[libvirt] regression in finding boot device

[Laine Stump]

I just built a fresh libvirt rpm from the head of git on my Fedora 14 
machine and updated all the libvirt packages (I'm not sure what version 
had been running previously, but it was at least 0.8.8-4 from 
virt-preview, probably something later built from source).

Just prior to the update, I had successfully started up a Fedora 15 
guest and stopped it. After the update, I started the F15 guest and got 
the following message on the virt-viewer console:

   Booting from Hard Disk...
   Boot failed: could not read the boot disk.

I downgraded to 0.8.8-4 from virt-preview, and was once again able to 
boot the guest. Upgraded again, still broken. Investigated some more, 
and I found that if I disable QEMU_CAPS_BOOTINDEX in the new libvirt, 
the guest boots with no problem.
(bootindex was showing up as "1" in the log; not knowing anything about 
how it worked, I decided to try just changing it to "0". That  didn't 
work. Switching back to the old method *did* work, though.)

This system is running qemu-kvm-0.14-7.fc14.x86_64.
If you'd like a look at the domain XML, the qemu logs, or access to the 
machine, just let me know.