Add the rt linux 4.1.3-rt3 as base
[kvmfornfv.git] / kernel / drivers / xen / events / events_base.c
diff --git a/kernel/drivers/xen/events/events_base.c b/kernel/drivers/xen/events/events_base.c
new file mode 100644 (file)
index 0000000..3838795
--- /dev/null
@@ -0,0 +1,1705 @@
+/*
+ * Xen event channels
+ *
+ * Xen models interrupts with abstract event channels.  Because each
+ * domain gets 1024 event channels, but NR_IRQ is not that large, we
+ * must dynamically map irqs<->event channels.  The event channels
+ * interface with the rest of the kernel by defining a xen interrupt
+ * chip.  When an event is received, it is mapped to an irq and sent
+ * through the normal interrupt processing path.
+ *
+ * There are four kinds of events which can be mapped to an event
+ * channel:
+ *
+ * 1. Inter-domain notifications.  This includes all the virtual
+ *    device events, since they're driven by front-ends in another domain
+ *    (typically dom0).
+ * 2. VIRQs, typically used for timers.  These are per-cpu events.
+ * 3. IPIs.
+ * 4. PIRQs - Hardware interrupts.
+ *
+ * Jeremy Fitzhardinge <jeremy@xensource.com>, XenSource Inc, 2007
+ */
+
+#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
+
+#include <linux/linkage.h>
+#include <linux/interrupt.h>
+#include <linux/irq.h>
+#include <linux/module.h>
+#include <linux/string.h>
+#include <linux/bootmem.h>
+#include <linux/slab.h>
+#include <linux/irqnr.h>
+#include <linux/pci.h>
+
+#ifdef CONFIG_X86
+#include <asm/desc.h>
+#include <asm/ptrace.h>
+#include <asm/irq.h>
+#include <asm/idle.h>
+#include <asm/io_apic.h>
+#include <asm/xen/page.h>
+#include <asm/xen/pci.h>
+#endif
+#include <asm/sync_bitops.h>
+#include <asm/xen/hypercall.h>
+#include <asm/xen/hypervisor.h>
+
+#include <xen/xen.h>
+#include <xen/hvm.h>
+#include <xen/xen-ops.h>
+#include <xen/events.h>
+#include <xen/interface/xen.h>
+#include <xen/interface/event_channel.h>
+#include <xen/interface/hvm/hvm_op.h>
+#include <xen/interface/hvm/params.h>
+#include <xen/interface/physdev.h>
+#include <xen/interface/sched.h>
+#include <xen/interface/vcpu.h>
+#include <asm/hw_irq.h>
+
+#include "events_internal.h"
+
+const struct evtchn_ops *evtchn_ops;
+
+/*
+ * This lock protects updates to the following mapping and reference-count
+ * arrays. The lock does not need to be acquired to read the mapping tables.
+ */
+static DEFINE_MUTEX(irq_mapping_update_lock);
+
+static LIST_HEAD(xen_irq_list_head);
+
+/* IRQ <-> VIRQ mapping. */
+static DEFINE_PER_CPU(int [NR_VIRQS], virq_to_irq) = {[0 ... NR_VIRQS-1] = -1};
+
+/* IRQ <-> IPI mapping */
+static DEFINE_PER_CPU(int [XEN_NR_IPIS], ipi_to_irq) = {[0 ... XEN_NR_IPIS-1] = -1};
+
+int **evtchn_to_irq;
+#ifdef CONFIG_X86
+static unsigned long *pirq_eoi_map;
+#endif
+static bool (*pirq_needs_eoi)(unsigned irq);
+
+#define EVTCHN_ROW(e)  (e / (PAGE_SIZE/sizeof(**evtchn_to_irq)))
+#define EVTCHN_COL(e)  (e % (PAGE_SIZE/sizeof(**evtchn_to_irq)))
+#define EVTCHN_PER_ROW (PAGE_SIZE / sizeof(**evtchn_to_irq))
+
+/* Xen will never allocate port zero for any purpose. */
+#define VALID_EVTCHN(chn)      ((chn) != 0)
+
+static struct irq_chip xen_dynamic_chip;
+static struct irq_chip xen_percpu_chip;
+static struct irq_chip xen_pirq_chip;
+static void enable_dynirq(struct irq_data *data);
+static void disable_dynirq(struct irq_data *data);
+
+static void clear_evtchn_to_irq_row(unsigned row)
+{
+       unsigned col;
+
+       for (col = 0; col < EVTCHN_PER_ROW; col++)
+               evtchn_to_irq[row][col] = -1;
+}
+
+static void clear_evtchn_to_irq_all(void)
+{
+       unsigned row;
+
+       for (row = 0; row < EVTCHN_ROW(xen_evtchn_max_channels()); row++) {
+               if (evtchn_to_irq[row] == NULL)
+                       continue;
+               clear_evtchn_to_irq_row(row);
+       }
+}
+
+static int set_evtchn_to_irq(unsigned evtchn, unsigned irq)
+{
+       unsigned row;
+       unsigned col;
+
+       if (evtchn >= xen_evtchn_max_channels())
+               return -EINVAL;
+
+       row = EVTCHN_ROW(evtchn);
+       col = EVTCHN_COL(evtchn);
+
+       if (evtchn_to_irq[row] == NULL) {
+               /* Unallocated irq entries return -1 anyway */
+               if (irq == -1)
+                       return 0;
+
+               evtchn_to_irq[row] = (int *)get_zeroed_page(GFP_KERNEL);
+               if (evtchn_to_irq[row] == NULL)
+                       return -ENOMEM;
+
+               clear_evtchn_to_irq_row(row);
+       }
+
+       evtchn_to_irq[EVTCHN_ROW(evtchn)][EVTCHN_COL(evtchn)] = irq;
+       return 0;
+}
+
+int get_evtchn_to_irq(unsigned evtchn)
+{
+       if (evtchn >= xen_evtchn_max_channels())
+               return -1;
+       if (evtchn_to_irq[EVTCHN_ROW(evtchn)] == NULL)
+               return -1;
+       return evtchn_to_irq[EVTCHN_ROW(evtchn)][EVTCHN_COL(evtchn)];
+}
+
+/* Get info for IRQ */
+struct irq_info *info_for_irq(unsigned irq)
+{
+       return irq_get_handler_data(irq);
+}
+
+/* Constructors for packed IRQ information. */
+static int xen_irq_info_common_setup(struct irq_info *info,
+                                    unsigned irq,
