturesSel<span class="hl opt">}</span> before
    reading from <span class="hl kwa">\field</span><span class="hl opt">{</span>DeviceFeatures<span class="hl opt">}</span>.
  <span class="hl opt">}</span>
  <span class="hl kwa">\hline</span> 
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>DriverFeatures<span class="hl opt">}{</span>Flags representing device features understood and activated by the driver<span class="hl opt">}{</span><span class="hl num">0x020</span><span class="hl opt">}{</span>W<span class="hl opt">}{</span><span class="hl slc">%</span>
    Writing to this register sets <span class="hl num">32</span> consecutive flag bits, first
    bit depending on the last value written to <span class="hl kwa">\field</span><span class="hl opt">{</span>DriverFeaturesSel<span class="hl opt">}</span>.
     Access to this register sets bits $<span class="hl kwa">\field</span><span class="hl opt">{</span>DriverFeaturesSel<span class="hl opt">}</span>*<span class="hl num">32</span>$
    to $(<span class="hl kwa">\field</span><span class="hl opt">{</span>DriverFeaturesSel<span class="hl opt">}</span>*<span class="hl num">32</span>)+<span class="hl num">31</span>$, eg. feature bits <span class="hl num">0</span> to <span class="hl num">31</span> if
    <span class="hl kwa">\field</span><span class="hl opt">{</span>DriverFeaturesSel<span class="hl opt">}</span> is set to <span class="hl num">0</span> and features bits <span class="hl num">32</span> to <span class="hl num">63</span> if
    <span class="hl kwa">\field</span><span class="hl opt">{</span>DriverFeaturesSel<span class="hl opt">}</span> is set to <span class="hl num">1</span>. Also see <span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Feature Bits<span class="hl opt">}</span>~<span class="hl kwa">\nameref</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Feature Bits<span class="hl opt">}</span>.
  <span class="hl opt">}</span>
  <span class="hl kwa">\hline</span> 
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>DriverFeaturesSel<span class="hl opt">}{</span>Activated (guest) features word selection<span class="hl opt">}{</span><span class="hl num">0x024</span><span class="hl opt">}{</span>W<span class="hl opt">}{</span><span class="hl slc">%</span>
    Writing to this register selects a set of <span class="hl num">32</span> activated feature
    bits accessible by writing to <span class="hl kwa">\field</span><span class="hl opt">{</span>DriverFeatures<span class="hl opt">}</span>.
    The driver MUST write a value to the <span class="hl kwa">\field</span><span class="hl opt">{</span>DriverFeaturesSel<span class="hl opt">}</span>
    register before writing to the <span class="hl kwa">\field</span><span class="hl opt">{</span>DriverFeatures<span class="hl opt">}</span> register.
  <span class="hl opt">}</span>
  <span class="hl kwa">\hline</span> 
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>QueueSel<span class="hl opt">}{</span>Virtual queue index<span class="hl opt">}{</span><span class="hl num">0x030</span><span class="hl opt">}{</span>W<span class="hl opt">}{</span><span class="hl slc">%</span>
    Writing to this register selects the virtual queue that the
    following operations on <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueNumMax<span class="hl opt">}</span>, <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueNum<span class="hl opt">}</span>, <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueReady<span class="hl opt">}</span>,
    <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueDescLow<span class="hl opt">}</span>, <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueDescHigh<span class="hl opt">}</span>, <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueAvailLow<span class="hl opt">}</span>, <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueAvailHigh<span class="hl opt">}</span>,
    <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueUsedLow<span class="hl opt">}</span> and <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueUsedHigh<span class="hl opt">}</span> apply to. The index
    number of the first queue is zero (<span class="hl num">0x0</span>). 
  <span class="hl opt">}</span>
  <span class="hl kwa">\hline</span> 
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>QueueNumMax<span class="hl opt">}{</span>Maximum virtual queue size<span class="hl opt">}{</span><span class="hl num">0x034</span><span class="hl opt">}{</span>R<span class="hl opt">}{</span><span class="hl slc">%</span>
    Reading from the register returns the maximum size (number of
    elements) of the queue the device is ready to process or
    zero (<span class="hl num">0x0</span>) if the queue is not available. This applies to the
    queue selected by writing to <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueSel<span class="hl opt">}</span>. The driver MUST NOT
    access this register when the queue is in use (so when <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueReady<span class="hl opt">}</span>
    is not zero).
  <span class="hl opt">}</span>
  <span class="hl kwa">\hline</span> 
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>QueueNum<span class="hl opt">}{</span>Virtual queue size<span class="hl opt">}{</span><span class="hl num">0x038</span><span class="hl opt">}{</span>W<span class="hl opt">}{</span><span class="hl slc">%</span>
    Queue size is the number of elements in the queue, therefore size
    of the Descriptor Table and both Available and Used rings.
    Writing to this register notifies the device what size of the
    queue the driver will use. This applies to the queue selected by
    writing to <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueSel<span class="hl opt">}</span>. The driver MUST NOT access this register when
    the queue is in use (so when <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueReady<span class="hl opt">}</span> is not zero).
  <span class="hl opt">}</span>
  <span class="hl kwa">\hline</span> 
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>QueueReady<span class="hl opt">}{</span>Virtual queue ready bit<span class="hl opt">}{</span><span class="hl num">0x044</span><span class="hl opt">}{</span>RW<span class="hl opt">}{</span><span class="hl slc">%</span>
    Writing one (<span class="hl num">0x1</span>) to this register notifies the device that the
    virtual queue is ready to be used. Reading from this register
    returns the last value written to it. Both read and write
    accesses apply to the queue selected by writing to <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueSel<span class="hl opt">}</span>.
    When the driver wants to stop using the queue it MUST write
    zero (<span class="hl num">0x0</span>) to this register and MUST read the value back to
    ensure synchronisation.
  <span class="hl opt">}</span>
  <span class="hl kwa">\hline</span> 
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>QueueNotify<span class="hl opt">}{</span>Queue notifier<span class="hl opt">}{</span><span class="hl num">0x050</span><span class="hl opt">}{</span>W<span class="hl opt">}{</span><span class="hl slc">%</span>
    Writing a queue index to this register notifies the device that
    there are new buffers to process in the queue.
  <span class="hl opt">}</span>
  <span class="hl kwa">\hline</span> 
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>InterruptStatus<span class="hl opt">}{</span>Interrupt status<span class="hl opt">}{</span><span class="hl num">0x60</span><span class="hl opt">}{</span>R<span class="hl opt">}{</span><span class="hl slc">%</span>
    Reading from this register returns a bit mask of events that
    caused the device interrupt to be asserted.
    From a moment when any of these events takes place, the
    device MUST be returning a value with the related
    bits set, ie. equal one (<span class="hl num">1</span>), and all other bits cleared, 
    ie. equal zero (<span class="hl num">0</span>), until the driver acknowledges the interrupt
    by writing a corresponding bit mask to the InterruptACK register.
    The following events are possible:
    <span class="hl kwa">\begin</span><span class="hl opt">{</span>description<span class="hl opt">}</span>
      <span class="hl kwa">\item</span><span class="hl opt">[</span>Used Ring Update<span class="hl opt">]</span> - bit <span class="hl num">0</span> - the interrupt was asserted
        because the device has updated the Used
        Ring in at least one of the active virtual queues.
      <span class="hl kwa">\item</span> <span class="hl opt">[</span>Configuration Change<span class="hl opt">]</span> - bit <span class="hl num">1</span> - the interrupt was
        asserted because the configuration of the device has changed.
    <span class="hl kwa">\end</span><span class="hl opt">{</span>description<span class="hl opt">}</span>
    Other bits of the value are reserved for future use and the
    driver MUST ignore them.
  <span class="hl opt">}</span>
  <span class="hl kwa">\hline</span> 
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>InterruptACK<span class="hl opt">}{</span>Interrupt acknowledge<span class="hl opt">}{</span><span class="hl num">0x064</span><span class="hl opt">}{</span>W<span class="hl opt">}{</span><span class="hl slc">%</span>
    Writing to this register notifies the device that the interrupt
    has been handled.
    When the driver finishes handling an interrupt, it MUST write
    a value to this register with bits corresponding to the handled
    events (as defined for <span class="hl kwa">\field</span><span class="hl opt">{</span>InterruptStatus<span class="hl opt">}</span>) set, ie.
    equal one (<span class="hl num">1</span>), and all other bits cleared, ie. equal zero (<span class="hl num">0</span>).
  <span class="hl opt">}</span>
  <span class="hl kwa">\hline</span> 
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>Status<span class="hl opt">}{</span>Device status<span class="hl opt">}{</span><span class="hl num">0x070</span><span class="hl opt">}{</span>RW<span class="hl opt">}{</span><span class="hl slc">%</span>
    Reading from this register returns the current device status
    flags.
    Writing non-zero values to this register sets the status flags,
    indicating the driver progress. Writing zero (<span class="hl num">0x0</span>) to this
    register triggers a device reset, including clearing all
    bits in <span class="hl kwa">\field</span><span class="hl opt">{</span>InterruptStatus<span class="hl opt">}</span> and ready bits in the
    <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueReady<span class="hl opt">}</span> register for all queues in the device. 
    See also p. <span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over MMIO / MMIO-specific Initialization And Device Operation / Device Initialization<span class="hl opt">}</span>~<span class="hl kwa">\nameref</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over MMIO / MMIO-specific Initialization And Device Operation / Device Initialization<span class="hl opt">}</span>.
  <span class="hl opt">}</span>
  <span class="hl kwa">\hline</span> 
  <span class="hl kwa">\mmiodreg</span><span class="hl opt">{</span>QueueDescLow<span class="hl opt">}{</span>QueueDescHigh<span class="hl opt">}{</span>Virtual queue&apos;s Descriptor Table <span class="hl num">64</span> bit long physical address<span class="hl opt">}{</span><span class="hl num">0x080</span><span class="hl opt">}{</span><span class="hl num">0x084</span><span class="hl opt">}{</span>W<span class="hl opt">}{</span><span class="hl slc">%</span>
    Writing to these two registers (lower <span class="hl num">32</span> bits of the address
    to <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueDescLow<span class="hl opt">}</span>, higher <span class="hl num">32</span> bits to <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueDescHigh<span class="hl opt">}</span>) notifies
    the device about location of the Descriptor Table of the queue
    selected by writing to <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueSel<span class="hl opt">}</span> register. The driver MUST NOT
    access this register when the queue is in use (so when <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueReady<span class="hl opt">}</span>
    is not zero).
  <span class="hl opt">}</span>
  <span class="hl kwa">\hline</span> 
  <span class="hl kwa">\mmiodreg</span><span class="hl opt">{</span>QueueAvailLow<span class="hl opt">}{</span>QueueAvailHigh<span class="hl opt">}{</span>Virtual queue&apos;s Available Ring <span class="hl num">64</span> bit long physical address<span class="hl opt">}{</span><span class="hl num">0x090</span><span class="hl opt">}{</span><span class="hl num">0x094</span><span class="hl opt">}{</span>W<span class="hl opt">}{</span><span class="hl slc">%</span>
    Writing to these two registers (lower <span class="hl num">32</span> bits of the address
    to <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueAvailLow<span class="hl opt">}</span>, higher <span class="hl num">32</span> bits to <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueAvailHigh<span class="hl opt">}</span>) notifies
    the device about location of the Available Ring of the queue
    selected by writing to <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueSel<span class="hl opt">}</span>. The driver MUST NOT
    access this register when the queue is in use (so when <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueReady<span class="hl opt">}</span>
    is not zero).
  <span class="hl opt">}</span>
  <span class="hl kwa">\hline</span> 
  <span class="hl kwa">\mmiodreg</span><span class="hl opt">{</span>QueueUsedLow<span class="hl opt">}{</span>QueueUsedHigh<span class="hl opt">}{</span>Virtual queue&apos;s Used Ring <span class="hl num">64</span> bit long physical address<span class="hl opt">}{</span><span class="hl num">0x0a0</span><span class="hl opt">}{</span><span class="hl num">0x0a4</span><span class="hl opt">}{</span>W<span class="hl opt">}{</span><span class="hl slc">%</span>
    Writing to these two registers (lower <span class="hl num">32</span> bits of the address
    to <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueUsedLow<span class="hl opt">}</span>, higher <span class="hl num">32</span> bits to <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueUsedHigh<span class="hl opt">}</span>) notifies
    the device about location of the Used Ring of the queue
    selected by writing to <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueSel<span class="hl opt">}</span>. The driver MUST NOT
    access this register when the queue is in use (so when <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueReady<span class="hl opt">}</span>
    is not zero).
  <span class="hl opt">}</span>
  <span class="hl kwa">\hline</span> 
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>ConfigGeneration<span class="hl opt">}{</span>Configuration atomicity value<span class="hl opt">}{</span><span class="hl num">0x0fc</span><span class="hl opt">}{</span>R<span class="hl opt">}{</span>
    Changes every time the configuration noticeably changes. This
    means the device may only change the value after a configuration
    read operation, but it MUST change if there is any risk of a
    device seeing an inconsistent configuration state.
  <span class="hl opt">}</span>
  <span class="hl kwa">\hline</span> 
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>Config<span class="hl opt">}{</span>Configuration space<span class="hl opt">}{</span><span class="hl num">0x100</span>+<span class="hl opt">}{</span>RW<span class="hl opt">}{</span>
    Device-specific configuration space starts at the offset <span class="hl num">0x100</span>
    and is accessed with byte alignment. Its meaning and size
    depend on the device and the driver.
  <span class="hl opt">}</span>
  <span class="hl kwa">\hline</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>longtable<span class="hl opt">}</span>

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>MMIO-specific Initialization And Device Operation<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over MMIO / MMIO-specific Initialization And Device Operation<span class="hl opt">}</span>

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Device Initialization<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over MMIO / MMIO-specific Initialization And Device Operation / Device Initialization<span class="hl opt">}</span>

The driver MUST start the device initialization by reading and
checking values from <span class="hl kwa">\field</span><span class="hl opt">{</span>MagicValue<span class="hl opt">}</span> and <span class="hl kwa">\field</span><span class="hl opt">{</span>Version<span class="hl opt">}</span>.
If both values are valid, it MUST read <span class="hl kwa">\field</span><span class="hl opt">{</span>DeviceID<span class="hl opt">}</span>
and if its value is zero (<span class="hl num">0x0</span>) MUST abort initialization and
MUST NOT access any other register.

Further initialization MUST follow the procedure described in
<span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:General Initialization And Device Operation / Device Initialization<span class="hl opt">}</span>~<span class="hl kwa">\nameref</span><span class="hl opt">{</span>sec:General Initialization And Device Operation / Device Initialization<span class="hl opt">}</span>.

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Virtqueue Configuration<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over MMIO / MMIO-specific Initialization And Device Operation / Virtqueue Configuration<span class="hl opt">}</span>

The driver MUST initialize the virtual queue in the following way:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>
<span class="hl kwa">\item</span> Select the queue writing its index (first queue is <span class="hl num">0</span>) to
   <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueSel<span class="hl opt">}</span>.

<span class="hl kwa">\item</span> Check if the queue is not already in use: read <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueReady<span class="hl opt">}</span>,
   returned value should be zero (<span class="hl num">0x0</span>).

<span class="hl kwa">\item</span> Read maximum queue size (number of elements) from
   <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueNumMax<span class="hl opt">}</span>. If the returned value is zero (<span class="hl num">0x0</span>) the
   queue is not available.

<span class="hl kwa">\item</span> Allocate and zero the queue pages, making sure the memory
   is physically contiguous. It is recommended to align the
   Used Ring to an optimal boundary (usually the page size).
   Size of the allocated queue MUST be smaller than or equal to
   the maximum size returned by the device.

<span class="hl kwa">\item</span> Notify the device about the queue size by writing the size to
   <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueNum<span class="hl opt">}</span>.

<span class="hl kwa">\item</span> Write physical addresses of the queue&apos;s Descriptor Table,
   Available Ring and Used Ring to (respectively) the
   <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueDescLow<span class="hl opt">}</span>/<span class="hl kwa">\field</span><span class="hl opt">{</span>QueueDescHigh<span class="hl opt">}</span>,
   <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueAvailLow<span class="hl opt">}</span>/<span class="hl kwa">\field</span><span class="hl opt">{</span>QueueAvailHigh<span class="hl opt">}</span> and
   <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueUsedLow<span class="hl opt">}</span>/<span class="hl kwa">\field</span><span class="hl opt">{</span>QueueUsedHigh<span class="hl opt">}</span> register pairs.

<span class="hl kwa">\item</span> Write <span class="hl num">0x1</span> to <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueReady<span class="hl opt">}</span>.
<span class="hl kwa">\end</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Notifying The Device<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over MMIO / MMIO-specific Initialization And Device Operation / Notifying The Device<span class="hl opt">}</span>

The driver MUST notify the device about new buffers being available in
a queue by writing the index of the updated queue to <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueNotify<span class="hl opt">}</span>.

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Notifications From The Device<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over MMIO / MMIO-specific Initialization And Device Operation / Notifications From The Device<span class="hl opt">}</span>

The memory mapped virtio device is using a single, dedicated
interrupt signal, which is asserted when at least one of the
bits described in the description of <span class="hl kwa">\field</span><span class="hl opt">{</span>InterruptStatus<span class="hl opt">}</span>
is set. This way the device may notify the
driver about a new used buffer being available in the queue
or about a change in the device configuration.

After receiving an interrupt, the driver MUST read
<span class="hl kwa">\field</span><span class="hl opt">{</span>InterruptStatus<span class="hl opt">}</span> to check what caused the interrupt
(see the register description). After the interrupt is handled,
the driver MUST acknowledge it by writing a bit mask
corresponding to the handled events to the InterruptACK register.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Legacy interface<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over MMIO / Legacy interface<span class="hl opt">}</span>

The legacy MMIO transport used page-based addressing, resulting
in a slightly different control register layout, the device
initialization and the virtual queue configuration procedure.

