diff --git a/arch/x86/include/asm/xen/interface.h b/arch/x86/include/asm/xen/interface.h
index e8506c1..1c10c88 100644
--- a/arch/x86/include/asm/xen/interface.h
+++ b/arch/x86/include/asm/xen/interface.h
@@ -61,9 +61,9 @@
 #define HYPERVISOR_VIRT_START mk_unsigned_long(__HYPERVISOR_VIRT_START)
 #endif
 
-#ifndef machine_to_phys_mapping
-#define machine_to_phys_mapping ((unsigned long *)HYPERVISOR_VIRT_START)
-#endif
+#define MACH2PHYS_VIRT_START  mk_unsigned_long(__MACH2PHYS_VIRT_START)
+#define MACH2PHYS_VIRT_END    mk_unsigned_long(__MACH2PHYS_VIRT_END)
+#define MACH2PHYS_NR_ENTRIES  ((MACH2PHYS_VIRT_END-MACH2PHYS_VIRT_START)>>__MACH2PHYS_SHIFT)
 
 /* Maximum number of virtual CPUs in multi-processor guests. */
 #define MAX_VIRT_CPUS 32
diff --git a/arch/x86/include/asm/xen/interface_32.h b/arch/x86/include/asm/xen/interface_32.h
index 42a7e00..8413688 100644
--- a/arch/x86/include/asm/xen/interface_32.h
+++ b/arch/x86/include/asm/xen/interface_32.h
@@ -32,6 +32,11 @@
 /* And the trap vector is... */
 #define TRAP_INSTR "int $0x82"
 
+#define __MACH2PHYS_VIRT_START 0xF5800000
+#define __MACH2PHYS_VIRT_END   0xF6800000
+
+#define __MACH2PHYS_SHIFT      2
+
 /*
  * Virtual addresses beyond this are not modifiable by guest OSes. The
  * machine->physical mapping table starts at this address, read-only.
diff --git a/arch/x86/include/asm/xen/interface_64.h b/arch/x86/include/asm/xen/interface_64.h
index 100d266..839a481 100644
--- a/arch/x86/include/asm/xen/interface_64.h
+++ b/arch/x86/include/asm/xen/interface_64.h
@@ -39,18 +39,7 @@
 #define __HYPERVISOR_VIRT_END   0xFFFF880000000000
 #define __MACH2PHYS_VIRT_START  0xFFFF800000000000
 #define __MACH2PHYS_VIRT_END    0xFFFF804000000000
-
-#ifndef HYPERVISOR_VIRT_START
-#define HYPERVISOR_VIRT_START mk_unsigned_long(__HYPERVISOR_VIRT_START)
-#define HYPERVISOR_VIRT_END   mk_unsigned_long(__HYPERVISOR_VIRT_END)
-#endif
-
-#define MACH2PHYS_VIRT_START  mk_unsigned_long(__MACH2PHYS_VIRT_START)
-#define MACH2PHYS_VIRT_END    mk_unsigned_long(__MACH2PHYS_VIRT_END)
-#define MACH2PHYS_NR_ENTRIES  ((MACH2PHYS_VIRT_END-MACH2PHYS_VIRT_START)>>3)
-#ifndef machine_to_phys_mapping
-#define machine_to_phys_mapping ((unsigned long *)HYPERVISOR_VIRT_START)
-#endif
+#define __MACH2PHYS_SHIFT       3
 
 /*
  * int HYPERVISOR_set_segment_base(unsigned int which, unsigned long base)
diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
index dd8c141..8760cc6 100644
--- a/arch/x86/include/asm/xen/page.h
+++ b/arch/x86/include/asm/xen/page.h
@@ -5,6 +5,7 @@
 #include <linux/types.h>
 #include <linux/spinlock.h>
 #include <linux/pfn.h>
+#include <linux/mm.h>
 
 #include <asm/uaccess.h>
 #include <asm/page.h>
@@ -35,6 +36,8 @@
 #define MAX_DOMAIN_PAGES						\
     ((unsigned long)((u64)CONFIG_XEN_MAX_DOMAIN_MEMORY * 1024 * 1024 * 1024 / PAGE_SIZE))
 
