Re: Porting SPICE to Xen

["Daniel P. Berrange" <berrange@redhat.com>]

On Thu, Jan 07, 2010 at 11:01:39AM +0000, Vincent Hanquez wrote:
> On 01/07/2010 04:33 AM, Thiago Camargo Martins Cordeiro wrote:
> >If this happen, it will work with paravirtualized domUs too? Or maybe 
> >it is only for HVM domains?!
> SPICE is 2 differents parts, the part that expose the PCI device to the 
> guest and "replace" the graphic card IIRC, and the actual remote desktop 
> protocol.

That's not entirely accurate terminology. SPICE is the remote desktop
protocol & client/server side libraries. When SPICE is integrated into
QEMU, it takes advantage of a new graphics card called "QXL", and the
corresponding guest OS drivers. IIUC, currently SPICE can't use the
Cirrus card, and the QXL card doesn't work with VNC, but those are both
just artifacts of the current integration of SPICE with QEMU, not problems
of SPICE or QXL themselves, which from an architectural POV are both
separate things.

> at the moment the 2 are fairly intertwined, so it would only work with 
> HVM domains [1], but depending on how the things get de-intertwined 
> (which is something qemu people want), it might be possible to have it 
> on PV. I wouldn't hold my breath on PV domain though.

It depends what you'd want from PV domain integration. I expect you could
make SPICE "work" with the PVFB, but it probably wouldn't offer much of a
performance benefit over VNC, because it'll be limited to dumb framebuffer
mode. To take full advantage of SPICE requries a graphics card supporting
the various advanced operations, which is what QXL supplies. Enhancing 
PVFB to support some of the advanced QXL features would be where the
significant work arrives

Daniel
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