Hi all-

I was excited to (belatedly) see the work done in D33129 and elsewhere to 
improve GPU passthrough support with ROM emulation. However I’m unsure how to 
interpret this comment: "it's only possible to use a ROM when using OVMF with 
enabled bus enumeration.” Does “OVMF” here refer to the normal tianocore/edk2 
UEFI boot rom? How does one enable bus enumeration with that?

I’m trying to pass through an AMD GPU to a Windows 10 machine on bhyve. The GPU 
in question is the only one in the box, so if I boot both the host and guest 
via UEFI it is initialized for EFI and works fine when Windows attaches to and 
initializes it. However (and not surprisingly), when I reboot the VM the GPU 
goes in to a funky state and the VM doesn’t come up.

The behavior is the same whether or not I have a ‘rom=‘ argument on the 
passthru device, so I’m assuming that the ROM is not actually being used. I’m 
further assuming that the aforementioned bus enumeration in the bootrom is the 
missing piece.

I did try rebuilding edk2-bhyve from the 202205 release. The build succeeded 
but the behavior was unchanged.

I’d love to get some guidance on this. Thanks!

JN

PS: Is there a known/supported way to get a GPU ROM file from FreeBSD? The one 
I have I obtained from a Linux host where this GPU was secondary.



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