Table <span class="hl kwa">\ref</span><span class="hl opt">{</span>tab:Virtio Trasport Options / Virtio Over MMIO / MMIO Device Legacy Register Layout<span class="hl opt">}</span> 
presents control registers layout, omitting
descriptions of registers which did not change their function
nor behaviour:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>longtable<span class="hl opt">}{</span>p<span class="hl opt">{</span><span class="hl num">0.2</span><span class="hl kwa">\textwidth</span><span class="hl opt">}</span>p<span class="hl opt">{</span><span class="hl num">0.7</span><span class="hl kwa">\textwidth</span><span class="hl opt">}}</span>
  <span class="hl kwa">\caption</span> <span class="hl opt">{</span>MMIO Device Legacy Register Layout<span class="hl opt">}</span>
  <span class="hl kwa">\label</span><span class="hl opt">{</span>tab:Virtio Trasport Options / Virtio Over MMIO / MMIO Device Legacy Register Layout<span class="hl opt">}</span> \\
  <span class="hl kwa">\hline</span>
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>Name<span class="hl opt">}{</span>Function<span class="hl opt">}{</span>Offset from base<span class="hl opt">}{</span>Direction<span class="hl opt">}{</span>Description<span class="hl opt">}</span> 
  <span class="hl kwa">\hline</span> 
  <span class="hl kwa">\hline</span> 
  <span class="hl kwa">\endfirsthead</span>
  <span class="hl kwa">\hline</span>
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>Name<span class="hl opt">}{</span>Function<span class="hl opt">}{</span>Offset from the base<span class="hl opt">}{</span>Direction<span class="hl opt">}{</span>Description<span class="hl opt">}</span> 
  <span class="hl kwa">\hline</span> 
  <span class="hl kwa">\hline</span> 
  <span class="hl kwa">\endhead</span>
  <span class="hl kwa">\endfoot</span>
  <span class="hl kwa">\endlastfoot</span>
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>MagicValue<span class="hl opt">}{</span>Magic value<span class="hl opt">}{</span><span class="hl num">0x000</span><span class="hl opt">}{</span>R<span class="hl opt">}{}</span>
  <span class="hl kwa">\hline</span>
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>Version<span class="hl opt">}{</span>Device version number<span class="hl opt">}{</span><span class="hl num">0x004</span><span class="hl opt">}{</span>R<span class="hl opt">}{</span>Legacy device MUST return value <span class="hl num">0x1</span>.<span class="hl opt">}</span>
  <span class="hl kwa">\hline</span>
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>DeviceID<span class="hl opt">}{</span>Virtio Subsystem Device ID<span class="hl opt">}{</span><span class="hl num">0x008</span><span class="hl opt">}{</span>R<span class="hl opt">}{}</span>
  <span class="hl kwa">\hline</span>
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>VendorID<span class="hl opt">}{</span>Virtio Subsystem Vendor ID<span class="hl opt">}{</span><span class="hl num">0x00c</span><span class="hl opt">}{</span>R<span class="hl opt">}{}</span>
  <span class="hl kwa">\hline</span>
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>HostFeatures<span class="hl opt">}{</span>Flags representing features the device supports<span class="hl opt">}{</span><span class="hl num">0x010</span><span class="hl opt">}{</span>R<span class="hl opt">}{}</span>
  <span class="hl kwa">\hline</span>
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>HostFeaturesSel<span class="hl opt">}{</span>Device (host) features word selection.<span class="hl opt">}{</span><span class="hl num">0x014</span><span class="hl opt">}{</span>W<span class="hl opt">}{}</span>
  <span class="hl kwa">\hline</span>
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>GuestFeatures<span class="hl opt">}{</span>Flags representing device features understood and activated by the driver<span class="hl opt">}{</span><span class="hl num">0x020</span><span class="hl opt">}{</span>W<span class="hl opt">}{}</span>
  <span class="hl kwa">\hline</span>
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>GuestFeaturesSel<span class="hl opt">}{</span>Activated (guest) features word selection<span class="hl opt">}{</span><span class="hl num">0x024</span><span class="hl opt">}{</span>W<span class="hl opt">}{}</span>
  <span class="hl kwa">\hline</span> 
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>GuestPageSize<span class="hl opt">}{</span>Guest page size<span class="hl opt">}{</span><span class="hl num">0x028</span><span class="hl opt">}{</span>W<span class="hl opt">}{</span><span class="hl slc">%</span>
    The driver MUST write the guest page size in bytes to the
    register during initialization, before any queues are used.
    This value MUST be a power of <span class="hl num">2</span> and is used by the device to
    calculate the Guest address of the first queue page
    (see QueuePFN).
  <span class="hl opt">}</span>
  <span class="hl kwa">\hline</span>
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>QueueSel<span class="hl opt">}{</span>Virtual queue index<span class="hl opt">}{</span><span class="hl num">0x030</span><span class="hl opt">}{</span>W<span class="hl opt">}{</span><span class="hl slc">%</span>
    Writing to this register selects the virtual queue that the
    following operations on the <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueNumMax<span class="hl opt">}</span>, <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueNum<span class="hl opt">}</span>, <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueAlign<span class="hl opt">}</span>
    and <span class="hl kwa">\field</span><span class="hl opt">{</span>QueuePFN<span class="hl opt">}</span> registers apply to. The index
    number of the first queue is zero (<span class="hl num">0x0</span>). 
.
  <span class="hl opt">}</span>
  <span class="hl kwa">\hline</span>
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>QueueNumMax<span class="hl opt">}{</span>Maximum virtual queue size<span class="hl opt">}{</span><span class="hl num">0x034</span><span class="hl opt">}{</span>R<span class="hl opt">}{</span><span class="hl slc">%</span>
    Reading from the register returns the maximum size of the queue
    the device is ready to process or zero (<span class="hl num">0x0</span>) if the queue is not
    available. This applies to the queue selected by writing to
    <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueSel<span class="hl opt">}</span> and is allowed only when <span class="hl kwa">\field</span><span class="hl opt">{</span>QueuePFN<span class="hl opt">}</span> is set to zero
    (<span class="hl num">0x0</span>), so when the queue is not actively used.
  <span class="hl opt">}</span>
  <span class="hl kwa">\hline</span>
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>QueueNum<span class="hl opt">}{</span>Virtual queue size<span class="hl opt">}{</span><span class="hl num">0x038</span><span class="hl opt">}{</span>W<span class="hl opt">}{</span><span class="hl slc">%</span>
    Queue size is the number of elements in the queue, therefore size
    of the descriptor table and both available and used rings.
    Writing to this register notifies the device what size of the
    queue the driver will use. This applies to the queue selected by
    writing to <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueSel<span class="hl opt">}</span>.
  <span class="hl opt">}</span>
  <span class="hl kwa">\hline</span>
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>QueueAlign<span class="hl opt">}{</span>Used Ring alignment in the virtual queue<span class="hl opt">}{</span><span class="hl num">0x03c</span><span class="hl opt">}{</span>W<span class="hl opt">}{</span><span class="hl slc">%</span>
    Writing to this register notifies the device about alignment
    boundary of the Used Ring in bytes. This value MUST be a power
    of <span class="hl num">2</span> and applies to the queue selected by writing to <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueSel<span class="hl opt">}</span>.
  <span class="hl opt">}</span>
  <span class="hl kwa">\hline</span>
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>QueuePFN<span class="hl opt">}{</span>Guest physical page number of the virtual queue<span class="hl opt">}{</span><span class="hl num">0x040</span><span class="hl opt">}{</span>RW<span class="hl opt">}{</span><span class="hl slc">%</span>
    Writing to this register notifies the device about location of the
    virtual queue in the Guest&apos;s physical address space. This value
    is the index number of a page starting with the queue
    Descriptor Table. Value zero (<span class="hl num">0x0</span>) means physical address zero
    (<span class="hl num">0x00000000</span>) and is illegal. When the driver stops using the
    queue it MUST write zero (<span class="hl num">0x0</span>) to this register.
    Reading from this register returns the currently used page
    number of the queue, therefore a value other than zero (<span class="hl num">0x0</span>)
    means that the queue is in use.
    Both read and write accesses apply to the queue selected by
    writing to <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueSel<span class="hl opt">}</span>.
  <span class="hl opt">}</span>
  <span class="hl kwa">\hline</span>
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>QueueNotify<span class="hl opt">}{</span>Queue notifier<span class="hl opt">}{</span><span class="hl num">0x050</span><span class="hl opt">}{</span>W<span class="hl opt">}{}</span>
  <span class="hl kwa">\hline</span>
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>InterruptStatus<span class="hl opt">}{</span>Interrupt status<span class="hl opt">}{</span><span class="hl num">0x60</span><span class="hl opt">}{</span>R<span class="hl opt">}{}</span>
  <span class="hl kwa">\hline</span>
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>InterruptACK<span class="hl opt">}{</span>Interrupt acknowledge<span class="hl opt">}{</span><span class="hl num">0x064</span><span class="hl opt">}{</span>W<span class="hl opt">}{}</span>
  <span class="hl kwa">\hline</span>
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>Status<span class="hl opt">}{</span>Device status<span class="hl opt">}{</span><span class="hl num">0x070</span><span class="hl opt">}{</span>RW<span class="hl opt">}{</span><span class="hl slc">%</span>
    Reading from this register returns the current device status
    flags.
    Writing non-zero values to this register sets the status flags,
    indicating the OS/driver progress. Writing zero (<span class="hl num">0x0</span>) to this
    register triggers a device reset. This should include
    setting <span class="hl kwa">\field</span><span class="hl opt">{</span>QueuePFN<span class="hl opt">}</span> to zero (<span class="hl num">0x0</span>) for all queues in the device.
    Also see <span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:General Initialization And Device Operation / Device Initialization<span class="hl opt">}</span>~<span class="hl kwa">\nameref</span><span class="hl opt">{</span>sec:General Initialization And Device Operation / Device Initialization<span class="hl opt">}</span>.
  <span class="hl opt">}</span>
  <span class="hl kwa">\hline</span>
  <span class="hl kwa">\mmioreg</span><span class="hl opt">{</span>Config<span class="hl opt">}{</span>Configuration space<span class="hl opt">}{</span><span class="hl num">0x100</span>+<span class="hl opt">}{</span>RW<span class="hl opt">}{}</span>
  <span class="hl kwa">\hline</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>longtable<span class="hl opt">}</span>

The virtual queue page size is defined by writing to <span class="hl kwa">\field</span><span class="hl opt">{</span>GuestPageSize<span class="hl opt">}</span>,
as written by the guest. This must be done before the
virtual queues are configured.

The virtual queue layout follows
p. <span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Virtqueues / Legacy Interfaces: A Note on Virtqueue Layout<span class="hl opt">}</span>~<span class="hl kwa">\nameref</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Virtqueues / Legacy Interfaces: A Note on Virtqueue Layout<span class="hl opt">}</span>,
with the alignment defined in <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueAlign<span class="hl opt">}</span>.

The virtual queue is configured as follows:
<span class="hl kwa">\begin</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>
<span class="hl kwa">\item</span> Select the queue writing its index (first queue is <span class="hl num">0</span>) to
   <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueSel<span class="hl opt">}</span>.

<span class="hl kwa">\item</span> Check if the queue is not already in use: read <span class="hl kwa">\field</span><span class="hl opt">{</span>QueuePFN<span class="hl opt">}</span>,
   returned value should be zero (<span class="hl num">0x0</span>).

<span class="hl kwa">\item</span> Read maximum queue size (number of elements) from
   <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueNumMax<span class="hl opt">}</span>. If the returned value is zero (<span class="hl num">0x0</span>) the
   queue is not available.

<span class="hl kwa">\item</span> Allocate and zero the queue pages in contiguous virtual
   memory, aligning the Used Ring to an optimal boundary (usually
   page size). Size of the allocated queue may be smaller than or
   equal to the maximum size returned by the device.

<span class="hl kwa">\item</span> Notify the device about the queue size by writing the size to
   <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueNum<span class="hl opt">}</span>.

<span class="hl kwa">\item</span> Notify the device about the used alignment by writing its value
   in bytes to <span class="hl kwa">\field</span><span class="hl opt">{</span>QueueAlign<span class="hl opt">}</span>.

<span class="hl kwa">\item</span> Write the physical number of the first page of the queue to
   the <span class="hl kwa">\field</span><span class="hl opt">{</span>QueuePFN<span class="hl opt">}</span> register.
<span class="hl kwa">\end</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>

Notification mechanisms did not change.

<span class="hl kwa">\section</span><span class="hl opt">{</span>Virtio Over Channel I/O<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio Over Channel I/O<span class="hl opt">}</span>

S/<span class="hl num">390</span> based virtual machines support neither PCI nor MMIO, so a
different transport is needed there.

virtio-ccw uses the standard channel I/O based mechanism used for
the majority of devices on S/<span class="hl num">390</span>. A virtual channel device with a
special control unit type acts as proxy to the virtio device
(similar to the way virtio-pci uses a PCI device) and
configuration and operation of the virtio device is accomplished
(mostly) via channel commands. This means virtio devices are
discoverable via standard operating system algorithms, and adding
virtio support is mainly a question of supporting a new control
unit type.

As the S/<span class="hl num">390</span> is a big endian machine, the data structures transmitted
via channel commands are big-endian: this is made clear by use of
the types be16, be32 and be64.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Basic Concepts<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio over channel I/O / Basic Concepts<span class="hl opt">}</span>

As a proxy device, virtio-ccw uses a channel-attached I/O control
unit with a special control unit type (<span class="hl num">0x3832</span>) and a control unit
model corresponding to the attached virtio device&apos;s subsystem
device ID, accessed via a virtual I/O subchannel and a virtual
channel path of type <span class="hl num">0x32</span>. This proxy device is discoverable via
normal channel subsystem device discovery (usually a STORE
SUBCHANNEL loop) and answers to the basic channel commands, most
importantly SENSE ID.

For a virtio-ccw proxy device, SENSE ID will return the following
information:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>tabular<span class="hl opt">}{</span> |l|l|l| <span class="hl opt">}</span>
<span class="hl kwa">\hline</span>
Bytes &amp; Description &amp; Contents \\
<span class="hl kwa">\hline \hline</span>
<span class="hl num">0</span>     &amp; reserved              &amp; <span class="hl num">0xff</span> \\
<span class="hl kwa">\hline</span>
<span class="hl num">1</span>-<span class="hl num">2</span>   &amp; control unit type     &amp; <span class="hl num">0x3832</span> \\
<span class="hl kwa">\hline</span>
<span class="hl num">3</span>     &amp; control unit model    &amp; &lt;virtio device id&gt; \\
<span class="hl kwa">\hline</span>
<span class="hl num">4</span>-<span class="hl num">5</span>   &amp; device type           &amp; zeroes (unset) \\
<span class="hl kwa">\hline</span>
<span class="hl num">6</span>     &amp; device model          &amp; zeroes (unset) \\
<span class="hl kwa">\hline</span>
<span class="hl num">7</span>-<span class="hl num">255</span> &amp; extended SenseId data &amp; zeroes (unset) \\
<span class="hl kwa">\hline</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>tabular<span class="hl opt">}</span>

A driver for virtio-ccw devices MUST check for a control unit
type of <span class="hl num">0x3832</span> and MUST ignore the device type and model.

In addition to the basic channel commands, virtio-ccw defines a
set of channel commands related to configuration and operation of
virtio:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
#define CCW_CMD_SET_VQ <span class="hl num">0x13</span>
#define CCW_CMD_VDEV_RESET <span class="hl num">0x33</span>
#define CCW_CMD_SET_IND <span class="hl num">0x43</span>
#define CCW_CMD_SET_CONF_IND <span class="hl num">0x53</span>
#define CCW_CMD_SET_IND_ADAPTER <span class="hl num">0x73</span>
#define CCW_CMD_READ_FEAT <span class="hl num">0x12</span>
#define CCW_CMD_WRITE_FEAT <span class="hl num">0x11</span>
#define CCW_CMD_READ_CONF <span class="hl num">0x22</span>
#define CCW_CMD_WRITE_CONF <span class="hl num">0x21</span>
#define CCW_CMD_WRITE_STATUS <span class="hl num">0x31</span>
#define CCW_CMD_READ_VQ_CONF <span class="hl num">0x32</span>
#define CCW_CMD_SET_VIRTIO_REV <span class="hl num">0x83</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

The virtio-ccw device acts like a normal channel device, as specified
in <span class="hl kwa">\hyperref</span><span class="hl opt">[</span>intro:S390 PoP<span class="hl opt">]{[</span>S390 PoP<span class="hl opt">]}</span> and <span class="hl kwa">\hyperref</span><span class="hl opt">[</span>intro:S390 Common I/O<span class="hl opt">]{[</span>S390 Common I/O<span class="hl opt">]}</span>. In particular:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>
<span class="hl kwa">\item</span> A device MUST post a unit check with command reject for any command
  it does not support.

<span class="hl kwa">\item</span> If a driver did not suppress length checks for a channel command,
  the device MUST present a subchannel status as detailed in the
  architecture when the actual length did not match the expected length.

<span class="hl kwa">\item</span> If a driver did suppress length checks for a channel command, the
  device MUST present a check condition if the transmitted data does
  not contain enough data to process the command. If the driver submitted
  a buffer that was too long, the device SHOULD accept the command.
  The driver SHOULD attempt to provide the correct length even if it
  suppresses length checks.
<span class="hl kwa">\end</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Device Initialization<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio over channel I/O / Device Initialization<span class="hl opt">}</span>

virtio-ccw uses several channel commands to set up a device.

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Setting the Virtio Revision<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio over channel I/O / Device Initialization / Setting the Virtio Revision<span class="hl opt">}</span>

CCW_CMD_SET_VIRTIO_REV is issued by the driver to set the revision of
the virtio-ccw transport it intends to drive the device with. It uses the
following communication structure:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
struct virtio_rev_info <span class="hl opt">{</span>
        be16 revision;
        be16 length;
        u8 data<span class="hl opt">[]</span>;
<span class="hl opt">}</span>;
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

<span class="hl kwa">\field</span><span class="hl opt">{</span>revision<span class="hl opt">}</span> contains the desired revision id, <span class="hl kwa">\field</span><span class="hl opt">{</span>length<span class="hl opt">}</span> the length of the
data portion and <span class="hl kwa">\field</span><span class="hl opt">{</span>data<span class="hl opt">}</span> revision-dependent additional desired options.

The following values are supported:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>tabular<span class="hl opt">}{</span> |l|l|l|l| <span class="hl opt">}</span>
<span class="hl kwa">\hline</span>
<span class="hl kwa">\field</span><span class="hl opt">{</span>revision<span class="hl opt">}</span> &amp; <span class="hl kwa">\field</span><span class="hl opt">{</span>length<span class="hl opt">}</span> &amp; <span class="hl kwa">\field</span><span class="hl opt">{</span>data<span class="hl opt">}</span>      &amp; remarks \\
<span class="hl kwa">\hline \hline</span>
<span class="hl num">0</span>        &amp; <span class="hl num">0</span>      &amp; &lt;empty&gt;   &amp; legacy interface; transitional devices only \\
<span class="hl kwa">\hline</span>
<span class="hl num">1</span>        &amp; <span class="hl num">0</span>      &amp; &lt;empty&gt;   &amp; Virtio <span class="hl num">1.0</span> \\
<span class="hl kwa">\hline</span>
<span class="hl num">2</span>-n      &amp;        &amp;           &amp; reserved for later revisions \\
<span class="hl kwa">\hline</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>tabular<span class="hl opt">}</span>

Note that a change in the virtio standard does not necessarily
correspond to a change in the virtio-ccw revision.

A device MUST post a unit check with command reject for any <span class="hl kwa">\field</span><span class="hl opt">{</span>revision<span class="hl opt">}</span>
it does not support. For any invalid combination of <span class="hl kwa">\field</span><span class="hl opt">{</span>revision<span class="hl opt">}</span>, <span class="hl kwa">\field</span><span class="hl opt">{</span>length<span class="hl opt">}</span>
and <span class="hl kwa">\field</span><span class="hl opt">{</span>data<span class="hl opt">}</span>, it MUST post a unit check with command reject as well. A
non-transitional device MUST reject revision id <span class="hl num">0</span>.

A driver SHOULD start with trying to set the highest revision it
supports and continue with lower revisions if it gets a command reject.

A driver MUST NOT issue any other virtio-ccw specific channel commands
prior to setting the revision.

A device MUST answer with command reject to any virtio-ccw specific
channel command that is not contained in the revision selected by the
driver.

After a revision has been successfully selected by the driver, it
MUST NOT attempt to select a different revision. A device MUST answer
to any such attempt with a command reject.

A device MUST treat the revision as unset from the time the associated
subchannel has been enabled until a revision has been successfully set
by the driver. This implies that revisions are not persistent across
disabling and enabling of the associated subchannel.

<span class="hl kwa">\paragraph</span><span class="hl opt">{</span>Legacy Interfaces: A Note on Setting the Virtio Revision<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio over channel I/O / Device Initialization / Setting the Virtio Revision / Legacy Interfaces: A Note on Setting the Virtio Revision<span class="hl opt">}</span>

A legacy device will not support the CCW_CMD_SET_VIRTIO_REV and answer
with a command reject. A non-transitional driver MUST stop trying to
operate this device in that case. A transitional driver MUST operate
the device as if it had been able to set revision <span class="hl num">0</span>.

A legacy driver will not issue the CCW_CMD_SET_VIRTIO_REV prior to
issuing other virtio-ccw specific channel commands. A non-transitional
device therefore MUST answer any such attempts with a command reject.
A transitional device MUST assume in this case that the driver is a
legacy driver and continue as if the driver selected revision <span class="hl num">0</span>. This
implies that the device MUST reject any command not valid for revision
<span class="hl num">0</span>, including a subsequent CCW_CMD_SET_VIRTIO_REV.

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Configuring a Virtqueue<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio over channel I/O / Device Initialization / Configuring a Virtqueue<span class="hl opt">}</span>

CCW_CMD_READ_VQ_CONF is issued by the driver to obtain information
about a queue. It uses the following structure for communicating:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
struct vq_config_block <span class="hl opt">{</span>
        be16 index;
        be16 max_num;
<span class="hl opt">}</span> __attribute__ ((packed));
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

The requested number of buffers for queue <span class="hl kwa">\field</span><span class="hl opt">{</span>index<span class="hl opt">}</span> is returned in
<span class="hl kwa">\field</span><span class="hl opt">{</span>max_num<span class="hl opt">}</span>.

Afterwards, CCW_CMD_SET_VQ is issued by the driver to inform the
device about the location used for its queue. The transmitted
structure is

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
struct vq_info_block <span class="hl opt">{</span>
        be64 desc;
        be32 res0;
        be16 index;
        be16 num;
        be64 avail;
        be64 used;
<span class="hl opt">}</span> __attribute__ ((packed));
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

<span class="hl kwa">\field</span><span class="hl opt">{</span>desc<span class="hl opt">}</span>, <span class="hl kwa">\field</span><span class="hl opt">{</span>avail<span class="hl opt">}</span> and <span class="hl kwa">\field</span><span class="hl opt">{</span>used<span class="hl opt">}</span> contain the guest addresses for the descriptor table,
available ring and used ring for queue <span class="hl kwa">\field</span><span class="hl opt">{</span>index<span class="hl opt">}</span>, respectively. The actual
virtqueue size (number of allocated buffers) is transmitted in <span class="hl kwa">\field</span><span class="hl opt">{</span>num<span class="hl opt">}</span>.
<span class="hl kwa">\field</span><span class="hl opt">{</span>res0<span class="hl opt">}</span> is reserved and MUST be ignored by the device.

<span class="hl kwa">\paragraph</span><span class="hl opt">{</span>Legacy Interface: A Note on Configuring a Virtqueue<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio over channel I/O / Device Initialization / Configuring a Virtqueue / Legacy Interface: A Note on Configuring a Virtqueue<span class="hl opt">}</span>

For a legacy driver or for a driver that selected revision <span class="hl num">0</span>,
CCW_CMD_SET_VQ uses the following communication block:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
struct vq_info_block_legacy <span class="hl opt">{</span>
        be64 queue;
        be32 align;
        be16 index;
        be16 num;
<span class="hl opt">}</span> __attribute__ ((packed));
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

<span class="hl kwa">\field</span><span class="hl opt">{</span>queue<span class="hl opt">}</span> contains the guest address for queue <span class="hl kwa">\field</span><span class="hl opt">{</span>index<span class="hl opt">}</span>, <span class="hl kwa">\field</span><span class="hl opt">{</span>num<span class="hl opt">}</span> the number of buffers
and <span class="hl kwa">\field</span><span class="hl opt">{</span>align<span class="hl opt">}</span> the alignment.

