block: add default get_block_status implementation for protocols

Protocols return raw data, so you can assume the offsets to pass
through unchanged.

Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

1 files changed, 5 insertions, 1 deletions

diff --git a/block.c b/block.c
index 82bbd6c933..3c39769c68 100644
--- a/block.c
+++ b/block.c
@@ -3094,7 +3094,11 @@ static int64_t coroutine_fn bdrv_co_get_block_status(BlockDriverState *bs,
 
     if (!bs->drv->bdrv_co_get_block_status) {
         *pnum = nb_sectors;
-        return BDRV_BLOCK_DATA;
+        ret = BDRV_BLOCK_DATA;
+        if (bs->drv->protocol_name) {
+            ret |= BDRV_BLOCK_OFFSET_VALID | (sector_num * BDRV_SECTOR_SIZE);
+        }
+        return ret;
     }
 
     ret = bs->drv->bdrv_co_get_block_status(bs, sector_num, nb_sectors, pnum);