diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index dd7b88f2ec7a6f30bf4ec628fc7f59112cf4d65e..5525163a03985a517e7a043c3daa92fe04d4bb6e 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1033,6 +1033,13 @@ static void xen_machine_halt(void)
 	xen_reboot(SHUTDOWN_poweroff);
 }
 
+static void xen_machine_power_off(void)
+{
+	if (pm_power_off)
+		pm_power_off();
+	xen_reboot(SHUTDOWN_poweroff);
+}
+
 static void xen_crash_shutdown(struct pt_regs *regs)
 {
 	xen_reboot(SHUTDOWN_crash);
@@ -1058,7 +1065,7 @@ int xen_panic_handler_init(void)
 static const struct machine_ops xen_machine_ops __initconst = {
 	.restart = xen_restart,
 	.halt = xen_machine_halt,
-	.power_off = xen_machine_halt,
+	.power_off = xen_machine_power_off,
 	.shutdown = xen_machine_halt,
 	.crash_shutdown = xen_crash_shutdown,
 	.emergency_restart = xen_emergency_restart,
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index dc708dcc62f1e5106fefebd390bc24bb1cf97cf1..673e968df3cfd6c67a1b8a9dc3885fcaad15249f 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -59,6 +59,7 @@
 #include <asm/page.h>
 #include <asm/init.h>
 #include <asm/pat.h>
+#include <asm/smp.h>
 
 #include <asm/xen/hypercall.h>
 #include <asm/xen/hypervisor.h>
@@ -1231,7 +1232,7 @@ static void xen_flush_tlb_others(const struct cpumask *cpus,
 {
 	struct {
 		struct mmuext_op op;
-		DECLARE_BITMAP(mask, NR_CPUS);
+		DECLARE_BITMAP(mask, num_processors);
 	} *args;
 	struct multicall_space mcs;
 
@@ -1599,6 +1600,11 @@ static void __init xen_map_identity_early(pmd_t *pmd, unsigned long max_pfn)
 		for (pteidx = 0; pteidx < PTRS_PER_PTE; pteidx++, pfn++) {
 			pte_t pte;
 
+#ifdef CONFIG_X86_32
+			if (pfn > max_pfn_mapped)
+				max_pfn_mapped = pfn;
+#endif
+
 			if (!pte_none(pte_page[pteidx]))
 				continue;
 
@@ -1766,7 +1772,9 @@ pgd_t * __init xen_setup_kernel_pagetable(pgd_t *pgd,
 	initial_kernel_pmd =
 		extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
 
-	max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->mfn_list));
+	max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->pt_base) +
+				  xen_start_info->nr_pt_frames * PAGE_SIZE +
+				  512*1024);
 
 	kernel_pmd = m2v(pgd[KERNEL_PGD_BOUNDARY].pgd);
 	memcpy(initial_kernel_pmd, kernel_pmd, sizeof(pmd_t) * PTRS_PER_PMD);
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index be1a464f6d66eac7f6d24ae74894b321dc1cd4b5..60aeeb56948f753f87559f3e4ff8c1f8704d21a4 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -227,11 +227,7 @@ char * __init xen_memory_setup(void)
 
 	memcpy(map_raw, map, sizeof(map));
 	e820.nr_map = 0;
-#ifdef CONFIG_X86_32
 	xen_extra_mem_start = mem_end;
-#else
-	xen_extra_mem_start = max((1ULL << 32), mem_end);
-#endif
 	for (i = 0; i < memmap.nr_entries; i++) {
 		unsigned long long end;
 
@@ -266,6 +262,12 @@ char * __init xen_memory_setup(void)
 		if (map[i].size > 0)
 			e820_add_region(map[i].addr, map[i].size, map[i].type);
 	}
+	/* Align the balloon area so that max_low_pfn does not get set
+	 * to be at the _end_ of the PCI gap at the far end (fee01000).
+	 * Note that xen_extra_mem_start gets set in the loop above to be
+	 * past the last E820 region. */
+	if (xen_initial_domain() && (xen_extra_mem_start < (1ULL<<32)))
+		xen_extra_mem_start = (1ULL<<32);
 
 	/*
 	 * In domU, the ISA region is normal, usable memory, but we
diff --git a/arch/x86/xen/smp.c b/arch/x86/xen/smp.c
index 41038c01de403e48c71052ab615dcf7f647f2653..b4533a86d7e410668e24033cae32d8382bf4111d 100644
--- a/arch/x86/xen/smp.c
+++ b/arch/x86/xen/smp.c
@@ -205,11 +205,18 @@ static void __init xen_smp_prepare_boot_cpu(void)
 static void __init xen_smp_prepare_cpus(unsigned int max_cpus)
 {
 	unsigned cpu;
+	unsigned int i;
 
 	xen_init_lock_cpu(0);
 
 	smp_store_cpu_info(0);
 	cpu_data(0).x86_max_cores = 1;
+
+	for_each_possible_cpu(i) {
+		zalloc_cpumask_var(&per_cpu(cpu_sibling_map, i), GFP_KERNEL);
+		zalloc_cpumask_var(&per_cpu(cpu_core_map, i), GFP_KERNEL);
+		zalloc_cpumask_var(&per_cpu(cpu_llc_shared_map, i), GFP_KERNEL);
+	}
 	set_cpu_sibling_map(0);
 
 	if (xen_smp_intr_init(0))
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 553da68bd510c8ef0c7fecc2f5676778d6525954..30df85d8fca860d69a75079951feb9bb725944f1 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -395,9 +395,9 @@ static void unmask_evtchn(int port)
 static void xen_irq_init(unsigned irq)
 {
 	struct irq_info *info;
+#ifdef CONFIG_SMP
 	struct irq_desc *desc = irq_to_desc(irq);
 
-#ifdef CONFIG_SMP
 	/* By default all event channels notify CPU#0. */
 	cpumask_copy(desc->irq_data.affinity, cpumask_of(0));
 #endif