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Virtqueue Layout<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio over channel I/O / Device Initialization / Virtqueue Layout<span class="hl opt">}</span>

The virtqueue is physically contiguous, with padding added to make the
used ring meet the align value:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>tabular<span class="hl opt">}{</span>|l|l|l|<span class="hl opt">}</span>
<span class="hl kwa">\hline</span>
Descriptor Table &amp; Available Ring (<span class="hl kwa">\ldots</span> padding<span class="hl kwa">\ldots</span>) &amp; Used Ring \\
<span class="hl kwa">\hline</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>tabular<span class="hl opt">}</span>

The calculation for total size is as follows:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
#define ALIGN(x) (((x) + align) &amp; ~align)
static inline unsigned vring_size(unsigned int num)
<span class="hl opt">{</span>
     return ALIGN(sizeof(struct vring_desc)*num
                  + sizeof(u16)*(<span class="hl num">3</span> + num))
          + ALIGN(sizeof(u16)*<span class="hl num">3</span> + sizeof(struct vring_used_elem)*num);
<span class="hl opt">}</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Communicating Status Information<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio over channel I/O / Device Initialization / Communicating Status Information<span class="hl opt">}</span>

The driver changes the status of a device via the
CCW_CMD_WRITE_STATUS command, which transmits an <span class="hl num">8</span> bit status
value.

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Handling Device Features<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio over channel I/O / Device Initialization / Handling Device Features<span class="hl opt">}</span>

Feature bits are arranged in an array of <span class="hl num">32</span> bit values, making
for a total of <span class="hl num">8192</span> feature bits. Feature bits are in
little-endian byte order.

The CCW commands dealing with features use the following
communication block:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
struct virtio_feature_desc <span class="hl opt">{</span>
        le32 features;
        u8 index;
<span class="hl opt">}</span> __attribute__ ((packed));
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

<span class="hl kwa">\field</span><span class="hl opt">{</span>features<span class="hl opt">}</span> are the <span class="hl num">32</span> bits of features currently accessed, while
<span class="hl kwa">\field</span><span class="hl opt">{</span>index<span class="hl opt">}</span> describes which of the feature bit values is to be
accessed.

The guest obtains the device&apos;s device feature set via the
CCW_CMD_READ_FEAT command. The device stores the features at <span class="hl kwa">\field</span><span class="hl opt">{</span>index<span class="hl opt">}</span>
to <span class="hl kwa">\field</span><span class="hl opt">{</span>features<span class="hl opt">}</span>.

For communicating its supported features to the device, the driver
uses the CCW_CMD_WRITE_FEAT command, denoting a <span class="hl kwa">\field</span><span class="hl opt">{</span>features<span class="hl opt">}</span>/<span class="hl kwa">\field</span><span class="hl opt">{</span>index<span class="hl opt">}</span>
combination.

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Device Configuration<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio over channel I/O / Device Initialization / Device Configuration<span class="hl opt">}</span>

The device&apos;s configuration space is located in host memory.

To obtain information from the configuration space, the driver
uses CCW_CMD_READ_CONF, specifying the guest memory for the device
to write to.

For changing configuration information, the driver uses
CCW_CMD_WRITE_CONF, specifying the guest memory for the device to
read from.

In both cases, the complete configuration space is transmitted.  This
allows the driver to compare the new configuration space with the old
version, and keep a generation count internally whenever it changes.

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Setting Up Indicators<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio over channel I/O / Device Initialization / Setting Up Indicators<span class="hl opt">}</span>

In order to set up the indicator bits for host-&gt;guest notification,
the driver uses different channel commands depending on whether it
wishes to use traditional I/O interrupts tied to a subchannel or
adapter I/O interrupts for virtqueue notifications. For any given
device, the two mechanisms are mutually exclusive.

For the configuration change indicators, only a mechanism using
traditional I/O interrupts is provided, regardless of whether
traditional or adapter I/O interrupts are used for virtqueue
notifications.

<span class="hl kwa">\paragraph</span><span class="hl opt">{</span>Setting Up Classic Queue Indicators<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio over channel I/O / Device Initialization / Setting Up Indicators / Setting Up Classic Queue Indicators<span class="hl opt">}</span>

Indicators for notification via classic I/O interrupts are contained
in a <span class="hl num">64</span> bit value per virtio-ccw proxy device.

To communicate the location of the indicator bits for host-&gt;guest
notification, the driver uses the CCW_CMD_SET_IND command,
pointing to a location containing the guest address of the
indicators in a <span class="hl num">64</span> bit value.

If the driver has already set up two-staged queue indicators via the
CCW_CMD_SET_IND_ADAPTER command, the device MUST post a unit check
with command reject to any subsequent CCW_CMD_SET_IND command.

<span class="hl kwa">\paragraph</span><span class="hl opt">{</span>Setting Up Configuration Change Indicators<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio over channel I/O / Device Initialization / Setting Up Indicators / Setting Up Configuration Change Indicators<span class="hl opt">}</span>

Indicators for configuration change host-&gt;guest notification are
contained in a <span class="hl num">64</span> bit value per virtio-ccw proxy device.

To communicate the location of the indicator bits used in the
configuration change host-&gt;guest notification, the driver issues the
CCW_CMD_SET_CONF_IND command, pointing to a location containing the
guest address of the indicators in a <span class="hl num">64</span> bit value.

<span class="hl kwa">\paragraph</span><span class="hl opt">{</span>Setting Up Two-Stage Queue Indicators<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio over channel I/O / Device Initialization / Setting Up Indicators / Setting Up Two-Stage Queue Indicators<span class="hl opt">}</span>

Indicators for notification via adapter I/O interrupts consist of
two stages:
<span class="hl kwa">\begin</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>
<span class="hl kwa">\item</span> a summary indicator byte covering the virtqueues for one or more
  virtio-ccw proxy devices
<span class="hl kwa">\item</span> a set of contigous indicator bits for the virtqueues for a
  virtio-ccw proxy device
<span class="hl kwa">\end</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>

To communicate the location of the summary and queue indicator bits,
the driver uses the CCW_CMD_SET_IND_ADAPTER command with the following
payload:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
struct virtio_thinint_area <span class="hl opt">{</span>
        be64 summary_indicator;
        be64 indicator;
        be64 bit_nr;
        u8 isc;
<span class="hl opt">}</span> __attribute__ ((packed));
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

<span class="hl kwa">\field</span><span class="hl opt">{</span>summary_indicator<span class="hl opt">}</span> contains the guest address of the <span class="hl num">8</span> bit summary
indicator.
<span class="hl kwa">\field</span><span class="hl opt">{</span>indicator<span class="hl opt">}</span> contains the guest address of an area wherin the indicators
for the devices are contained, starting at <span class="hl kwa">\field</span><span class="hl opt">{</span>bit_nr<span class="hl opt">}</span>, one bit per
virtqueue of the device. Bit numbers start at the left, i.e. the most
significant bit in the first byte is assigned the bit number <span class="hl num">0</span>.
<span class="hl kwa">\field</span><span class="hl opt">{</span>isc<span class="hl opt">}</span> contains the I/O interruption subclass to be used for the adapter
I/O interrupt. It may be different from the isc used by the proxy
virtio-ccw device&apos;s subchannel.

If the driver has already set up classic queue indicators via the
CCW_CMD_SET_IND command, the device MUST post a unit check with
command reject to any subsequent CCW_CMD_SET_IND_ADAPTER command.

<span class="hl kwa">\paragraph</span><span class="hl opt">{</span>Legacy Interfaces: A Note on Setting Up Indicators<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio over channel I/O / Device Initialization / Setting Up Indicators / Legacy Interfaces: A Note on Setting Up Indicators<span class="hl opt">}</span>

Legacy devices will only support classic queue indicators; they will
reject CCW_CMD_SET_IND_ADAPTER as they don&apos;t know that command.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Device Operation<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio over channel I/O / Device Operation<span class="hl opt">}</span>

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Host-&gt;Guest Notification<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio over channel I/O / Device Operation / Host-&gt;Guest Notification<span class="hl opt">}</span>

There are two modes of operation regarding host-&gt;guest notification,
classic I/O interrupts and adapter I/O interrupts. The mode to be
used is determined by the driver by using CCW_CMD_SET_IND respectively
CCW_CMD_SET_IND_ADAPTER to set up queue indicators.

For configuration changes, the driver always uses classic I/O
interrupts.

<span class="hl kwa">\paragraph</span><span class="hl opt">{</span>Notification via Classic I/O Interrupts<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio over channel I/O / Device Operation / Host-&gt;Guest Notification / Notification via Classic I/O Interrupts<span class="hl opt">}</span>

If the driver used the CCW_CMD_SET_IND command to set up queue
indicators, the device will use classic I/O interrupts for
host-&gt;guest notification about virtqueue activity.

For notifying the driver of virtqueue buffers, the device sets the
corresponding bit in the guest-provided indicators. If an
interrupt is not already pending for the subchannel, the device
generates an unsolicited I/O interrupt.

If the device wants to notify the driver about configuration
changes, it sets bit <span class="hl num">0</span> in the configuration indicators and
generates an unsolicited I/O interrupt, if needed. This also
applies if adapter I/O interrupts are used for queue notifications.

<span class="hl kwa">\paragraph</span><span class="hl opt">{</span>Notification via Adapter I/O Interrupts<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio over channel I/O / Device Operation / Host-&gt;Guest Notification / Notification via Adapter I/O Interrupts<span class="hl opt">}</span>

If the driver used the CCW_CMD_SET_IND_ADAPTER command to set up
queue indicators, the device will use adapter I/O interrupts for
host-&gt;guest notification about virtqueue activity.

For notifying the driver of virtqueue buffers, the device sets the
bit in the guest-provided indicator area at the corresponding offset.
The guest-provided summary indicator is set to <span class="hl num">0x01</span>. An adapter I/O
interrupt for the corresponding interruption subclass is generated.
The device SHOULD only generate an adapter I/O interrupt if the
summary indicator had not been set prior to notification. The driver
MUST clear the summary indicator after receiving an adapter I/O
interrupt before it processes the queue indicators.

<span class="hl kwa">\paragraph</span><span class="hl opt">{</span>Legacy Interfaces: A Note on Host-&gt;Guest Notification<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio over channel I/O / Device Operation / Host-&gt;Guest Notification / Legacy Interfaces: A Note on Host-&gt;Guest Notification<span class="hl opt">}</span>

As legacy devices and drivers support only classic queue indicators,
host-&gt;guest notification will always be done via classic I/O interrupts.

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Guest-&gt;Host Notification<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio over channel I/O / Device Operation / Guest-&gt;Host Notification<span class="hl opt">}</span>

For notifying the device of virtqueue buffers, the driver
unfortunately can&apos;t use a channel command (the asynchronous
characteristics of channel I/O interact badly with the host block
I/O backend). Instead, it uses a diagnose <span class="hl num">0x500</span> call with subcode
<span class="hl num">3</span> specifying the queue, as follows:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>tabular<span class="hl opt">}{</span> |l|l|l| <span class="hl opt">}</span>
<span class="hl kwa">\hline</span>
GPR  &amp;   Input Value     &amp; Output Value \\
<span class="hl kwa">\hline \hline</span>
  <span class="hl num">1</span>   &amp;       <span class="hl num">0x3</span>         &amp;              \\
<span class="hl kwa">\hline</span>
  <span class="hl num">2</span>   &amp;  Subchannel ID    &amp; Host Cookie  \\
<span class="hl kwa">\hline</span>
  <span class="hl num">3</span>   &amp; Virtqueue number  &amp;              \\
<span class="hl kwa">\hline</span>
  <span class="hl num">4</span>   &amp;   Host Cookie     &amp;              \\
<span class="hl kwa">\hline</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>tabular<span class="hl opt">}</span>

The device MUST ignore bits <span class="hl num">0</span>-<span class="hl num">31</span> (counting from the left) of GPR2.
This aligns passing the subchannel ID with the way it is passed
for the existing I/O instructions.

Host cookie is an optional per-virtqueue <span class="hl num">64</span> bit value that can be
used by the hypervisor to speed up the notification execution.
For each notification, the output value is returned in GPR2 and
should be passed in GPR4 for the next notification:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
info-&gt;cookie = do_notify(schid,
                         virtqueue_get_queue_index(vq),
                         info-&gt;cookie);
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Resetting Devices<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Virtio Transport Options / Virtio over channel I/O / Device Operation / Resetting Devices<span class="hl opt">}</span>

In order to reset a device, a driver sends the
CCW_CMD_VDEV_RESET command.


<span class="hl kwa">\chapter</span><span class="hl opt">{</span>Device Types<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types<span class="hl opt">}</span>

On top of the queues, config space and feature negotiation facilities
built into virtio, several specific devices are defined.

The following device IDs are used to identify different types of virtio
devices.  Some device IDs are reserved for devices which are not currently
defined in this standard.

Discovering what devices are available and their type is bus-dependent.

<span class="hl kwa">\begin</span><span class="hl opt">{</span>tabular<span class="hl opt">} {</span> |l|c| <span class="hl opt">}</span>
<span class="hl kwa">\hline</span>
Device ID  &amp;  Virtio Device    \\
<span class="hl kwa">\hline \hline</span>
<span class="hl num">0</span>          &amp; reserved (invalid) \\
<span class="hl kwa">\hline</span>
<span class="hl num">1</span>          &amp;   network card     \\
<span class="hl kwa">\hline</span>
<span class="hl num">2</span>          &amp;   block device     \\
<span class="hl kwa">\hline</span>
<span class="hl num">3</span>          &amp;      console       \\
<span class="hl kwa">\hline</span>
<span class="hl num">4</span>          &amp;  entropy source    \\
<span class="hl kwa">\hline</span>
<span class="hl num">5</span>          &amp; memory ballooning  \\
<span class="hl kwa">\hline</span>
<span class="hl num">6</span>          &amp;     ioMemory       \\
<span class="hl kwa">\hline</span>
<span class="hl num">7</span>          &amp;       rpmsg        \\
<span class="hl kwa">\hline</span>
<span class="hl num">8</span>          &amp;     SCSI host      \\
<span class="hl kwa">\hline</span>
<span class="hl num">9</span>          &amp;   <span class="hl num">9</span>P transport     \\
<span class="hl kwa">\hline</span>
<span class="hl num">10</span>         &amp;   mac80211 wlan    \\
<span class="hl kwa">\hline</span>
<span class="hl num">11</span>         &amp;   rproc serial     \\
<span class="hl kwa">\hline</span>
<span class="hl num">12</span>         &amp;   virtio CAIF      \\
<span class="hl kwa">\hline</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>tabular<span class="hl opt">}</span>

Some of the devices above are unspecified by this <span class="hl kwb">document</span>,
because they are seen as immature or especially niche.  Be warned
that they may only be specified by the sole existing implementation;
they may become part of a future specification, be abandoned
entirely, or live on outside this standard.  We shall speak of
them no further.

<span class="hl kwa">\section</span><span class="hl opt">{</span>Network Device<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Network Device<span class="hl opt">}</span>

The virtio network device is a virtual ethernet card, and is the
most complex of the devices supported so far by virtio. It has
enhanced rapidly and demonstrates clearly how support for new
features should be added to an existing device. Empty buffers are
placed in one virtqueue for receiving packets, and outgoing
packets are enqueued into another for transmission in that order.
A third command queue is used to control advanced filtering
features.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Device ID<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device ID<span class="hl opt">}</span>

 <span class="hl num">1</span>

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Virtqueues<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Network Device / Virtqueues<span class="hl opt">}</span>

<span class="hl kwa">\begin</span><span class="hl opt">{</span>description<span class="hl opt">}</span>
<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl num">0</span><span class="hl opt">]</span> receiveq0
<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl num">1</span><span class="hl opt">]</span> transmitq0
<span class="hl kwa">\item</span><span class="hl opt">[</span>...<span class="hl opt">]</span>
<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl num">2</span>N<span class="hl opt">]</span> receiveqN
<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl num">2</span>N+<span class="hl num">1</span><span class="hl opt">]</span> transmitqN
<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl num">2</span>N+<span class="hl num">2</span><span class="hl opt">]</span> controlq
<span class="hl kwa">\end</span><span class="hl opt">{</span>description<span class="hl opt">}</span>

 N=<span class="hl num">0</span> if VIRTIO_NET_F_MQ is not negotiated, otherwise N is derived
 from <span class="hl kwa">\field</span><span class="hl opt">{</span>max_virtqueue_pairs<span class="hl opt">}</span> control field.

 controlq only exists if VIRTIO_NET_F_CTRL_VQ set.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Feature bits<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Network Device / Feature bits<span class="hl opt">}</span>

<span class="hl kwa">\begin</span><span class="hl opt">{</span>description<span class="hl opt">}</span>
<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_NET_F_CSUM (<span class="hl num">0</span>)<span class="hl opt">]</span> Device handles packets with partial checksum

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_NET_F_GUEST_CSUM (<span class="hl num">1</span>)<span class="hl opt">]</span> Driver handles packets with partial checksum

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_NET_F_CTRL_GUEST_OFFLOADS (<span class="hl num">2</span>)<span class="hl opt">]</span> Control channel offloads
        reconfiguration support.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_NET_F_MAC (<span class="hl num">5</span>)<span class="hl opt">]</span> Device has given MAC address.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_NET_F_GUEST_TSO4 (<span class="hl num">7</span>)<span class="hl opt">]</span> Driver can receive TSOv4.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_NET_F_GUEST_TSO6 (<span class="hl num">8</span>)<span class="hl opt">]</span> Driver can receive TSOv6.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_NET_F_GUEST_ECN (<span class="hl num">9</span>)<span class="hl opt">]</span> Driver can receive TSO with ECN.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_NET_F_GUEST_UFO (<span class="hl num">10</span>)<span class="hl opt">]</span> Driver can receive UFO.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_NET_F_HOST_TSO4 (<span class="hl num">11</span>)<span class="hl opt">]</span> Device can receive TSOv4.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_NET_F_HOST_TSO6 (<span class="hl num">12</span>)<span class="hl opt">]</span> Device can receive TSOv6.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_NET_F_HOST_ECN (<span class="hl num">13</span>)<span class="hl opt">]</span> Device can receive TSO with ECN.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_NET_F_HOST_UFO (<span class="hl num">14</span>)<span class="hl opt">]</span> Device can receive UFO.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_NET_F_MRG_RXBUF (<span class="hl num">15</span>)<span class="hl opt">]</span> Driver can merge receive buffers.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_NET_F_STATUS (<span class="hl num">16</span>)<span class="hl opt">]</span> Configuration status field is
    available.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_NET_F_CTRL_VQ (<span class="hl num">17</span>)<span class="hl opt">]</span> Control channel is available.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_NET_F_CTRL_RX (<span class="hl num">18</span>)<span class="hl opt">]</span> Control channel RX mode support.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_NET_F_CTRL_VLAN (<span class="hl num">19</span>)<span class="hl opt">]</span> Control channel VLAN filtering.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_NET_F_GUEST_ANNOUNCE(<span class="hl num">21</span>)<span class="hl opt">]</span> Driver can send gratuitous
    packets.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_NET_F_MQ(<span class="hl num">22</span>)<span class="hl opt">]</span> Device supports multiqueue with automatic
    receive steering.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_NET_F_CTRL_MAC_ADDR(<span class="hl num">23</span>)<span class="hl opt">]</span> Set MAC address through control
    channel.
<span class="hl kwa">\end</span><span class="hl opt">{</span>description<span class="hl opt">}</span>

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Legacy Interface: Feature bits<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Network Device / Feature bits / Legacy Interface: Feature bits<span class="hl opt">}</span>
<span class="hl kwa">\begin</span><span class="hl opt">{</span>description<span class="hl opt">}</span>
<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_NET_F_GSO (<span class="hl num">6</span>)<span class="hl opt">]</span> Device handles packets with any GSO type.
<span class="hl kwa">\end</span><span class="hl opt">{</span>description<span class="hl opt">}</span>

This was supposed to indicate segmentation offload support, but
upon further investigation it became clear that multiple bits
were required.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Device configuration layout<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device configuration layout<span class="hl opt">}</span>

Three configuration fields are currently defined. The <span class="hl kwa">\field</span><span class="hl opt">{</span>mac<span class="hl opt">}</span> address field
always exists (though is only valid if VIRTIO_NET_F_MAC is set), and
<span class="hl kwa">\field</span><span class="hl opt">{</span>status<span class="hl opt">}</span> only exists if VIRTIO_NET_F_STATUS is set. Two
read-only bits (for the driver) are currently defined for the status field:
VIRTIO_NET_S_LINK_UP and VIRTIO_NET_S_ANNOUNCE.

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
#define VIRTIO_NET_S_LINK_UP     <span class="hl num">1</span>
#define VIRTIO_NET_S_ANNOUNCE    <span class="hl num">2</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

The following driver-read-only field, <span class="hl kwa">\field</span><span class="hl opt">{</span>max_virtqueue_pairs<span class="hl opt">}</span> only exists if
VIRTIO_NET_F_MQ is set. This field specifies the maximum number
of each of transmit and receive virtqueues (receiveq0..receiveqN
and transmitq0..transmitqN respectively;
 N=<span class="hl kwa">\field</span><span class="hl opt">{</span>max_virtqueue_pairs<span class="hl opt">}</span> - <span class="hl num">1</span>) that can be configured once VIRTIO_NET_F_MQ
is negotiated.  Legal values for this field are <span class="hl num">1</span> to <span class="hl num">0x8000</span>.

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
/* Note: LEGACY version was not little endian! */
struct virtio_net_config <span class="hl opt">{</span>
        u8 mac<span class="hl opt">[</span><span class="hl num">6</span><span class="hl opt">]</span>;
        le16 status;
        le16 max_virtqueue_pairs;
<span class="hl opt">}</span>;
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Legacy Interface: Device configuration layout<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device configuration layout / Legacy Interface: Device configuration layout<span class="hl opt">}</span>
For legacy devices, <span class="hl kwa">\field</span><span class="hl opt">{</span>status<span class="hl opt">}</span> and <span class="hl kwa">\field</span><span class="hl opt">{</span>max_virtqueue_pairs<span class="hl opt">}</span> in struct virtio_net_config are the
native endian of the guest rather than (necessarily) little-endian.


