GPU passthrough support for Stoney [Radeon R2/R3/R4/R5 Graphics]?

[Micah Morton]

Hi folks,

I'm interested in running a VM on a system with an integrated Stoney
[Radeon R2/R3/R4/R5 Graphics] card and passing through the graphics
card to the VM using the IOMMU. I'm wondering whether this is feasible
and supposed to be doable with the right setup (as opposed to passing
a discrete GPU to the VM, which I think is definitely doable?).

So far, I can do all the qemu/kvm/vfio/iommu stuff to run the VM and
pass the integrated GPU to it, but the drm driver in the VM fails
during amdgpu_device_init(). Specifically, the logs show the SMU being
unresponsive, which leads to a 'SMU firmware load failed' error
message and kernel panic. I can share VM logs and the invocation of
qemu and such if helpful, but first wanted to know at a high level if
this should be feasible?

P.S.: I'm not initializing the GPU in the host bios or host kernel at
all, so I should be passing a fresh GPU to the VM. Also, I'm pretty
sure I'm running the correct VGA bios for this GPU in the guest VM
bios before guest boot.

Any comments/suggestions would be appreciated!

Micah