[Qemu-devel] migrating instances from qemu-kvm to qemu

[Serge E. Hallyn]

Hi,

at https://bugs.launchpad.net/ubuntu/+source/libvirt/+bug/1291321
it was found that migrating running vms from a machine with
qemu-kvm to one with qemu, migration fails due to some mismatches.
The first one we usually hit is

Length mismatch: vga.vram: 1000000 in != 800000

while the second one is network card (and I have not gone beyond
that).  The vga one can be handled on the command line by
specifying the -global cirrus-vga.vrammem_mb=8.  However that
doesn't help with a libvirt migration.

I guess this happens at ram_load() unfortunately - is there any
good way that this could be detected at incoming migration time
and the virtual hardware modified as needed for migration to
continue?

thanks,
-serge