commit 1b0b2e6d06c26185ecc820e868e025c894f979f7
author Stefan Hajnoczi <stefanha@redhat.com> Wed Mar 31 15:27:27 2021 +0100
committer Kevin Wolf <kwolf@redhat.com> Tue May 18 11:08:13 2021 +0200
tree b301894b1230a5217f05dac54b2775882ffd8fdb
parent e3fc91aaaacbdc2a88bbb4109c8a1cded628e36f

block/export: improve vu_blk_sect_range_ok()

The checks in vu_blk_sect_range_ok() assume VIRTIO_BLK_SECTOR_SIZE is
equal to BDRV_SECTOR_SIZE. This is true, but let's add a
QEMU_BUILD_BUG_ON() to make it explicit.

We might as well check that the request buffer size is a multiple of
VIRTIO_BLK_SECTOR_SIZE while we're at it.

Suggested-by: Max Reitz <mreitz@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Message-Id: <20210331142727.391465-1-stefanha@redhat.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Signed-off-by: Kevin Wolf <kwolf@redhat.com>

block/export/vhost-user-blk-server.c

diff --git a/block/export/vhost-user-blk-server.c b/block/export/vhost-user-blk-server.c
index fa06996..1862563 100644
--- a/block/export/vhost-user-blk-server.c
+++ b/block/export/vhost-user-blk-server.c
@@ -70,9 +70,16 @@
 static bool vu_blk_sect_range_ok(VuBlkExport *vexp, uint64_t sector,
                                  size_t size)
 {
-    uint64_t nb_sectors = size >> BDRV_SECTOR_BITS;
+    uint64_t nb_sectors;
     uint64_t total_sectors;
 
+    if (size % VIRTIO_BLK_SECTOR_SIZE) {
+        return false;
+    }
+
+    nb_sectors = size >> VIRTIO_BLK_SECTOR_BITS;
+
+    QEMU_BUILD_BUG_ON(BDRV_SECTOR_SIZE != VIRTIO_BLK_SECTOR_SIZE);
     if (nb_sectors > BDRV_REQUEST_MAX_SECTORS) {
         return false;
     }