On Wed, 21 Dec 2011, Emmett Culley wrote:
I tore my hair out for a while after rebooting into 6.2 because none of the VM guests would start. After trying lots of things, like down grading qemu-kvm (which fixed it when I upgraded via the CR repository and didn't this time), cloning a VM, and even beginning to create new VM to restore from backup.
Luckily I discovered that there is a log for each VM and found in each case it failed because vmvga is not compiled into KVM. So I changed them all to cirrus via virt-manager and they all work again.
The host machine is all up to date and all of the guest start and operate as usual.
What worked for me was running "virsh edit" against each (now shutdown) domain, removing all the <address> tags in the <devices> section, e.g.,
<devices> <disk> <address type='pci' .../> </disk> <interface> <address type='pci' .../> </interface> <memballoon> <address type='pci' .../> </memballoon> </devices>
All the VMs started without any issue after that, though I'll admit have haven't tried re-starting them since the fix.