25641fc705
Since hypervisor will not drain the TX bufring, once the channels are revoked: - Setup vmbus orphan handler properly. - Make sure that suspension will not wait the TX bufring draining forever. - GC the pending TX descs on detach path, before freeing the busdma stuffs. MFC after: 1 week Sponsored by: Microsoft Differential Revision: https://reviews.freebsd.org/D8559