Return an Error so that it can be propagated later.
Tested-by: NStefan Hajnoczi <stefanha@redhat.com>
Acked-by: NStefan Hajnoczi <stefanha@redhat.com>
[AF: Rebased]
Signed-off-by: NAndreas Färber <afaerber@suse.de>
Signed-off-by: NPaolo Bonzini <pbonzini@redhat.com>