After much trial and error, I finally got my AMD Ryzen 4750G APU to pass through its iGPU to a Windows 10 VM in both Unraid and Proxmox (both Qemu/KVM). Thsi involved the ACS override patch in the kernel (pcie_acs_override=downstream,multifunction) as well as clearnign the EFI frame buffer (video=efifb:off), I also had to boot to my hypervisor in UEFI mode, but my guest had to be in SeaBIOS mode on a Q35 machine.
One issue I’ve been struggling with is that as soon as I install from AMD’s site (or let Windows 10 install automatically) any AMD Radeon drivers for the iGPU, the video output becomes a complete mess (see pic attached below). If I “disable device” for the iGPU in Device Manager (thanks to RDP, no way I could use a display connected via HDMI/DP), video output returns to normal. If I run DDU to uninstall all AMD drivers, everything returns to normal as well.
I have seen reports that AMD may now be checking to see if we run their GPUs in a VM and this could cause issues. Two posts that come to mind are:
I have followed the suggestions as best I could, setting my vendor_id to something random, turning on the kvm hidden_state, and even ioapic driver=‘kvm’ – all to no avail. I also tried the following, so Windows doesn’t think it’s in a VM anymore, with no success:
I have also tried with AMD drivers 20.9.1 (Sept 2020) and 20.45.36 (Feb/Mar 2021), in addition to the AMD Pro 20.Q4 (which wouldn’t even install since APUs aren’t supported) which was suggested in one of the posts I linked above.
I was hoping to get some input here as to what I could try next? I feel like I’m so close, and would love to make a guide on what I did to get this running, as several users on different forums seem to be wanting to do the same, whether it’d be on Proxmox or Unraid. At this point, without AMD drivers, the system is usable, but refresh rate seems to be ~30hz (based on visual appearance) or less, and I’m hoping official drivers can fix that.
I’ve attached my Unraid VM config below for reference, it reads as a Qemu config just formatted as XML.
Thanks in advance!
Example image: https://i.imgur.com/1EMWDJo.png
VM config: https://pastebin.com/BJy9F2AP