VFIO "boot GPU" selection

Operating Systems & Open Source Virtualization
1

I’m fairly new to the whole GPU passthrough game, so please bear with me here.

I have 2 GPUs in an ASUS Pro WS X570-ACE board.

The problem is that as far as I can tell there is no way to select the “boot” GPU in BIOS on that board. (Maybe I’m missing something?)

I want the system to boot with the tiny Zotac GT710 that sits in a tiny PCIx1 slot, while i would like to run the Windows VM with the Radeon VII in the top most PCI x16 slot.

Obviously, while booting, the Radeon VII is first in line and gets selected to display the boot process.

Unfortunately that blocks it from being used in the VM. The infamous “reset bug” does not allow it to be re-assigned to the VM after bios grabbed it (or at least that’s what I’ve been able to find out so far)

I have found a workaround though! When I physically unplug the monitor from the Radeon VII, then the GT710 gets to be the “BIOS GPU” and voila, the windows VM boots fine with the Radeon VII.

Is there a way to boot the system without reaching under the desk to unplug the monitor every time? A BIOS setting I’m currently not aware of? some linux kernel magic trick maybe?

If I have to I’ll byte the bullet and buy some other board. Is there a x570 board that has the ability to select the boot GPU in BIOS? From what I googled so far Gigabyte seems to allow that but I’m not sure if that’s true for x570 boards. Can somebody confirm this?

Thanks in advance for your help!

1 Like
2

add
video=vesafb:off,efifb:off
to your kernel command line.
this basically undoes the GPU settings your BIOS set on startup.
this may or may not result in a black screen after grub.

3

You’re gonna have to get a Gigabyte board to find that feature that you’re looking for because it’s only on Gigabyte boards. The Aorus Master should be good as of the latest 1.0.0.4B AGESA.

Radeon VII has not had traction yet on the reset bug fix because the person that fixed it for Vega 10 and Navi @gnif does not have a Radeon VII. Before a fix can be made, the fixer needs the hardware, and that’s indeterminate. If you send your Radeon VII to him in Australia, there could be hope the reset bug can be fixed on the VII.