Re: [Qemu-devel] Spice project is now open

[Yaniv Kamay]

----- "Anthony Liguori" <address@hidden> wrote:

> Yaniv Kamay wrote:
> > Hi,
> >
> > Spice project is now open, for more information visit
> http://spice-space.org,
> > due to a server relocation the site will be down during this
> weekend.
> >
> > Spice ship patched QEMU based on fairly old KVM snapshot as a
> reference
> > implementation. The Spice team plane to push all the relevant bits
> into
> > QEMU upstream.
> >   
> 
> Historically, we have not supported multiple display mechanisms
> favoring 
> making one mechanism as good as it can be.
> 
> Supporting both Spice and VNC would go against this policy.  It's not
> 
> outside the realm of possibility, but there has to be a good 
> justification for it.
> 
> We need to separate the advantages of having a paravirtual display 
> driver from the advantages of a remote display protocol.  For
> instance, 
> VNC is capable of doing ARGB cursor offloading to the client.  We do
> not 
> support it in QEMU because the VGA drivers we emulate do not support 
> this functionality.  Likewise, VNC can support sound tunneling and
> QEMU 
> does implement this (although virt-manager does not yet).
> 
> So from a protocol perspective, what are the advantages of Spice over
> VNC?
> 
> Obviously, the disadvantages are that for all practical purposes, it's
> a 
> closed protocol.  While there is now a specification, there is not a 
> clear mechanism for extending it by third parties.  VNC has a
> published 
> protocol and there's a documented process for extending by third 
> parties.  There are a large number of existing VNC clients so from an
> 
> interoperability perspective, VNC clearly wins.
> 
> Since VNC is extensible (and we've extended it many times for QEMU),
> if 
> Spice possesses unique encoding mechanisms that are advantageous, why
> 
> wouldn't we just add those mechanisms to VNC as an extension?

I'm not getting into this discussion and is not going to happen, you have all
the necessary information on spiec-space.org in order to take intelligent
decision. The QEMU community can choose to reject Spice if it decide to do so.

> 
> Regards,
> 
> Anthony Liguori