virtio-blk: use BDRV_REQ_REGISTERED_BUF optimization hint
Register guest RAM using BlockRAMRegistrar and set the
BDRV_REQ_REGISTERED_BUF flag so block drivers can optimize memory
accesses in I/O requests.
This is for vdpa-blk, vhost-user-blk, and other I/O interfaces that rely
on DMA mapping/unmapping.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Reviewed-by: Stefano Garzarella <sgarzare@redhat.com>
Message-id:
20221013185908.
1297568-14-stefanha@redhat.com
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>