one out of four existing kvm guest's not starting after system upgrade

Thomas Fjellstrom
2012-02-18T04:56:38Z

I just updated my kvm host, kernel upgraded from 2.6.38 up to 3.2, and
qemu+qemu-kvm updated (not sure from what to what). But after the upgrade, one
of my guests will not start up. It gets stuck with 60-80% cpu use, almost no
memory is allocated by qemu/kvm, and no output of any kind is seen (in the
host console, or a bunch of the guest output options like curses display,
stdio output, virsh console, vnc or sdl output). I normally use libvirt to
manage the guests, but I've attempted to run qemu manually, and have the same
problems.

What can cause this?

Just tested booting back into the old kernel, the one guest still won't start,
while the rest do. I'm thoroughly confused.