diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 7d46c84414188bf401777e4d65a9652e5cc09fa5..63b83ceebd1a0984403af50aaefe29331d5f3132 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -30,6 +30,7 @@
 #include <linux/console.h>
 #include <linux/pci.h>
 #include <linux/gfp.h>
+#include <linux/memblock.h>
 
 #include <xen/xen.h>
 #include <xen/interface/xen.h>
@@ -1183,6 +1184,8 @@ asmlinkage void __init xen_start_kernel(void)
 	local_irq_disable();
 	early_boot_irqs_off();
 
+	memblock_init();
+
 	xen_raw_console_write("mapping kernel into physical memory\n");
 	pgd = xen_setup_kernel_pagetable(pgd, xen_start_info->nr_pages);
 
diff --git a/mm/memblock.c b/mm/memblock.c
index 9ad39690a2bdf20311230463576ff90c47d3a25e..ae8b06c828c7fdeac2548ea4d85ecf94b52f257c 100644
--- a/mm/memblock.c
+++ b/mm/memblock.c
@@ -752,6 +752,12 @@ void __init memblock_analyze(void)
 
 void __init memblock_init(void)
 {
+	static int init_done __initdata = 0;
+
+	if (init_done)
+		return;
+	init_done = 1;
+
 	/* Hookup the initial arrays */
 	memblock.memory.regions	= memblock_memory_init_regions;
 	memblock.memory.max		= INIT_MEMBLOCK_REGIONS;