Re: [Qemu-devel] [PATCH v4 0/6] save/restore on Xen

[Anthony Liguori]

On 01/23/2012 11:05 AM, Stefano Stabellini wrote:
> On Mon, 23 Jan 2012, Anthony Liguori wrote:
> > > However the issue of patch #4, "do not reset videoram on resume", still
> > > remains: no matter what parameter I pass to Qemu, if qemu_system_reset
> > > is called on resume the videoram is going to be overwritten by 0xff.
> >
> > The memset(0xff) looks dubious to me.  My guess is that this could be moved to
> > the vgabios-cirrus which would solve your problem.
> >
> > > In this regard, don't you think it would be advantageous to Qemu in
> > > general not to reset the videram in resume? It can be pretty large, so
> > > it is a significant waste of a memset.
> >
> > It claims to fix a real bug.  Moving the memset to vgabios would do what you
> > want to do in a more robust way I think.
>
> I think it does fix a bug (Win2K expects RAM to be 0xff at boot, or so a
> comment on qemu-xen claims) but certainly it is not supposed to run at
> restore time.
> I agree that moving the memset to vgabios should be a better way to fix
> the problem, I'll give it a look.
> Unfortutely it means finding a Win2K install CD to repro the bug, sigh.

Right, it's a bit annoying, but a much nicer solution :-)

Thanks,

Anthony Liguori