I have been trying for a few hours now all the combos - my situation is i need the iGPU for transcodes and if i turn CSM on then i cant have the igpu in multi monitor mode bois wont even post. It takes away the "set primary GPU" option and then wont post.
Why is it so difficult to passthrough an 7900xt?
I just did a google looks like you need linux kernal 6.+ - looks like i need to upgrade from 6.11 to 6.12 rc4
To get my 7900xt working I had to do a few things.
1) Disable SAM (asrock z790)
2) Had to add vbios from Techpowerup
3) Update to 6.12rc4 for new Linux kernel (has amd support for 7000 series)
4) add to vm xml
<features>
<acpi/>
<apic/>
<hyperv mode='custom'>
<relaxed state='on'/>
<vapic state='on'/>
<spinlocks state='on' retries='8191'/>
<vendor_id state='on' value='1234567890ab'/>
</hyperv>
<kvm>
<hidden state='on'/>
</kvm>
Go to settings for your Windows VM, and enable XML view in the upper right corner. We will need to edit 2 blocks:
add the following to <hyperv mode='custom'> block
<vpindex state='on'/> <synic state='on'/> <stimer state='on'/>
add the following to <clock offset='localtime'> block
<timer name='hypervclock' present='yes'/>
Few things I set while testing but have not turned on/off yet
1) Not legacy boot as I need igpu to run in unraid as primary for transcodes
2) have turned on PCIE override to both
3) Allow unsafe interrupts
I now get similar performance as my baremetal 5800x3d did. pretty happy with that.