RE: RE: AMD graphics PCI passthrough possible?

[Alex Mattioli]

Hi Jamex,

Am glad the guide was of help and it works well for Linux. I'm really not sure 
what could be going wrong with the Windows VM though, I suggest you try 
installing windows directly on the physical host to see if the card drivers 
work at all.

Cheers
Alex 

 


-----Original Message-----
From: James Steele <jsteele.em...@gmail.com> 
Sent: 08 October 2021 11:03
To: users@cloudstack.apache.org
Subject: Re: RE: AMD graphics PCI passthrough possible?

Hi, and thanks for the tips everyone. 

Using https://lab.piszki.pl/cloudstack-kvm-and-running-vm-with-vgpu/ as a 
guide, I got the Radeon Pro WX 5100 PCI id's and modified Grub on my Ubuntu 
20.04 host with this:

GRUB_CMDLINE_LINUX_DEFAULT="intel_iommu=on kvm.ignore_msrs=1 
vfio-pci.ids=1002:67c7,1002:aaf0"

The Radeon card can now be assigned easily to Linux guests by adding this in 
the Cloudstack WebUI (Compute, Instances, then select the Instance, Settings) 
instance settings:

#Name:
extraconfig-1


#Value:
<devices>
  <hostdev mode='subsystem' type='pci' managed='yes'>
    <driver name='vfio'/>
    <source>
      <address domain='0x0000' bus='0xd9' slot='0x00' function='0x0'/>
    </source>
    <alias name='hostdev0' />
      <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0' 
multifunction='on'/>
  </hostdev>
  <hostdev mode='subsystem' type='pci' managed='yes'>
    <driver name='vfio'/>
    <source>
      <address domain='0x0000' bus='0xd9' slot='0x00' function='0x1'/>
    </source>
    <alias name='hostdev1'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x07' 
function='0x1'/>
  </hostdev>
</devices>


Linux guests work perfectly, the card is detected and is available straight 
away.
However with a Windows guest I have had nothing but problems! 
The Radeon device will turn up OK inside the Windows guest when passed through 
with these 2x settings:

#Name:
extraconfig-1

#Value:
<features>
  <hyperv>
    <vendor_id state='on' value='randomid'/>
  </hyperv>
</features>


#Name:
extraconfig-2

#Value:
<devices>
  <hostdev mode='subsystem' type='pci' managed='yes'>
    <driver name='vfio'/>
    <source>
      <address domain='0x0000' bus='0xd9' slot='0x00' function='0x0'/>
    </source>
    <alias name='hostdev0' />
      <address type='pci' domain='0x0000' bus='0x00' slot='0x00' function='0x0' 
multifunction='on'/>
  </hostdev>
  <hostdev mode='subsystem' type='pci' managed='yes'>
    <driver name='vfio'/>
    <source>
      <address domain='0x0000' bus='0xd9' slot='0x00' function='0x1'/>
    </source>
    <alias name='hostdev1'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x00' 
function='0x1'/>
  </hostdev>
</devices>


But when I install the AMD video driver (the onboard audio installs 
automatically) and then reboot, the system always hangs.
I have tried multiple Windows OS versions and multiple AMD driver versions.

I don't know whether the AMD driver is broke, or this card is just not 
supported somehow.
If anyone has any ideas I would be pleased to hear them.

Many thanks, Jim