+                                    enum xen_irq_type type,
+                                    unsigned evtchn,
+                                    unsigned short cpu)
+{
+       int ret;
+
+       BUG_ON(info->type != IRQT_UNBOUND && info->type != type);
+
+       info->type = type;
+       info->irq = irq;
+       info->evtchn = evtchn;
+       info->cpu = cpu;
+
+       ret = set_evtchn_to_irq(evtchn, irq);
+       if (ret < 0)
+               return ret;
+
+       irq_clear_status_flags(irq, IRQ_NOREQUEST|IRQ_NOAUTOEN);
+
+       return xen_evtchn_port_setup(info);
+}
+
+static int xen_irq_info_evtchn_setup(unsigned irq,
+                                    unsigned evtchn)
+{
+       struct irq_info *info = info_for_irq(irq);
+
+       return xen_irq_info_common_setup(info, irq, IRQT_EVTCHN, evtchn, 0);
+}
+
+static int xen_irq_info_ipi_setup(unsigned cpu,
+                                 unsigned irq,
+                                 unsigned evtchn,
+                                 enum ipi_vector ipi)
+{
+       struct irq_info *info = info_for_irq(irq);
+
+       info->u.ipi = ipi;
+
+       per_cpu(ipi_to_irq, cpu)[ipi] = irq;
+
+       return xen_irq_info_common_setup(info, irq, IRQT_IPI, evtchn, 0);
+}
+
+static int xen_irq_info_virq_setup(unsigned cpu,
+                                  unsigned irq,
+                                  unsigned evtchn,
+                                  unsigned virq)
+{
+       struct irq_info *info = info_for_irq(irq);
+
+       info->u.virq = virq;
+
+       per_cpu(virq_to_irq, cpu)[virq] = irq;
+
+       return xen_irq_info_common_setup(info, irq, IRQT_VIRQ, evtchn, 0);
+}
+
+static int xen_irq_info_pirq_setup(unsigned irq,
+                                  unsigned evtchn,
+                                  unsigned pirq,
+                                  unsigned gsi,
+                                  uint16_t domid,
+                                  unsigned char flags)
+{
+       struct irq_info *info = info_for_irq(irq);
+
+       info->u.pirq.pirq = pirq;
+       info->u.pirq.gsi = gsi;
+       info->u.pirq.domid = domid;
+       info->u.pirq.flags = flags;
+
+       return xen_irq_info_common_setup(info, irq, IRQT_PIRQ, evtchn, 0);
+}
+
+static void xen_irq_info_cleanup(struct irq_info *info)
+{
+       set_evtchn_to_irq(info->evtchn, -1);
+       info->evtchn = 0;
+}
+
+/*
+ * Accessors for packed IRQ information.
+ */
+unsigned int evtchn_from_irq(unsigned irq)
+{
+       if (unlikely(WARN(irq >= nr_irqs, "Invalid irq %d!\n", irq)))
+               return 0;
+
+       return info_for_irq(irq)->evtchn;
+}
+
+unsigned irq_from_evtchn(unsigned int evtchn)
+{
+       return get_evtchn_to_irq(evtchn);
+}
+EXPORT_SYMBOL_GPL(irq_from_evtchn);
+
+int irq_from_virq(unsigned int cpu, unsigned int virq)
+{
+       return per_cpu(virq_to_irq, cpu)[virq];
+}
+
+static enum ipi_vector ipi_from_irq(unsigned irq)
+{
+       struct irq_info *info = info_for_irq(irq);
+
+       BUG_ON(info == NULL);
+       BUG_ON(info->type != IRQT_IPI);
+
+       return info->u.ipi;
+}
+
+static unsigned virq_from_irq(unsigned irq)
+{
+       struct irq_info *info = info_for_irq(irq);
+
+       BUG_ON(info == NULL);
+       BUG_ON(info->type != IRQT_VIRQ);
+
+       return info->u.virq;
+}
+
+static unsigned pirq_from_irq(unsigned irq)
+{
+       struct irq_info *info = info_for_irq(irq);
+
+       BUG_ON(info == NULL);
+       BUG_ON(info->type != IRQT_PIRQ);
+
+       return info->u.pirq.pirq;
+}
+
+static enum xen_irq_type type_from_irq(unsigned irq)
+{
+       return info_for_irq(irq)->type;
+}
+
+unsigned cpu_from_irq(unsigned irq)
+{
+       return info_for_irq(irq)->cpu;
+}
+
+unsigned int cpu_from_evtchn(unsigned int evtchn)
+{
+       int irq = get_evtchn_to_irq(evtchn);
+       unsigned ret = 0;
+
+       if (irq != -1)
+               ret = cpu_from_irq(irq);
+
+       return ret;
+}
+
+#ifdef CONFIG_X86
+static bool pirq_check_eoi_map(unsigned irq)
+{
+       return test_bit(pirq_from_irq(irq), pirq_eoi_map);
+}
+#endif
+
+static bool pirq_needs_eoi_flag(unsigned irq)
+{
+       struct irq_info *info = info_for_irq(irq);
+       BUG_ON(info->type != IRQT_PIRQ);
+
+       return info->u.pirq.flags & PIRQ_NEEDS_EOI;
+}
+
+static void bind_evtchn_to_cpu(unsigned int chn, unsigned int cpu)
+{
+       int irq = get_evtchn_to_irq(chn);
+       struct irq_info *info = info_for_irq(irq);
+
+       BUG_ON(irq == -1);
+#ifdef CONFIG_SMP
+       cpumask_copy(irq_get_irq_data(irq)->affinity, cpumask_of(cpu));
+#endif
+       xen_evtchn_port_bind_to_cpu(info, cpu);
+
+       info->cpu = cpu;
+}
+
+static void xen_evtchn_mask_all(void)
+{
+       unsigned int evtchn;
+
+       for (evtchn = 0; evtchn < xen_evtchn_nr_channels(); evtchn++)
+               mask_evtchn(evtchn);
+}
+
+/**
+ * notify_remote_via_irq - send event to remote end of event channel via irq
+ * @irq: irq of event channel to send event to
+ *
+ * Unlike notify_remote_via_evtchn(), this is safe to use across
+ * save/restore. Notifications on a broken connection are silently
+ * dropped.
