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<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">Hi,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">In function virPCIDeviceIsBehindSwitchLackingACS, I noticed that(line 8):<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">1 if (virPCIDeviceGetParent(dev, &parent) < 0)<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">2 return -1;<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">3 if (!parent) {<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">4 /* if we have no parent, and this is the root bus, ACS doesn't come<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">5 * into play since devices on the root bus can't P2P without going<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">6 * through the root IOMMU.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">7 */<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">8 if (dev->address.bus == 0) {<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">9 return 0;<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">10 } else {<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">11 virReportError(VIR_ERR_INTERNAL_ERROR,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">12 _("Failed to find parent device for %s"),<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">13 dev->name);<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">14 return -1;<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">15 }<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">16 }<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">Why we just return 0 only if device’s bus is 0?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">In my server, I can see a root bus which bus number is greater than 0, see the
<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">results(just a part) after I run lspci -t:<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">+-[0000:80]-+-02.0-[81-83]--+-00.0<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">| | \-00.1<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">| +-05.0<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">| +-05.1<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">| +-05.2<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">| \-05.4<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">+-[0000:7f]-+-08.0<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">| +-08.2<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">| +-08.3<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">| + . . .<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">| \-1f.2<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">\-[0000:00]-+-00.0<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New""> +-01.0-[01]----00.0<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New""> +-02.0-[02]--+-00.0<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New""> | +-00.1<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New""> | +-00.2<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New""> | \-00.3<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New""> +-02.2-[03]--<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New""> +-03.0-[04-0b]----00.0-[05-0b]--+-08.0-[06-08]----00.0<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New""> | \-10.0-[09-0b]----00.0<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New""> +-05.0<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New""> +-05.1<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New""> +-05.2<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New""> +-05.4<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New""> +-11.0<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New""> +-11.4<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New""> +-16.0<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New""> +-16.1<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New""> +-1a.0<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">If I assign the device 0000:81:00.0 to a VM, I get “Failed to find parent device”.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">I think I should get no error with return value 0 just like bus number is 0, because<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">bus 80 is the root bus as well in my case.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">In the <<Intel C610 Series Chipset and Intel X99 Chipset Platform Controller Hub(PCH)>><o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">Datasheet, I found that(Chapter 9.1):<o:p></o:p></span></p>
<p class="MsoNormal" style="text-indent:33.0pt"><span style="font-size:14.0pt;font-family:"Courier New"">For some server platforms, it may be desirable to have multiple PCHs in the system<o:p></o:p></span></p>
<p class="MsoNormal" style="text-indent:33.0pt"><span style="font-size:14.0pt;font-family:"Courier New"">Which means some PCH’s may reside on a bus greater than 0.<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">So, is this a bug?<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New""><o:p> </o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">Thanks,<o:p></o:p></span></p>
<p class="MsoNormal"><span style="font-size:14.0pt;font-family:"Courier New"">Zongyong Wu<o:p></o:p></span></p>
<p class="MsoNormal"><o:p> </o:p></p>
<p class="MsoNormal"><o:p> </o:p></p>
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