Comment 55 for bug 795717

$ uname -srvi
Linux 2.6.38-13-generic #52-Ubuntu SMP Tue Nov 8 16:53:51 UTC 2011 x86_64
$ sudo virsh dumpxml opsi-1720 | grep cpu
  <vcpu>2</vcpu>
$ sudo virsh start opsi-1720
$ ssh root@opsi-1720
root@opsi-1720's password:
Last login: Fri Nov 11 17:30:14 2011
[root@opsi-1720 ~]# lsb_release -a
LSB Version: :core-4.0-ia32:core-4.0-noarch:graphics-4.0-ia32:graphics-4.0-noarch:printing-4.0-ia32:printing-4.0-noarch
Distributor ID: ScientificSL
Description: Scientific Linux SL release 5.7 (Boron)
Release: 5.7
Codename: Boron
[root@opsi-1720 ~]# grep QEM /proc/cpuinfo
model name : QEMU Virtual CPU version 0.14.0
model name : QEMU Virtual CPU version 0.14.0
[root@opsi-1720 ~]#

works for me