Index: xen-3.0.4-testing/tools/python/xen/xend/XendDomainInfo.py
===================================================================
--- xen-3.0.4-testing.orig/tools/python/xen/xend/XendDomainInfo.py
+++ xen-3.0.4-testing/tools/python/xen/xend/XendDomainInfo.py
@@ -1431,7 +1431,7 @@ class XendDomainInfo:
             xc.domain_setmaxmem(self.domid, maxmem)
 
             # Make sure there's enough RAM available for the domain
-            balloon.free(memory + shadow)
+            balloon.free(memory + shadow + 512)
 
             # Set up the shadow memory
             shadow_cur = xc.shadow_mem_control(self.domid, shadow / 1024)