AMD GPU problems under Xen

[Alex Deucher]

On Mon, Nov 28, 2022 at 2:18 AM Demi Marie Obenour
<demi at invisiblethingslab.com> wrote:
>
> Dear Christian:
>
> What is the status of the AMDGPU work for Xen dom0?  That was mentioned in
> https://lore.kernel.org/dri-devel/b2dec9b3-03a7-e7ac-306e-1da024af8982@amd.com/
> and there have been bug reports to Qubes OS about problems with AMDGPU
> under Xen (such as https://github.com/QubesOS/qubes-issues/issues/7648).

I would say it's a work in progress.  It depends what GPU  you have
and what type of xen setup you are using (PV vs PVH, etc.).  In
general, your best bet currently is dGPU add in boards because they
are largely self contained.  APUs and platforms with integrated dGPUs
are a bit more complicated as they tend to have more platform
dependencies like ACPI tables and methods in order for the driver to
be able to initialize the hardware properly.  Additionally, GPUs map a
lot of system memory so bounce buffers aren't really viable.  You'll
really need IOMMU,

Alex

> --
> Sincerely,
> Demi Marie Obenour (she/her/hers)
> Invisible Things Lab