+ */
+void notify_remote_via_irq(int irq)
+{
+       int evtchn = evtchn_from_irq(irq);
+
+       if (VALID_EVTCHN(evtchn))
+               notify_remote_via_evtchn(evtchn);
+}
+EXPORT_SYMBOL_GPL(notify_remote_via_irq);
+
+static void xen_irq_init(unsigned irq)
+{
+       struct irq_info *info;
+#ifdef CONFIG_SMP
+       /* By default all event channels notify CPU#0. */
+       cpumask_copy(irq_get_irq_data(irq)->affinity, cpumask_of(0));
+#endif
+
+       info = kzalloc(sizeof(*info), GFP_KERNEL);
+       if (info == NULL)
+               panic("Unable to allocate metadata for IRQ%d\n", irq);
+
+       info->type = IRQT_UNBOUND;
+       info->refcnt = -1;
+
+       irq_set_handler_data(irq, info);
+
+       list_add_tail(&info->list, &xen_irq_list_head);
+}
+
+static int __must_check xen_allocate_irqs_dynamic(int nvec)
+{
+       int i, irq = irq_alloc_descs(-1, 0, nvec, -1);
+
+       if (irq >= 0) {
+               for (i = 0; i < nvec; i++)
+                       xen_irq_init(irq + i);
+       }
+
+       return irq;
+}
+
+static inline int __must_check xen_allocate_irq_dynamic(void)
+{
+
+       return xen_allocate_irqs_dynamic(1);
+}
+
+static int __must_check xen_allocate_irq_gsi(unsigned gsi)
+{
+       int irq;
+
+       /*
+        * A PV guest has no concept of a GSI (since it has no ACPI
+        * nor access to/knowledge of the physical APICs). Therefore
+        * all IRQs are dynamically allocated from the entire IRQ
+        * space.
+        */
+       if (xen_pv_domain() && !xen_initial_domain())
+               return xen_allocate_irq_dynamic();
+
+       /* Legacy IRQ descriptors are already allocated by the arch. */
+       if (gsi < NR_IRQS_LEGACY)
+               irq = gsi;
+       else
+               irq = irq_alloc_desc_at(gsi, -1);
+
+       xen_irq_init(irq);
+
+       return irq;
+}
+
+static void xen_free_irq(unsigned irq)
+{
+       struct irq_info *info = irq_get_handler_data(irq);
+
+       if (WARN_ON(!info))
+               return;
+
+       list_del(&info->list);
+
+       irq_set_handler_data(irq, NULL);
+
+       WARN_ON(info->refcnt > 0);
+
+       kfree(info);
+
+       /* Legacy IRQ descriptors are managed by the arch. */
+       if (irq < NR_IRQS_LEGACY)
+               return;
+
+       irq_free_desc(irq);
+}
+
+static void xen_evtchn_close(unsigned int port)
+{
+       struct evtchn_close close;
+
+       close.port = port;
+       if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
+               BUG();
+}
+
+static void pirq_query_unmask(int irq)
+{
+       struct physdev_irq_status_query irq_status;
+       struct irq_info *info = info_for_irq(irq);
+
+       BUG_ON(info->type != IRQT_PIRQ);
+
+       irq_status.irq = pirq_from_irq(irq);
+       if (HYPERVISOR_physdev_op(PHYSDEVOP_irq_status_query, &irq_status))
+               irq_status.flags = 0;
+
+       info->u.pirq.flags &= ~PIRQ_NEEDS_EOI;
+       if (irq_status.flags & XENIRQSTAT_needs_eoi)
+               info->u.pirq.flags |= PIRQ_NEEDS_EOI;
+}
+
+static void eoi_pirq(struct irq_data *data)
+{
+       int evtchn = evtchn_from_irq(data->irq);
+       struct physdev_eoi eoi = { .irq = pirq_from_irq(data->irq) };
+       int rc = 0;
+
+       irq_move_irq(data);
+
+       if (VALID_EVTCHN(evtchn))
+               clear_evtchn(evtchn);
+
+       if (pirq_needs_eoi(data->irq)) {
+               rc = HYPERVISOR_physdev_op(PHYSDEVOP_eoi, &eoi);
+               WARN_ON(rc);
+       }
+}
+
+static void mask_ack_pirq(struct irq_data *data)
+{
+       disable_dynirq(data);
+       eoi_pirq(data);
+}
+
+static unsigned int __startup_pirq(unsigned int irq)
+{
+       struct evtchn_bind_pirq bind_pirq;
+       struct irq_info *info = info_for_irq(irq);
+       int evtchn = evtchn_from_irq(irq);
+       int rc;
+
+       BUG_ON(info->type != IRQT_PIRQ);
+
+       if (VALID_EVTCHN(evtchn))
+               goto out;
+
+       bind_pirq.pirq = pirq_from_irq(irq);
+       /* NB. We are happy to share unless we are probing. */
+       bind_pirq.flags = info->u.pirq.flags & PIRQ_SHAREABLE ?
