Index: xen-4.1.0-testing/xen/arch/x86/mm.c
===================================================================
--- xen-4.1.0-testing.orig/xen/arch/x86/mm.c
+++ xen-4.1.0-testing/xen/arch/x86/mm.c
@@ -160,6 +160,8 @@ static int get_superpage(unsigned long m
 #endif
 static void put_superpage(unsigned long mfn);
 
+bool_t __read_mostly mpt_valid;
+
 #define l1_disallow_mask(d)                                     \
     ((d != dom_io) &&                                           \
      (rangeset_is_empty((d)->iomem_caps) &&                     \
Index: xen-4.1.0-testing/xen/arch/x86/traps.c
===================================================================
--- xen-4.1.0-testing.orig/xen/arch/x86/traps.c
+++ xen-4.1.0-testing/xen/arch/x86/traps.c
@@ -1343,6 +1343,7 @@ asmlinkage void __init do_early_page_fau
         unsigned long *stk = (unsigned long *)regs;
         printk("Early fatal page fault at %04x:%p (cr2=%p, ec=%04x)\n", 
                regs->cs, _p(regs->eip), _p(cr2), regs->error_code);
+        show_page_walk(cr2);
         printk("Stack dump: ");
         while ( ((long)stk & ((PAGE_SIZE - 1) & ~(BYTES_PER_LONG - 1))) != 0 )
             printk("%p ", _p(*stk++));
Index: xen-4.1.0-testing/xen/arch/x86/x86_32/mm.c
===================================================================
--- xen-4.1.0-testing.orig/xen/arch/x86/x86_32/mm.c
+++ xen-4.1.0-testing/xen/arch/x86/x86_32/mm.c
@@ -123,6 +123,8 @@ void __init paging_init(void)
 #undef CNT
 #undef MFN
 
+    mpt_valid = 1;
+
     /* Create page tables for ioremap()/map_domain_page_global(). */
     for ( i = 0; i < (IOREMAP_MBYTES >> (L2_PAGETABLE_SHIFT - 20)); i++ )
     {
Index: xen-4.1.0-testing/xen/arch/x86/x86_32/traps.c
===================================================================
--- xen-4.1.0-testing.orig/xen/arch/x86/x86_32/traps.c
+++ xen-4.1.0-testing/xen/arch/x86/x86_32/traps.c
@@ -164,7 +164,8 @@ void show_page_walk(unsigned long addr)
     l3t += (cr3 & 0xFE0UL) >> 3;
     l3e = l3t[l3_table_offset(addr)];
     mfn = l3e_get_pfn(l3e);
-    pfn = mfn_valid(mfn) ? get_gpfn_from_mfn(mfn) : INVALID_M2P_ENTRY;
+    pfn = mfn_valid(mfn) && mpt_valid ?
+          get_gpfn_from_mfn(mfn) : INVALID_M2P_ENTRY;
     printk(" L3[0x%03lx] = %"PRIpte" %08lx\n",
            l3_table_offset(addr), l3e_get_intpte(l3e), pfn);
     unmap_domain_page(l3t);
@@ -175,7 +176,8 @@ void show_page_walk(unsigned long addr)
     l2t = map_domain_page(mfn);
     l2e = l2t[l2_table_offset(addr)];
     mfn = l2e_get_pfn(l2e);
-    pfn = mfn_valid(mfn) ? get_gpfn_from_mfn(mfn) : INVALID_M2P_ENTRY;
+    pfn = mfn_valid(mfn) && mpt_valid ?
+          get_gpfn_from_mfn(mfn) : INVALID_M2P_ENTRY;
     printk(" L2[0x%03lx] = %"PRIpte" %08lx %s\n",
            l2_table_offset(addr), l2e_get_intpte(l2e), pfn,
            (l2e_get_flags(l2e) & _PAGE_PSE) ? "(PSE)" : "");
@@ -188,7 +190,8 @@ void show_page_walk(unsigned long addr)
     l1t = map_domain_page(mfn);
     l1e = l1t[l1_table_offset(addr)];
     mfn = l1e_get_pfn(l1e);
-    pfn = mfn_valid(mfn) ? get_gpfn_from_mfn(mfn) : INVALID_M2P_ENTRY;
+    pfn = mfn_valid(mfn) && mpt_valid ?
+          get_gpfn_from_mfn(mfn) : INVALID_M2P_ENTRY;
     printk(" L1[0x%03lx] = %"PRIpte" %08lx\n",
            l1_table_offset(addr), l1e_get_intpte(l1e), pfn);
     unmap_domain_page(l1t);
Index: xen-4.1.0-testing/xen/arch/x86/x86_64/mm.c
===================================================================
--- xen-4.1.0-testing.orig/xen/arch/x86/x86_64/mm.c
+++ xen-4.1.0-testing/xen/arch/x86/x86_64/mm.c
@@ -749,6 +749,8 @@ void __init paging_init(void)
 #undef CNT
 #undef MFN
 
