I struggeled for a while with Debian Squeeze, trying to persuade it to run as a libvirt/kvm guest on my Ubuntu 12.04 host. After successful installation, the guests failed to boot the kernel with the messages:
Loading Linux 2.6.32-5-amd ...
unaligned pointer 0x8ebf0002
Aborted. Press any key to exit.
For my own reference, I record here the solution I just found after trying all sorts of things like installing different versions of grub into the virtual machine:
