Re: [Qemu-devel] [RFC v2 11/12] Add virtio-gpu vhost-user backend

[Gerd Hoffmann]

On Fri, Jun 01, 2018 at 06:27:48PM +0200, Marc-André Lureau wrote:
> Add to virtio-gpu devices a "vhost-user" property. When set, the
> associated vhost-user backend is used to handle the virtio rings.
> 
> For now, a socketpair is created for the backend to share the rendering
> results with qemu via a simple VHOST_GPU protocol.

Why this isn't a separate device, like vhost-user-input-pci?

> +typedef struct VhostGpuUpdate {
> +    uint32_t scanout_id;
> +    uint32_t x;
> +    uint32_t y;
> +    uint32_t width;
> +    uint32_t height;
> +    uint8_t data[];
> +} QEMU_PACKED VhostGpuUpdate;

Hmm, when designing a new protocol I think we can do better than just
squeering the pixels into a tcp stream.  Use shared memory instead?  Due
to vhost we are limited to linux anyway, so we might even consider stuff
like dmabufs here.

cheers,
  Gerd