+                                       BIND_PIRQ__WILL_SHARE : 0;
+       rc = HYPERVISOR_event_channel_op(EVTCHNOP_bind_pirq, &bind_pirq);
+       if (rc != 0) {
+               pr_warn("Failed to obtain physical IRQ %d\n", irq);
+               return 0;
+       }
+       evtchn = bind_pirq.port;
+
+       pirq_query_unmask(irq);
+
+       rc = set_evtchn_to_irq(evtchn, irq);
+       if (rc)
+               goto err;
+
+       info->evtchn = evtchn;
+       bind_evtchn_to_cpu(evtchn, 0);
+
+       rc = xen_evtchn_port_setup(info);
+       if (rc)
+               goto err;
+
+out:
+       unmask_evtchn(evtchn);
+       eoi_pirq(irq_get_irq_data(irq));
+
+       return 0;
+
+err:
+       pr_err("irq%d: Failed to set port to irq mapping (%d)\n", irq, rc);
+       xen_evtchn_close(evtchn);
+       return 0;
+}
+
+static unsigned int startup_pirq(struct irq_data *data)
+{
+       return __startup_pirq(data->irq);
+}
+
+static void shutdown_pirq(struct irq_data *data)
+{
+       unsigned int irq = data->irq;
+       struct irq_info *info = info_for_irq(irq);
+       unsigned evtchn = evtchn_from_irq(irq);
+
+       BUG_ON(info->type != IRQT_PIRQ);
+
+       if (!VALID_EVTCHN(evtchn))
+               return;
+
+       mask_evtchn(evtchn);
+       xen_evtchn_close(evtchn);
+       xen_irq_info_cleanup(info);
+}
+
+static void enable_pirq(struct irq_data *data)
+{
+       startup_pirq(data);
+}
+
+static void disable_pirq(struct irq_data *data)
+{
+       disable_dynirq(data);
+}
+
+int xen_irq_from_gsi(unsigned gsi)
+{
+       struct irq_info *info;
+
+       list_for_each_entry(info, &xen_irq_list_head, list) {
+               if (info->type != IRQT_PIRQ)
+                       continue;
+
+               if (info->u.pirq.gsi == gsi)
+                       return info->irq;
+       }
+
+       return -1;
+}
+EXPORT_SYMBOL_GPL(xen_irq_from_gsi);
+
+static void __unbind_from_irq(unsigned int irq)
+{
+       int evtchn = evtchn_from_irq(irq);
+       struct irq_info *info = irq_get_handler_data(irq);
+
+       if (info->refcnt > 0) {
+               info->refcnt--;
+               if (info->refcnt != 0)
+                       return;
+       }
+
+       if (VALID_EVTCHN(evtchn)) {
+               unsigned int cpu = cpu_from_irq(irq);
+
+               xen_evtchn_close(evtchn);
+
+               switch (type_from_irq(irq)) {
+               case IRQT_VIRQ:
+                       per_cpu(virq_to_irq, cpu)[virq_from_irq(irq)] = -1;
+                       break;
+               case IRQT_IPI:
+                       per_cpu(ipi_to_irq, cpu)[ipi_from_irq(irq)] = -1;
+                       break;
+               default:
+                       break;
+               }
+
+               xen_irq_info_cleanup(info);
+       }
+
+       BUG_ON(info_for_irq(irq)->type == IRQT_UNBOUND);
+
+       xen_free_irq(irq);
+}
+
+/*
+ * Do not make any assumptions regarding the relationship between the
+ * IRQ number returned here and the Xen pirq argument.
+ *
+ * Note: We don't assign an event channel until the irq actually started
+ * up.  Return an existing irq if we've already got one for the gsi.
+ *
+ * Shareable implies level triggered, not shareable implies edge
+ * triggered here.
+ */
+int xen_bind_pirq_gsi_to_irq(unsigned gsi,
+                            unsigned pirq, int shareable, char *name)
+{
+       int irq = -1;
+       struct physdev_irq irq_op;
+       int ret;
+
+       mutex_lock(&irq_mapping_update_lock);
+
+       irq = xen_irq_from_gsi(gsi);
+       if (irq != -1) {
+               pr_info("%s: returning irq %d for gsi %u\n",
+                       __func__, irq, gsi);
+               goto out;
+       }
+
+       irq = xen_allocate_irq_gsi(gsi);
+       if (irq < 0)
+               goto out;
+
+       irq_op.irq = irq;
+       irq_op.vector = 0;
+
+       /* Only the privileged domain can do this. For non-priv, the pcifront
+        * driver provides a PCI bus that does the call to do exactly
+        * this in the priv domain. */
+       if (xen_initial_domain() &&
+           HYPERVISOR_physdev_op(PHYSDEVOP_alloc_irq_vector, &irq_op)) {
+               xen_free_irq(irq);
+               irq = -ENOSPC;
+               goto out;
+       }
+
+       ret = xen_irq_info_pirq_setup(irq, 0, pirq, gsi, DOMID_SELF,
+                              shareable ? PIRQ_SHAREABLE : 0);
+       if (ret < 0) {
+               __unbind_from_irq(irq);
+               irq = ret;
+               goto out;
+       }
+
+       pirq_query_unmask(irq);
+       /* We try to use the handler with the appropriate semantic for the
+        * type of interrupt: if the interrupt is an edge triggered
+        * interrupt we use handle_edge_irq.
+        *
+        * On the other hand if the interrupt is level triggered we use
+        * handle_fasteoi_irq like the native code does for this kind of
+        * interrupts.
+        *
+        * Depending on the Xen version, pirq_needs_eoi might return true
+        * not only for level triggered interrupts but for edge triggered
+        * interrupts too. In any case Xen always honors the eoi mechanism,
+        * not injecting any more pirqs of the same kind if the first one
+        * hasn't received an eoi yet. Therefore using the fasteoi handler
+        * is the right choice either way.
