According to Charles Duffy of Freenode's #qemu channel, -snapshot is simply incompatible with savevm.
Therefore it would be nice if this was clearer. For example, attempting to use savevm would say "error, savevm doesn't work with -snapshot." -- To UNSUBSCRIBE, email to debian-bugs-dist-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org