+extern unsigned long *machine_to_phys_mapping;
+extern unsigned int   machine_to_phys_order;
 
 extern unsigned long get_phys_to_machine(unsigned long pfn);
 extern bool set_phys_to_machine(unsigned long pfn, unsigned long mfn);
@@ -69,10 +72,8 @@
 	if (xen_feature(XENFEAT_auto_translated_physmap))
 		return mfn;
 
-#if 0
 	if (unlikely((mfn >> machine_to_phys_order) != 0))
-		return max_mapnr;
-#endif
+		return ~0;
 
 	pfn = 0;
 	/*
diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 235c0f4..7250bef 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -75,6 +75,11 @@
 enum xen_domain_type xen_domain_type = XEN_NATIVE;
 EXPORT_SYMBOL_GPL(xen_domain_type);
 
+unsigned long *machine_to_phys_mapping = (void *)MACH2PHYS_VIRT_START;
+EXPORT_SYMBOL(machine_to_phys_mapping);
+unsigned int   machine_to_phys_order;
+EXPORT_SYMBOL(machine_to_phys_order);
+
 struct start_info *xen_start_info;
 EXPORT_SYMBOL_GPL(xen_start_info);
 
@@ -1090,6 +1095,8 @@
 /* First C function to be called on Xen boot */
 asmlinkage void __init xen_start_kernel(void)
 {
+	struct physdev_set_iopl set_iopl;
+	int rc;
 	pgd_t *pgd;
 
 	if (!xen_start_info)
@@ -1097,6 +1104,8 @@
 
 	xen_domain_type = XEN_PV_DOMAIN;
 
+	xen_setup_machphys_mapping();
+
 	/* Install Xen paravirt ops */
 	pv_info = xen_info;
 	pv_init_ops = xen_init_ops;
@@ -1202,10 +1211,18 @@
 #else
 	pv_info.kernel_rpl = 0;
 #endif
-
 	/* set the limit of our address space */
 	xen_reserve_top();
 
+	/* We used to do this in xen_arch_setup, but that is too late on AMD
+	 * were early_cpu_init (run before ->arch_setup()) calls early_amd_init
+	 * which pokes 0xcf8 port.
+	 */
+	set_iopl.iopl = 1;
+	rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
+	if (rc != 0)
+		xen_raw_printk("physdev_op failed %d\n", rc);
+
 #ifdef CONFIG_X86_32
 	/* set up basic CPUID stuff */
 	cpu_detect(&new_cpu_data);
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 276c67b..790af90 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -2034,6 +2034,20 @@
 	set_page_prot(pmd, PAGE_KERNEL_RO);
 }
 
+void __init xen_setup_machphys_mapping(void)
+{
+	struct xen_machphys_mapping mapping;
+	unsigned long machine_to_phys_nr_ents;
+
+	if (HYPERVISOR_memory_op(XENMEM_machphys_mapping, &mapping) == 0) {
+		machine_to_phys_mapping = (unsigned long *)mapping.v_start;
+		machine_to_phys_nr_ents = mapping.max_mfn + 1;
+	} else {
+		machine_to_phys_nr_ents = MACH2PHYS_NR_ENTRIES;
+	}
+	machine_to_phys_order = fls(machine_to_phys_nr_ents - 1);
+}
+
 #ifdef CONFIG_X86_64
 static void convert_pfn_mfn(void *v)
 {
diff --git a/arch/x86/xen/setup.c b/arch/x86/xen/setup.c
index 769c4b0..38fdffa 100644
--- a/arch/x86/xen/setup.c
+++ b/arch/x86/xen/setup.c
@@ -248,8 +248,7 @@
 	else
 		extra_pages = 0;
 
-	if (!xen_initial_domain())
-		xen_add_extra_mem(extra_pages);
+	xen_add_extra_mem(extra_pages);
 
 	return "Xen";
 }
@@ -337,9 +336,6 @@
 
 void __init xen_arch_setup(void)
 {
-	struct physdev_set_iopl set_iopl;
-	int rc;
-
 	xen_panic_handler_init();
 
