Paolo Bonzini writes: > On 03/25/2011 07:27 AM, Jason Wang wrote: > > We need to keep DIR register unchanged across migration, but currently it > > depends on the media_changed flags from block layer and we do not > > save/restore > > it which could let the guest driver think the floppy have changed after > > migration. To fix this, a new filed media_changed in FDrive strcutre was > > introduced in order to save and restore the it from block layer through > > pre_save/post_load callbacks. > > I guess you can avoid saving if the media changed flag is zero, too > (which should be the common case after the guest has booted, right?). > > Paolo >
Yes, zero is the common case, but the bdrv_open() called by listening qemu in dest mode would always set the media_changed to one, so we must save and restore it during migration.