<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Device Initialization<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device Initialization<span class="hl opt">}</span>

<span class="hl kwa">\begin</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>
<span class="hl kwa">\item</span> The initialization routine should identify the receive and
  transmission virtqueues, up to N+<span class="hl num">1</span> of each kind. If
  VIRTIO_NET_F_MQ feature bit is negotiated,
  N=<span class="hl kwa">\field</span><span class="hl opt">{</span>max_virtqueue_pairs<span class="hl opt">}</span>-<span class="hl num">1</span>, otherwise identify N=<span class="hl num">0</span>.

<span class="hl kwa">\item</span> If the VIRTIO_NET_F_MAC feature bit is set, the configuration
  space <span class="hl kwa">\field</span><span class="hl opt">{</span>mac<span class="hl opt">}</span> entry indicates the “physical” address of the
  network card, otherwise a private MAC address should be
  assigned. All drivers are expected to negotiate this feature if
  it is set.

<span class="hl kwa">\item</span> If the VIRTIO_NET_F_CTRL_VQ feature bit is negotiated,
  identify the control virtqueue.

<span class="hl kwa">\item</span> If the VIRTIO_NET_F_STATUS feature bit is negotiated, the link
  status can be read from the bottom bit of <span class="hl kwa">\field</span><span class="hl opt">{</span>status<span class="hl opt">}</span>.
  Otherwise, the link should be assumed active.

<span class="hl kwa">\item</span> Only receiveq0, transmitq0 and controlq are used by default.
  To use more queues driver must negotiate the VIRTIO_NET_F_MQ
  feature; initialize up to <span class="hl kwa">\field</span><span class="hl opt">{</span>max_virtqueue_pairs<span class="hl opt">}</span> of each of
  transmit and receive queues;
  execute VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET command specifying the
  number of the transmit and receive queues that is going to be
  used and wait until the device consumes the controlq buffer and
  acks this command.
  The receive virtqueue should be filled with receive buffers
  before multiqueue is activated
  (see <span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device Operation / Control Virtqueue / Automatic receive steering in multiqueue mode<span class="hl opt">}</span>~<span class="hl kwa">\nameref</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device Operation / Control Virtqueue / Automatic receive steering in multiqueue mode<span class="hl opt">}</span>).
  This is described in detail below in <span class="hl kwa">\nameref</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device Operation / Setting Up Receive Buffers<span class="hl opt">}</span>.

<span class="hl kwa">\item</span> A driver can indicate that it will generate checksumless
  packets by negotating the VIRTIO_NET_F_CSUM feature. This 
  “checksum offload” is a common feature on modern network cards.

<span class="hl kwa">\item</span> If that feature is negotiated<span class="hl kwa">\footnote</span><span class="hl opt">{</span>ie. VIRTIO_NET_F_HOST_TSO* and VIRTIO_NET_F_HOST_UFO are
dependent on VIRTIO_NET_F_CSUM; a device which offers the offload
features must offer the checksum feature, and a driver which
accepts the offload features must accept the checksum feature.
Similar logic applies to the VIRTIO_NET_F_GUEST_TSO4 features
depending on VIRTIO_NET_F_GUEST_CSUM.
<span class="hl opt">}</span>, a driver can use TCP or UDP
  segmentation offload by negotiating the VIRTIO_NET_F_HOST_TSO4 (IPv4
  TCP), VIRTIO_NET_F_HOST_TSO6 (IPv6 TCP) and VIRTIO_NET_F_HOST_UFO
  (UDP fragmentation) features. It should not send TCP packets
  requiring segmentation offload which have the Explicit Congestion
  Notification bit set, unless the VIRTIO_NET_F_HOST_ECN feature is
  negotiated.<span class="hl kwa">\footnote</span><span class="hl opt">{</span>This is a common restriction in real, older network cards.
<span class="hl opt">}</span>

<span class="hl kwa">\item</span> The converse features are also available: a driver can save
  the virtual device some work by negotiating these features.<span class="hl kwa">\footnote</span><span class="hl opt">{</span>For example, a network packet transported between two guests on
the same system may not require checksumming at all, nor segmentation,
if both guests are amenable.
<span class="hl opt">}</span>
   The VIRTIO_NET_F_GUEST_CSUM feature indicates that partially
  checksummed packets can be received, and if it can do that then
  the VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6,
  VIRTIO_NET_F_GUEST_UFO and VIRTIO_NET_F_GUEST_ECN are the input
  equivalents of the features described above.
  See <span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device Operation / Setting Up Receive Buffers<span class="hl opt">}</span>~<span class="hl kwa">\nameref</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device Operation / Setting Up Receive Buffers<span class="hl opt">}</span> and <span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device Operation / Setting Up Receive Buffers<span class="hl opt">}</span>~<span class="hl kwa">\nameref</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device Operation / Setting Up Receive Buffers<span class="hl opt">}</span> below.
<span class="hl kwa">\end</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Device Operation<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device Operation<span class="hl opt">}</span>

Packets are transmitted by placing them in the
transmitq0..transmitqN, and buffers for incoming packets are
placed in the receiveq0..receiveqN. In each case, the packet
itself is preceeded by a header:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
/* Note: LEGACY version was not little endian! */
struct virtio_net_hdr <span class="hl opt">{</span>
#define VIRTIO_NET_HDR_F_NEEDS_CSUM    <span class="hl num">1</span>
        u8 flags;
#define VIRTIO_NET_HDR_GSO_NONE        <span class="hl num">0</span>
#define VIRTIO_NET_HDR_GSO_TCPV4       <span class="hl num">1</span>
#define VIRTIO_NET_HDR_GSO_UDP         <span class="hl num">3</span>
#define VIRTIO_NET_HDR_GSO_TCPV6       <span class="hl num">4</span>
#define VIRTIO_NET_HDR_GSO_ECN      <span class="hl num">0x80</span>
        u8 gso_type;
        le16 hdr_len;
        le16 gso_size;
        le16 csum_start;
        le16 csum_offset;
/* Only if VIRTIO_NET_F_MRG_RXBUF: */
        le16 num_buffers;
<span class="hl opt">}</span>;
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

The controlq is used to control device features such as
filtering.

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Legacy Interface: Device Operation<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device Operation / Legacy Interface: Device Operation<span class="hl opt">}</span>
For legacy devices, the fields in struct virtio_net_hdr are the
native endian of the guest rather than (necessarily) little-endian.

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Packet Transmission<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device Operation / Packet Transmission<span class="hl opt">}</span>

Transmitting a single packet is simple, but varies depending on
the different features the driver negotiated.

<span class="hl kwa">\begin</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>
<span class="hl kwa">\item</span> If the driver negotiated VIRTIO_NET_F_CSUM, and the packet has
  not been fully checksummed, then the virtio_net_hdr&apos;s fields
  are set as follows. Otherwise, the packet must be fully
  checksummed, and flags is zero.
  <span class="hl kwa">\begin</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>
  <span class="hl kwa">\item \field</span><span class="hl opt">{</span>flags<span class="hl opt">}</span> has the VIRTIO_NET_HDR_F_NEEDS_CSUM set,

  <span class="hl kwa">\item \field</span><span class="hl opt">{</span>csum_start<span class="hl opt">}</span> is set to the offset within the packet to begin checksumming,
    and

  <span class="hl kwa">\item \field</span><span class="hl opt">{</span>csum_offset<span class="hl opt">}</span> indicates how many bytes after the csum_start the
    new (<span class="hl num">16</span> bit ones&apos; complement) checksum should be placed.
  <span class="hl kwa">\end</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>

For example, consider a partially checksummed TCP (IPv4) packet.
It will have a <span class="hl num">14</span> byte ethernet header and <span class="hl num">20</span> byte IP header
followed by the TCP header (with the TCP checksum field <span class="hl num">16</span> bytes
into that header). <span class="hl kwa">\field</span><span class="hl opt">{</span>csum_start<span class="hl opt">}</span> will be <span class="hl num">14</span>+<span class="hl num">20</span> = <span class="hl num">34</span> (the TCP
checksum includes the header), and <span class="hl kwa">\field</span><span class="hl opt">{</span>csum_offset<span class="hl opt">}</span> will be <span class="hl num">16</span>. The
value in the TCP checksum field should be initialized to the sum
of the TCP pseudo header, so that replacing it by the ones&apos;
complement checksum of the TCP header and body will give the
correct result.

<span class="hl kwa">\item</span> If the driver negotiated
  VIRTIO_NET_F_HOST_TSO4, TSO6 or UFO, and the packet requires
  TCP segmentation or UDP fragmentation, then <span class="hl kwa">\field</span><span class="hl opt">{</span>gso_type<span class="hl opt">}</span>
  is set to VIRTIO_NET_HDR_GSO_TCPV4, TCPV6 or UDP.
  (Otherwise, it is set to VIRTIO_NET_HDR_GSO_NONE). In this
  case, packets larger than <span class="hl num">1514</span> bytes can be transmitted: the
  metadata indicates how to replicate the packet header to cut it
  into smaller packets. The other gso fields are set:

  <span class="hl kwa">\begin</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>
  <span class="hl kwa">\item \field</span><span class="hl opt">{</span>hdr_len<span class="hl opt">}</span> is a hint to the device as to how much of the header
    needs to be kept to copy into each packet, usually set to the
    length of the headers, including the transport header.<span class="hl kwa">\footnote</span><span class="hl opt">{</span>Due to various bugs in implementations, this field is not useful
as a guarantee of the transport header size.
<span class="hl opt">}</span>

  <span class="hl kwa">\item \field</span><span class="hl opt">{</span>gso_size<span class="hl opt">}</span> is the maximum size of each packet beyond that
    header (ie. MSS).

  <span class="hl kwa">\item</span> If the driver negotiated the VIRTIO_NET_F_HOST_ECN feature,
    the VIRTIO_NET_HDR_GSO_ECN bit may be set in <span class="hl kwa">\field</span><span class="hl opt">{</span>gso_type<span class="hl opt">}</span> as
    well, indicating that the TCP packet has the ECN bit set.<span class="hl kwa">\footnote</span><span class="hl opt">{</span>This case is not handled by some older hardware, so is called out
specifically in the protocol.
<span class="hl opt">}</span>
   <span class="hl kwa">\end</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>

<span class="hl kwa">\item</span> If the driver negotiated the VIRTIO_NET_F_MRG_RXBUF feature,
  <span class="hl kwa">\field</span><span class="hl opt">{</span>num_buffers<span class="hl opt">}</span> is set to zero.

<span class="hl kwa">\item</span> The header and packet are added as one output buffer to the
  transmitq, and the device is notified of the new entry
  (see <span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device Initialization<span class="hl opt">}</span>~<span class="hl kwa">\nameref</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device Initialization<span class="hl opt">}</span>).<span class="hl kwa">\footnote</span><span class="hl opt">{</span>Note that the header will be two bytes longer for the
VIRTIO_NET_F_MRG_RXBUF case.
<span class="hl opt">}</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>

<span class="hl kwa">\paragraph</span><span class="hl opt">{</span>Packet Transmission Interrupt<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device Operation / Packet Transmission / Packet Transmission Interrupt<span class="hl opt">}</span>

Often a driver will suppress transmission interrupts using the
VRING_AVAIL_F_NO_INTERRUPT flag
 (see <span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:Device Types / Block Device<span class="hl opt">}</span>~<span class="hl kwa">\nameref</span><span class="hl opt">{</span>sec:Device Types / Block Device<span class="hl opt">}</span>)
and check for used packets in the transmit path of following
packets.

The normal behavior in this interrupt handler is to retrieve and
new descriptors from the used ring and free the corresponding
headers and packets.

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Setting Up Receive Buffers<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device Operation / Setting Up Receive Buffers<span class="hl opt">}</span>

It is generally a good idea to keep the receive virtqueue as
fully populated as possible: if it runs out, network performance
will suffer.

If the VIRTIO_NET_F_GUEST_TSO4, VIRTIO_NET_F_GUEST_TSO6 or
VIRTIO_NET_F_GUEST_UFO features are used, the Driver will need to
accept packets of up to <span class="hl num">65550</span> bytes long (the maximum size of a
TCP or UDP packet, plus the <span class="hl num">14</span> byte ethernet header), otherwise
<span class="hl num">1514</span>. bytes. So unless VIRTIO_NET_F_MRG_RXBUF is negotiated, every
buffer in the receive queue needs to be at least this length.<span class="hl kwa">\footnote</span><span class="hl opt">{</span>Obviously each one can be split across multiple descriptor
elements.
<span class="hl opt">}</span>

If VIRTIO_NET_F_MRG_RXBUF is negotiated, each buffer must be at
least the size of the struct virtio_net_hdr.

If VIRTIO_NET_F_MQ is negotiated, each of receiveq0...receiveqN
that will be used should be populated with receive buffers.

<span class="hl kwa">\paragraph</span><span class="hl opt">{</span>Packet Receive Interrupt<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device Operation / Setting Up Receive Buffers / Packet Receive Interrupt<span class="hl opt">}</span>

When a packet is copied into a buffer in the receiveq, the
optimal path is to disable further interrupts for the receiveq
(see <span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:General Initialization And Device Operation / Device Operation / Receiving Used Buffers From The Device<span class="hl opt">}</span>~<span class="hl kwa">\nameref</span><span class="hl opt">{</span>sec:General Initialization And Device Operation / Device Operation / Receiving Used Buffers From The Device<span class="hl opt">}</span>) and process
packets until no more are found, then re-enable them.

Processing packet involves:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>
<span class="hl kwa">\item</span> If the driver negotiated the VIRTIO_NET_F_MRG_RXBUF feature,
  then <span class="hl kwa">\field</span><span class="hl opt">{</span>num_buffers<span class="hl opt">}</span> indicates how many descriptors
  this packet is spread over (including this one). This allows
  receipt of large packets without having to allocate large
  buffers. In this case, there will be at least <span class="hl kwa">\field</span><span class="hl opt">{</span>num_buffers<span class="hl opt">}</span> in
  the used ring, and they should be chained together to form a
  single packet. The other buffers will not begin with a struct
  virtio_net_hdr.

<span class="hl kwa">\item</span> If the VIRTIO_NET_F_MRG_RXBUF feature was not negotiated, or
  <span class="hl kwa">\field</span><span class="hl opt">{</span>num_buffers<span class="hl opt">}</span> is one, then the entire packet will be
  contained within this buffer, immediately following the struct
  virtio_net_hdr.

<span class="hl kwa">\item</span> If the VIRTIO_NET_F_GUEST_CSUM feature was negotiated, the
  VIRTIO_NET_HDR_F_NEEDS_CSUM bit in <span class="hl kwa">\field</span><span class="hl opt">{</span>flags<span class="hl opt">}</span> may be
  set: if so, the checksum on the packet is incomplete and
  <span class="hl kwa">\field</span><span class="hl opt">{</span>csum_start<span class="hl opt">}</span> and <span class="hl kwa">\field</span><span class="hl opt">{</span>csum_offset<span class="hl opt">}</span> indicate how to calculate
  it (see Packet Transmission point <span class="hl num">1</span>).

<span class="hl kwa">\item</span> If the VIRTIO_NET_F_GUEST_TSO4, TSO6 or UFO options were
  negotiated, then <span class="hl kwa">\field</span><span class="hl opt">{</span>gso_type<span class="hl opt">}</span> may be something other than
  VIRTIO_NET_HDR_GSO_NONE, and <span class="hl kwa">\field</span><span class="hl opt">{</span>gso_size<span class="hl opt">}</span> field indicates the
  desired MSS (see Packet Transmission point <span class="hl num">2</span>).
<span class="hl kwa">\end</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Control Virtqueue<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device Operation / Control Virtqueue<span class="hl opt">}</span>

The driver uses the control virtqueue (if VIRTIO_NET_F_CTRL_VQ is
negotiated) to send commands to manipulate various features of
the device which would not easily map into the configuration
space.

All commands are of the following form:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
struct virtio_net_ctrl <span class="hl opt">{</span>
        u8 class;
        u8 command;
        u8 command-specific-data<span class="hl opt">[]</span>;
        u8 ack;
<span class="hl opt">}</span>;

/* ack values */
#define VIRTIO_NET_OK     <span class="hl num">0</span>
#define VIRTIO_NET_ERR    <span class="hl num">1</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

The <span class="hl kwa">\field</span><span class="hl opt">{</span>class<span class="hl opt">}</span>, <span class="hl kwa">\field</span><span class="hl opt">{</span>command<span class="hl opt">}</span> and command-specific-data are set by the
driver, and the device sets the <span class="hl kwa">\field</span><span class="hl opt">{</span>ack<span class="hl opt">}</span> byte. There is little it can
do except issue a diagnostic if <span class="hl kwa">\field</span><span class="hl opt">{</span>ack<span class="hl opt">}</span> is not
VIRTIO_NET_OK.

<span class="hl kwa">\paragraph</span><span class="hl opt">{</span>Packet Receive Filtering<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device Operation / Control Virtqueue / Packet Receive Filtering<span class="hl opt">}</span>

If the VIRTIO_NET_F_CTRL_RX feature is negotiated, the driver can
send control commands for promiscuous mode, multicast receiving,
and filtering of MAC addresses.

Note that in general, these commands are best-effort: unwanted
packets may still arrive.

<span class="hl kwa">\paragraph</span><span class="hl opt">{</span>Setting Promiscuous Mode<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device Operation / Control Virtqueue / Setting Promiscuous Mode<span class="hl opt">}</span>

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
#define VIRTIO_NET_CTRL_RX    <span class="hl num">0</span>
 #define VIRTIO_NET_CTRL_RX_PROMISC      <span class="hl num">0</span>
 #define VIRTIO_NET_CTRL_RX_ALLMULTI     <span class="hl num">1</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

The class VIRTIO_NET_CTRL_RX has two commands:
VIRTIO_NET_CTRL_RX_PROMISC turns promiscuous mode on and off, and
VIRTIO_NET_CTRL_RX_ALLMULTI turns all-multicast receive on and
off. The command-specific-data is one byte containing <span class="hl num">0</span> (off) or
<span class="hl num">1</span> (on).

<span class="hl kwa">\paragraph</span><span class="hl opt">{</span>Setting MAC Address Filtering<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device Operation / Control Virtqueue / Setting MAC Address Filtering<span class="hl opt">}</span>

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
struct virtio_net_ctrl_mac <span class="hl opt">{</span>
        le32 entries;
        u8 macs<span class="hl opt">[</span>entries<span class="hl opt">][</span><span class="hl num">6</span><span class="hl opt">]</span>;
<span class="hl opt">}</span>;

#define VIRTIO_NET_CTRL_MAC    <span class="hl num">1</span>
 #define VIRTIO_NET_CTRL_MAC_TABLE_SET        <span class="hl num">0</span>
 #define VIRTIO_NET_CTRL_MAC_ADDR_SET         <span class="hl num">1</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

The device can filter incoming packets by any number of destination
MAC addresses.<span class="hl kwa">\footnote</span><span class="hl opt">{</span>Since there are no guarentees, it can use a hash filter or
silently switch to allmulti or promiscuous mode if it is given too
many addresses.
<span class="hl opt">}</span> This table is set using the class
VIRTIO_NET_CTRL_MAC and the command VIRTIO_NET_CTRL_MAC_TABLE_SET. The
command-specific-data is two variable length tables of <span class="hl num">6</span>-byte MAC
addresses. The first table contains unicast addresses, and the second
contains multicast addresses.

When VIRTIO_NET_F_MAC_ADDR is not negotiated, <span class="hl kwa">\field</span><span class="hl opt">{</span>mac<span class="hl opt">}</span> in the
config space is writeable and is used to set the default MAC
address which rx filtering accepts.
When VIRTIO_NET_F_MAC_ADDR is negotiated, <span class="hl kwa">\field</span><span class="hl opt">{</span>mac<span class="hl opt">}</span> in the
config space becomes read-only for the driver.
The VIRTIO_NET_CTRL_MAC_ADDR_SET command is used to set the
default MAC address which rx filtering
accepts.

Depending on whether VIRTIO_NET_F_MAC_ADDR has been negotiated,
<span class="hl kwa">\field</span><span class="hl opt">{</span>mac<span class="hl opt">}</span> in config space or the VIRTIO_NET_CTRL_MAC_ADDR_SET
is used to set the default MAC address which rx filtering
accepts.
The command-specific-data for VIRTIO_NET_CTRL_MAC_ADDR_SET is
the <span class="hl num">6</span>-byte MAC address.

The
VIRTIO_NET_CTRL_MAC_ADDR_SET command is atomic whereas
<span class="hl kwa">\field</span><span class="hl opt">{</span>mac<span class="hl opt">}</span> in config space is not, therefore drivers
MUST negotiate VIRTIO_NET_F_MAC_ADDR if they change
mac address when device is accepting incoming packets.

<span class="hl kwa">\subparagraph</span><span class="hl opt">{</span>Legacy Interface: Setting MAC Address Filtering<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device Operation / Control Virtqueue / Setting MAC Address Filtering / Legacy Interface: Setting MAC Address Filtering<span class="hl opt">}</span>
For legacy devices, <span class="hl kwa">\field</span><span class="hl opt">{</span>entries<span class="hl opt">}</span> in struct virtio_net_ctrl_mac is the
native endian of the guest rather than (necessarily) little-endian.

