[vfio-users] (good) working GPU for passthrough?

[Kash Pande]

On 2019-01-30 8:04 a.m., Tobias Geiger wrote:
> So it seems - i still suffer from the reset bug, despite the VM being
> 100% UEFI and Q35 now. 


I probably spoke too early when I said before that the reset issue is
fixed by proper PCIe layout.


The issue seems to be hardware-related, that there is no PCI quirk in
QEMU/vfio_pci to fully reset the GPU using PSP mode1 reset.


There is allegedly code in AMDGPU.ko to reset the GPU, but I believe
this is related to GPU hang reset, not full GPU / VM reboot reset.
Additionally, this code didn't work as advertised for me, last night,
when testing in a Linux guest.


There is an option to vfio_pci called disable_idle_d3 and when set to Y
it will prevent the vfio-bound PCI devices from entering the D3 idle
state that the card then gets stuck in. Of course, your card at idle
will be consuming about 50-60W more than needed.


If I simply start a VFIO guest, the GPU idles at 3 watts. I can reboot
as much as I want.


Kash


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