diff --git a/arch/x86/pci/xen.c b/arch/x86/pci/xen.c
index 4bd08b0fc8ea..99ddab79215e 100644
--- a/arch/x86/pci/xen.c
+++ b/arch/x86/pci/xen.c
@@ -491,8 +491,11 @@ int __init pci_xen_initial_domain(void)
 #endif
 	__acpi_register_gsi = acpi_register_gsi_xen;
 	__acpi_unregister_gsi = NULL;
-	/* Pre-allocate legacy irqs */
-	for (irq = 0; irq < nr_legacy_irqs(); irq++) {
+	/*
+	 * Pre-allocate the legacy IRQs.  Use NR_LEGACY_IRQS here
+	 * because we don't have a PIC and thus nr_legacy_irqs() is zero.
+	 */
+	for (irq = 0; irq < NR_IRQS_LEGACY; irq++) {
 		int trigger, polarity;
 
 		if (acpi_get_override_irq(irq, &trigger, &polarity) == -1)
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 7ab29518a3b9..e345891450c3 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -393,6 +393,9 @@ static unsigned long __init xen_set_identity_and_remap_chunk(
 	unsigned long i = 0;
 	unsigned long n = end_pfn - start_pfn;
 
+	if (remap_pfn == 0)
+		remap_pfn = nr_pages;
+
 	while (i < n) {
 		unsigned long cur_pfn = start_pfn + i;
 		unsigned long left = n - i;
@@ -438,17 +441,29 @@ static unsigned long __init xen_set_identity_and_remap_chunk(
 	return remap_pfn;
 }
 
-static void __init xen_set_identity_and_remap(unsigned long nr_pages)
+static unsigned long __init xen_count_remap_pages(
+	unsigned long start_pfn, unsigned long end_pfn, unsigned long nr_pages,
+	unsigned long remap_pages)
+{
+	if (start_pfn >= nr_pages)
+		return remap_pages;
+
+	return remap_pages + min(end_pfn, nr_pages) - start_pfn;
+}
+
+static unsigned long __init xen_foreach_remap_area(unsigned long nr_pages,
+	unsigned long (*func)(unsigned long start_pfn, unsigned long end_pfn,
+			      unsigned long nr_pages, unsigned long last_val))
 {
 	phys_addr_t start = 0;
-	unsigned long last_pfn = nr_pages;
+	unsigned long ret_val = 0;
 	const struct e820entry *entry = xen_e820_map;
 	int i;
 
 	/*
 	 * Combine non-RAM regions and gaps until a RAM region (or the
-	 * end of the map) is reached, then set the 1:1 map and
-	 * remap the memory in those non-RAM regions.
+	 * end of the map) is reached, then call the provided function
+	 * to perform its duty on the non-RAM region.
 	 *
 	 * The combined non-RAM regions are rounded to a whole number
 	 * of pages so any partial pages are accessible via the 1:1
@@ -466,14 +481,13 @@ static void __init xen_set_identity_and_remap(unsigned long nr_pages)
 				end_pfn = PFN_UP(entry->addr);
 
 			if (start_pfn < end_pfn)
-				last_pfn = xen_set_identity_and_remap_chunk(
-						start_pfn, end_pfn, nr_pages,
-						last_pfn);
+				ret_val = func(start_pfn, end_pfn, nr_pages,
+					       ret_val);
 			start = end;
 		}
 	}
 
-	pr_info("Released %ld page(s)\n", xen_released_pages);
+	return ret_val;
 }
 
 /*
@@ -596,35 +610,6 @@ static void __init xen_ignore_unusable(void)
 	}
 }
 
-static unsigned long __init xen_count_remap_pages(unsigned long max_pfn)
-{
-	unsigned long extra = 0;
-	unsigned long start_pfn, end_pfn;
-	const struct e820entry *entry = xen_e820_map;
-	int i;
-
-	end_pfn = 0;
-	for (i = 0; i < xen_e820_map_entries; i++, entry++) {
-		start_pfn = PFN_DOWN(entry->addr);
-		/* Adjacent regions on non-page boundaries handling! */
-		end_pfn = min(end_pfn, start_pfn);
-
-		if (start_pfn >= max_pfn)
-			return extra + max_pfn - end_pfn;
-
-		/* Add any holes in map to result. */
-		extra += start_pfn - end_pfn;
-
-		end_pfn = PFN_UP(entry->addr + entry->size);
-		end_pfn = min(end_pfn, max_pfn);
-
-		if (entry->type != E820_RAM)
-			extra += end_pfn - start_pfn;
-	}
-
-	return extra;
-}
-
 bool __init xen_is_e820_reserved(phys_addr_t start, phys_addr_t size)
 {
 	struct e820entry *entry;
@@ -804,7 +789,7 @@ char * __init xen_memory_setup(void)
 	max_pages = xen_get_max_pages();
 
