And this is also the trivial part to describe: I want a
machine like the one in qemu-0.11.
Yes, but there might be a ton of reasons to want a
machine like the one in qemu 0.11.
The need to migrate to old qemu is very rare,
it is a completely separate decision
one might take long after starting qemu,
Doesn't work. If you have a qemu 0.11 machine, a virtio nic and your
guest uses MSI-X you simply can't migrate to qemu 0.10. End of story.
If you want to be able to migrate to 0.10 you have to start in 0.10
compat mode with MSI-X disabled. So IMHO it does makes sense to tie the
savevm format to -M pc-<version>.
cheers,
Gerd
