Hi,
       Okay, I've got this fixed for certain now. Definitely. I think.

       The problem turned out to be that qemudCanonicalizeMachine()
was using the alias in the default machine types if the domain's machine
types didn't have an alias that matched.

       We even have a test for this now, so hopefully it'll stay fixed
too :-)

       If you want to test this, try the machine-types-fixes branch on:

 git://gitorious.org/~markmc/libvirt/markmc-staging.git

Thanks,
Mark.