Legacy drivers that didn&apos;t negotiate VIRTIO_NET_F_MAC_ADDR
changed <span class="hl kwa">\field</span><span class="hl opt">{</span>mac<span class="hl opt">}</span> in config space when NIC is accepting
incoming packets. These drivers always wrote the mac value from
first to last byte, therefore after detecting such drivers,
a transitional device MAY defer MAC update, or MAY defer
processing incoming packets until driver writes the last byte
of <span class="hl kwa">\field</span><span class="hl opt">{</span>mac<span class="hl opt">}</span> in the config space.

<span class="hl kwa">\paragraph</span><span class="hl opt">{</span>VLAN Filtering<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device Operation / Control Virtqueue / VLAN Filtering<span class="hl opt">}</span>

If the driver negotiates the VIRTION_NET_F_CTRL_VLAN feature, it
can control a VLAN filter table in the device.

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
#define VIRTIO_NET_CTRL_VLAN       <span class="hl num">2</span>
 #define VIRTIO_NET_CTRL_VLAN_ADD             <span class="hl num">0</span>
 #define VIRTIO_NET_CTRL_VLAN_DEL             <span class="hl num">1</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

Both the VIRTIO_NET_CTRL_VLAN_ADD and VIRTIO_NET_CTRL_VLAN_DEL
command take a little-endian <span class="hl num">16</span>-bit VLAN id as the command-specific-data.

<span class="hl kwa">\subparagraph</span><span class="hl opt">{</span>Legacy Interface: VLAN Filtering<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device Operation / Control Virtqueue / VLAN Filtering / Legacy Interface: VLAN Filtering<span class="hl opt">}</span>
For legacy devices, the VLAN id is in the
native endian of the guest rather than (necessarily) little-endian.

<span class="hl kwa">\paragraph</span><span class="hl opt">{</span>Gratuitous Packet Sending<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device Operation / Control Virtqueue / Gratuitous Packet Sending<span class="hl opt">}</span>

If the driver negotiates the VIRTIO_NET_F_GUEST_ANNOUNCE (depends
on VIRTIO_NET_F_CTRL_VQ), it can ask the driver to send gratuitous
packets; this is usually done after the guest has been physically
migrated, and needs to announce its presence on the new network
links. (As hypervisor does not have the knowledge of guest
network configuration (eg. tagged vlan) it is simplest to prod
the guest in this way).

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
#define VIRTIO_NET_CTRL_ANNOUNCE       <span class="hl num">3</span>
 #define VIRTIO_NET_CTRL_ANNOUNCE_ACK             <span class="hl num">0</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

The Driver needs to check VIRTIO_NET_S_ANNOUNCE bit in status
field when it notices the changes of device configuration. The
command VIRTIO_NET_CTRL_ANNOUNCE_ACK is used to indicate that
driver has recevied the notification and device would clear the
VIRTIO_NET_S_ANNOUNCE bit in the status filed after it received
this command.

Processing this notification involves:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>
<span class="hl kwa">\item</span> Sending the gratuitous packets or marking there are pending
  gratuitous packets to be sent and letting deferred routine to
  send them.

<span class="hl kwa">\item</span> Sending VIRTIO_NET_CTRL_ANNOUNCE_ACK command through control
  vq.
<span class="hl kwa">\end</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>

<span class="hl kwa">\paragraph</span><span class="hl opt">{</span>Automatic receive steering in multiqueue mode<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device Operation / Control Virtqueue / Automatic receive steering in multiqueue mode<span class="hl opt">}</span>

If the driver negotiates the VIRTIO_NET_F_MQ feature bit (depends
on VIRTIO_NET_F_CTRL_VQ), it MAY transmit outgoing packets on one
of the multiple transmitq0..transmitqN and ask the device to
queue incoming packets into one of the multiple receiveq0..receiveqN
depending on the packet flow.

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
/* Note: LEGACY version was not little endian! */
struct virtio_net_ctrl_mq <span class="hl opt">{</span>
        le16 virtqueue_pairs;
<span class="hl opt">}</span>;

#define VIRTIO_NET_CTRL_MQ    <span class="hl num">4</span>
 #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET        <span class="hl num">0</span>
 #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MIN        <span class="hl num">1</span>
 #define VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX        <span class="hl num">0x8000</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

Multiqueue is disabled by default. The driver enables multiqueue by
executing the VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET command, specifying
the number of the transmit and receive queues to be used; subsequently,
transmitq0..transmitqn and receiveq0..receiveqn where
n=virtqueue_pairs-<span class="hl num">1</span> MAY be used. All these virtqueues MUST have
been pre-configured in advance. The range of legal values for the
<span class="hl kwa">\field</span><span class="hl opt">{</span>virtqueue_pairs<span class="hl opt">}</span> field is between <span class="hl num">1</span> and <span class="hl kwa">\field</span><span class="hl opt">{</span>max_virtqueue_pairs<span class="hl opt">}</span>.

When multiqueue is enabled, the device MUST use automatic receive steering
based on packet flow. Programming of the receive steering
classificator is implicit. After the driver transmitted a packet of a specific
flow on transmitqX, the device MUST cause incoming packets for this flow to
be steered to receiveqX. For uni-directional protocols, or where
no packets have been transmitted yet, the device MAY steer a packet
to a random queue out of the specified receiveq0..receiveqn.

Multiqueue is disabled by setting <span class="hl kwa">\field</span><span class="hl opt">{</span>virtqueue_pairs<span class="hl opt">}</span> to <span class="hl num">1</span> (this is
the default). After the command has been consumed by the device, the
device MUST NOT steer new packets to virtqueues
receveq1..receiveqN (i.e. other than receiveq0) and MUST NOT read from
transmitq1..transmitqN (i.e. other than transmitq0); accordingly,
the driver MUST NOT transmit new packets on virtqueues other than
transmitq0.

<span class="hl kwa">\subparagraph</span><span class="hl opt">{</span>Legacy Interface: Automatic receive steering in multiqueue mode<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device Operation / Control Virtqueue / Automatic receive steering in multiqueue mode / Legacy Interface: Automatic receive steering in multiqueue mode<span class="hl opt">}</span>
For legacy devices, <span class="hl kwa">\field</span><span class="hl opt">{</span>virtqueue_pairs<span class="hl opt">}</span> is in the
native endian of the guest rather than (necessarily) little-endian.

<span class="hl kwa">\paragraph</span><span class="hl opt">{</span>Offloads State Configuration<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device Operation / Control Virtqueue / Offloads State Configuration<span class="hl opt">}</span>

If the VIRTIO_NET_F_CTRL_GUEST_OFFLOADS feature is negotiated, the driver can
send control commands for dynamic offloads state configuration.

<span class="hl kwa">\subparagraph</span><span class="hl opt">{</span>Setting Offloads State<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device Operation / Control Virtqueue / Offloads State Configuration / Setting Offloads State<span class="hl opt">}</span>

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
le64 offloads;

#define VIRTIO_NET_F_GUEST_CSUM       <span class="hl num">1</span>
#define VIRTIO_NET_F_GUEST_TSO4       <span class="hl num">7</span>
#define VIRTIO_NET_F_GUEST_TSO6       <span class="hl num">8</span>
#define VIRTIO_NET_F_GUEST_ECN        <span class="hl num">9</span>
#define VIRTIO_NET_F_GUEST_UFO        <span class="hl num">10</span>

#define VIRTIO_NET_CTRL_GUEST_OFFLOADS       <span class="hl num">5</span>
 #define VIRTIO_NET_CTRL_GUEST_OFFLOADS_SET   <span class="hl num">0</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

The class VIRTIO_NET_CTRL_GUEST_OFFLOADS has one command:
VIRTIO_NET_CTRL_GUEST_OFFLOADS_SET applies the new offloads configuration.

le64 value passed as command data is a bitmask, bits set define
offloads to be enabled, bits cleared - offloads to be disabled.

There is a corresponding device feature for each offload. Upon feature
negotiation corresponding offload gets enabled to preserve backward
compartibility.

Corresponding feature must be negotiated at startup in order to allow dynamic
change of specific offload state.


<span class="hl kwa">\subparagraph</span><span class="hl opt">{</span>Legacy Interface: Setting Offloads State<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Network Device / Device Operation / Control Virtqueue / Offloads State Configuration / Setting Offloads State / Legacy Interface: Setting Offloads State<span class="hl opt">}</span>
For legacy devices, <span class="hl kwa">\field</span><span class="hl opt">{</span>offloads<span class="hl opt">}</span> is the
native endian of the guest rather than (necessarily) little-endian.


<span class="hl kwa">\section</span><span class="hl opt">{</span>Block Device<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Block Device<span class="hl opt">}</span>

The virtio block device is a simple virtual block device (ie.
disk). Read and write requests (and other exotic requests) are
placed in the queue, and serviced (probably out of order) by the
device except where noted.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Device ID<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Block Device / Device ID<span class="hl opt">}</span>
  <span class="hl num">2</span>

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Virtqueues<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Block Device / Virtqueues<span class="hl opt">}</span>
<span class="hl kwa">\begin</span><span class="hl opt">{</span>description<span class="hl opt">}</span>
<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl num">0</span><span class="hl opt">]</span> requestq
<span class="hl kwa">\end</span><span class="hl opt">{</span>description<span class="hl opt">}</span>

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Feature bits<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Block Device / Feature bits<span class="hl opt">}</span>

<span class="hl kwa">\begin</span><span class="hl opt">{</span>description<span class="hl opt">}</span>
<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_BLK_F_SIZE_MAX (<span class="hl num">1</span>)<span class="hl opt">]</span> Maximum size of any single segment is
    in <span class="hl kwa">\field</span><span class="hl opt">{</span>size_max<span class="hl opt">}</span>.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_BLK_F_SEG_MAX (<span class="hl num">2</span>)<span class="hl opt">]</span> Maximum number of segments in a
    request is in <span class="hl kwa">\field</span><span class="hl opt">{</span>seg_max<span class="hl opt">}</span>.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_BLK_F_GEOMETRY (<span class="hl num">4</span>)<span class="hl opt">]</span> Disk-style geometry specified in
    <span class="hl kwa">\field</span><span class="hl opt">{</span>geometry<span class="hl opt">}</span>.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_BLK_F_RO (<span class="hl num">5</span>)<span class="hl opt">]</span> Device is read-only.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_BLK_F_BLK_SIZE (<span class="hl num">6</span>)<span class="hl opt">]</span> Block size of disk is in <span class="hl kwa">\field</span><span class="hl opt">{</span>blk_size<span class="hl opt">}</span>.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_BLK_F_TOPOLOGY (<span class="hl num">10</span>)<span class="hl opt">]</span> Device exports information on optimal I/O
    alignment.
<span class="hl kwa">\end</span><span class="hl opt">{</span>description<span class="hl opt">}</span>

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Legacy Interface: Feature bits<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Block Device / Feature bits / Legacy Interface: Feature bits<span class="hl opt">}</span>

<span class="hl kwa">\begin</span><span class="hl opt">{</span>description<span class="hl opt">}</span>
<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_BLK_F_BARRIER (<span class="hl num">0</span>)<span class="hl opt">]</span> Device supports request barriers.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_BLK_F_SCSI (<span class="hl num">7</span>)<span class="hl opt">]</span> Device supports scsi packet commands.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_BLK_F_FLUSH (<span class="hl num">9</span>)<span class="hl opt">]</span> Cache flush command support.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_BLK_F_CONFIG_WCE (<span class="hl num">11</span>)<span class="hl opt">]</span> Device can toggle its cache between writeback
    and writethrough modes.
<span class="hl kwa">\end</span><span class="hl opt">{</span>description<span class="hl opt">}</span>

VIRTIO_BLK_F_FLUSH was also called VIRTIO_BLK_F_WCE: Legacy drivers
should only negotiate this feature if they are capable of sending
VIRTIO_BLK_T_FLUSH commands.

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Device configuration layout<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Block Device / Feature bits / Device configuration layout<span class="hl opt">}</span>

The <span class="hl kwa">\field</span><span class="hl opt">{</span>capacity<span class="hl opt">}</span> of the device (expressed in <span class="hl num">512</span>-byte sectors) is always
present. The availability of the others all depend on various feature
bits as indicated above.

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
/* Note: LEGACY version was not little endian! */
struct virtio_blk_config <span class="hl opt">{</span>
        le64 capacity;
        le32 size_max;
        le32 seg_max;
        struct virtio_blk_geometry <span class="hl opt">{</span>
                le16 cylinders;
                u8 heads;
                u8 sectors;
        <span class="hl opt">}</span> geometry;
        le32 blk_size;
        struct virtio_blk_topology <span class="hl opt">{</span>
                // # of logical blocks per physical block (log2)
                u8 physical_block_exp;
                // offset of first aligned logical block
                u8 alignment_offset;
                // suggested minimum I/O size in blocks
                le16 min_io_size;
                // optimal (suggested maximum) I/O size in blocks
                le32 opt_io_size;
        <span class="hl opt">}</span> topology;
        u8 reserved;
<span class="hl opt">}</span>;
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>


<span class="hl kwa">\paragraph</span><span class="hl opt">{</span>Legacy Interface: Device configuration layout<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Block Device / Feature bits / Device configuration layout / Legacy Interface: Device configuration layout<span class="hl opt">}</span>
For legacy devices, the fields in struct virtio_blk_config are the
native endian of the guest rather than (necessarily) little-endian.


<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Device Initialization<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Block Device / Device Initialization<span class="hl opt">}</span>

<span class="hl kwa">\begin</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>
<span class="hl kwa">\item</span> The device size should be read from <span class="hl kwa">\field</span><span class="hl opt">{</span>capacity<span class="hl opt">}</span>.
  No requests should be submitted which goes
  beyond this limit.

<span class="hl kwa">\item</span> If the VIRTIO_BLK_F_BLK_SIZE feature is negotiated,
  <span class="hl kwa">\field</span><span class="hl opt">{</span>blk_size<span class="hl opt">}</span> can be read to determine the optimal sector size
  for the driver to use. This does not affect the units used in
  the protocol (always <span class="hl num">512</span> bytes), but awareness of the correct
  value can affect performance.

<span class="hl kwa">\item</span> If the VIRTIO_BLK_F_RO feature is set by the device, any write
  requests will fail.

<span class="hl kwa">\item</span> If the VIRTIO_BLK_F_TOPOLOGY feature is negotiated, the fields in the
  <span class="hl kwa">\field</span><span class="hl opt">{</span>topology<span class="hl opt">}</span> struct can be read to determine the physical block size and optimal
  I/O lengths for the driver to use. This also does not affect the units
  in the protocol, only performance.
<span class="hl kwa">\end</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Legacy Interface: Device Initialization<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Block Device / Device Initialization / Legacy Interface: Device Initialization<span class="hl opt">}</span>

The <span class="hl kwa">\field</span><span class="hl opt">{</span>reserved<span class="hl opt">}</span> field used to be called <span class="hl kwa">\field</span><span class="hl opt">{</span>writeback<span class="hl opt">}</span>.  If the
VIRTIO_BLK_F_CONFIG_WCE feature is offered, the cache mode should be
read from <span class="hl kwa">\field</span><span class="hl opt">{</span>writeback<span class="hl opt">}</span> if available; the
driver can also write to the field in order to toggle the cache
between writethrough (<span class="hl num">0</span>) and writeback (<span class="hl num">1</span>) mode.  If the feature is
not available, the driver can instead look at the result of
negotiating VIRTIO_BLK_F_FLUSH: the cache will be in writeback mode
after reset if and only if VIRTIO_BLK_F_FLUSH is negotiated.

Some older legacy devices did not operate in writethrough mode even
after a driver announced lack of support for VIRTIO_BLK_F_FLUSH.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Device Operation<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Block Device / Device Operation<span class="hl opt">}</span>

The driver queues requests to the virtqueue, and they are used by
the device (not necessarily in order). Each request is of form:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
struct virtio_blk_req <span class="hl opt">{</span>
        le32 type;
        le32 reserved;
        le64 sector;
        u8 data<span class="hl opt">[][</span><span class="hl num">512</span><span class="hl opt">]</span>;
        u8 status;
<span class="hl opt">}</span>;
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

The type of the request is either a read (VIRTIO_BLK_T_IN), a write
(VIRTIO_BLK_T_OUT), or a flush (VIRTIO_BLK_T_FLUSH or
VIRTIO_BLK_T_FLUSH_OUT<span class="hl kwa">\footnote</span><span class="hl opt">{</span>The FLUSH and FLUSH_OUT types are equivalent, the device does not
distinguish between them
<span class="hl opt">}</span>).

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
#define VIRTIO_BLK_T_IN           <span class="hl num">0</span>
#define VIRTIO_BLK_T_OUT          <span class="hl num">1</span>
#define VIRTIO_BLK_T_FLUSH        <span class="hl num">4</span>
#define VIRTIO_BLK_T_FLUSH_OUT    <span class="hl num">5</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

The <span class="hl kwa">\field</span><span class="hl opt">{</span>sector<span class="hl opt">}</span> number indicates the offset (multiplied by <span class="hl num">512</span>) where
the read or write is to occur. This field is unused and set to <span class="hl num">0</span>
for scsi packet commands and for flush commands.

The final <span class="hl kwa">\field</span><span class="hl opt">{</span>status<span class="hl opt">}</span> byte is written by the device: either
VIRTIO_BLK_S_OK for success, VIRTIO_BLK_S_IOERR for device or driver
error or VIRTIO_BLK_S_UNSUPP for a request unsupported by device:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
#define VIRTIO_BLK_S_OK        <span class="hl num">0</span>
#define VIRTIO_BLK_S_IOERR     <span class="hl num">1</span>
#define VIRTIO_BLK_S_UNSUPP    <span class="hl num">2</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

Any writes completed before the submission of the flush command should
be committed to non-volatile storage by the device.

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Legacy Interface: Device Operation<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Block Device / Device Operation / Legacy Interface: Device Operation<span class="hl opt">}</span>
For legacy devices, the fields in struct virtio_blk_req are the
native endian of the guest rather than (necessarily) little-endian.

The <span class="hl kwa">\field</span><span class="hl opt">{</span>reserved<span class="hl opt">}</span> field was previously called <span class="hl kwa">\field</span><span class="hl opt">{</span>ioprio<span class="hl opt">}</span>.  <span class="hl kwa">\field</span><span class="hl opt">{</span>ioprio<span class="hl opt">}</span>
is a hint about the relative priorities of requests to the device:
higher numbers indicate more important requests.

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
#define VIRTIO_BLK_T_BARRIER     <span class="hl num">0x80000000</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

If the device has VIRTIO_BLK_F_BARRIER
feature the high bit (VIRTIO_BLK_T_BARRIER) indicates that this
request acts as a barrier and that all preceeding requests must be
complete before this one, and all following requests must not be
started until this is complete. Note that a barrier does not flush
caches in the underlying backend device in host, and thus does not
serve as data consistency guarantee. Driver must use FLUSH request to
flush the host cache.

If the device has VIRTIO_BLK_F_SCSI feature, it can also support
scsi packet command requests, each of these requests is of form:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
/* All fields are in guest&apos;s native endian. */
struct virtio_scsi_pc_req <span class="hl opt">{</span>
        u32 type;
        u32 ioprio;
        u64 sector;
        u8 cmd<span class="hl opt">[]</span>;
        u8 data<span class="hl opt">[][</span><span class="hl num">512</span><span class="hl opt">]</span>;
#define SCSI_SENSE_BUFFERSIZE   <span class="hl num">96</span>
        u8 sense<span class="hl opt">[</span>SCSI_SENSE_BUFFERSIZE<span class="hl opt">]</span>;
        u32 errors;
        u32 data_len;
        u32 sense_len;
        u32 residual;
        u8 status;
<span class="hl opt">}</span>;
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

A request type can also be a scsi packet command (VIRTIO_BLK_T_SCSI_CMD or
VIRTIO_BLK_T_SCSI_CMD_OUT).  The two types are equivalent, the device
does not distinguish between them:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
#define VIRTIO_BLK_T_SCSI_CMD     <span class="hl num">2</span>
#define VIRTIO_BLK_T_SCSI_CMD_OUT <span class="hl num">3</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

The <span class="hl kwa">\field</span><span class="hl opt">{</span>cmd<span class="hl opt">}</span> field is only present for scsi packet command requests,
and indicates the command to perform. This field must reside in a
single, separate device-readable buffer; command length can be derived
from the length of this buffer.

Note that these first three (four for scsi packet commands)
fields are always device-readable: <span class="hl kwa">\field</span><span class="hl opt">{</span>data<span class="hl opt">}</span> is either device-readable
or device-writable, depending on the request. The size of the read or
write can be derived from the total size of the request buffers.

<span class="hl kwa">\field</span><span class="hl opt">{</span>sense<span class="hl opt">}</span> is only present for scsi packet command requests,
and indicates the buffer for scsi sense data.

<span class="hl kwa">\field</span><span class="hl opt">{</span>data_len<span class="hl opt">}</span> is only present for scsi packet command
requests, this field is deprecated, and should be ignored by the
driver. Historically, devices copied data length there.

<span class="hl kwa">\field</span><span class="hl opt">{</span>sense_len<span class="hl opt">}</span> is only present for scsi packet command
requests and indicates the number of bytes actually written to
the <span class="hl kwa">\field</span><span class="hl opt">{</span>sense<span class="hl opt">}</span> buffer.

<span class="hl kwa">\field</span><span class="hl opt">{</span>residual<span class="hl opt">}</span> field is only present for scsi packet command
requests and indicates the residual size, calculated as data
length - number of bytes actually transferred.