 	HYPERVISOR_vm_assist(VMASST_CMD_enable, VMASST_TYPE_4gb_segments);
@@ -356,11 +352,6 @@
 	xen_enable_sysenter();
 	xen_enable_syscall();
 
-	set_iopl.iopl = 1;
-	rc = HYPERVISOR_physdev_op(PHYSDEVOP_set_iopl, &set_iopl);
-	if (rc != 0)
-		printk(KERN_INFO "physdev_op failed %d\n", rc);
-
 #ifdef CONFIG_ACPI
 	if (!(xen_start_info->flags & SIF_INITDOMAIN)) {
 		printk(KERN_INFO "ACPI in unprivileged domain disabled\n");
diff --git a/drivers/xen/Makefile b/drivers/xen/Makefile
index eb8a78d..533a199 100644
--- a/drivers/xen/Makefile
+++ b/drivers/xen/Makefile
@@ -8,9 +8,12 @@
 obj-$(CONFIG_HOTPLUG_CPU)	+= cpu_hotplug.o
 obj-$(CONFIG_XEN_XENCOMM)	+= xencomm.o
 obj-$(CONFIG_XEN_BALLOON)	+= balloon.o
-obj-$(CONFIG_XEN_DEV_EVTCHN)	+= evtchn.o
+obj-$(CONFIG_XEN_DEV_EVTCHN)	+= xen-evtchn.o
 obj-$(CONFIG_XENFS)		+= xenfs/
 obj-$(CONFIG_XEN_SYS_HYPERVISOR)	+= sys-hypervisor.o
 obj-$(CONFIG_XEN_PLATFORM_PCI)	+= platform-pci.o
 obj-$(CONFIG_SWIOTLB_XEN)	+= swiotlb-xen.o
 obj-$(CONFIG_XEN_DOM0)		+= pci.o
+
+xen-evtchn-y			:= evtchn.o
+
diff --git a/drivers/xen/balloon.c b/drivers/xen/balloon.c
index 500290b..2b17ad5 100644
--- a/drivers/xen/balloon.c
+++ b/drivers/xen/balloon.c
@@ -50,6 +50,7 @@
 #include <asm/pgtable.h>
 #include <asm/uaccess.h>
 #include <asm/tlb.h>
+#include <asm/e820.h>
 
 #include <asm/xen/hypervisor.h>
 #include <asm/xen/hypercall.h>
@@ -119,7 +120,7 @@
 }
 
 /* balloon_append: add the given page to the balloon. */
-static void balloon_append(struct page *page)
+static void __balloon_append(struct page *page)
 {
 	/* Lowmem is re-populated first, so highmem pages go at list tail. */
 	if (PageHighMem(page)) {
@@ -130,7 +131,11 @@
 		list_add(&page->lru, &ballooned_pages);
 		balloon_stats.balloon_low++;
 	}
+}
 
+static void balloon_append(struct page *page)
+{
+	__balloon_append(page);
 	totalram_pages--;
 }
 
@@ -191,7 +196,7 @@
 
 static int increase_reservation(unsigned long nr_pages)
 {
-	unsigned long  pfn, i, flags;
+	unsigned long  pfn, i;
 	struct page   *page;
 	long           rc;
 	struct xen_memory_reservation reservation = {
@@ -203,8 +208,6 @@
 	if (nr_pages > ARRAY_SIZE(frame_list))
 		nr_pages = ARRAY_SIZE(frame_list);
 
-	spin_lock_irqsave(&xen_reservation_lock, flags);
-
 	page = balloon_first_page();
 	for (i = 0; i < nr_pages; i++) {
 		BUG_ON(page == NULL);
@@ -247,14 +250,12 @@
 	balloon_stats.current_pages += rc;
 
  out:
-	spin_unlock_irqrestore(&xen_reservation_lock, flags);
-
 	return rc < 0 ? rc : rc != nr_pages;
 }
 
 static int decrease_reservation(unsigned long nr_pages)
 {
-	unsigned long  pfn, i, flags;
+	unsigned long  pfn, i;
 	struct page   *page;
 	int            need_sleep = 0;
 	int ret;
@@ -292,8 +293,6 @@
 	kmap_flush_unused();
 	flush_tlb_all();
 
