diff --git a/xen/arch/x86/numa.c b/xen/arch/x86/numa.c
index f1066c59c7..ce79ee44ce 100644
--- a/xen/arch/x86/numa.c
+++ b/xen/arch/x86/numa.c
@@ -270,6 +270,10 @@ void __init numa_initmem_init(unsigned long start_pfn, unsigned long end_pfn)
     /* setup dummy node covering all memory */
     memnode_shift = BITS_PER_LONG - 1;
     memnodemap = _memnodemap;
+    /* Dummy node only uses 1 slot in reality */
+    memnodemap[0] = 0;
+    memnodemapsize = 1;
+
     nodes_clear(node_online_map);
     node_set_online(0);
     for ( i = 0; i < nr_cpu_ids; i++ )