3 files changed, 35 insertions, 14 deletions

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index 6aba2a23e2c3..7e8d3bc80af6 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -1174,6 +1174,15 @@ asmlinkage void __init xen_start_kernel(void)
 
         xen_smp_init();
 
+#ifdef CONFIG_ACPI_NUMA
+        /*
+         * The pages we from Xen are not related to machine pages, so
+         * any NUMA information the kernel tries to get from ACPI will
+         * be meaningless.  Prevent it from trying.
+         */
+        acpi_numa = -1;
+#endif
+
         pgd = (pgd_t *)xen_start_info->pt_base;
 
         if (!xen_initial_domain())
diff --git a/drivers/video/xen-fbfront.c b/drivers/video/xen-fbfront.c
index 4abb0b9ed653..3e6934d4bea8 100644
--- a/drivers/video/xen-fbfront.c
+++ b/drivers/video/xen-fbfront.c
@@ -562,26 +562,24 @@ static void xenfb_init_shared_page(struct xenfb_info *info,
 static int xenfb_connect_backend(struct xenbus_device *dev,
                                  struct xenfb_info *info)
 {
-        int ret, evtchn;
+        int ret, evtchn, irq;
         struct xenbus_transaction xbt;
 
         ret = xenbus_alloc_evtchn(dev, &evtchn);
         if (ret)
                 return ret;
-        ret = bind_evtchn_to_irqhandler(evtchn, xenfb_event_handler,
+        irq = bind_evtchn_to_irqhandler(evtchn, xenfb_event_handler,
                                         0, dev->devicetype, info);
-        if (ret < 0) {
+        if (irq < 0) {
                 xenbus_free_evtchn(dev, evtchn);
                 xenbus_dev_fatal(dev, ret, "bind_evtchn_to_irqhandler");
-                return ret;
+                return irq;
         }
-        info->irq = ret;
-
  again:
         ret = xenbus_transaction_start(&xbt);
         if (ret) {
                 xenbus_dev_fatal(dev, ret, "starting transaction");
-                return ret;
+                goto unbind_irq;
         }
         ret = xenbus_printf(xbt, dev->nodename, "page-ref", "%lu",
                             virt_to_mfn(info->page));
@@ -603,20 +601,25 @@ static int xenfb_connect_backend(struct xenbus_device *dev,
                 if (ret == -EAGAIN)
                         goto again;
                 xenbus_dev_fatal(dev, ret, "completing transaction");
-                return ret;
+                goto unbind_irq;
         }
 
         xenbus_switch_state(dev, XenbusStateInitialised);
+        info->irq = irq;
         return 0;
 
  error_xenbus:
         xenbus_transaction_end(xbt, 1);
         xenbus_dev_fatal(dev, ret, "writing xenstore");
+ unbind_irq:
+        unbind_from_irqhandler(irq, info);
         return ret;
 }
 
 static void xenfb_disconnect_backend(struct xenfb_info *info)
 {
+        /* Prevent xenfb refresh */
+        info->update_wanted = 0;
         if (info->irq >= 0)
                 unbind_from_irqhandler(info->irq, info);
         info->irq = -1;
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 65f8637d13cf..74681478100a 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -170,6 +170,9 @@ static struct irq_info *info_for_irq(unsigned irq)
 
 static unsigned int evtchn_from_irq(unsigned irq)
 {
+        if (unlikely(WARN(irq < 0 || irq >= nr_irqs, "Invalid irq %d!\n", irq)))
+                return 0;
+
         return info_for_irq(irq)->evtchn;
 }
 
@@ -405,15 +408,21 @@ static int find_unbound_irq(void)
 {
         struct irq_data *data;
         int irq, res;
-        int start = get_nr_hw_irqs();
+        int bottom = get_nr_hw_irqs();
+        int top = nr_irqs-1;
 
-        if (start == nr_irqs)
+        if (bottom == nr_irqs)
                 goto no_irqs;
 
-        /* nr_irqs is a magic value. Must not use it.*/
-        for (irq = nr_irqs-1; irq > start; irq--) {
+        /* This loop starts from the top of IRQ space and goes down.
+         * We need this b/c if we have a PCI device in a Xen PV guest
+         * we do not have an IO-APIC (though the backend might have them)
+         * mapped in. To not have a collision of physical IRQs with the Xen
+         * event channels start at the top of the IRQ space for virtual IRQs.
+         */
+        for (irq = top; irq > bottom; irq--) {
                 data = irq_get_irq_data(irq);
-                /* only 0->15 have init'd desc; handle irq > 16 */
+                /* only 15->0 have init'd desc; handle irq > 16 */
                 if (!data)
                         break;
                 if (data->chip == &no_irq_chip)
@@ -424,7 +433,7 @@ static int find_unbound_irq(void)
                         return irq;
         }
 
-        if (irq == start)
+        if (irq == bottom)
                 goto no_irqs;
 
         res = irq_alloc_desc_at(irq, -1);