-	spin_lock_irqsave(&xen_reservation_lock, flags);
-
 	/* No more mappings: invalidate P2M and add to balloon. */
 	for (i = 0; i < nr_pages; i++) {
 		pfn = mfn_to_pfn(frame_list[i]);
@@ -308,8 +307,6 @@
 
 	balloon_stats.current_pages -= nr_pages;
 
-	spin_unlock_irqrestore(&xen_reservation_lock, flags);
-
 	return need_sleep;
 }
 
@@ -395,7 +392,7 @@
 
 static int __init balloon_init(void)
 {
-	unsigned long pfn;
+	unsigned long pfn, extra_pfn_end;
 	struct page *page;
 
 	if (!xen_pv_domain())
@@ -416,10 +413,15 @@
 	register_balloon(&balloon_sysdev);
 
 	/* Initialise the balloon with excess memory space. */
-	for (pfn = xen_start_info->nr_pages; pfn < max_pfn; pfn++) {
+	extra_pfn_end = min(e820_end_of_ram_pfn(),
+			    (unsigned long)PFN_DOWN(xen_extra_mem_start + xen_extra_mem_size));
+	for (pfn = PFN_UP(xen_extra_mem_start);
+	     pfn < extra_pfn_end;
+	     pfn++) {
 		page = pfn_to_page(pfn);
-		if (!PageReserved(page))
-			balloon_append(page);
+		/* totalram_pages doesn't include the boot-time
+		   balloon extension, so don't subtract from it. */
+		__balloon_append(page);
 	}
 
 	target_watch.callback = watch_target;
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 321a0c8..2811bb9 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -278,17 +278,17 @@
 	cpumask_copy(irq_to_desc(irq)->affinity, cpumask_of(cpu));
 #endif
 
-	__clear_bit(chn, cpu_evtchn_mask(cpu_from_irq(irq)));
-	__set_bit(chn, cpu_evtchn_mask(cpu));
+	clear_bit(chn, cpu_evtchn_mask(cpu_from_irq(irq)));
+	set_bit(chn, cpu_evtchn_mask(cpu));
 
 	irq_info[irq].cpu = cpu;
 }
 
 static void init_evtchn_cpu_bindings(void)
 {
+	int i;
 #ifdef CONFIG_SMP
 	struct irq_desc *desc;
-	int i;
 
 	/* By default all event channels notify CPU#0. */
 	for_each_irq_desc(i, desc) {
@@ -296,7 +296,10 @@
 	}
 #endif
 
-	memset(cpu_evtchn_mask(0), ~0, sizeof(struct cpu_evtchn_s));
+	for_each_possible_cpu(i)
+		memset(cpu_evtchn_mask(i),
+		       (i == 0) ? ~0 : 0, sizeof(struct cpu_evtchn_s));
+
 }
 
 static inline void clear_evtchn(int port)
@@ -752,7 +755,7 @@
 		goto out;
 
 	if (xen_initial_domain()) {
-		unmap_irq.pirq = info->u.pirq.gsi;
+		unmap_irq.pirq = info->u.pirq.pirq;
 		unmap_irq.domid = DOMID_SELF;
 		rc = HYPERVISOR_physdev_op(PHYSDEVOP_unmap_pirq, &unmap_irq);
 		if (rc) {
diff --git a/drivers/xen/evtchn.c b/drivers/xen/evtchn.c
index fec6ba3..ef11daf 100644
--- a/drivers/xen/evtchn.c
+++ b/drivers/xen/evtchn.c
@@ -69,20 +69,51 @@
 	const char *name;
 };
 
-/* Who's bound to each port? */
-static struct per_user_data *port_user[NR_EVENT_CHANNELS];
+/*
+ * Who's bound to each port?  This is logically an array of struct
+ * per_user_data *, but we encode the current enabled-state in bit 0.
+ */
+static unsigned long *port_user;
 static DEFINE_SPINLOCK(port_user_lock); /* protects port_user[] and ring_prod */
 
