Red Hat Bugzilla – Bug 623523
Wrong size of video memory setting in guest
Last modified: 2010-08-23 01:38:07 EDT
Created attachment 438332 [details]
Windows VRAM size
Description of problem:
Inconsistent VRAM between guest and XML definition.
Version-Release number of selected component (if applicable):
Steps to Reproduce:
Set video ram in guest:
<model type='cirrus' vram='9216' heads='1'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0'/>
On Linux guest:
(II) VESA(0): VESA VBE Total Mem: 16384 kB
On Windows guest:
Memory Size: 4 MB
The guest video memory should be consistent with specified.
Attached log and screenshot for reference.
Created attachment 438333 [details]
Xorg.0.log for cirrus
This issue has been proposed when we are only considering blocker
issues in the current Red Hat Enterprise Linux release.
** If you would still like this issue considered for the current
release, ask your support representative to file as a blocker on
your behalf. Otherwise ask that it be considered for the next
Red Hat Enterprise Linux release. **
Sorry, I put a wrong number for linux guest, the correct size as following.
On Linux guest:
(II) VESA(0): VESA VBE Total Mem: 4096 kB
I don't think it's a bug. We looked at it actually while I was in Beijing,
and the driver on XOrg for cirrus was always limiting the memory to 4MB.
I would not be surprized if the driver on Windows didn't do the same, because
all real cirrus logic based card only had 4MB of memory at the maximum.
And from my recollection of the mid-90's a graphic card like this with
4MB was rather high-end, then other chipset were developped taking advantage
of more memory.
So I think this is a limitation of the Cirrus Logic drivers both for Linux
and Windows, I don't think it's a libvirt bug actually. In any case I don't
see this fixed at the libvirt level or for 6.0
But the value vram='9216' doesn't make sense in XML description, if we should make some changes in XML to corresponding with the real allocated memory size?
This is a known limitation of the Cirrus card in QEMU, you can't change the VRAM. This bit of XML was added for the SVGA and SPICE QXL cards which are configurable. Hopefully we can make Cirrus configurable too in the future.
OK, thanks for the explanation! Close it with NOTABUG.