Index: /trunk/src/VBox/VMM/PGMSharedPage.cpp
===================================================================
--- /trunk/src/VBox/VMM/PGMSharedPage.cpp	(revision 30247)
+++ /trunk/src/VBox/VMM/PGMSharedPage.cpp	(revision 30248)
@@ -140,5 +140,8 @@
     /* Execute on the VCPU that issued the original request to make sure we're in the right cr3 context. */
     if (pVCpu->idCpu != idCpu)
+    {
+        Assert(pVM->cCpus > 1);
         return VINF_SUCCESS;
+    }
 
     /* Flush all pending handy page operations before changing any shared page assignments. */