[CentOS-virt] new libvirt: CentOS 6.2 versus 6.0

Bradley bradley at stygianresearch.com
Wed Feb 22 20:24:17 EST 2012

On Thu, February 16, 2012 1:24 pm, Dmitry E. Mikhailov wrote:
> Hi,
> About half a year ago I installed a stock CentOS 6.0/64bit onto an Intel
> server to virtualize our Linux fileserver and four WinXP boxes with rdp each.
> Since recent times I didn't do any upgrades of the server's OS. Now I have
> CentOS 6.2.
> After an upgrade I noticed that all virtual cpu name changed to
> QEMU Virtual CPU version (cpu64-rhel6)
> Second, a killer app on one of WinXP servers stopped working since upgrade.
> It's a russian proprietary accounting app named 1C ver. 8.1 (1cv8.exe). It
> would just hang loading single virtual CPU to 100%. I traced by
> trial-and-error that the problem is related to virtual CPU identification.
> Following solution would help:
>   <cpu match='exact'>
>     <model>Penryn</model>
>     <vendor>Intel</vendor>
>     <feature policy='require' name='tm2'/>
>     <feature policy='require' name='est'/>
>     <feature policy='require' name='monitor'/>
>     <feature policy='require' name='ds'/>
>     <feature policy='require' name='ss'/>
>     <feature policy='require' name='vme'/>
>     <feature policy='require' name='ht'/>
>     <feature policy='require' name='dca'/>
>     <feature policy='require' name='pbe'/>
>     <feature policy='require' name='tm'/>
>     <feature policy='require' name='vmx'/>
>     <feature policy='require' name='ds_cpl'/>
>     <feature policy='require' name='xtpr'/>
>     <feature policy='require' name='acpi'/>
>     <feature policy='disable' name='nx'/>
>     <feature policy='disable' name='pae'/>
>   </cpu>
> It wasn't working before I disabled PAE and NX.
> Double checked. If I delete <cpu> part and thus leave it 'default', the
> application won't work.


I'd like to thank you for this post.  I was having the same issue as your number 2.  For me, it
was an application running on windows 7, but the description of it loading at 100% was exact.  I
too went down the path of the virtual cpu change and setting the cpu type.  I never managed to
solve it until i say your post.  I had the exact same require settings, but no disable settings. 
For my app, all I had to do was disable NX.  I still have PAE enabled.  Rather I have the generic
feature enabled instead of tied to a CPU.

Up until now, I had marked it down as bios issue, since I believe the bios had changed from centos
5.7 to 6.2.

I had put the issue on a back burner since it wasn't a critical app and I was able to run in on a
physical windows 7 box.

Have you checked /usr/share/qemu-kvm/cpu-model/cpu-x86_64.conf to see what has changed from 6.0 to
6.2?  The equivalent doesn't exist on my centos 5.7 box, so I'm having trouble determining the
defaults from 5.7.

Bradley Leonard
EMail:  bradley at stygianresearch.com

Rob   - "The hills are alive with the..the..sound of monkeys?"
Bucky - "It's in the key of delicious."

Life is simple. Humans make it complicated.

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