On Wed, Dec 02, 2015 at 11:11:28AM +0100, Cornelia Huck wrote: > On Wed, 2 Dec 2015 13:54:09 +0800 > Jason Wang <jasow...@redhat.com> wrote: > > > I wonder instead of rolling back in post_plugged(), maybe we could just > > delay the region setups to post_plugged(). > > If this is the saner thing to do for pci, sure. > > > Or just call transport > > specific device_plugged() after get_features() call in > > virtio_bus_device_plugged(). > > The problem is that the VERSION_1 bit is only added in the > ->device_plugged() callbacks by the transport, so ->get_features() can > only be called after that. We have a dependency in both directions :( > > > And I'm not sure we need to handle > > migration compatibility in this case. > > The thing we would need to care about is basically the host kernel on > the target supporting less than the host kernel on the source.
This is a fundamental problem, we have it with other features like transport offloads. We don't have a solution for this now. kvm has the same issue. > Do we > care about that in other contexts right now?
