diff --git a/src/mem/packet.hh b/src/mem/packet.hh
index c588622702..e7a5335a89 100644
--- a/src/mem/packet.hh
+++ b/src/mem/packet.hh
@@ -590,6 +590,15 @@ class Packet : public FastAlloc, public Printable
         setDest(Broadcast);
     }
 
+    void
+    setSize(unsigned size)
+    {
+        assert(!flags.isSet(VALID_SIZE));
+
+        this->size = size;
+        flags.set(VALID_SIZE);
+    }
+
 
     /**
      * Set the data pointer to the following value that should not be