Someone on the /r/VFIO discord with a Ryzen APU (he usually boots his VM from
the console, rather than having a graphical host) confirmed the crashiness by
running Furmark, which crashed his GPU driver in ten minutes; his dmesg showed
that as well.

13877  0.1  0.0      0     0 pts/1    ZNl+ 10:09   0:00 [GpuTest] <defunct>
[90972.383503] [drm:amdgpu_job_timedout [amdgpu]] *ERROR* ring gfx timeout,
last signaled seq=36081, last emitted seq=36083
[90972.383512] [drm] IP block:psp is hung!
[90972.383514] [drm] GPU recovery disabled.