1 files changed, 7 insertions, 4 deletions

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index b8e279479a6b..3506cd4f9a43 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -353,8 +353,13 @@ static pteval_t pte_mfn_to_pfn(pteval_t val)
 {
         if (val & _PAGE_PRESENT) {
                 unsigned long mfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT;
+                unsigned long pfn = mfn_to_pfn(mfn);
+
                 pteval_t flags = val & PTE_FLAGS_MASK;
-                val = ((pteval_t)mfn_to_pfn(mfn) << PAGE_SHIFT) | flags;
+                if (unlikely(pfn == ~0))
+                        val = flags & ~_PAGE_PRESENT;
+                else
+                        val = ((pteval_t)pfn << PAGE_SHIFT) | flags;
         }
 
         return val;
@@ -1859,7 +1864,6 @@ pgd_t * __init xen_setup_kernel_pagetable(pgd_t *pgd,
 #endif  /* CONFIG_X86_64 */
 
 static unsigned char dummy_mapping[PAGE_SIZE] __page_aligned_bss;
-static unsigned char fake_ioapic_mapping[PAGE_SIZE] __page_aligned_bss;
 
 static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
 {
@@ -1900,7 +1904,7 @@ static void xen_set_fixmap(unsigned idx, phys_addr_t phys, pgprot_t prot)
                  * We just don't map the IO APIC - all access is via
                  * hypercalls.  Keep the address in the pte for reference.
                  */
-                pte = pfn_pte(PFN_DOWN(__pa(fake_ioapic_mapping)), PAGE_KERNEL);
+                pte = pfn_pte(PFN_DOWN(__pa(dummy_mapping)), PAGE_KERNEL);
                 break;
 #endif
 
@@ -2065,7 +2069,6 @@ void __init xen_init_mmu_ops(void)
         pv_mmu_ops = xen_mmu_ops;
 
         memset(dummy_mapping, 0xff, PAGE_SIZE);
-        memset(fake_ioapic_mapping, 0xfd, PAGE_SIZE);
 }
 
 /* Protected by xen_reservation_lock. */