[libvirt] qemu qxl video memory parameter - windows bsod with spice

[Emre Erenoglu]

Hi,

Please see the below discussion with the spice community.

libvirt is adding a parameter about video ram to qemu process and this
parameter might be responsible of a crash in the qxl at higher resolutions.
Spice people tell me that their default ram should be 64 Mbytes.

I'm using libvirt 0.9.0 and qemu 0.14,  virt-manager 0.8.7. When configuring
a guest in virt-manager, cirrus driver is added as default, then you can
change it to qxl, but the 9 MB videoram parameter can't be adjusted and it
does not automatically change to 64 MB. If you add a 2nd qxl video card,
then it has 64 MB memory.

The parameter that qemu gets with one qxl device is:

     -vga qxl -global qxl-vga.vram_size=9437184

The parameter that qemu gets with a second qxl device is:

     -vga qxl -global qxl-vga.vram_size=9437184 -device
qxl,id=video1,vram_size=67108864,bus=pci.0,addr=0x8

Is this a bug in libvirt or other related tools?

Thanks,
Br,
Emre

---------- Forwarded message ----------
From: Emre Erenoglu <erenoglu at gmail.com>
Date: Wed, May 4, 2011 at 7:42 PM
Subject: Re: [Spice-devel] windows bsod with spice 0.8.1
To: Emre Erenoglu <erenoglu at gmail.com>, spice-devel at freedesktop.org


On Wed, May 4, 2011 at 6:00 PM, Alon Levy <alevy at redhat.com> wrote:

> On Wed, May 04, 2011 at 05:10:31PM +0400, Emre Erenoglu wrote:
> > On Wed, May 4, 2011 at 2:12 PM, Alon Levy <alevy at redhat.com> wrote:
> >
> > > On Wed, May 04, 2011 at 01:45:39PM +0400, Emre Erenoglu wrote:
> > > > On Wed, Apr 27, 2011 at 1:16 AM, Emre Erenoglu <erenoglu at gmail.com>
> > > wrote:
> > > >
> > > > > Hi,
> > > > >
> > > > > I started to see frequent crashes with my guests running windows xp
> and
> > > > > windows server 2003 x86.  The bsod appears on qxldd.dll. I can give
> > > further
> > > > > info if needed.
> > > > >
> > > > > The host is Linux x86_64, qemu 0.14, spice 0.8.1. Guest has qxl
> 0.6.1
> > > > > drivers loaded. I may revert back to 0.8.0 since it was not
> crashing.
> > > > > Nothing changed in the guests when I upgraded spice from 0.8.0 to
> > > 0.8.1.
> > > > >
> > > > >
> > > > Some updates on the original issue. I checked a lot and I found out
> that
> > > the
> > > > issue continued with any version of spice and guest qxl drivers.
> > > >
> > > > I finally digged down to the point that, the qemu comment line which
> > > states
> > > > "   -global qxl-vga.vram_size=9xxxxxx  " parameter is the problem.
> When
> > > the
> > > > guest is started with 9 MB of video memory given as comment line
> > > parameter
> > > > to qemu, the guest qxldd driver crashes with BSOD.
> > >
> > > Why was it started with 9MB? anyway, good catch, we should add a check
> for
> > > this
> > > in the driver (and probably just refuse to load). Could you open a bug
> on
> > > this
> > > in bugzilla.freedesktop.org?
> > >
> >
> > This is added by libvirt (virt-manager) when launching qemu. Do we need
> to
> > file it against libvirt or against spice?  I will post this to the
> libvirt
> > list also.
> >
> > Btw, rather than refusing to load, I think we should just limit the
> possible
> > resolutions. I'm not sure if the resolutions are the issue though. The
> crash
> > was not happening immediately and it was working OK with that 9 MB
> memory.
> > When I launched outlook, or IE8, or just in the middle of an application,
> it
> > could crash and bsod.
>
> But that number doesn't make any sense - the spice default is 64MB, we
> never tested
> with less then that. It is probably fixable like you say, but until that's
> fixed why
> not stick to the spice default?


Well, this parameter is not configurable from the virt-manager UI and it
configures 9 MB to the command line of qemu by libvirt (even latest 0.9.0)
version.
When you add a 2nd VGA adapter, it adds 64 MB to that adapter correctly
(-device qxl,id=video1,vram_size=67108864,bus=pci.0,addr=0x8)

I guess i need to file a bug report to libvirt too.

Emre
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