From: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>

Signed-off-by: Vladimir Sementsov-Ogievskiy <vsementsov@virtuozzo.com>
Reviewed-by: Eric Blake <eblake@redhat.com>
Tested-by: Kirill Tkhai <ktkhai@virtuozzo.com>
Reviewed-by: Hanna Reitz <hreitz@redhat.com>
Message-Id: <20210914122454.141075-10-vsementsov@virtuozzo.com>
Signed-off-by: Hanna Reitz <hreitz@redhat.com>
---
 block/qcow2.h          | 1 +
 block/qcow2-refcount.c | 6 ++++++
 2 files changed, 7 insertions(+)

diff --git a/block/qcow2.h b/block/qcow2.h
index b8b1093b61..58fd7f1678 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -586,6 +586,7 @@ typedef enum QCow2MetadataOverlap {
     (QCOW2_OL_CACHED | QCOW2_OL_INACTIVE_L2)
 
 #define L1E_OFFSET_MASK 0x00fffffffffffe00ULL
+#define L1E_RESERVED_MASK 0x7f000000000001ffULL
 #define L2E_OFFSET_MASK 0x00fffffffffffe00ULL
 #define L2E_STD_RESERVED_MASK 0x3f000000000001feULL
 
diff --git a/block/qcow2-refcount.c b/block/qcow2-refcount.c
index 3c89e09599..1c246b9227 100644
--- a/block/qcow2-refcount.c
+++ b/block/qcow2-refcount.c
@@ -1902,6 +1902,12 @@ static int check_refcounts_l1(BlockDriverState *bs,
             continue;
         }
 
+        if (l1_table[i] & L1E_RESERVED_MASK) {
+            fprintf(stderr, "ERROR found L1 entry with reserved bits set: "
+                    "%" PRIx64 "\n", l1_table[i]);
+            res->corruptions++;
+        }
+
         l2_offset = l1_table[i] & L1E_OFFSET_MASK;
 
         /* Mark L2 table as used */
-- 
2.31.1