Re: [PATCH v6 00/10] Support virtio-gpu DRM native context

["Alex Bennée" <alex.bennee@linaro.org>]

Dmitry Osipenko <dmitry.osipenko@collabora.com> writes:

> On 1/27/25 19:17, Alex Bennée wrote:
>> Dmitry Osipenko <dmitry.osipenko@collabora.com> writes:
>> 
>>> This patchset adds DRM native context support to VirtIO-GPU on Qemu.
>>>
>>> Contarary to Virgl and Venus contexts that mediates high level GFX APIs,
>>> DRM native context [1] mediates lower level kernel driver UAPI, which
>>> reflects in a less CPU overhead and less/simpler code needed to support it.
>>> DRM context consists of a host and guest parts that have to be implemented
>>> for each GPU driver. On a guest side, DRM context presents a virtual GPU as
>>> a real/native host GPU device for GL/VK applications.
>>>
>>> [1] https://www.youtube.com/watch?v=9sFP_yddLLQ
>>>
>>> Today there are four DRM native context drivers existing in a wild:
>>>
>>>   - Freedreno (Qualcomm SoC GPUs), completely upstreamed
>>>   - AMDGPU, completely upstreamed
>> 
>> Well good news and bad news.
>> 
>> I can verify that AMD native context works when I run my Aarch64 guest
>> on my Aarch64 host with -accel TCG (therefor avoiding KVM all together).
>> I get potato frame rates though (~150FPS) although I suspect that is
>> because the PCI errata workaround.
>> 
>> When it comes to graphics memory allocation is there anything I can do
>> to force all allocations to be very aligned? Is this in the purview of
>> the AMD drm drivers or TTM itself?
>
> All GPU allocations should be aligned to a page size. Alignment is
> specified by AMD driver. I don't expect that alignment is the problem.
> What's the size of your host and guest pages?

4k AFAIK.

-- 
Alex Bennée
Virtualisation Tech Lead @ Linaro