-irqreturn_t evtchn_interrupt(int irq, void *data)
+static inline struct per_user_data *get_port_user(unsigned port)
+{
+	return (struct per_user_data *)(port_user[port] & ~1);
+}
+
+static inline void set_port_user(unsigned port, struct per_user_data *u)
+{
+	port_user[port] = (unsigned long)u;
+}
+
+static inline bool get_port_enabled(unsigned port)
+{
+	return port_user[port] & 1;
+}
+
+static inline void set_port_enabled(unsigned port, bool enabled)
+{
+	if (enabled)
+		port_user[port] |= 1;
+	else
+		port_user[port] &= ~1;
+}
+
+static irqreturn_t evtchn_interrupt(int irq, void *data)
 {
 	unsigned int port = (unsigned long)data;
 	struct per_user_data *u;
 
 	spin_lock(&port_user_lock);
 
-	u = port_user[port];
+	u = get_port_user(port);
+
+	WARN(!get_port_enabled(port),
+	     "Interrupt for port %d, but apparently not enabled; per-user %p\n",
+	     port, u);
 
 	disable_irq_nosync(irq);
+	set_port_enabled(port, false);
 
 	if ((u->ring_prod - u->ring_cons) < EVTCHN_RING_SIZE) {
 		u->ring[EVTCHN_RING_MASK(u->ring_prod)] = port;
@@ -92,9 +123,8 @@
 			kill_fasync(&u->evtchn_async_queue,
 				    SIGIO, POLL_IN);
 		}
-	} else {
+	} else
 		u->ring_overflow = 1;
-	}
 
 	spin_unlock(&port_user_lock);
 
@@ -198,9 +228,18 @@
 		goto out;
 
 	spin_lock_irq(&port_user_lock);
-	for (i = 0; i < (count/sizeof(evtchn_port_t)); i++)
-		if ((kbuf[i] < NR_EVENT_CHANNELS) && (port_user[kbuf[i]] == u))
-			enable_irq(irq_from_evtchn(kbuf[i]));
+
+	for (i = 0; i < (count/sizeof(evtchn_port_t)); i++) {
+		unsigned port = kbuf[i];
+
+		if (port < NR_EVENT_CHANNELS &&
+		    get_port_user(port) == u &&
+		    !get_port_enabled(port)) {
+			set_port_enabled(port, true);
+			enable_irq(irq_from_evtchn(port));
+		}
+	}
+
 	spin_unlock_irq(&port_user_lock);
 
 	rc = count;
@@ -222,8 +261,9 @@
 	 * interrupt handler yet, and our caller has already
 	 * serialized bind operations.)
 	 */
-	BUG_ON(port_user[port] != NULL);
-	port_user[port] = u;
+	BUG_ON(get_port_user(port) != NULL);
+	set_port_user(port, u);
+	set_port_enabled(port, true); /* start enabled */
 
 	rc = bind_evtchn_to_irqhandler(port, evtchn_interrupt, IRQF_DISABLED,
 				       u->name, (void *)(unsigned long)port);
@@ -239,10 +279,7 @@
 
 	unbind_from_irqhandler(irq, (void *)(unsigned long)port);
 
-	/* make sure we unbind the irq handler before clearing the port */
-	barrier();
-
-	port_user[port] = NULL;
+	set_port_user(port, NULL);
 }
 
 static long evtchn_ioctl(struct file *file,
@@ -333,15 +370,17 @@
 		spin_lock_irq(&port_user_lock);
 
 		rc = -ENOTCONN;
-		if (port_user[unbind.port] != u) {
+		if (get_port_user(unbind.port) != u) {
 			spin_unlock_irq(&port_user_lock);
 			break;
 		}
 
-		evtchn_unbind_from_user(u, unbind.port);
+		disable_irq(irq_from_evtchn(unbind.port));
 
 		spin_unlock_irq(&port_user_lock);
 
