[vfio-users] vga passthrough works but no grub screen for linux guest

[Christoph Willing]

I have vga passthrough working with a linux guest running in qemu-3.1.0
on a host with two Nvidia Quadro K600 cards and the nvidia binary driver
430.26 installed. A dedicated keyboard & mouse is also passed through
successfully so, in general, I'm pretty happy with the setup but ...

when I use OVMF and run the guest without passthrough (just a regular
qemu vm running on the host display) I see a grub screen to select a
particular kernel, followed by the usual console output during bootup
before X starts. However, when running with passthrough enabled, the
guest vm's monitor (Samsung U28D590) shows nothing until X starts -
there is no grub screen and no console output.

Before I had the nvidia binary driver installed in the guest, I had some
console output while booting but still no grub screen.

Is there some way I can see everything including the grub screen, or is
it normal not to see that in the guest?

Thanks for any insights or suggestions,
chris