+        */
+       if (shareable)
+               irq_set_chip_and_handler_name(irq, &xen_pirq_chip,
+                               handle_fasteoi_irq, name);
+       else
+               irq_set_chip_and_handler_name(irq, &xen_pirq_chip,
+                               handle_edge_irq, name);
+
+out:
+       mutex_unlock(&irq_mapping_update_lock);
+
+       return irq;
+}
+
+#ifdef CONFIG_PCI_MSI
+int xen_allocate_pirq_msi(struct pci_dev *dev, struct msi_desc *msidesc)
+{
+       int rc;
+       struct physdev_get_free_pirq op_get_free_pirq;
+
+       op_get_free_pirq.type = MAP_PIRQ_TYPE_MSI;
+       rc = HYPERVISOR_physdev_op(PHYSDEVOP_get_free_pirq, &op_get_free_pirq);
+
+       WARN_ONCE(rc == -ENOSYS,
+                 "hypervisor does not support the PHYSDEVOP_get_free_pirq interface\n");
+
+       return rc ? -1 : op_get_free_pirq.pirq;
+}
+
+int xen_bind_pirq_msi_to_irq(struct pci_dev *dev, struct msi_desc *msidesc,
+                            int pirq, int nvec, const char *name, domid_t domid)
+{
+       int i, irq, ret;
+
+       mutex_lock(&irq_mapping_update_lock);
+
+       irq = xen_allocate_irqs_dynamic(nvec);
+       if (irq < 0)
+               goto out;
+
+       for (i = 0; i < nvec; i++) {
+               irq_set_chip_and_handler_name(irq + i, &xen_pirq_chip, handle_edge_irq, name);
+
+               ret = xen_irq_info_pirq_setup(irq + i, 0, pirq + i, 0, domid,
+                                             i == 0 ? 0 : PIRQ_MSI_GROUP);
+               if (ret < 0)
+                       goto error_irq;
+       }
+
+       ret = irq_set_msi_desc(irq, msidesc);
+       if (ret < 0)
+               goto error_irq;
+out:
+       mutex_unlock(&irq_mapping_update_lock);
+       return irq;
+error_irq:
+       for (; i >= 0; i--)
+               __unbind_from_irq(irq + i);
+       mutex_unlock(&irq_mapping_update_lock);
+       return ret;
+}
+#endif
+
+int xen_destroy_irq(int irq)
+{
+       struct physdev_unmap_pirq unmap_irq;
+       struct irq_info *info = info_for_irq(irq);
+       int rc = -ENOENT;
+
+       mutex_lock(&irq_mapping_update_lock);
+
+       /*
+        * If trying to remove a vector in a MSI group different
+        * than the first one skip the PIRQ unmap unless this vector
+        * is the first one in the group.
+        */
+       if (xen_initial_domain() && !(info->u.pirq.flags & PIRQ_MSI_GROUP)) {
+               unmap_irq.pirq = info->u.pirq.pirq;
+               unmap_irq.domid = info->u.pirq.domid;
+               rc = HYPERVISOR_physdev_op(PHYSDEVOP_unmap_pirq, &unmap_irq);
+               /* If another domain quits without making the pci_disable_msix
+                * call, the Xen hypervisor takes care of freeing the PIRQs
+                * (free_domain_pirqs).
+                */
+               if ((rc == -ESRCH && info->u.pirq.domid != DOMID_SELF))
+                       pr_info("domain %d does not have %d anymore\n",
+                               info->u.pirq.domid, info->u.pirq.pirq);
+               else if (rc) {
+                       pr_warn("unmap irq failed %d\n", rc);
+                       goto out;
+               }
+       }
+
+       xen_free_irq(irq);
+
+out:
+       mutex_unlock(&irq_mapping_update_lock);
+       return rc;
+}
+
+int xen_irq_from_pirq(unsigned pirq)
+{
+       int irq;
+
+       struct irq_info *info;
+
+       mutex_lock(&irq_mapping_update_lock);
+
+       list_for_each_entry(info, &xen_irq_list_head, list) {
+               if (info->type != IRQT_PIRQ)
+                       continue;
+               irq = info->irq;
+               if (info->u.pirq.pirq == pirq)
+                       goto out;
+       }
+       irq = -1;
+out:
+       mutex_unlock(&irq_mapping_update_lock);
+
+       return irq;
+}
+
+
+int xen_pirq_from_irq(unsigned irq)
+{
+       return pirq_from_irq(irq);
+}
+EXPORT_SYMBOL_GPL(xen_pirq_from_irq);
+
+int bind_evtchn_to_irq(unsigned int evtchn)
+{
+       int irq;
+       int ret;
+
+       if (evtchn >= xen_evtchn_max_channels())
+               return -ENOMEM;
+
+       mutex_lock(&irq_mapping_update_lock);
+
+       irq = get_evtchn_to_irq(evtchn);
+
+       if (irq == -1) {
+               irq = xen_allocate_irq_dynamic();
+               if (irq < 0)
+                       goto out;
+
+               irq_set_chip_and_handler_name(irq, &xen_dynamic_chip,
+                                             handle_edge_irq, "event");
+
+               ret = xen_irq_info_evtchn_setup(irq, evtchn);
+               if (ret < 0) {
+                       __unbind_from_irq(irq);
+                       irq = ret;
+                       goto out;
+               }
+               /* New interdomain events are bound to VCPU 0. */
+               bind_evtchn_to_cpu(evtchn, 0);
+       } else {
+               struct irq_info *info = info_for_irq(irq);
+               WARN_ON(info == NULL || info->type != IRQT_EVTCHN);
+       }
+
+out:
+       mutex_unlock(&irq_mapping_update_lock);
+
+       return irq;
+}
+EXPORT_SYMBOL_GPL(bind_evtchn_to_irq);
+
+static int bind_ipi_to_irq(unsigned int ipi, unsigned int cpu)
+{
+       struct evtchn_bind_ipi bind_ipi;
+       int evtchn, irq;
+       int ret;
+
+       mutex_lock(&irq_mapping_update_lock);
+
+       irq = per_cpu(ipi_to_irq, cpu)[ipi];
+
+       if (irq == -1) {
+               irq = xen_allocate_irq_dynamic();
+               if (irq < 0)
+                       goto out;
+
+               irq_set_chip_and_handler_name(irq, &xen_percpu_chip,
+                                             handle_percpu_irq, "ipi");
+
+               bind_ipi.vcpu = cpu;
+               if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi,
+                                               &bind_ipi) != 0)
+                       BUG();
+               evtchn = bind_ipi.port;
+
+               ret = xen_irq_info_ipi_setup(cpu, irq, evtchn, ipi);
+               if (ret < 0) {
+                       __unbind_from_irq(irq);
+                       irq = ret;
+                       goto out;
+               }
+               bind_evtchn_to_cpu(evtchn, cpu);
+       } else {
+               struct irq_info *info = info_for_irq(irq);
+               WARN_ON(info == NULL || info->type != IRQT_IPI);
+       }
+
+ out:
+       mutex_unlock(&irq_mapping_update_lock);
+       return irq;
+}
+
+int bind_interdomain_evtchn_to_irq(unsigned int remote_domain,
+                                  unsigned int remote_port)
+{
+       struct evtchn_bind_interdomain bind_interdomain;
