1 files changed, 44 insertions, 7 deletions

diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 056d11faef21..09f3059cb00b 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -33,6 +33,9 @@
 /* These are code, but not functions.  Defined in entry.S */
 extern const char xen_hypervisor_callback[];
 extern const char xen_failsafe_callback[];
+#ifdef CONFIG_X86_64
+extern const char nmi[];
+#endif
 extern void xen_sysenter_target(void);
 extern void xen_syscall_target(void);
 extern void xen_syscall32_target(void);
@@ -215,13 +218,19 @@ static void __init xen_set_identity_and_release_chunk(
         unsigned long pfn;
 
         /*
-         * If the PFNs are currently mapped, the VA mapping also needs
-         * to be updated to be 1:1.
+         * If the PFNs are currently mapped, clear the mappings
+         * (except for the ISA region which must be 1:1 mapped) to
+         * release the refcounts (in Xen) on the original frames.
          */
-        for (pfn = start_pfn; pfn <= max_pfn_mapped && pfn < end_pfn; pfn++)
+        for (pfn = start_pfn; pfn <= max_pfn_mapped && pfn < end_pfn; pfn++) {
+                pte_t pte = __pte_ma(0);
+
+                if (pfn < PFN_UP(ISA_END_ADDRESS))
+                        pte = mfn_pte(pfn, PAGE_KERNEL_IO);
+
                 (void)HYPERVISOR_update_va_mapping(
-                        (unsigned long)__va(pfn << PAGE_SHIFT),
-                        mfn_pte(pfn, PAGE_KERNEL_IO), 0);
+                        (unsigned long)__va(pfn << PAGE_SHIFT), pte, 0);
+        }
 
         if (start_pfn < nr_pages)
                 *released += xen_release_chunk(
@@ -313,6 +322,17 @@ static void xen_align_and_add_e820_region(u64 start, u64 size, int type)
         e820_add_region(start, end - start, type);
 }
 
+void xen_ignore_unusable(struct e820entry *list, size_t map_size)
+{
+        struct e820entry *entry;
+        unsigned int i;
+
+        for (i = 0, entry = list; i < map_size; i++, entry++) {
+                if (entry->type == E820_UNUSABLE)
+                        entry->type = E820_RAM;
+        }
+}
+
 /**
  * machine_specific_memory_setup - Hook for machine specific memory setup.
  **/
@@ -353,6 +373,17 @@ char * __init xen_memory_setup(void)
         }
         BUG_ON(rc);
 
+        /*
+         * Xen won't allow a 1:1 mapping to be created to UNUSABLE
+         * regions, so if we're using the machine memory map leave the
+         * region as RAM as it is in the pseudo-physical map.
+         *
+         * UNUSABLE regions in domUs are not handled and will need
+         * a patch in the future.
+         */
+        if (xen_initial_domain())
+                xen_ignore_unusable(map, memmap.nr_entries);
+
         /* Make sure the Xen-supplied memory map is well-ordered. */
         sanitize_e820_map(map, memmap.nr_entries, &memmap.nr_entries);
 
@@ -525,7 +556,13 @@ void xen_enable_syscall(void)
         }
 #endif /* CONFIG_X86_64 */
 }
-
+void __cpuinit xen_enable_nmi(void)
+{
+#ifdef CONFIG_X86_64
+        if (register_callback(CALLBACKTYPE_nmi, nmi))
+                BUG();
+#endif
+}
 void __init xen_arch_setup(void)
 {
         xen_panic_handler_init();
@@ -543,7 +580,7 @@ void __init xen_arch_setup(void)
 
         xen_enable_sysenter();
         xen_enable_syscall();
-
+        xen_enable_nmi();
 #ifdef CONFIG_ACPI
         if (!(xen_start_info->flags & SIF_INITDOMAIN)) {
                 printk(KERN_INFO "ACPI in unprivileged domain disabled\n");