Re: [Qemu-devel] [PATCH v6 05/11] vhost-user: add vhost_user_gpu_set_socket()

[Gerd Hoffmann]

On Tue, Apr 23, 2019 at 03:19:58PM +0200, Marc-André Lureau wrote:
> Add a new vhost-user message to give a unix socket to a vhost-user
> backend for GPU display updates.

Can you split input/gpu into two patch series?

> +Wire format
> +===========
> +
> +Unless specified differently, numbers are in the machine native byte
> +order.
> +
> +A vhost-user-gpu request consists of 2 header fields and a payload.
> +
> ++---------+------+---------+
> +| request | size | payload |
> ++---------+------+---------+
> +
> +Header
> +------
> +
> +:request: ``u32``, type of the request
> +
> +:size: ``u32``, size of the payload
> +
> +A reply consists only of a payload, whose content depends on the request.

I'd suggest to use the same format for replies, only with "request"
meaning "status" in replies.  Allows for OK/ERROR status in replies,
and having a size field in replies too should make things more robust.
Also allows for an empty reply (status=ok,size=0).

cheers,
  Gerd