+       int err;
+
+       bind_interdomain.remote_dom  = remote_domain;
+       bind_interdomain.remote_port = remote_port;
+
+       err = HYPERVISOR_event_channel_op(EVTCHNOP_bind_interdomain,
+                                         &bind_interdomain);
+
+       return err ? : bind_evtchn_to_irq(bind_interdomain.local_port);
+}
+EXPORT_SYMBOL_GPL(bind_interdomain_evtchn_to_irq);
+
+static int find_virq(unsigned int virq, unsigned int cpu)
+{
+       struct evtchn_status status;
+       int port, rc = -ENOENT;
+
+       memset(&status, 0, sizeof(status));
+       for (port = 0; port < xen_evtchn_max_channels(); port++) {
+               status.dom = DOMID_SELF;
+               status.port = port;
+               rc = HYPERVISOR_event_channel_op(EVTCHNOP_status, &status);
+               if (rc < 0)
+                       continue;
+               if (status.status != EVTCHNSTAT_virq)
+                       continue;
+               if (status.u.virq == virq && status.vcpu == cpu) {
+                       rc = port;
+                       break;
+               }
+       }
+       return rc;
+}
+
+/**
+ * xen_evtchn_nr_channels - number of usable event channel ports
+ *
+ * This may be less than the maximum supported by the current
+ * hypervisor ABI. Use xen_evtchn_max_channels() for the maximum
+ * supported.
+ */
+unsigned xen_evtchn_nr_channels(void)
+{
+        return evtchn_ops->nr_channels();
+}
+EXPORT_SYMBOL_GPL(xen_evtchn_nr_channels);
+
+int bind_virq_to_irq(unsigned int virq, unsigned int cpu, bool percpu)
+{
+       struct evtchn_bind_virq bind_virq;
+       int evtchn, irq, ret;
+
+       mutex_lock(&irq_mapping_update_lock);
+
+       irq = per_cpu(virq_to_irq, cpu)[virq];
+
+       if (irq == -1) {
+               irq = xen_allocate_irq_dynamic();
+               if (irq < 0)
+                       goto out;
+
+               if (percpu)
+                       irq_set_chip_and_handler_name(irq, &xen_percpu_chip,
+                                                     handle_percpu_irq, "virq");
+               else
+                       irq_set_chip_and_handler_name(irq, &xen_dynamic_chip,
+                                                     handle_edge_irq, "virq");
+
+               bind_virq.virq = virq;
+               bind_virq.vcpu = cpu;
+               ret = HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
+                                               &bind_virq);
+               if (ret == 0)
+                       evtchn = bind_virq.port;
+               else {
+                       if (ret == -EEXIST)
+                               ret = find_virq(virq, cpu);
+                       BUG_ON(ret < 0);
+                       evtchn = ret;
+               }
+
+               ret = xen_irq_info_virq_setup(cpu, irq, evtchn, virq);
+               if (ret < 0) {
+                       __unbind_from_irq(irq);
+                       irq = ret;
+                       goto out;
+               }
+
+               bind_evtchn_to_cpu(evtchn, cpu);
+       } else {
+               struct irq_info *info = info_for_irq(irq);
+               WARN_ON(info == NULL || info->type != IRQT_VIRQ);
+       }
+
+out:
+       mutex_unlock(&irq_mapping_update_lock);
+
+       return irq;
+}
+
+static void unbind_from_irq(unsigned int irq)
+{
+       mutex_lock(&irq_mapping_update_lock);
+       __unbind_from_irq(irq);
+       mutex_unlock(&irq_mapping_update_lock);
+}
+
+int bind_evtchn_to_irqhandler(unsigned int evtchn,
+                             irq_handler_t handler,
+                             unsigned long irqflags,
+                             const char *devname, void *dev_id)
+{
+       int irq, retval;
+
+       irq = bind_evtchn_to_irq(evtchn);
+       if (irq < 0)
+               return irq;
+       retval = request_irq(irq, handler, irqflags, devname, dev_id);
+       if (retval != 0) {
+               unbind_from_irq(irq);
+               return retval;
+       }
+
+       return irq;
+}
+EXPORT_SYMBOL_GPL(bind_evtchn_to_irqhandler);
+
+int bind_interdomain_evtchn_to_irqhandler(unsigned int remote_domain,
+                                         unsigned int remote_port,
+                                         irq_handler_t handler,
+                                         unsigned long irqflags,
+                                         const char *devname,
+                                         void *dev_id)
+{
+       int irq, retval;
+
+       irq = bind_interdomain_evtchn_to_irq(remote_domain, remote_port);
+       if (irq < 0)
+               return irq;
+
+       retval = request_irq(irq, handler, irqflags, devname, dev_id);
+       if (retval != 0) {
+               unbind_from_irq(irq);
+               return retval;
+       }
+
+       return irq;
+}
+EXPORT_SYMBOL_GPL(bind_interdomain_evtchn_to_irqhandler);
+
+int bind_virq_to_irqhandler(unsigned int virq, unsigned int cpu,
+                           irq_handler_t handler,
+                           unsigned long irqflags, const char *devname, void *dev_id)
+{
+       int irq, retval;
+
+       irq = bind_virq_to_irq(virq, cpu, irqflags & IRQF_PERCPU);
+       if (irq < 0)
+               return irq;
+       retval = request_irq(irq, handler, irqflags, devname, dev_id);
+       if (retval != 0) {
+               unbind_from_irq(irq);
+               return retval;
+       }
+
+       return irq;
+}
+EXPORT_SYMBOL_GPL(bind_virq_to_irqhandler);
+
+int bind_ipi_to_irqhandler(enum ipi_vector ipi,
+                          unsigned int cpu,
+                          irq_handler_t handler,
+                          unsigned long irqflags,
+                          const char *devname,
+                          void *dev_id)
+{
+       int irq, retval;
+
+       irq = bind_ipi_to_irq(ipi, cpu);
+       if (irq < 0)
+               return irq;
+
+       irqflags |= IRQF_NO_SUSPEND | IRQF_FORCE_RESUME | IRQF_EARLY_RESUME;
+       retval = request_irq(irq, handler, irqflags, devname, dev_id);
+       if (retval != 0) {
+               unbind_from_irq(irq);
+               return retval;
+       }
+
+       return irq;
+}
+
+void unbind_from_irqhandler(unsigned int irq, void *dev_id)
+{
+       struct irq_info *info = irq_get_handler_data(irq);
+
+       if (WARN_ON(!info))
+               return;
+       free_irq(irq, dev_id);
+       unbind_from_irq(irq);
+}
+EXPORT_SYMBOL_GPL(unbind_from_irqhandler);
+
+/**
+ * xen_set_irq_priority() - set an event channel priority.