Historically, devices assumed that <span class="hl kwa">\field</span><span class="hl opt">{</span>type<span class="hl opt">}</span>, <span class="hl kwa">\field</span><span class="hl opt">{</span>ioprio<span class="hl opt">}</span> and
<span class="hl kwa">\field</span><span class="hl opt">{</span>sector<span class="hl opt">}</span> reside in a single, separate device-readable buffer;
<span class="hl kwa">\field</span><span class="hl opt">{</span>errors<span class="hl opt">}</span>, <span class="hl kwa">\field</span><span class="hl opt">{</span>data_len<span class="hl opt">}</span>, <span class="hl kwa">\field</span><span class="hl opt">{</span>sense_len<span class="hl opt">}</span> and residual reside in a single,
separate device-writable buffer; <span class="hl kwa">\field</span><span class="hl opt">{</span>sense<span class="hl opt">}</span> in a separate
device-writable buffer of size <span class="hl num">96</span> bytes, by itself; <span class="hl kwa">\field</span><span class="hl opt">{</span>errors<span class="hl opt">}</span>,
<span class="hl kwa">\field</span><span class="hl opt">{</span>data_len<span class="hl opt">}</span>, <span class="hl kwa">\field</span><span class="hl opt">{</span>sense_len<span class="hl opt">}</span> and <span class="hl kwa">\field</span><span class="hl opt">{</span>residual<span class="hl opt">}</span> in a single device-writable buffer;
and <span class="hl kwa">\field</span><span class="hl opt">{</span>status<span class="hl opt">}</span> is a separate device-writable buffer of size <span class="hl num">1</span>
byte, by itself.


<span class="hl kwa">\section</span><span class="hl opt">{</span>Console Device<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Console Device<span class="hl opt">}</span>

The virtio console device is a simple device for data input and
output. A device may have one or more ports. Each port has a pair
of input and output virtqueues. Moreover, a device has a pair of
control IO virtqueues. The control virtqueues are used to
communicate information between the device and the driver about
ports being opened and closed on either side of the connection,
indication from the device about whether a particular port is a
console port, adding new ports, port hot-plug/unplug, etc., and
indication from the driver about whether a port or a device was
successfully added, port open/close, etc.. For data IO, one or
more empty buffers are placed in the receive queue for incoming
data and outgoing characters are placed in the transmit queue.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Device ID<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Console Device / Device ID<span class="hl opt">}</span>

  <span class="hl num">3</span>

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Virtqueues<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Console Device / Virtqueues<span class="hl opt">}</span>

<span class="hl kwa">\begin</span><span class="hl opt">{</span>description<span class="hl opt">}</span>
<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl num">0</span><span class="hl opt">]</span> receiveq(port0)
<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl num">1</span><span class="hl opt">]</span> transmitq(port0)
<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl num">2</span><span class="hl opt">]</span> control receiveq
<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl num">3</span><span class="hl opt">]</span> control transmitq
<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl num">4</span><span class="hl opt">]</span> receiveq(port1)
<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl num">5</span><span class="hl opt">]</span> transmitq(port1)
<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\ldots</span><span class="hl opt">]</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>description<span class="hl opt">}</span>

The port <span class="hl num">0</span> receive and transmit queues always exist: other queues
only exist if VIRTIO_CONSOLE_F_MULTIPORT is set.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Feature bits<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Console Device / Feature bits<span class="hl opt">}</span>

<span class="hl kwa">\begin</span><span class="hl opt">{</span>description<span class="hl opt">}</span>
<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_CONSOLE_F_SIZE (<span class="hl num">0</span>)<span class="hl opt">]</span> Configuration <span class="hl kwa">\field</span><span class="hl opt">{</span>cols<span class="hl opt">}</span> and <span class="hl kwa">\field</span><span class="hl opt">{</span>rows<span class="hl opt">}</span>
    are valid.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_CONSOLE_F_MULTIPORT (<span class="hl num">1</span>)<span class="hl opt">]</span> Device has support for multiple
    ports; <span class="hl kwa">\field</span><span class="hl opt">{</span>nr_ports<span class="hl opt">}</span> and <span class="hl kwa">\field</span><span class="hl opt">{</span>max_nr_ports<span class="hl opt">}</span> are
    valid and control virtqueues will be used.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_CONSOLE_F_EMERG_WRITE (<span class="hl num">2</span>)<span class="hl opt">]</span> Device has support for emergency write.
    Configuration field emerg_wr is valid.
<span class="hl kwa">\end</span><span class="hl opt">{</span>description<span class="hl opt">}</span>

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Device configuration layout<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Console Device / Device configuration layout<span class="hl opt">}</span>

  The size of the console is supplied
  in the configuration space if the VIRTIO_CONSOLE_F_SIZE feature
  is set. Furthermore, if the VIRTIO_CONSOLE_F_MULTIPORT feature
  is set, the maximum number of ports supported by the device can
  be fetched.

  If VIRTIO_CONSOLE_F_EMERG_WRITE is set then the driver can use emergency write
  to output a single character without initializing virtio queues, or even
  acknowledging the feature.

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
/* Note: LEGACY version was not little endian! */
struct virtio_console_config <span class="hl opt">{</span>
        le16 cols;
        le16 rows;
        le32 max_nr_ports;
        le32 emerg_wr;
<span class="hl opt">}</span>;
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Legacy Interface: Device configuration layout<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Console Device / Device configuration layout / Legacy Interface: Device configuration layout<span class="hl opt">}</span>
For legacy devices, the fields in struct virtio_console_config are the
native endian of the guest rather than (necessarily) little-endian.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Device Initialization<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Console Device / Device Initialization<span class="hl opt">}</span>

<span class="hl kwa">\begin</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>
<span class="hl kwa">\item</span> If the VIRTIO_CONSOLE_F_EMERG_WRITE feature is offered,
  <span class="hl kwa">\field</span><span class="hl opt">{</span>emerg_wr<span class="hl opt">}</span> field of the configuration can be written at any time.
  Thus it should work for very early boot debugging output as well as
  catastophic OS failures (eg. virtio ring corruption).

<span class="hl kwa">\item</span> If the VIRTIO_CONSOLE_F_SIZE feature is negotiated, the driver
  can read the console dimensions from <span class="hl kwa">\field</span><span class="hl opt">{</span>cols<span class="hl opt">}</span> and <span class="hl kwa">\field</span><span class="hl opt">{</span>rows<span class="hl opt">}</span>.

<span class="hl kwa">\item</span> If the VIRTIO_CONSOLE_F_MULTIPORT feature is negotiated, the
  driver can spawn multiple ports, not all of which may be
  attached to a console. Some could be generic ports. In this
  case, the control virtqueues are enabled and according to
  <span class="hl kwa">\field</span><span class="hl opt">{</span>max_nr_ports<span class="hl opt">}</span>, the appropriate number
  of virtqueues are created. A control message indicating the
  driver is ready is sent to the device. The device can then send
  control messages for adding new ports to the device. After
  creating and initializing each port, a
  VIRTIO_CONSOLE_PORT_READY control message is sent to the device
  for that port so the device can let the driver know of any additional
  configuration options set for that port.

<span class="hl kwa">\item</span> The receiveq for each port is populated with one or more
  receive buffers.
<span class="hl kwa">\end</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Device Operation<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Console Device / Device Operation<span class="hl opt">}</span>

<span class="hl kwa">\begin</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>
<span class="hl kwa">\item</span> For output, a buffer containing the characters is placed in
  the port&apos;s transmitq.<span class="hl kwa">\footnote</span><span class="hl opt">{</span>Because this is high importance and low bandwidth, the current
Linux implementation polls for the buffer to be used, rather than
waiting for an interrupt, simplifying the implementation
significantly. However, for generic serial ports with the
O_NONBLOCK flag set, the polling limitation is relaxed and the
consumed buffers are freed upon the next write or poll call or
when a port is closed or hot-unplugged.
<span class="hl opt">}</span>

<span class="hl kwa">\item</span> When a buffer is used in the receiveq (signalled by an
  interrupt), the contents is the input to the port associated
  with the virtqueue for which the notification was received.

<span class="hl kwa">\item</span> If the driver negotiated the VIRTIO_CONSOLE_F_SIZE feature, a
  configuration change interrupt may occur. The updated size can
  be read from the configuration fields.  This size applies to port <span class="hl num">0</span> only.

<span class="hl kwa">\item</span> If the driver negotiated the VIRTIO_CONSOLE_F_MULTIPORT
  feature, active ports are announced by the device using the
  VIRTIO_CONSOLE_PORT_ADD control message. The same message is
  used for port hot-plug as well.
<span class="hl kwa">\end</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Multiport Device Operation<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Console Device / Device Operation / Multiport Device Operation<span class="hl opt">}</span>

If the driver negotiated the VIRTIO_CONSOLE_F_MULTIPORT, the two
control queues are used to manipulate the different console ports: the
control receiveq for messages from the device to the driver, and the
control sendq for driver-to-device messages.  The layout of the
control messages is:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
/* Note: LEGACY version was not little endian! */
struct virtio_console_control <span class="hl opt">{</span>
        le32 id;    /* Port number */
        le16 event; /* The kind of control event */
        le16 value; /* Extra information for the event */
<span class="hl opt">}</span>;
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

The values for <span class="hl kwa">\field</span><span class="hl opt">{</span>event<span class="hl opt">}</span> are:
<span class="hl kwa">\begin</span><span class="hl opt">{</span>description<span class="hl opt">}</span>
<span class="hl kwa">\item</span> <span class="hl opt">[</span>VIRTIO_CONSOLE_DEVICE_READY (<span class="hl num">0</span>)<span class="hl opt">]</span> Sent by the driver at initialization
  to indicate that it is ready to receive control messages.  A value of
  <span class="hl num">1</span> indicates success, and <span class="hl num">0</span> indicates failure.  The port number is unused.
<span class="hl kwa">\item</span> <span class="hl opt">[</span>VIRTIO_CONSOLE_DEVICE_ADD (<span class="hl num">1</span>)<span class="hl opt">]</span> Sent by the device, to create a new
  port.  The device MUST NOT specify a port which exists.  <span class="hl kwa">\field</span><span class="hl opt">{</span>value<span class="hl opt">}</span> is unused.
<span class="hl kwa">\item</span> <span class="hl opt">[</span>VIRTIO_CONSOLE_DEVICE_REMOVE (<span class="hl num">2</span>)<span class="hl opt">]</span> Sent by the device, to remove an
  existing port.  The device MUST NOT specify a port which has not been
  created with VIRTIO_CONSOLE_DEVICE_ADD.  <span class="hl kwa">\field</span><span class="hl opt">{</span>value<span class="hl opt">}</span> is unused.
<span class="hl kwa">\item</span> <span class="hl opt">[</span>VIRTIO_CONSOLE_PORT_READY (<span class="hl num">3</span>)<span class="hl opt">]</span> Sent by the driver in response
  to the device&apos;s VIRTIO_CONSOLE_PORT_ADD message, to indicate that
  the port is ready to be used. A <span class="hl kwa">\field</span><span class="hl opt">{</span>value<span class="hl opt">}</span> of <span class="hl num">1</span> indicates success, and <span class="hl num">0</span>
  indicates failure.
<span class="hl kwa">\item</span> <span class="hl opt">[</span>VIRTIO_CONSOLE_CONSOLE_PORT (<span class="hl num">4</span>)<span class="hl opt">]</span> Sent by the device to nominate
  a port as a console port.  There may be more than one console port.
  The driver SHOULD treat the port in a manner suitable for text
  console access; the driver MUST respond with a VIRTIO_CONSOLE_PORT_OPEN
  message.  The driver MUST set <span class="hl kwa">\field</span><span class="hl opt">{</span>value<span class="hl opt">}</span> to <span class="hl num">1</span>.
<span class="hl kwa">\item</span> <span class="hl opt">[</span>VIRTIO_CONSOLE_RESIZE (<span class="hl num">5</span>)<span class="hl opt">]</span> Sent by the device to indicate
  a console size change.  <span class="hl kwa">\field</span><span class="hl opt">{</span>value<span class="hl opt">}</span> is unused.  The buffer is followed by the number of columns and rows:
<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
struct virtio_console_resize <span class="hl opt">{</span>
        le16 cols;
        le16 rows;
<span class="hl opt">}</span>;
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
<span class="hl kwa">\item</span> <span class="hl opt">[</span>VIRTIO_CONSOLE_PORT_OPEN (<span class="hl num">6</span>)<span class="hl opt">]</span> This message is sent by both the
  device and the driver.  <span class="hl kwa">\field</span><span class="hl opt">{</span>value<span class="hl opt">}</span> MUST BE set to <span class="hl num">0</span> (port
  closed) or <span class="hl num">1</span> (port open).  This allows for ports to be used directly
  by guest and host processes to communicate in an application-defined
  manner.
<span class="hl kwa">\item</span> <span class="hl opt">[</span>VIRTIO_CONSOLE_PORT_NAME (<span class="hl num">7</span>)<span class="hl opt">]</span> Sent by the device to give a tag
  to the port.  This control command is immediately
  followed by the UTF-<span class="hl num">8</span> name of the port for identification
  within the guest (without a NUL terminator).
<span class="hl kwa">\end</span><span class="hl opt">{</span>description<span class="hl opt">}</span>

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Legacy Interface: Device Operation<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Console Device / Device Operation / Legacy Interface: Device Operation<span class="hl opt">}</span>
For legacy devices, the fields in struct virtio_console_control are the
native endian of the guest rather than (necessarily) little-endian.


<span class="hl kwa">\section</span><span class="hl opt">{</span>Entropy Device<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Entropy Device<span class="hl opt">}</span>

The virtio entropy device supplies high-quality randomness for
guest use.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Device ID<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Entropy Device / Device ID<span class="hl opt">}</span>
  <span class="hl num">4</span>

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Virtqueues<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Entropy Device / Virtqueues<span class="hl opt">}</span>
<span class="hl kwa">\begin</span><span class="hl opt">{</span>description<span class="hl opt">}</span>
<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl num">0</span><span class="hl opt">]</span> requestq
<span class="hl kwa">\end</span><span class="hl opt">{</span>description<span class="hl opt">}</span>

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Feature bits<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Entropy Device / Feature bits<span class="hl opt">}</span>
  None currently defined

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Device configuration layout<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Entropy Device / Device configuration layout<span class="hl opt">}</span>
  None currently defined.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Device Initialization<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Entropy Device / Device Initialization<span class="hl opt">}</span>

<span class="hl kwa">\begin</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>
<span class="hl kwa">\item</span> The virtqueue is initialized
<span class="hl kwa">\end</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Device Operation<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Entropy Device / Device Operation<span class="hl opt">}</span>

When the driver requires random bytes, it places the descriptor
of one or more buffers in the queue. It will be completely filled
by random data by the device.

<span class="hl kwa">\section</span><span class="hl opt">{</span>Memory Balloon Device<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Memory Balloon Device<span class="hl opt">}</span>

The virtio memory balloon device is a primitive device for
managing guest memory: the device asks for a certain amount of
memory, and the driver supplies it (or withdraws it, if the device
has more than it asks for). This allows the guest to adapt to
changes in allowance of underlying physical memory. If the
feature is negotiated, the device can also be used to communicate
guest memory statistics to the host.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Device ID<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Memory Balloon Device / Device ID<span class="hl opt">}</span>
  <span class="hl num">5</span>

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Virtqueues<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Memory Balloon Device / Virtqueues<span class="hl opt">}</span>
<span class="hl kwa">\begin</span><span class="hl opt">{</span>description<span class="hl opt">}</span>
<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl num">0</span><span class="hl opt">]</span> inflateq
<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl num">1</span><span class="hl opt">]</span> deflateq
<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl num">2</span><span class="hl opt">]</span> statsq.
<span class="hl kwa">\end</span><span class="hl opt">{</span>description<span class="hl opt">}</span>

  Virtqueue <span class="hl num">2</span> only exists if VIRTIO_BALLON_F_STATS_VQ set.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Feature bits<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Memory Balloon Device / Feature bits<span class="hl opt">}</span>
<span class="hl kwa">\begin</span><span class="hl opt">{</span>description<span class="hl opt">}</span>
<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_BALLOON_F_MUST_TELL_HOST (<span class="hl num">0</span>)<span class="hl opt">]</span> Host must be told before
    pages from the balloon are used.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_BALLOON_F_STATS_VQ (<span class="hl num">1</span>)<span class="hl opt">]</span> A virtqueue for reporting guest
    memory statistics is present.
<span class="hl kwa">\end</span><span class="hl opt">{</span>description<span class="hl opt">}</span>

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Device configuration layout<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Memory Balloon Device / Device configuration layout<span class="hl opt">}</span>
  Both fields of this configuration
  are always available.

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
struct virtio_balloon_config <span class="hl opt">{</span>
        le32 num_pages;
        le32 actual;
<span class="hl opt">}</span>;
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Legacy Interface: Device configuration layout<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Memory Balloon Device / Device configuration layout / Legacy Interface: Device configuration layout<span class="hl opt">}</span>
Note that these fields are always little endian, despite convention
that legacy device fields are guest endian.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Device Initialization<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Memory Balloon Device / Device Initialization<span class="hl opt">}</span>

<span class="hl kwa">\begin</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>
<span class="hl kwa">\item</span> The inflate and deflate virtqueues are identified.

<span class="hl kwa">\item</span> If the VIRTIO_BALLOON_F_STATS_VQ feature bit is negotiated:
  <span class="hl kwa">\begin</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>
  <span class="hl kwa">\item</span> Identify the stats virtqueue.

  <span class="hl kwa">\item</span> Add one empty buffer to the stats virtqueue and notify the
    device.
  <span class="hl kwa">\end</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>

Device operation begins immediately.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Device Operation<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Memory Balloon Device / Device Operation<span class="hl opt">}</span>

The device is driven by the receipt of a
configuration change interrupt.

<span class="hl kwa">\begin</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>
<span class="hl kwa">\item \field</span><span class="hl opt">{</span>num_pages<span class="hl opt">}</span> configuration field is examined. If this is
  greater than the <span class="hl kwa">\field</span><span class="hl opt">{</span>actual<span class="hl opt">}</span> number of pages, memory must be given
  to the balloon. If it is less than <span class="hl kwa">\field</span><span class="hl opt">{</span>actual<span class="hl opt">}</span>,
  memory may be taken back from the balloon for general
  use.

<span class="hl kwa">\item</span> To supply memory to the balloon (aka. inflate):
  <span class="hl kwa">\begin</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>
  <span class="hl kwa">\item</span> The driver constructs an array of addresses of unused memory
    pages. These addresses are divided by <span class="hl num">4096</span><span class="hl kwa">\footnote</span><span class="hl opt">{</span>This is historical, and independent of the guest page size
<span class="hl opt">}</span> and the descriptor
    describing the resulting <span class="hl num">32</span>-bit array is added to the inflateq.
  <span class="hl kwa">\end</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>

<span class="hl kwa">\item</span> To remove memory from the balloon (aka. deflate):
  <span class="hl kwa">\begin</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>
  <span class="hl kwa">\item</span> The driver constructs an array of addresses of memory pages
    it has previously given to the balloon, as described above.
    This descriptor is added to the deflateq.

  <span class="hl kwa">\item</span> If the VIRTIO_BALLOON_F_MUST_TELL_HOST feature is negotiated, the
    guest may not use these requested pages until that descriptor
    in the deflateq has been used by the device.

  <span class="hl kwa">\item</span> Otherwise, the guest may begin to re-use pages previously
    given to the balloon before the device has acknowledged their
    withdrawl.<span class="hl kwa">\footnote</span><span class="hl opt">{</span>In this case, deflation advice is merely a courtesy
<span class="hl opt">}</span>
  <span class="hl kwa">\end</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>

<span class="hl kwa">\item</span> In either case, once the device has completed the inflation or
  deflation, <span class="hl kwa">\field</span><span class="hl opt">{</span>actual<span class="hl opt">}</span> should be
  updated to reflect the new number of pages in the balloon.<span class="hl kwa">\footnote</span><span class="hl opt">{</span>As updates to device configuration space are not atomic, this field
isn&apos;t particularly reliable, but can be used to diagnose buggy guests.
<span class="hl opt">}</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Memory Statistics<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Memory Balloon Device / Device Operation / Memory Statistics<span class="hl opt">}</span>

The stats virtqueue is atypical because communication is driven
by the device (not the driver). The channel becomes active at
driver initialization time when the driver adds an empty buffer
and notifies the device. A request for memory statistics proceeds
as follows:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>
<span class="hl kwa">\item</span> The device pushes the buffer onto the used ring and sends an
  interrupt.

<span class="hl kwa">\item</span> The driver pops the used buffer and discards it.

<span class="hl kwa">\item</span> The driver collects memory statistics and writes them into a
  new buffer.

<span class="hl kwa">\item</span> The driver adds the buffer to the virtqueue and notifies the
  device.

<span class="hl kwa">\item</span> The device pops the buffer (retaining it to initiate a
  subsequent request) and consumes the statistics.
<span class="hl kwa">\end</span><span class="hl opt">{</span>enumerate<span class="hl opt">}</span>

  Each statistic consists of a <span class="hl num">16</span> bit
  tag and a <span class="hl num">64</span> bit value. All statistics are optional and the
  driver may choose which ones to supply. To guarantee backwards
  compatibility, unsupported statistics should be omitted.

