1 files changed, 10 insertions, 0 deletions
diff --git a/include/exec/ramblock.h b/include/exec/ramblock.h
index 07d50864d8..664701b759 100644
--- a/include/exec/ramblock.h
+++ b/include/exec/ramblock.h
@@ -59,6 +59,16 @@ struct RAMBlock {
      */
     unsigned long *clear_bmap;
     uint8_t clear_bmap_shift;
+
+    /*
+     * RAM block length that corresponds to the used_length on the migration
+     * source (after RAM block sizes were synchronized). Especially, after
+     * starting to run the guest, used_length and postcopy_length can differ.
+     * Used to register/unregister uffd handlers and as the size of the received
+     * bitmap. Receiving any page beyond this length will bail out, as it
+     * could not have been valid on the source.
+     */
+    ram_addr_t postcopy_length;
 };
 #endif
 #endif