Re: [RFC PATCH v3 1/2] virtio-gpu: add resource create blob

[Gurchetan Singh <gurchetansingh@chromium.org>]

On Fri, May 15, 2020 at 3:42 AM Gerd Hoffmann <kraxel@redhat.com> wrote:
>
>   Hi,
>
> > +\field{blob_mem} can only be VIRTIO_GPU_BLOB_MEM_HOST3D and
> > +VIRTIO_GPU_BLOB_MEM_HOST3D_GUEST if VIRTIO_GPU_F_VIRGL is supported.
> > +VIRTIO_GPU_BLOB_MEM_GUEST is valid regardless whether VIRTIO_GPU_F_VIRGL
> > +is supported or not.
>
> Would it be useful to explicitly announce which VIRTIO_GPU_BLOB_MEM*
> variants are supported instead of having implicit rules?  Using a
> config space field for example?

In 2D mode, I don't think anybody is going to advertise support
VIRTIO_GPU_BLOB_MEM_HOST3D / VIRTIO_GPU_BLOB_MEM_HOST3D_GUEST.  I'm
thinking we can just have various checks in the kernel and write in
the spec, like the current model.

https://github.com/torvalds/linux/blob/master/drivers/gpu/drm/virtio/virtgpu_ioctl.c#L238

> cheers,
>   Gerd
>