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

[Marc-André Lureau]

Hi

On Fri, Apr 26, 2019 at 9:33 AM Gerd Hoffmann <address@hidden> wrote:
>
> 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).


That brings more questions and ambiguity imho.

Can we leave that for future protocol extensions negotiated with
GET/SET_PROTOCOL_FEATURES ?



--
Marc-André Lureau