AMD RX6800 PCI Passthrough

yaro014

Active Member
Dec 27, 2012
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I’m using latest proxmox 6.3-3. Just installed the AMD RX6800 and I wanted to do the passthrough.
The below apeared in my system:

➜ ~ lspci| grep "b0\|b1\|af" af:00.0 PCI bridge: Advanced Micro Devices, Inc. [AMD/ATI] Device 1478 (rev c3) b0:00.0 PCI bridge: Advanced Micro Devices, Inc. [AMD/ATI] Device 1479 b1:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Device 73bf (rev c3) b1:00.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] Device ab28 b1:00.2 USB controller: Advanced Micro Devices, Inc. [AMD/ATI] Device 73a6 b1:00.3 Serial bus controller [0c80]: Advanced Micro Devices, Inc. [AMD/ATI] Device 73a4 ➜ ~ lspci -n -s b1:00 b1:00.0 0300: 1002:73bf (rev c3) b1:00.1 0403: 1002:ab28 b1:00.2 0c03: 1002:73a6 b1:00.3 0c80: 1002:73a4 ➜ ~ lspci -n -s b0:00 b0:00.0 0604: 1002:1479 ➜ ~ lspci -n -s af:00 af:00.0 0604: 1002:1478 (rev c3)
I’ve added the lspci devices to vfio.conf ( I also have 2080TI passed thru to a separate VM which works fine, hence the other pci ids)
➜ ~ cat /etc/modprobe.d/vfio.conf alias pci:v00001033d00000194sv000017AAsd000021D2bc0Csc03i30 vfio-pci options vfio-pci ids=10de:1c81,10de:0fb9,10de:1e07,10de:10f7,10de:1ad6,10de:1ad7,1912:0014,1002:1478,1002:1479,1002:73bf,1002:ab28,1002:73a6,1002:73a4
My iommu groups for this:
➜ ~ find /sys/kernel/iommu_groups/ -type l|grep -i "b0\|b1\|af" /sys/kernel/iommu_groups/144/devices/0000:b0:00.0 /sys/kernel/iommu_groups/147/devices/0000:b1:00.2 /sys/kernel/iommu_groups/145/devices/0000:b1:00.0 /sys/kernel/iommu_groups/143/devices/0000:af:00.0 /sys/kernel/iommu_groups/148/devices/0000:b1:00.3 /sys/kernel/iommu_groups/146/devices/0000:b1:00.1 ➜ ~ find /sys/kernel/iommu_groups/ -type l|grep -i "144\|147\|145\|143\|148\|146" /sys/kernel/iommu_groups/144/devices/0000:b0:00.0 /sys/kernel/iommu_groups/147/devices/0000:b1:00.2 /sys/kernel/iommu_groups/145/devices/0000:b1:00.0 /sys/kernel/iommu_groups/143/devices/0000:af:00.0 /sys/kernel/iommu_groups/148/devices/0000:b1:00.3 /sys/kernel/iommu_groups/146/devices/0000:b1:00.1
I have created a new VM with below config ( I also tried to pass entire b1:00 and this is a second try by passing through all devices separately):
bios: ovmf machine: q35 hostpci0: b1:00.0,pcie=1,x-vga=1 hostpci1: b1:00.1,pcie=1 hostpci2: b1:00.2,pcie=1 hostpci3: b1:00.3,pcie=1
Now, whatever I could try I cannot get the proper resolution to work. I tried fedora workstation 33, ubuntu 20.04, 20.10 and all of them are sort of in nomodeset at very low resolution. I’ve tried installing latest mesa from ppa and no results, I also tried installing AMD drivers from AMD site but it fails on DKMS and not even install the driver.

So I have two questions. First, why am I not able to pass through the devices b0:00 and af:00 - they are not visible in a PCI picker in proxmox web ui as well as I’ve tried to edit the config but I got the :
``` kvm: -device vfio-pci,host=0000:b0:00.0,id=hostpci4,bus=ich9-pcie-port-5,addr=0x0: vfio 0000:b0:00.0: failed to open /dev/vfio/144: No such file or directory ```
Second question, if these devices dont need to be passed thru, why am I not getting the proper display resolution out of the box.
 
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