+		evtchn_unbind_from_user(u, unbind.port);
+
 		rc = 0;
 		break;
 	}
@@ -355,7 +394,7 @@
 
 		if (notify.port >= NR_EVENT_CHANNELS) {
 			rc = -EINVAL;
-		} else if (port_user[notify.port] != u) {
+		} else if (get_port_user(notify.port) != u) {
 			rc = -ENOTCONN;
 		} else {
 			notify_remote_via_evtchn(notify.port);
@@ -431,7 +470,7 @@
 
 	filp->private_data = u;
 
-	return 0;
+	return nonseekable_open(inode, filp);;
 }
 
 static int evtchn_release(struct inode *inode, struct file *filp)
@@ -444,14 +483,21 @@
 	free_page((unsigned long)u->ring);
 
 	for (i = 0; i < NR_EVENT_CHANNELS; i++) {
-		if (port_user[i] != u)
+		if (get_port_user(i) != u)
 			continue;
 
-		evtchn_unbind_from_user(port_user[i], i);
+		disable_irq(irq_from_evtchn(i));
 	}
 
 	spin_unlock_irq(&port_user_lock);
 
+	for (i = 0; i < NR_EVENT_CHANNELS; i++) {
+		if (get_port_user(i) != u)
+			continue;
+
+		evtchn_unbind_from_user(get_port_user(i), i);
+	}
+
 	kfree(u->name);
 	kfree(u);
 
@@ -467,12 +513,12 @@
 	.fasync  = evtchn_fasync,
 	.open    = evtchn_open,
 	.release = evtchn_release,
-	.llseek = noop_llseek,
+	.llseek	 = no_llseek,
 };
 
 static struct miscdevice evtchn_miscdev = {
 	.minor        = MISC_DYNAMIC_MINOR,
-	.name         = "evtchn",
+	.name         = "xen/evtchn",
 	.fops         = &evtchn_fops,
 };
 static int __init evtchn_init(void)
@@ -482,8 +528,11 @@
 	if (!xen_domain())
 		return -ENODEV;
 
+	port_user = kcalloc(NR_EVENT_CHANNELS, sizeof(*port_user), GFP_KERNEL);
+	if (port_user == NULL)
+		return -ENOMEM;
+
 	spin_lock_init(&port_user_lock);
-	memset(port_user, 0, sizeof(port_user));
 
 	/* Create '/dev/misc/evtchn'. */
 	err = misc_register(&evtchn_miscdev);
@@ -499,6 +548,9 @@
 
 static void __exit evtchn_cleanup(void)
 {
+	kfree(port_user);
+	port_user = NULL;
+
 	misc_deregister(&evtchn_miscdev);
 }
 
diff --git a/include/xen/interface/memory.h b/include/xen/interface/memory.h
index d7a6c13..eac3ce1 100644
--- a/include/xen/interface/memory.h
+++ b/include/xen/interface/memory.h
@@ -141,6 +141,19 @@
 DEFINE_GUEST_HANDLE_STRUCT(xen_machphys_mfn_list);
 
 /*
+ * Returns the location in virtual address space of the machine_to_phys
+ * mapping table. Architectures which do not have a m2p table, or which do not
+ * map it by default into guest address space, do not implement this command.
+ * arg == addr of xen_machphys_mapping_t.
+ */
+#define XENMEM_machphys_mapping     12
+struct xen_machphys_mapping {
+    unsigned long v_start, v_end; /* Start and end virtual addresses.   */
+    unsigned long max_mfn;        /* Maximum MFN that can be looked up. */
+};
+DEFINE_GUEST_HANDLE_STRUCT(xen_machphys_mapping_t);
+
+/*
  * Sets the GPFN at which a particular page appears in the specified guest's
  * pseudophysical address space.
  * arg == addr of xen_add_to_physmap_t.
diff --git a/include/xen/page.h b/include/xen/page.h
index eaf85fa..0be36b9 100644
--- a/include/xen/page.h
+++ b/include/xen/page.h
@@ -1 +1,8 @@
+#ifndef _XEN_PAGE_H
+#define _XEN_PAGE_H
+
 #include <asm/xen/page.h>
+
+extern phys_addr_t xen_extra_mem_start, xen_extra_mem_size;
+
+#endif	/* _XEN_PAGE_H */