[libvirt] a problem about the progress's display of migration with non-shared storage

Hi all, I found a problem about the progress's display of migration with non-shared storage. In the commit: 7b7600b3e6734117b3db39ba5c31ae33a40fb5bb (qemu_migration: Introduce qemuMigrationDriveMirror), it use drive mirror instead of block migration. And after the driver mirror, then process the VM migration(no block). But only in the VM migration stage, libvirt set the progress of migration(in qemuMigrationWaitForCompletion). In the drive mirror stage, libvirt is waiting the completion of drive mirror, and don't set the progress of migration. So, the libvirt can't display the progress of migration in the drive mirror stage. For users, they are not concerned about the implementation details of the two stages. They think the two stages are both migration. So, I think libvirt need consider the progress of drive mirror for migration. But I don't have a good solution. Any idea about this problem? Thanks for advance Regards