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
/* Note: LEGACY version was not little endian! */
struct virtio_balloon_stat <span class="hl opt">{</span>
#define VIRTIO_BALLOON_S_SWAP_IN  <span class="hl num">0</span>
#define VIRTIO_BALLOON_S_SWAP_OUT <span class="hl num">1</span>
#define VIRTIO_BALLOON_S_MAJFLT   <span class="hl num">2</span>
#define VIRTIO_BALLOON_S_MINFLT   <span class="hl num">3</span>
#define VIRTIO_BALLOON_S_MEMFREE  <span class="hl num">4</span>
#define VIRTIO_BALLOON_S_MEMTOT   <span class="hl num">5</span>
        le16 tag;
        le64 val;
<span class="hl opt">}</span> __attribute__((packed));
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

<span class="hl kwa">\paragraph</span><span class="hl opt">{</span>Legacy Interface: Memory Statistics<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Memory Balloon Device / Device Operation / Memory Statistics / Legacy Interface: Memory Statistics<span class="hl opt">}</span>
For legacy devices, the fields in struct virtio_balloon_stat are the
native endian of the guest rather than (necessarily) little-endian.


<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Memory Statistics Tags<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / Memory Balloon Device / Device Operation / Memory Statistics Tags<span class="hl opt">}</span>

<span class="hl kwa">\begin</span><span class="hl opt">{</span>description<span class="hl opt">}</span>
<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_BALLOON_S_SWAP_IN (<span class="hl num">0</span>)<span class="hl opt">]</span> The amount of memory that has been
  swapped in (in bytes).

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_BALLOON_S_SWAP_OUT (<span class="hl num">1</span>)<span class="hl opt">]</span> The amount of memory that has been
  swapped out to disk (in bytes).

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_BALLOON_S_MAJFLT (<span class="hl num">2</span>)<span class="hl opt">]</span> The number of major page faults that
  have occurred.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_BALLOON_S_MINFLT (<span class="hl num">3</span>)<span class="hl opt">]</span> The number of minor page faults that
  have occurred.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_BALLOON_S_MEMFREE (<span class="hl num">4</span>)<span class="hl opt">]</span> The amount of memory not being used
  for any purpose (in bytes).

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_BALLOON_S_MEMTOT (<span class="hl num">5</span>)<span class="hl opt">]</span> The total amount of memory available
  (in bytes).
<span class="hl kwa">\end</span><span class="hl opt">{</span>description<span class="hl opt">}</span>

<span class="hl kwa">\section</span><span class="hl opt">{</span>SCSI Host Device<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / SCSI Host Device<span class="hl opt">}</span>

The virtio SCSI host device groups together one or more virtual
logical units (such as disks), and allows communicating to them
using the SCSI protocol. An instance of the device represents a
SCSI host to which many targets and LUNs are attached.

The virtio SCSI device services two kinds of requests:
<span class="hl kwa">\begin</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>
<span class="hl kwa">\item</span> command requests for a logical unit;

<span class="hl kwa">\item</span> task management functions related to a logical unit, target or
  command.
<span class="hl kwa">\end</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>

The device is also able to send out notifications about added and
removed logical units. Together, these capabilities provide a
SCSI transport protocol that uses virtqueues as the transfer
medium. In the transport protocol, the virtio driver acts as the
initiator, while the virtio SCSI host provides one or more
targets that receive and process the requests.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Device ID<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / SCSI Host Device / Device ID<span class="hl opt">}</span>
  <span class="hl num">8</span>

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Virtqueues<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / SCSI Host Device / Virtqueues<span class="hl opt">}</span>

<span class="hl kwa">\begin</span><span class="hl opt">{</span>description<span class="hl opt">}</span>
<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl num">0</span><span class="hl opt">]</span> controlq
<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl num">1</span><span class="hl opt">]</span> eventq
<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl num">2</span><span class="hl kwa">\ldots</span> n<span class="hl opt">]</span> request queues
<span class="hl kwa">\end</span><span class="hl opt">{</span>description<span class="hl opt">}</span>

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Feature bits<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / SCSI Host Device / Feature bits<span class="hl opt">}</span>

<span class="hl kwa">\begin</span><span class="hl opt">{</span>description<span class="hl opt">}</span>
<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_SCSI_F_INOUT (<span class="hl num">0</span>)<span class="hl opt">]</span> A single request can include both
    device-readable and device-writable data buffers.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_SCSI_F_HOTPLUG (<span class="hl num">1</span>)<span class="hl opt">]</span> The host should enable
    hot-plug/hot-unplug of new LUNs and targets on the SCSI bus.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_SCSI_F_CHANGE (<span class="hl num">2</span>)<span class="hl opt">]</span> The host will <span class="hl kwb">report</span> changes to LUN
    parameters via a VIRTIO_SCSI_T_PARAM_CHANGE event.
<span class="hl kwa">\end</span><span class="hl opt">{</span>description<span class="hl opt">}</span>

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Device configuration layout<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / SCSI Host Device / Device configuration layout<span class="hl opt">}</span>

  All fields of this configuration are always available. <span class="hl kwa">\field</span><span class="hl opt">{</span>sense_size<span class="hl opt">}</span>
  and <span class="hl kwa">\field</span><span class="hl opt">{</span>cdb_size<span class="hl opt">}</span> are writable by the driver.

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
/* Note: LEGACY version was not little endian! */
struct virtio_scsi_config <span class="hl opt">{</span>
        le32 num_queues;
        le32 seg_max;
        le32 max_sectors;
        le32 cmd_per_lun;
        le32 event_info_size;
        le32 sense_size;
        le32 cdb_size;
        le16 max_channel;
        le16 max_target;
        le32 max_lun;
<span class="hl opt">}</span>;
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

<span class="hl kwa">\begin</span><span class="hl opt">{</span>description<span class="hl opt">}</span>
<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\field</span><span class="hl opt">{</span>num_queues<span class="hl opt">}]</span> is the total number of request virtqueues exposed by
    the device. The driver is free to use only one request queue,
    or it can use more to achieve better performance.

<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\field</span><span class="hl opt">{</span>seg_max<span class="hl opt">}]</span> is the maximum number of segments that can be in a
    command. A bidirectional command can include <span class="hl kwa">\field</span><span class="hl opt">{</span>seg_max<span class="hl opt">}</span> input
    segments and <span class="hl kwa">\field</span><span class="hl opt">{</span>seg_max<span class="hl opt">}</span> output segments.

<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\field</span><span class="hl opt">{</span>max_sectors<span class="hl opt">}]</span> is a hint to the driver about the maximum transfer
    size it should use.

<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\field</span><span class="hl opt">{</span>cmd_per_lun<span class="hl opt">}]</span> is a hint to the driver about the maximum number of
    linked commands it should send to one LUN. The actual value
    to be used is the minimum of <span class="hl kwa">\field</span><span class="hl opt">{</span>cmd_per_lun<span class="hl opt">}</span> and the virtqueue
    size.

<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\field</span><span class="hl opt">{</span>event_info_size<span class="hl opt">}]</span> is the maximum size that the device will fill
    for buffers that the driver places in the eventq. The driver
    should always put buffers at least of this size. It is
    written by the device depending on the set of negotated
    features.

<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\field</span><span class="hl opt">{</span>sense_size<span class="hl opt">}]</span> is the maximum size of the sense data that the
    device will write. The default value is written by the device
    and will always be <span class="hl num">96</span>, but the driver can modify it. It is
    restored to the default when the device is reset.

<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\field</span><span class="hl opt">{</span>cdb_size<span class="hl opt">}]</span> is the maximum size of the CDB that the driver will
    write. The default value is written by the device and will
    always be <span class="hl num">32</span>, but the driver can likewise modify it. It is
    restored to the default when the device is reset.

<span class="hl kwa">\item</span><span class="hl opt">[</span><span class="hl kwa">\field</span><span class="hl opt">{</span>max_channel<span class="hl opt">}</span>, <span class="hl kwa">\field</span><span class="hl opt">{</span>max_target<span class="hl opt">}</span> and <span class="hl kwa">\field</span><span class="hl opt">{</span>max_lun<span class="hl opt">}]</span> can be used by the driver
    as hints to constrain scanning the logical units on the
    host.
<span class="hl kwa">\end</span><span class="hl opt">{</span>description<span class="hl opt">}</span>

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Legacy Interface: Device configuration layout<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / SCSI Host Device / Device configuration layout / Legacy Interface: Device configuration layout<span class="hl opt">}</span>
For legacy devices, the fields in struct virtio_scsi_config are the
native endian of the guest rather than (necessarily) little-endian.

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Device Initialization<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / SCSI Host Device / Device Initialization<span class="hl opt">}</span>

The initialization routine should first of all discover the
device&apos;s virtqueues.

If the driver uses the eventq, it should then place at least a
buffer in the eventq.

The driver can immediately issue requests (for example, INQUIRY
or REPORT LUNS) or task management functions (for example, I_T
RESET).

<span class="hl kwa">\subsection</span><span class="hl opt">{</span>Device Operation<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / SCSI Host Device / Device Operation<span class="hl opt">}</span>

Device operation consists of operating request queues, the control
queue and the event queue.

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Device Operation: Request Queues<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / SCSI Host Device / Device Operation / Device Operation: Request Queues<span class="hl opt">}</span>

The driver queues requests to an arbitrary request queue, and
they are used by the device on that same queue. It is the
responsibility of the driver to ensure strict request ordering
for commands placed on different queues, because they will be
consumed with no order constraints.

Requests have the following format:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
/* Note: LEGACY version was not little endian! */
struct virtio_scsi_req_cmd <span class="hl opt">{</span>
        // Device-readable part
        u8 lun<span class="hl opt">[</span><span class="hl num">8</span><span class="hl opt">]</span>;
        le64 id;
        u8 task_attr;
        u8 prio;
        u8 crn;
        u8 cdb<span class="hl opt">[</span>cdb_size<span class="hl opt">]</span>;
        u8 dataout<span class="hl opt">[]</span>;
        // Device-writable part
        le32 sense_len;
        le32 residual;
        le16 status_qualifier;
        u8 status;
        u8 response;
        u8 sense<span class="hl opt">[</span>sense_size<span class="hl opt">]</span>;
        u8 datain<span class="hl opt">[]</span>;
<span class="hl opt">}</span>;


/* command-specific response values */
#define VIRTIO_SCSI_S_OK                <span class="hl num">0</span>
#define VIRTIO_SCSI_S_OVERRUN           <span class="hl num">1</span>
#define VIRTIO_SCSI_S_ABORTED           <span class="hl num">2</span>
#define VIRTIO_SCSI_S_BAD_TARGET        <span class="hl num">3</span>
#define VIRTIO_SCSI_S_RESET             <span class="hl num">4</span>
#define VIRTIO_SCSI_S_BUSY              <span class="hl num">5</span>
#define VIRTIO_SCSI_S_TRANSPORT_FAILURE <span class="hl num">6</span>
#define VIRTIO_SCSI_S_TARGET_FAILURE    <span class="hl num">7</span>
#define VIRTIO_SCSI_S_NEXUS_FAILURE     <span class="hl num">8</span>
#define VIRTIO_SCSI_S_FAILURE           <span class="hl num">9</span>

/* task_attr */
#define VIRTIO_SCSI_S_SIMPLE            <span class="hl num">0</span>
#define VIRTIO_SCSI_S_ORDERED           <span class="hl num">1</span>
#define VIRTIO_SCSI_S_HEAD              <span class="hl num">2</span>
#define VIRTIO_SCSI_S_ACA               <span class="hl num">3</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

<span class="hl kwa">\field</span><span class="hl opt">{</span>lun<span class="hl opt">}</span> addresses a target and logical unit in the
virtio-scsi device&apos;s SCSI domain. The only supported format for
the <span class="hl kwa">\field</span><span class="hl opt">{</span>lun<span class="hl opt">}</span> field is: first byte set to <span class="hl num">1</span>, second byte set to target,
third and fourth byte representing a single level LUN structure,
followed by four zero bytes. With this representation, a
virtio-scsi device can serve up to <span class="hl num">256</span> targets and <span class="hl num">16384</span> LUNs per
target.

<span class="hl kwa">\field</span><span class="hl opt">{</span>id<span class="hl opt">}</span> is the command identifier (“tag”).

<span class="hl kwa">\field</span><span class="hl opt">{</span>task_attr<span class="hl opt">}</span>, <span class="hl kwa">\field</span><span class="hl opt">{</span>prio<span class="hl opt">}</span> and <span class="hl kwa">\field</span><span class="hl opt">{</span>crn<span class="hl opt">}</span> should be left to zero. <span class="hl kwa">\field</span><span class="hl opt">{</span>task_attr<span class="hl opt">}</span> defines
the task attribute as in the table above, but all task attributes
may be mapped to SIMPLE by the device; <span class="hl kwa">\field</span><span class="hl opt">{</span>crn<span class="hl opt">}</span> may also be provided
by clients, but is generally expected to be <span class="hl num">0</span>. The maximum CRN
value defined by the protocol is <span class="hl num">255</span>, since CRN is stored in an
<span class="hl num">8</span>-bit integer.

All of these fields are defined in SAM. They are always
device-readable, as are <span class="hl kwa">\field</span><span class="hl opt">{</span>cdb<span class="hl opt">}</span> and <span class="hl kwa">\field</span><span class="hl opt">{</span>dataout<span class="hl opt">}</span>. <span class="hl kwa">\field</span><span class="hl opt">{</span>cdb_size<span class="hl opt">}</span> is
taken from the configuration space.

<span class="hl kwa">\field</span><span class="hl opt">{</span>sense<span class="hl opt">}</span> and subsequent fields are always device-writable. <span class="hl kwa">\field</span><span class="hl opt">{</span>sense_len<span class="hl opt">}</span>
indicates the number of bytes actually written to the sense
buffer. <span class="hl kwa">\field</span><span class="hl opt">{</span>residual<span class="hl opt">}</span> indicates the residual size,
calculated as “data_length - number_of_transferred_bytes”, for
read or write operations. For bidirectional commands, the
number_of_transferred_bytes includes both read and written bytes.
A <span class="hl kwa">\field</span><span class="hl opt">{</span>residual<span class="hl opt">}</span> that is less than the size of <span class="hl kwa">\field</span><span class="hl opt">{</span>datain<span class="hl opt">}</span> means that
the dataout field was processed entirely. A <span class="hl kwa">\field</span><span class="hl opt">{</span>residual<span class="hl opt">}</span> that
exceeds the size of <span class="hl kwa">\field</span><span class="hl opt">{</span>datain<span class="hl opt">}</span> means that <span class="hl kwa">\field</span><span class="hl opt">{</span>dataout<span class="hl opt">}</span> was
processed partially and <span class="hl kwa">\field</span><span class="hl opt">{</span>datain<span class="hl opt">}</span> was not processed at
all.

The <span class="hl kwa">\field</span><span class="hl opt">{</span>status<span class="hl opt">}</span> byte is written by the device to be the status code as
defined in SAM.

The <span class="hl kwa">\field</span><span class="hl opt">{</span>response<span class="hl opt">}</span> byte is written by the device to be one of the
following:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>description<span class="hl opt">}</span>

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_SCSI_S_OK<span class="hl opt">]</span> when the request was completed and the <span class="hl kwa">\field</span><span class="hl opt">{</span>status<span class="hl opt">}</span>
  byte is filled with a SCSI status code (not necessarily
  &quot;GOOD&quot;).

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_SCSI_S_OVERRUN<span class="hl opt">]</span> if the content of the CDB requires
  transferring more data than is available in the data buffers.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_SCSI_S_ABORTED<span class="hl opt">]</span> if the request was cancelled due to an
  ABORT TASK or ABORT TASK SET task management function.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_SCSI_S_BAD_TARGET<span class="hl opt">]</span> if the request was never processed
  because the target indicated by <span class="hl kwa">\field</span><span class="hl opt">{</span>lun<span class="hl opt">}</span> does not exist.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_SCSI_S_RESET<span class="hl opt">]</span> if the request was cancelled due to a bus
  or device reset (including a task management function).

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_SCSI_S_TRANSPORT_FAILURE<span class="hl opt">]</span> if the request failed due to a
  problem in the connection between the host and the target
  (severed link).

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_SCSI_S_TARGET_FAILURE<span class="hl opt">]</span> if the target is suffering a
  failure and the driver should not retry on other paths.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_SCSI_S_NEXUS_FAILURE<span class="hl opt">]</span> if the nexus is suffering a failure
  but retrying on other paths might yield a different result.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_SCSI_S_BUSY<span class="hl opt">]</span> if the request failed but retrying on the
  same path should work.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_SCSI_S_FAILURE<span class="hl opt">]</span> for other host or driver error. In
  particular, if neither <span class="hl kwa">\field</span><span class="hl opt">{</span>dataout<span class="hl opt">}</span> nor <span class="hl kwa">\field</span><span class="hl opt">{</span>datain<span class="hl opt">}</span> is empty, and the
  VIRTIO_SCSI_F_INOUT feature has not been negotiated, the
  request will be immediately returned with a response equal to
  VIRTIO_SCSI_S_FAILURE.
<span class="hl kwa">\end</span><span class="hl opt">{</span>description<span class="hl opt">}</span>

<span class="hl kwa">\paragraph</span><span class="hl opt">{</span>Legacy Interface: Device Operation: Request Queues<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / SCSI Host Device / Device Operation / Device Operation: Request Queues / Legacy Interface: Device Operation: Request Queues<span class="hl opt">}</span>
For legacy devices, the fields in struct virtio_scsi_req_cmd are the
native endian of the guest rather than (necessarily) little-endian.

<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Device Operation: controlq<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / SCSI Host Device / Device Operation / Device Operation: controlq<span class="hl opt">}</span>

The controlq is used for other SCSI transport operations.
Requests have the following format:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
struct virtio_scsi_ctrl <span class="hl opt">{</span>
        le32 type;
...
        u8 response;
<span class="hl opt">}</span>;

/* response values valid for all commands */
#define VIRTIO_SCSI_S_OK                       <span class="hl num">0</span>
#define VIRTIO_SCSI_S_BAD_TARGET               <span class="hl num">3</span>
#define VIRTIO_SCSI_S_BUSY                     <span class="hl num">5</span>
#define VIRTIO_SCSI_S_TRANSPORT_FAILURE        <span class="hl num">6</span>
#define VIRTIO_SCSI_S_TARGET_FAILURE           <span class="hl num">7</span>
#define VIRTIO_SCSI_S_NEXUS_FAILURE            <span class="hl num">8</span>
#define VIRTIO_SCSI_S_FAILURE                  <span class="hl num">9</span>
#define VIRTIO_SCSI_S_INCORRECT_LUN            <span class="hl num">12</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

The <span class="hl kwa">\field</span><span class="hl opt">{</span>type<span class="hl opt">}</span> identifies the remaining fields.

The following commands are defined:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>
<span class="hl kwa">\item</span> Task management function.
<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
#define VIRTIO_SCSI_T_TMF                      <span class="hl num">0</span>

#define VIRTIO_SCSI_T_TMF_ABORT_TASK           <span class="hl num">0</span>
#define VIRTIO_SCSI_T_TMF_ABORT_TASK_SET       <span class="hl num">1</span>
#define VIRTIO_SCSI_T_TMF_CLEAR_ACA            <span class="hl num">2</span>
#define VIRTIO_SCSI_T_TMF_CLEAR_TASK_SET       <span class="hl num">3</span>
#define VIRTIO_SCSI_T_TMF_I_T_NEXUS_RESET      <span class="hl num">4</span>
#define VIRTIO_SCSI_T_TMF_LOGICAL_UNIT_RESET   <span class="hl num">5</span>
#define VIRTIO_SCSI_T_TMF_QUERY_TASK           <span class="hl num">6</span>
#define VIRTIO_SCSI_T_TMF_QUERY_TASK_SET       <span class="hl num">7</span>

/* Note: LEGACY version was not little endian! */
struct virtio_scsi_ctrl_tmf
<span class="hl opt">{</span>
        // Device-readable part
        le32 type;
        le32 subtype;
        u8   lun<span class="hl opt">[</span><span class="hl num">8</span><span class="hl opt">]</span>;
        le64 id;
        // Device-writable part
        u8   response;
<span class="hl opt">}</span>

/* command-specific response values */
#define VIRTIO_SCSI_S_FUNCTION_COMPLETE        <span class="hl num">0</span>
#define VIRTIO_SCSI_S_FUNCTION_SUCCEEDED       <span class="hl num">10</span>
#define VIRTIO_SCSI_S_FUNCTION_REJECTED        <span class="hl num">11</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

  The <span class="hl kwa">\field</span><span class="hl opt">{</span>type<span class="hl opt">}</span> is VIRTIO_SCSI_T_TMF; <span class="hl kwa">\field</span><span class="hl opt">{</span>subtype<span class="hl opt">}</span> defines. All
  fields except <span class="hl kwa">\field</span><span class="hl opt">{</span>response<span class="hl opt">}</span> are filled by the driver. <span class="hl kwa">\field</span><span class="hl opt">{</span>subtype<span class="hl opt">}</span>
  must always be specified and identifies the requested
  task management function.

  Other fields may be irrelevant for the requested TMF; if so,
  they are ignored but they should still be present. <span class="hl kwa">\field</span><span class="hl opt">{</span>lun<span class="hl opt">}</span>
  field is in the same format specified for request queues; the
  single level LUN is ignored when the task management function
  addresses a whole I_T nexus. When relevant, the value of <span class="hl kwa">\field</span><span class="hl opt">{</span>id<span class="hl opt">}</span>
  is matched against the id values passed on the requestq.

