Comment 40 for bug 604335

virt-manager 0.8.7 (on 11.10) does not support virtio block serial numbers. If you even provide a serial number virt-manger will not start the VM guest.

Meanwhile I've confirmed that if you just edit libvirt with "virsh edit ..." to insert <serial>FOO</serial> and boot the VM with "virsh start ..." the /dev/disk/by-id of 11.04 guest on 11.04 host works:

nutznboltz@grub-bug:~$ lsb_release -ds
Ubuntu 11.04
nutznboltz@grub-bug:~$ uname -a
Linux grub-bug 2.6.38-8-virtual #42-Ubuntu SMP Mon Apr 11 04:06:34 UTC 2011 x86_64 x86_64 x86_64 GNU/Linux
nutznboltz@grub-bug:~$ ls -l /dev/disk/by-id
total 0
lrwxrwxrwx 1 root root 9 2011-06-17 11:04 ata-QEMU_DVD-ROM_QM00003 -> ../../sr0
lrwxrwxrwx 1 root root 9 2011-06-17 11:04 virtio-WD-NUTZ9A966149 -> ../../vda
lrwxrwxrwx 1 root root 10 2011-06-17 11:04 virtio-WD-NUTZ9A966149-part1 -> ../../vda1
lrwxrwxrwx 1 root root 10 2011-06-17 11:04 virtio-WD-NUTZ9A966149-part2 -> ../../vda2