GPU Passthrough Pinning CPU core at 100% and using all RAM

[barronpm]

I'm setting up GPU passthrough for a VM, but when I boot the VM, it pins a core at 100% utilization and uses all RAM given to it when I specify the vbios file.
I'm using a PowerColor Vega 56

Reading the GPU rom from the rom file and parsing it with https://github.com/awilliam/rom-parser shows the error:
Error, ran off the end
This is resolved by using the vbios from TechPowerUp
https://www.techpowerup.com/vgabios/200963/powercolor-rxvega56-8192-180320
but this results in the error described above

vm conf:

agent: 1,fstrim_cloned_disks=1
bios: ovmf
bootdisk: scsi0
cores: 6
efidisk0: local-lvm:vm-110-disk-1,size=4M
hostpci0: 04:00,pcie=1,x-vga=1,romfile=vbios.rom
machine: q35
memory: 8192
name: Jellyfin
net0: virtio=12:98:9a:67:9d:8c,bridge=vmbr1,firewall=1
numa: 0
onboot: 1
ostype: l26
scsi0: local-lvm:vm-110-disk-0,discard=on,size=32G
scsihw: virtio-scsi-pci
smbios1: uuid=8399b265-c424-4286-8ad3-3673db809e35
sockets: 1
vmgenid: 3a3b8e06-28c8-48a1-ae7f-4a822f169279

When I don't have the vbios specified, the VM boots, but glxinfo fails with this message:
Error: unable to open display

lspci -k shows that the amdgpu driver is in use

 

[Stefan_R]

When I don't have the vbios specified, the VM boots, but glxinfo fails with this message:
Error: unable to open display

lspci -k shows that the amdgpu driver is in use

Are you sure that the issue is with passthrough then? Usually, when the VM boots and even the correct driver binds to the device that's an indicator that the passthrough is working fine.

I'd try without the 'romfile' option and see if there's maybe a configuration error in your VM. Does it show you a command prompt when you boot like that? Does dmesg report something?