AMD GPU Passthrough Fail - End of File qemu monitor

[kwilinsi]

Components:

CPU: AMD Ryzen 5 5600G

Motherboard: MSI B550-A Pro

GPU: AMD Radeon RX 560

 

 

I'm trying to pass through an AMD GPU to an Ubuntu desktop VM.

 

The VM works fine in VNC, but when using GPU passthrough, I get this error in the libvirt log:

2022-03-25 21:42:07.299+0000: 19863: error : qemuMonitorIO:578 : internal error: End of file from qemu monitor

It also shows "tainted: high-privileges" and "tainted: host-cpu".

 

I have also tried creating a Windows VM, and I get exactly the same error message. I have also tried passing it through with and without the sound card on the GPU.

 

At one point I actually managed to get the passthrough to work, with the Ubuntu login screen appearing on the monitor. But when I rebooted to add a keyboard, it didn't work anymore, and I have not been able to replicate that (even deleting the VM and recreating the same settings).

 

Note that I have PCIe ACS override disabled, as it was not needed for separately IOMMU groups. The graphics and sound components of the card are by themselves in IOMMU group 9:

[1002:67ff] 10:00.0 VGA compatible controller: Advanced Micro Devices, Inc. [AMD/ATI] Baffin [Radeon RX 550 640SP / RX 560/560X] (rev cf)

[1002:aae0] 10:00.1 Audio device: Advanced Micro Devices, Inc. [AMD/ATI] Baffin HDMI/DP Audio [Radeon RX 550 640SP / RX 560/560X]

[ghost82]

11 hours ago, kwilinsi said:

internal error: End of file from qemu monitor

 

11 hours ago, kwilinsi said:

It also shows "tainted: high-privileges" and "tainted: host-cpu".

 

First error happens when you shutdown the vm and it's a not fatal error: on sigterm qemu closes the monitor, libvirt doesn't expect it and throws the error. A patch for libvirt was introduced to mask this error, but it was reverted, so this is expected behavior.

 

Second are not errors but warnings, 'tainted' means you are running the vm with a custom config, perfectly fine.

 

11 hours ago, kwilinsi said:

At one point I actually managed to get the passthrough to work, with the Ubuntu login screen appearing on the monitor.

This sounds like amd reset bug. Unraid 6.10 RCx includes the patch in the kernel, if you are not on 6.10 you can give it a try.

 

11 hours ago, kwilinsi said:

I have also tried passing it through with and without the sound card on the GPU

You must always isolate all the components of the gpu (attach to vfio).

You should always pass all the components of the gpu to the vm, and set them in a multifunction device; some drivers don't like device with missing components or components in different slots/buses.