+ * @irq:irq bound to an event channel.
+ * @priority: priority between XEN_IRQ_PRIORITY_MAX and XEN_IRQ_PRIORITY_MIN.
+ */
+int xen_set_irq_priority(unsigned irq, unsigned priority)
+{
+       struct evtchn_set_priority set_priority;
+
+       set_priority.port = evtchn_from_irq(irq);
+       set_priority.priority = priority;
+
+       return HYPERVISOR_event_channel_op(EVTCHNOP_set_priority,
+                                          &set_priority);
+}
+EXPORT_SYMBOL_GPL(xen_set_irq_priority);
+
+int evtchn_make_refcounted(unsigned int evtchn)
+{
+       int irq = get_evtchn_to_irq(evtchn);
+       struct irq_info *info;
+
+       if (irq == -1)
+               return -ENOENT;
+
+       info = irq_get_handler_data(irq);
+
+       if (!info)
+               return -ENOENT;
+
+       WARN_ON(info->refcnt != -1);
+
+       info->refcnt = 1;
+
+       return 0;
+}
+EXPORT_SYMBOL_GPL(evtchn_make_refcounted);
+
+int evtchn_get(unsigned int evtchn)
+{
+       int irq;
+       struct irq_info *info;
+       int err = -ENOENT;
+
+       if (evtchn >= xen_evtchn_max_channels())
+               return -EINVAL;
+
+       mutex_lock(&irq_mapping_update_lock);
+
+       irq = get_evtchn_to_irq(evtchn);
+       if (irq == -1)
+               goto done;
+
+       info = irq_get_handler_data(irq);
+
+       if (!info)
+               goto done;
+
+       err = -EINVAL;
+       if (info->refcnt <= 0)
+               goto done;
+
+       info->refcnt++;
+       err = 0;
+ done:
+       mutex_unlock(&irq_mapping_update_lock);
+
+       return err;
+}
+EXPORT_SYMBOL_GPL(evtchn_get);
+
+void evtchn_put(unsigned int evtchn)
+{
+       int irq = get_evtchn_to_irq(evtchn);
+       if (WARN_ON(irq == -1))
+               return;
+       unbind_from_irq(irq);
+}
+EXPORT_SYMBOL_GPL(evtchn_put);
+
+void xen_send_IPI_one(unsigned int cpu, enum ipi_vector vector)
+{
+       int irq;
+
+#ifdef CONFIG_X86
+       if (unlikely(vector == XEN_NMI_VECTOR)) {
+               int rc =  HYPERVISOR_vcpu_op(VCPUOP_send_nmi, cpu, NULL);
+               if (rc < 0)
+                       printk(KERN_WARNING "Sending nmi to CPU%d failed (rc:%d)\n", cpu, rc);
+               return;
+       }
+#endif
+       irq = per_cpu(ipi_to_irq, cpu)[vector];
+       BUG_ON(irq < 0);
+       notify_remote_via_irq(irq);
+}
+
+static DEFINE_PER_CPU(unsigned, xed_nesting_count);
+
+static void __xen_evtchn_do_upcall(void)
+{
+       struct vcpu_info *vcpu_info = __this_cpu_read(xen_vcpu);
+       int cpu = get_cpu();
+       unsigned count;
+
+       do {
+               vcpu_info->evtchn_upcall_pending = 0;
+
+               if (__this_cpu_inc_return(xed_nesting_count) - 1)
+                       goto out;
+
+               xen_evtchn_handle_events(cpu);
+
+               BUG_ON(!irqs_disabled());
+
+               count = __this_cpu_read(xed_nesting_count);
+               __this_cpu_write(xed_nesting_count, 0);
+       } while (count != 1 || vcpu_info->evtchn_upcall_pending);
+
+out:
+
+       put_cpu();
+}
+
+void xen_evtchn_do_upcall(struct pt_regs *regs)
+{
+       struct pt_regs *old_regs = set_irq_regs(regs);
+
+       irq_enter();
+#ifdef CONFIG_X86
+       exit_idle();
+       inc_irq_stat(irq_hv_callback_count);
+#endif
+
+       __xen_evtchn_do_upcall();
+
+       irq_exit();
+       set_irq_regs(old_regs);
+}
+
+void xen_hvm_evtchn_do_upcall(void)
+{
+       __xen_evtchn_do_upcall();
+}
+EXPORT_SYMBOL_GPL(xen_hvm_evtchn_do_upcall);
+
+/* Rebind a new event channel to an existing irq. */
+void rebind_evtchn_irq(int evtchn, int irq)
+{
+       struct irq_info *info = info_for_irq(irq);
+
+       if (WARN_ON(!info))
+               return;
+
+       /* Make sure the irq is masked, since the new event channel
+          will also be masked. */
+       disable_irq(irq);
+
+       mutex_lock(&irq_mapping_update_lock);
+
+       /* After resume the irq<->evtchn mappings are all cleared out */
+       BUG_ON(get_evtchn_to_irq(evtchn) != -1);
+       /* Expect irq to have been bound before,
+          so there should be a proper type */
+       BUG_ON(info->type == IRQT_UNBOUND);
+
+       (void)xen_irq_info_evtchn_setup(irq, evtchn);
+
+       mutex_unlock(&irq_mapping_update_lock);
+
+        bind_evtchn_to_cpu(evtchn, info->cpu);
+       /* This will be deferred until interrupt is processed */
+       irq_set_affinity(irq, cpumask_of(info->cpu));
+
+       /* Unmask the event channel. */
+       enable_irq(irq);
+}
+
+/* Rebind an evtchn so that it gets delivered to a specific cpu */
+static int rebind_irq_to_cpu(unsigned irq, unsigned tcpu)
+{
+       struct evtchn_bind_vcpu bind_vcpu;
+       int evtchn = evtchn_from_irq(irq);
+       int masked;
+
+       if (!VALID_EVTCHN(evtchn))
+               return -1;
+
+       /*
+        * Events delivered via platform PCI interrupts are always
+        * routed to vcpu 0 and hence cannot be rebound.
