Re: [QEMU PATCH v4 12/13] virtio-gpu: Initialize Venus

[Huang Rui]

On Thu, Aug 31, 2023 at 11:51:50PM +0800, Dmitry Osipenko wrote:
> On 8/31/23 13:40, Antonio Caggiano wrote:
> > Hi Huang,
> > 
> > Thank you for pushing this forward!
> > 
> > On 31/08/2023 11:32, Huang Rui wrote:
> >> From: Antonio Caggiano <antonio.caggiano@collabora.com>
> >>
> >> Request Venus when initializing VirGL.
> >>
> >> Signed-off-by: Antonio Caggiano <antonio.caggiano@collabora.com>
> >> Signed-off-by: Huang Rui <ray.huang@amd.com>
> >> ---
> >>
> >> v1->v2:
> >>      - Rebase to latest version
> >>
> >>   hw/display/virtio-gpu-virgl.c | 2 ++
> >>   1 file changed, 2 insertions(+)
> >>
> >> diff --git a/hw/display/virtio-gpu-virgl.c
> >> b/hw/display/virtio-gpu-virgl.c
> >> index 83cd8c8fd0..c5a62665bd 100644
> >> --- a/hw/display/virtio-gpu-virgl.c
> >> +++ b/hw/display/virtio-gpu-virgl.c
> >> @@ -887,6 +887,8 @@ int virtio_gpu_virgl_init(VirtIOGPU *g)
> >>       }
> >>   #endif
> >>   +    flags |= VIRGL_RENDERER_VENUS;
> >> +
> > 
> > VIRGL_RENDERER_VENUS is a symbol only available from virglrenderer 0.9.1
> > [0] and only if VIRGL_RENDERER_UNSTABLE_APIS is defined.
> > 
> > Luckily for us, VIRGL_RENDERER_UNSTABLE_APIS is defined unconditionally
> > from virglrenderer 0.9.0 [1], so we could check for that in
> > qemu/meson.build
> > 
> > e.g.
> > 
> > 
> >   if virgl.version().version_compare('>= 0.9.0')
> >     message('Enabling virglrenderer unstable APIs')
> >     virgl = declare_dependency(compile_args:
> > '-DVIRGL_RENDERER_UNSTABLE_APIS',
> >                                dependencies: virgl)
> >   endif
> > 
> > 
> > Also, while testing this with various versions of virglrenderer, I
> > realized there are no guarantees for Venus backend to be available in
> > the linked library. Virglrenderer should be built with
> > -Dvenus_experimental=true, and if that is not the case, the following
> > virgl_renderer_init would fail for previous versions of virglrenderer or
> > in case it has not been built with venus support.
> > 
> > I would suggest another approach for that which tries initializing Venus
> > only if VIRGL_RENDERER_VENUS is actually defined. Then, if it fails
> > cause virglrenderer has not been built with venus support, try again
> > falling back to virgl only.
> 
> All the APIs will be stabilized with the upcoming virglrender 1.0
> release that will happen soon. There is also a venus protocol bump, qemu
> will have to bump virglrenderer's version dependency to 1.0 for venus
> and other new features.
> 

Dmitry, do you know the timeline of virglrender 1.0?

Thanks,
Ray