 	/* How many extra pages do we need due to remapping? */
-	max_pages += xen_count_remap_pages(max_pfn);
+	max_pages += xen_foreach_remap_area(max_pfn, xen_count_remap_pages);
 
 	if (max_pages > max_pfn)
 		extra_pages += max_pages - max_pfn;
@@ -922,7 +907,9 @@ char * __init xen_memory_setup(void)
 	 * Set identity map on non-RAM pages and prepare remapping the
 	 * underlying RAM.
 	 */
-	xen_set_identity_and_remap(max_pfn);
+	xen_foreach_remap_area(max_pfn, xen_set_identity_and_remap_chunk);
+
+	pr_info("Released %ld page(s)\n", xen_released_pages);
 
 	return "Xen";
 }
diff --git a/arch/x86/xen/time.c b/arch/x86/xen/time.c
index a0a4e554c6f1..6deba5bc7e34 100644
--- a/arch/x86/xen/time.c
+++ b/arch/x86/xen/time.c
@@ -290,11 +290,11 @@ static int xen_vcpuop_set_next_event(unsigned long delta,
 	WARN_ON(!clockevent_state_oneshot(evt));
 
 	single.timeout_abs_ns = get_abs_timeout(delta);
-	single.flags = VCPU_SSHOTTMR_future;
+	/* Get an event anyway, even if the timeout is already expired */
+	single.flags = 0;
 
 	ret = HYPERVISOR_vcpu_op(VCPUOP_set_singleshot_timer, cpu, &single);
-
-	BUG_ON(ret != 0 && ret != -ETIME);
+	BUG_ON(ret != 0);
 
 	return ret;
 }
diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
index 9b7a35c9e51d..030e91b38e32 100644
--- a/drivers/xen/Makefile
+++ b/drivers/xen/Makefile
@@ -8,6 +8,7 @@ nostackp := $(call cc-option, -fno-stack-protector)
 CFLAGS_features.o			:= $(nostackp)
 
 CFLAGS_efi.o				+= -fshort-wchar
+LDFLAGS					+= $(call ld-option, --no-wchar-size-warning)
 
 dom0-$(CONFIG_PCI) += pci.o
 dom0-$(CONFIG_USB_SUPPORT) += dbgp.o
diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index cb7138c97c69..71d49a95f8c0 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -487,7 +487,8 @@ static void eoi_pirq(struct irq_data *data)
 	if (!VALID_EVTCHN(evtchn))
 		return;
 
-	if (unlikely(irqd_is_setaffinity_pending(data))) {
+	if (unlikely(irqd_is_setaffinity_pending(data)) &&
+	    likely(!irqd_irq_disabled(data))) {
 		int masked = test_and_set_mask(evtchn);
 
 		clear_evtchn(evtchn);
@@ -1370,7 +1371,8 @@ static void ack_dynirq(struct irq_data *data)
 	if (!VALID_EVTCHN(evtchn))
 		return;
 
-	if (unlikely(irqd_is_setaffinity_pending(data))) {
+	if (unlikely(irqd_is_setaffinity_pending(data)) &&
+	    likely(!irqd_irq_disabled(data))) {
 		int masked = test_and_set_mask(evtchn);
 
 		clear_evtchn(evtchn);
diff --git a/drivers/xen/gntdev.c b/drivers/xen/gntdev.c
index dc495383ad73..67939578cd6d 100644
--- a/drivers/xen/gntdev.c
+++ b/drivers/xen/gntdev.c
@@ -748,7 +748,7 @@ static long gntdev_ioctl_notify(struct gntdev_priv *priv, void __user *u)
 	return rc;
 }
 
-#define GNTDEV_COPY_BATCH 24
+#define GNTDEV_COPY_BATCH 16
 
 struct gntdev_copy_batch {
 	struct gnttab_copy ops[GNTDEV_COPY_BATCH];