Re: [Qemu-devel] [PATCH] qxl: make sure primary surface is saved on migration also in compat mode

[Yonit Halperin <yhalperi@redhat.com>]

On 02/14/2012 10:35 AM, Gerd Hoffmann wrote:
> On 02/14/12 09:10, Yonit Halperin wrote:
>> RHBZ #790083
>>
>> Signed-off-by: Yonit Halperin<yhalperi@redhat.com>
>
> You are doing two things in one patch:  (a) fix the compat mode bug,
> which also matches the patch description, and (b) skip vram when it is
> unused (in compat mode).
>
> I'd love to see (b) done in a different way: simply walk all surfaces
> and tag them dirty.  Will have the same effect for compat mode (no
> surfaces used ->  nothing tagged dirty) and additionally it will (in
> native mode) only migrate over the vram areas which are actually filled
> with surfaces.
>
I can do it, by retrieving the surfaces addresses from the tracked guest 
commands. However, if we already do it, it would be even better if we 
just dirty only the areas that are actually modified by the update_area 
calls. The problem is that (1) spice-server updates surfaces also 
without request from driver. We can add a cb to the interface or use the 
async_complete cb with a special flag (2) async_complete cb is called 
from spice server context. We can add a pipe for update_area dirty 
events, and make sure that it is handled, before migration moves from 
the live stage.

Yonit.
> thanks,
>    Gerd