diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index c237b810b03f..21ed8d7f75a5 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -2126,7 +2126,7 @@ __init pgd_t *xen_setup_kernel_pagetable(pgd_t *pgd,
 {
 	pmd_t *kernel_pmd;
 
-	level2_kernel_pgt = extend_brk(sizeof(pmd_t *) * PTRS_PER_PMD, PAGE_SIZE);
+	level2_kernel_pgt = extend_brk(sizeof(pmd_t) * PTRS_PER_PMD, PAGE_SIZE);
 
 	max_pfn_mapped = PFN_DOWN(__pa(xen_start_info->pt_base) +
 				  xen_start_info->nr_pt_frames * PAGE_SIZE +
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index b1dbdaa23ecc..769c4b01fa32 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -118,16 +118,18 @@ static unsigned long __init xen_return_unused_memory(unsigned long max_pfn,
 						     const struct e820map *e820)
 {
 	phys_addr_t max_addr = PFN_PHYS(max_pfn);
-	phys_addr_t last_end = 0;
+	phys_addr_t last_end = ISA_END_ADDRESS;
 	unsigned long released = 0;
 	int i;
 
+	/* Free any unused memory above the low 1Mbyte. */
 	for (i = 0; i < e820->nr_map && last_end < max_addr; i++) {
 		phys_addr_t end = e820->map[i].addr;
 		end = min(max_addr, end);
 
-		released += xen_release_chunk(last_end, end);
-		last_end = e820->map[i].addr + e820->map[i].size;
+		if (last_end < end)
+			released += xen_release_chunk(last_end, end);
+		last_end = max(last_end, e820->map[i].addr + e820->map[i].size);
 	}
 
 	if (last_end < max_addr)
@@ -164,6 +166,7 @@ char * __init xen_memory_setup(void)
 		XENMEM_memory_map;
 	rc = HYPERVISOR_memory_op(op, &memmap);
 	if (rc == -ENOSYS) {
+		BUG_ON(xen_initial_domain());
 		memmap.nr_entries = 1;
 		map[0].addr = 0ULL;
 		map[0].size = mem_end;
@@ -201,12 +204,13 @@ char * __init xen_memory_setup(void)
 	}
 
 	/*
-	 * Even though this is normal, usable memory under Xen, reserve
-	 * ISA memory anyway because too many things think they can poke
+	 * In domU, the ISA region is normal, usable memory, but we
+	 * reserve ISA memory anyway because too many things poke
 	 * about in there.
 	 *
-	 * In a dom0 kernel, this region is identity mapped with the
-	 * hardware ISA area, so it really is out of bounds.
+	 * In Dom0, the host E820 information can leave gaps in the
+	 * ISA range, which would cause us to release those pages.  To
+	 * avoid this, we unconditionally reserve them here.
 	 */
 	e820_add_region(ISA_START_ADDRESS, ISA_END_ADDRESS - ISA_START_ADDRESS,
 			E820_RESERVED);
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 97612f548a8e..321a0c8346e5 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -1299,9 +1299,6 @@ static void restore_cpu_virqs(unsigned int cpu)
 		evtchn_to_irq[evtchn] = irq;
 		irq_info[irq] = mk_virq_info(evtchn, virq);
 		bind_evtchn_to_cpu(evtchn, cpu);
-
-		/* Ready for use. */
-		unmask_evtchn(evtchn);
 	}
 }
 
@@ -1327,10 +1324,6 @@ static void restore_cpu_ipis(unsigned int cpu)
 		evtchn_to_irq[evtchn] = irq;
 		irq_info[irq] = mk_ipi_info(evtchn, ipi);
 		bind_evtchn_to_cpu(evtchn, cpu);
-
-		/* Ready for use. */
-		unmask_evtchn(evtchn);
-
 	}
 }
 
@@ -1390,6 +1383,7 @@ void xen_poll_irq(int irq)
 void xen_irq_resume(void)
 {
 	unsigned int cpu, irq, evtchn;
+	struct irq_desc *desc;
 
 	init_evtchn_cpu_bindings();
 
@@ -1408,6 +1402,23 @@ void xen_irq_resume(void)
 		restore_cpu_virqs(cpu);
 		restore_cpu_ipis(cpu);
 	}
+
+	/*
+	 * Unmask any IRQF_NO_SUSPEND IRQs which are enabled. These
+	 * are not handled by the IRQ core.
+	 */
+	for_each_irq_desc(irq, desc) {
+		if (!desc->action || !(desc->action->flags & IRQF_NO_SUSPEND))
+			continue;
+		if (desc->status & IRQ_DISABLED)
+			continue;
+
+		evtchn = evtchn_from_irq(irq);
+		if (evtchn == -1)
+			continue;
+
+		unmask_evtchn(evtchn);
+	}
 }
 
 static struct irq_chip xen_dynamic_chip __read_mostly = {