What would be really cool about this change is that we could introduce a
new set of commands to manipulate device state. We could save/restore
individual device state and that would allow us to dump device state via
the monitor and to manipulate individual fields of the device state. I
think this could be pretty useful for debugging.
I'd be reluctant to expose the savevm state to the user.
For debugging qemu I don't see it providing any real benefit over firing up
GDB and poking directly at the device directly.
For debugging the guest there is some argument for exposing the device state
(preferably via the gdb stub). However I think the savevm data tends to expose
too many internal implementation details,