+    mpt_valid = 1;
+
     /* Create user-accessible L2 directory to map the MPT for compat guests. */
     BUILD_BUG_ON(l4_table_offset(RDWR_MPT_VIRT_START) !=
                  l4_table_offset(HIRO_COMPAT_MPT_VIRT_START));
Index: xen-4.1.0-testing/xen/arch/x86/x86_64/traps.c
===================================================================
--- xen-4.1.0-testing.orig/xen/arch/x86/x86_64/traps.c
+++ xen-4.1.0-testing/xen/arch/x86/x86_64/traps.c
@@ -176,7 +176,8 @@ void show_page_walk(unsigned long addr)
     l4t = mfn_to_virt(mfn);
     l4e = l4t[l4_table_offset(addr)];
     mfn = l4e_get_pfn(l4e);
-    pfn = mfn_valid(mfn) ? get_gpfn_from_mfn(mfn) : INVALID_M2P_ENTRY;
+    pfn = mfn_valid(mfn) && mpt_valid ?
+          get_gpfn_from_mfn(mfn) : INVALID_M2P_ENTRY;
     printk(" L4[0x%03lx] = %"PRIpte" %016lx\n",
            l4_table_offset(addr), l4e_get_intpte(l4e), pfn);
     if ( !(l4e_get_flags(l4e) & _PAGE_PRESENT) ||
@@ -186,7 +187,8 @@ void show_page_walk(unsigned long addr)
     l3t = mfn_to_virt(mfn);
     l3e = l3t[l3_table_offset(addr)];
     mfn = l3e_get_pfn(l3e);
-    pfn = mfn_valid(mfn) ? get_gpfn_from_mfn(mfn) : INVALID_M2P_ENTRY;
+    pfn = mfn_valid(mfn) && mpt_valid ?
+          get_gpfn_from_mfn(mfn) : INVALID_M2P_ENTRY;
     printk(" L3[0x%03lx] = %"PRIpte" %016lx%s\n",
            l3_table_offset(addr), l3e_get_intpte(l3e), pfn,
            (l3e_get_flags(l3e) & _PAGE_PSE) ? " (PSE)" : "");
@@ -198,7 +200,8 @@ void show_page_walk(unsigned long addr)
     l2t = mfn_to_virt(mfn);
     l2e = l2t[l2_table_offset(addr)];
     mfn = l2e_get_pfn(l2e);
-    pfn = mfn_valid(mfn) ? get_gpfn_from_mfn(mfn) : INVALID_M2P_ENTRY;
+    pfn = mfn_valid(mfn) && mpt_valid ?
+          get_gpfn_from_mfn(mfn) : INVALID_M2P_ENTRY;
     printk(" L2[0x%03lx] = %"PRIpte" %016lx %s\n",
            l2_table_offset(addr), l2e_get_intpte(l2e), pfn,
            (l2e_get_flags(l2e) & _PAGE_PSE) ? "(PSE)" : "");
@@ -210,7 +213,8 @@ void show_page_walk(unsigned long addr)
     l1t = mfn_to_virt(mfn);
     l1e = l1t[l1_table_offset(addr)];
     mfn = l1e_get_pfn(l1e);
-    pfn = mfn_valid(mfn) ? get_gpfn_from_mfn(mfn) : INVALID_M2P_ENTRY;
+    pfn = mfn_valid(mfn) && mpt_valid ?
+          get_gpfn_from_mfn(mfn) : INVALID_M2P_ENTRY;
     printk(" L1[0x%03lx] = %"PRIpte" %016lx\n",
            l1_table_offset(addr), l1e_get_intpte(l1e), pfn);
 }
Index: xen-4.1.0-testing/xen/include/asm-x86/mm.h
===================================================================
--- xen-4.1.0-testing.orig/xen/include/asm-x86/mm.h
+++ xen-4.1.0-testing/xen/include/asm-x86/mm.h
@@ -467,6 +467,8 @@ TYPE_SAFE(unsigned long,mfn);
 #define SHARED_M2P_ENTRY         (~0UL - 1UL)
 #define SHARED_M2P(_e)           ((_e) == SHARED_M2P_ENTRY)
 
+extern bool_t mpt_valid;
+
 #ifdef CONFIG_COMPAT
 #define compat_machine_to_phys_mapping ((unsigned int *)RDWR_COMPAT_MPT_VIRT_START)
 #define set_gpfn_from_mfn(mfn, pfn) ({                         \