diff --git a/block/qcow2.c b/block/qcow2.c
index 318d95d972ef..4a9888cc7f91 100644
--- a/block/qcow2.c
+++ b/block/qcow2.c
@@ -52,7 +52,7 @@
 typedef struct {
     uint32_t magic;
     uint32_t len;
-} QCowExtension;
+} QEMU_PACKED QCowExtension;
 
 #define  QCOW2_EXT_MAGIC_END 0
 #define  QCOW2_EXT_MAGIC_BACKING_FORMAT 0xE2792ACA
diff --git a/block/qcow2.h b/block/qcow2.h
index c90e5d6c6e6c..455e38de64f1 100644
--- a/block/qcow2.h
+++ b/block/qcow2.h
@@ -86,7 +86,7 @@ typedef struct QCowHeader {
 
     uint32_t refcount_order;
     uint32_t header_length;
-} QCowHeader;
+} QEMU_PACKED QCowHeader;
 
 typedef struct QCowSnapshot {
     uint64_t l1_table_offset;