  The outcome of the task management function is written by the
  device in <span class="hl kwa">\field</span><span class="hl opt">{</span>response<span class="hl opt">}</span>. The command-specific response
  values map <span class="hl num">1</span>-to-<span class="hl num">1</span> with those defined in SAM.

<span class="hl kwa">\item</span> Asynchronous notification query.
<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
#define VIRTIO_SCSI_T_AN_QUERY                    <span class="hl num">1</span>

struct virtio_scsi_ctrl_an <span class="hl opt">{</span>
    // Device-readable part
    le32 type;
    u8   lun<span class="hl opt">[</span><span class="hl num">8</span><span class="hl opt">]</span>;
    le32 event_requested;
    // Device-writable part
    le32 event_actual;
    u8   response;
<span class="hl opt">}</span>

#define VIRTIO_SCSI_EVT_ASYNC_OPERATIONAL_CHANGE  <span class="hl num">2</span>
#define VIRTIO_SCSI_EVT_ASYNC_POWER_MGMT          <span class="hl num">4</span>
#define VIRTIO_SCSI_EVT_ASYNC_EXTERNAL_REQUEST    <span class="hl num">8</span>
#define VIRTIO_SCSI_EVT_ASYNC_MEDIA_CHANGE        <span class="hl num">16</span>
#define VIRTIO_SCSI_EVT_ASYNC_MULTI_HOST          <span class="hl num">32</span>
#define VIRTIO_SCSI_EVT_ASYNC_DEVICE_BUSY         <span class="hl num">64</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

  By sending this command, the driver asks the device which
  events the given LUN can <span class="hl kwb">report</span>, as described in paragraphs <span class="hl num">6.6</span>
  and A<span class="hl num">.6</span> of the SCSI MMC specification. The driver writes the
  events it is interested in into <span class="hl kwa">\field</span><span class="hl opt">{</span>event_requested<span class="hl opt">}</span>; the device
  responds by writing the events that it supports into
  <span class="hl kwa">\field</span><span class="hl opt">{</span>event_actual<span class="hl opt">}</span>.

  The <span class="hl kwa">\field</span><span class="hl opt">{</span>type<span class="hl opt">}</span> is VIRTIO_SCSI_T_AN_QUERY. <span class="hl kwa">\field</span><span class="hl opt">{</span>lun<span class="hl opt">}</span> and <span class="hl kwa">\field</span><span class="hl opt">{</span>event_requested<span class="hl opt">}</span>
  are written by the driver. <span class="hl kwa">\field</span><span class="hl opt">{</span>event_actual<span class="hl opt">}</span> and <span class="hl kwa">\field</span><span class="hl opt">{</span>response<span class="hl opt">}</span>
  fields are written by the device.

  No command-specific values are defined for the <span class="hl kwa">\field</span><span class="hl opt">{</span>response<span class="hl opt">}</span> byte.

<span class="hl kwa">\item</span> Asynchronous notification subscription.
<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
#define VIRTIO_SCSI_T_AN_SUBSCRIBE                <span class="hl num">2</span>

struct virtio_scsi_ctrl_an <span class="hl opt">{</span>
        // Device-readable part
        le32 type;
        u8   lun<span class="hl opt">[</span><span class="hl num">8</span><span class="hl opt">]</span>;
        le32 event_requested;
        // Device-writable part
        le32 event_actual;
        u8   response;
<span class="hl opt">}</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

  By sending this command, the driver asks the specified LUN to
  <span class="hl kwb">report</span> events for its physical interface, again as described in
  the SCSI MMC specification. The driver writes the events it is
  interested in into <span class="hl kwa">\field</span><span class="hl opt">{</span>event_requested<span class="hl opt">}</span>; the device responds by
  writing the events that it supports into <span class="hl kwa">\field</span><span class="hl opt">{</span>event_actual<span class="hl opt">}</span>.

  Event types are the same as for the asynchronous notification
  query message.

  The <span class="hl kwa">\field</span><span class="hl opt">{</span>type<span class="hl opt">}</span> is VIRTIO_SCSI_T_AN_SUBSCRIBE. <span class="hl kwa">\field</span><span class="hl opt">{</span>lun<span class="hl opt">}</span> and
  <span class="hl kwa">\field</span><span class="hl opt">{</span>event_requested<span class="hl opt">}</span> are written by the driver.
  <span class="hl kwa">\field</span><span class="hl opt">{</span>event_actual<span class="hl opt">}</span> and <span class="hl kwa">\field</span><span class="hl opt">{</span>response<span class="hl opt">}</span> are written by the device.

  No command-specific values are defined for the response byte.
<span class="hl kwa">\end</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>

<span class="hl kwa">\paragraph</span><span class="hl opt">{</span>Legacy Interface: Device Operation: controlq<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / SCSI Host Device / Device Operation / Device Operation: controlq / Legacy Interface: Device Operation: controlq<span class="hl opt">}</span>

For legacy devices, the fields in struct virtio_scsi_ctrl, struct
virtio_scsi_ctrl_tmf, struct virtio_scsi_ctrl_an and struct
virtio_scsi_ctrl_an are the native endian of the guest rather than
(necessarily) little-endian.


<span class="hl kwa">\subsubsection</span><span class="hl opt">{</span>Device Operation: eventq<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / SCSI Host Device / Device Operation / Device Operation: eventq<span class="hl opt">}</span>

The eventq is used by the device to <span class="hl kwb">report</span> information on logical
units that are attached to it. The driver should always leave a
few buffers ready in the eventq. In general, the device will not
queue events to cope with an empty eventq, and will end up
dropping events if it finds no buffer ready. However, when
reporting events for many LUNs (e.g. when a whole target
disappears), the device can throttle events to avoid dropping
them. For this reason, placing <span class="hl num">10</span>-<span class="hl num">15</span> buffers on the event queue
should be enough.

Buffers are placed in the eventq and filled by the device when
interesting events occur. The buffers should be strictly
device-writable and the size of the buffers should be
at least the value given in the device&apos;s configuration
information.

Buffers returned by the device on the eventq will be referred to
as &quot;events&quot; in the rest of this section. Events have the
following format:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
#define VIRTIO_SCSI_T_EVENTS_MISSED   <span class="hl num">0x80000000</span>

struct virtio_scsi_event <span class="hl opt">{</span>
        // Device-writable part
        le32 event;
        u8  lun<span class="hl opt">[</span><span class="hl num">8</span><span class="hl opt">]</span>;
        le32 reason;
<span class="hl opt">}</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

If bit <span class="hl num">31</span> is set in <span class="hl kwa">\field</span><span class="hl opt">{</span>event<span class="hl opt">}</span>, the device failed to <span class="hl kwb">report</span>
an event due to missing buffers. In this case, the driver should
poll the logical units for unit attention conditions, and/or do
whatever form of bus scan is appropriate for the guest operating
system.

The meaning of <span class="hl kwa">\field</span><span class="hl opt">{</span>reason<span class="hl opt">}</span> depends on the
contents of <span class="hl kwa">\field</span><span class="hl opt">{</span>event<span class="hl opt">}</span>. The following events are defined:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>
<span class="hl kwa">\item</span> No event.
<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
#define VIRTIO_SCSI_T_NO_EVENT         <span class="hl num">0</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

  This event is fired in the following cases:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>
<span class="hl kwa">\item</span> When the device detects in the eventq a buffer that is
    shorter than what is indicated in the configuration field, it
    might use it immediately and put this dummy value in the
    event field. A well-written driver will never observe this
    situation.

<span class="hl kwa">\item</span> When events are dropped, the device may signal this event as
    soon as the drivers makes a buffer available, in order to
    request action from the driver. In this case, of course, this
    event will be reported with the VIRTIO_SCSI_T_EVENTS_MISSED
    flag.
<span class="hl kwa">\end</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>

<span class="hl kwa">\item</span> Transport reset
<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
#define VIRTIO_SCSI_T_TRANSPORT_RESET  <span class="hl num">1</span>

#define VIRTIO_SCSI_EVT_RESET_HARD         <span class="hl num">0</span>
#define VIRTIO_SCSI_EVT_RESET_RESCAN       <span class="hl num">1</span>
#define VIRTIO_SCSI_EVT_RESET_REMOVED      <span class="hl num">2</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

  By sending this event, the device signals that a logical unit
  on a target has been reset, including the case of a new device
  appearing or disappearing on the bus.The device fills in all
  fields. <span class="hl kwa">\field</span><span class="hl opt">{</span>event<span class="hl opt">}</span> is set to
  VIRTIO_SCSI_T_TRANSPORT_RESET. <span class="hl kwa">\field</span><span class="hl opt">{</span>lun<span class="hl opt">}</span> addresses a
  logical unit in the SCSI host.

  The <span class="hl kwa">\field</span><span class="hl opt">{</span>reason<span class="hl opt">}</span> value is one of the three \#define values appearing
  above:

  <span class="hl kwa">\begin</span><span class="hl opt">{</span>description<span class="hl opt">}</span>
  <span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_SCSI_EVT_RESET_REMOVED<span class="hl opt">]</span> (“LUN/target removed”) is used
    if the target or logical unit is no longer able to receive
    commands.

  <span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_SCSI_EVT_RESET_HARD<span class="hl opt">]</span> (“LUN hard reset”) is used if the
    logical unit has been reset, but is still present.

  <span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_SCSI_EVT_RESET_RESCAN<span class="hl opt">]</span> (“rescan LUN/target”) is used if
    a target or logical unit has just appeared on the device.
  <span class="hl kwa">\end</span><span class="hl opt">{</span>description<span class="hl opt">}</span>

  The “removed” and “rescan” events, when sent for LUN <span class="hl num">0</span>, may
  apply to the entire target. After receiving them the driver
  should ask the initiator to rescan the target, in order to
  detect the case when an entire target has appeared or
  disappeared. These two events will never be reported unless the
  VIRTIO_SCSI_F_HOTPLUG feature was negotiated between the device
  and the driver.

  Events will also be reported via sense codes (this obviously
  does not apply to newly appeared buses or targets, since the
  application has never discovered them):

  <span class="hl kwa">\begin</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>
  <span class="hl kwa">\item</span> “LUN/target removed” maps to sense key ILLEGAL REQUEST, asc
    <span class="hl num">0x25</span>, ascq <span class="hl num">0x00</span> (LOGICAL UNIT NOT SUPPORTED)

  <span class="hl kwa">\item</span> “LUN hard reset” maps to sense key UNIT ATTENTION, asc <span class="hl num">0x29</span>
    (POWER ON, RESET OR BUS DEVICE RESET OCCURRED)

  <span class="hl kwa">\item</span> “rescan LUN/target” maps to sense key UNIT ATTENTION, asc
    <span class="hl num">0x3f</span>, ascq <span class="hl num">0x0e</span> (REPORTED LUNS DATA HAS CHANGED)
  <span class="hl kwa">\end</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>

  The preferred way to detect transport reset is always to use
  events, because sense codes are only seen by the driver when it
  sends a SCSI command to the logical unit or target. However, in
  case events are dropped, the initiator will still be able to
  synchronize with the actual state of the controller if the
  driver asks the initiator to rescan of the SCSI bus. During the
  rescan, the initiator will be able to observe the above sense
  codes, and it will process them as if it the driver had
  received the equivalent event.

  <span class="hl kwa">\item</span> Asynchronous notification
<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
#define VIRTIO_SCSI_T_ASYNC_NOTIFY     <span class="hl num">2</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

  By sending this event, the device signals that an asynchronous
  event was fired from a physical interface.

  All fields are written by the device. The event field is set to
  VIRTIO_SCSI_T_ASYNC_NOTIFY. The lun field addresses a logical
  unit in the SCSI host. The reason field is a subset of the
  events that the driver has subscribed to via the &quot;Asynchronous
  notification subscription&quot; command.

  When dropped events are reported, the driver should poll for
  asynchronous events manually using SCSI commands.

  <span class="hl kwa">\item</span> LUN parameter change
<span class="hl kwa">\begin</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>
#define VIRTIO_SCSI_T_PARAM_CHANGE  <span class="hl num">3</span>
<span class="hl kwa">\end</span><span class="hl opt">{</span>lstlisting<span class="hl opt">}</span>

  By sending this event, the device signals that the configuration parameters
  (for example the capacity) of a logical unit have changed.
  The event field is set to VIRTIO_SCSI_T_PARAM_CHANGE.
  The lun field addresses a logical unit in the SCSI host.

  The same event is also reported as a unit attention condition.
  The reason field contains the additional sense code and additional sense code qualifier,
  respectively in bits <span class="hl num">0</span>.<span class="hl num">.7</span> and <span class="hl num">8</span>.<span class="hl num">.15</span>.
  For example, a change in capacity will be reported as asc <span class="hl num">0x2a</span>, ascq <span class="hl num">0x09</span>
  (CAPACITY DATA HAS CHANGED).

  For MMC devices (inquiry type <span class="hl num">5</span>) there would be some overlap between this
  event and the asynchronous notification event.
  For simplicity, as of this version of the specification the host must
  never <span class="hl kwb">report</span> this event for MMC devices.
<span class="hl kwa">\end</span><span class="hl opt">{</span>itemize<span class="hl opt">}</span>

<span class="hl kwa">\paragraph</span><span class="hl opt">{</span>Legacy Interface: Device Operation: eventq<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Device Types / SCSI Host Device / Device Operation / Device Operation: eventq / Legacy Interface: Device Operation: eventq<span class="hl opt">}</span>
For legacy devices, the fields in struct virtio_scsi_event are the
native endian of the guest rather than (necessarily) little-endian.

<span class="hl kwa">\chapter</span><span class="hl opt">{</span>Reserved Feature Bits<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Reserved Feature Bits<span class="hl opt">}</span>

Currently there are four device-independent feature bits defined:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>description<span class="hl opt">}</span>
  <span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_F_RING_INDIRECT_DESC (<span class="hl num">28</span>)<span class="hl opt">]</span> Negotiating this feature indicates
  that the driver can use descriptors with the VRING_DESC_F_INDIRECT
  flag set, as described in <span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Virtqueues / The Virtqueue Descriptor Table / Indirect Descriptors<span class="hl opt">}</span>~<span class="hl kwa">\nameref</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Virtqueues / The Virtqueue Descriptor Table / Indirect Descriptors<span class="hl opt">}</span>.

  <span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_F_RING_EVENT_IDX(<span class="hl num">29</span>)<span class="hl opt">]</span> This feature enables the <span class="hl kwa">\field</span><span class="hl opt">{</span>used_event<span class="hl opt">}</span>
  and the <span class="hl kwa">\field</span><span class="hl opt">{</span>avail_event<span class="hl opt">}</span> fields. If set, it indicates that the
  device should ignore <span class="hl kwa">\field</span><span class="hl opt">{</span>flags<span class="hl opt">}</span> in the available ring
  structure. Instead, <span class="hl kwa">\field</span><span class="hl opt">{</span>used_event<span class="hl opt">}</span> in this structure is
  used by driver to suppress device interrupts. Further, the
  driver should ignore the <span class="hl kwa">\field</span><span class="hl opt">{</span>flags<span class="hl opt">}</span> field in the used ring
  structure. Instead, <span class="hl kwa">\field</span><span class="hl opt">{</span>avail_event<span class="hl opt">}</span> in this structure is
  used by the device to suppress notifications. If unset, the
  driver should ignore <span class="hl kwa">\field</span><span class="hl opt">{</span>used_event<span class="hl opt">}</span>; the device should
  ignore <span class="hl kwa">\field</span><span class="hl opt">{</span>avail_event<span class="hl opt">}</span> and the <span class="hl kwa">\field</span><span class="hl opt">{</span>flags<span class="hl opt">}</span> fields should be used,

  <span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_F_VERSION_1(<span class="hl num">32</span>)<span class="hl opt">]</span> This feature must be offered by any device
  compliant with this specification, and acknowledged by all device
  drivers.
<span class="hl kwa">\end</span><span class="hl opt">{</span>description<span class="hl opt">}</span>

In addition, bit <span class="hl num">30</span> is used by qemu&apos;s implementation to check for experimental
early versions of virtio which did not perform correct feature negotiation,
and should not be used.

<span class="hl kwa">\section</span><span class="hl opt">{</span>Legacy Interface: Reserved Feature Bits<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Reserved Feature Bits / Legacy Interface: Reserved Feature Bits<span class="hl opt">}</span>

Legacy or transitional devices may offer the following:

<span class="hl kwa">\begin</span><span class="hl opt">{</span>description<span class="hl opt">}</span>
<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_F_NOTIFY_ON_EMPTY (<span class="hl num">24</span>)<span class="hl opt">]</span> Negotiating this feature
  indicates that the driver wants an interrupt if the device runs
  out of available descriptors on a virtqueue, even though
  interrupts are suppressed using the VRING_AVAIL_F_NO_INTERRUPT
  flag or the <span class="hl kwa">\field</span><span class="hl opt">{</span>used_event<span class="hl opt">}</span> field. An example of this is the
  networking driver: it doesn&apos;t need to know every time a packet
  is transmitted, but it does need to free the transmitted
  packets a finite time after they are transmitted. It can avoid
  using a timer if the device interrupts it when all the packets
  are transmitted.

<span class="hl kwa">\item</span><span class="hl opt">[</span>VIRTIO_F_ANY_LAYOUT (<span class="hl num">27</span>)<span class="hl opt">]</span> This feature indicates that the device
  accepts arbitrary descriptor layouts, as described in Section
  <span class="hl kwa">\ref</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Virtqueues / Message Framing / Legacy Interface: Message Framing<span class="hl opt">}</span>~<span class="hl kwa">\nameref</span><span class="hl opt">{</span>sec:Basic Facilities of a Virtio Device / Virtqueues / Message Framing / Legacy Interface: Message Framing<span class="hl opt">}</span>.
<span class="hl kwa">\end</span><span class="hl opt">{</span>description<span class="hl opt">}</span>

<span class="hl kwa">\chapter</span><span class="hl opt">{</span>virtio_ring.h<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:virtio-ring.h<span class="hl opt">}</span>

This file is also available at the link
<span class="hl kwa">\url</span><span class="hl opt">{</span><span class="hl kwa">\virtiourlbase</span>/listings/virtio_ring.h<span class="hl opt">}</span>.
All definitions in this section are for non-normative reference
only.

<span class="hl kwa">\lstinputlisting</span><span class="hl opt">{</span>virtio-ring.h<span class="hl opt">}</span>

<span class="hl kwa">\chapter</span><span class="hl opt">{</span>Creating New Device Types<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Creating New Device Types<span class="hl opt">}</span>

Various considerations are necessary when creating a new device
type.

<span class="hl kwa">\section</span><span class="hl opt">{</span>How Many Virtqueues?<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Creating New Device Types / How Many Virtqueues?<span class="hl opt">}</span>

It is possible that a very simple device will operate entirely
through its device configuration space, but most will need at least one
virtqueue in which it will place requests. A device with both
input and output (eg. console and network devices described here)
need two queues: one which the driver fills with buffers to
receive input, and one which the driver places buffers to
transmit output.

<span class="hl kwa">\section</span><span class="hl opt">{</span>What Device Configuration Space Layout?<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Creating New Device Types / What Device Configuration Space Layout?<span class="hl opt">}</span>

Device configuration space should only be used for initialization-time
parameters.  It is a limited resource with no synchronization between
field written by the driver, so for most uses it is better to use a virtqueue to update
configuration information (the network device does this for filtering,
otherwise the table in the config space could potentially be very
large).

Devices must not assume that configuration fields over <span class="hl num">32</span> bits wide
are atomically writable by the driver.

<span class="hl kwa">\section</span><span class="hl opt">{</span>What Device Number?<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Creating New Device Types / What Device Number?<span class="hl opt">}</span>

Device numbers can be reserved by the OASIS committee: email
virtio-dev&#64;lists.oasis-open.org to secure a unique one.

Meanwhile for experimental drivers, use <span class="hl num">65535</span> and work backwards.

<span class="hl kwa">\section</span><span class="hl opt">{</span>How many MSI-X vectors?  (for PCI)<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Creating New Device Types / How many MSI-X vectors?  (for PCI)<span class="hl opt">}</span>

Using the optional MSI-X capability devices can speed up
interrupt processing by removing the need to read ISR Status
register by guest driver (which might be an expensive operation),
reducing interrupt sharing between devices and queues within the
device, and handling interrupts from multiple CPUs. However, some
systems impose a limit (which might be as low as <span class="hl num">256</span>) on the
total number of MSI-X vectors that can be allocated to all
devices. Devices and/or drivers should take this into
account, limiting the number of vectors used unless the device is
expected to cause a high volume of interrupts. Devices can
control the number of vectors used by limiting the MSI-X Table
Size or not presenting MSI-X capability in PCI configuration
space. Drivers can control this by mapping events to as small
number of vectors as possible, or disabling MSI-X capability
altogether.

<span class="hl kwa">\section</span><span class="hl opt">{</span>Device Improvements<span class="hl opt">}</span><span class="hl kwa">\label</span><span class="hl opt">{</span>sec:Creating New Device Types / Device Improvements<span class="hl opt">}</span>

Any change to device configuration space, or new virtqueues, or
behavioural changes, should be indicated by negotiation of a new
feature bit. This establishes clarity<span class="hl kwa">\footnote</span><span class="hl opt">{</span>Even if it does mean documenting design or implementation
mistakes!
<span class="hl opt">}</span> and avoids future expansion problems.

Clusters of functionality which are always implemented together
can use a single bit, but if one feature makes sense without the
others they should not be gratuitously grouped together to
conserve feature bits.


</code></pre></td></tr></table>
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