+        */
+       if (xen_hvm_domain() && !xen_have_vector_callback)
+               return -1;
+
+       /* Send future instances of this interrupt to other vcpu. */
+       bind_vcpu.port = evtchn;
+       bind_vcpu.vcpu = tcpu;
+
+       /*
+        * Mask the event while changing the VCPU binding to prevent
+        * it being delivered on an unexpected VCPU.
+        */
+       masked = test_and_set_mask(evtchn);
+
+       /*
+        * If this fails, it usually just indicates that we're dealing with a
+        * virq or IPI channel, which don't actually need to be rebound. Ignore
+        * it, but don't do the xenlinux-level rebind in that case.
+        */
+       if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_vcpu, &bind_vcpu) >= 0)
+               bind_evtchn_to_cpu(evtchn, tcpu);
+
+       if (!masked)
+               unmask_evtchn(evtchn);
+
+       return 0;
+}
+
+static int set_affinity_irq(struct irq_data *data, const struct cpumask *dest,
+                           bool force)
+{
+       unsigned tcpu = cpumask_first_and(dest, cpu_online_mask);
+
+       return rebind_irq_to_cpu(data->irq, tcpu);
+}
+
+static void enable_dynirq(struct irq_data *data)
+{
+       int evtchn = evtchn_from_irq(data->irq);
+
+       if (VALID_EVTCHN(evtchn))
+               unmask_evtchn(evtchn);
+}
+
+static void disable_dynirq(struct irq_data *data)
+{
+       int evtchn = evtchn_from_irq(data->irq);
+
+       if (VALID_EVTCHN(evtchn))
+               mask_evtchn(evtchn);
+}
+
+static void ack_dynirq(struct irq_data *data)
+{
+       int evtchn = evtchn_from_irq(data->irq);
+
+       irq_move_irq(data);
+
+       if (VALID_EVTCHN(evtchn))
+               clear_evtchn(evtchn);
+}
+
+static void mask_ack_dynirq(struct irq_data *data)
+{
+       disable_dynirq(data);
+       ack_dynirq(data);
+}
+
+static int retrigger_dynirq(struct irq_data *data)
+{
+       unsigned int evtchn = evtchn_from_irq(data->irq);
+       int masked;
+
+       if (!VALID_EVTCHN(evtchn))
+               return 0;
+
+       masked = test_and_set_mask(evtchn);
+       set_evtchn(evtchn);
+       if (!masked)
+               unmask_evtchn(evtchn);
+
+       return 1;
+}
+
+static void restore_pirqs(void)
+{
+       int pirq, rc, irq, gsi;
+       struct physdev_map_pirq map_irq;
+       struct irq_info *info;
+
+       list_for_each_entry(info, &xen_irq_list_head, list) {
+               if (info->type != IRQT_PIRQ)
+                       continue;
+
+               pirq = info->u.pirq.pirq;
+               gsi = info->u.pirq.gsi;
+               irq = info->irq;
+
+               /* save/restore of PT devices doesn't work, so at this point the
+                * only devices present are GSI based emulated devices */
+               if (!gsi)
+                       continue;
+
+               map_irq.domid = DOMID_SELF;
+               map_irq.type = MAP_PIRQ_TYPE_GSI;
+               map_irq.index = gsi;
+               map_irq.pirq = pirq;
+
+               rc = HYPERVISOR_physdev_op(PHYSDEVOP_map_pirq, &map_irq);
+               if (rc) {
+                       pr_warn("xen map irq failed gsi=%d irq=%d pirq=%d rc=%d\n",
+                               gsi, irq, pirq, rc);
+                       xen_free_irq(irq);
+                       continue;
+               }
+
+               printk(KERN_DEBUG "xen: --> irq=%d, pirq=%d\n", irq, map_irq.pirq);
+
+               __startup_pirq(irq);
+       }
+}
+
+static void restore_cpu_virqs(unsigned int cpu)
+{
+       struct evtchn_bind_virq bind_virq;
+       int virq, irq, evtchn;
+
+       for (virq = 0; virq < NR_VIRQS; virq++) {
+               if ((irq = per_cpu(virq_to_irq, cpu)[virq]) == -1)
+                       continue;
+
+               BUG_ON(virq_from_irq(irq) != virq);
+
+               /* Get a new binding from Xen. */
+               bind_virq.virq = virq;
+               bind_virq.vcpu = cpu;
+               if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
+                                               &bind_virq) != 0)
+                       BUG();
+               evtchn = bind_virq.port;
+
+               /* Record the new mapping. */
+               (void)xen_irq_info_virq_setup(cpu, irq, evtchn, virq);
+               bind_evtchn_to_cpu(evtchn, cpu);
+       }
+}
+
+static void restore_cpu_ipis(unsigned int cpu)
+{
+       struct evtchn_bind_ipi bind_ipi;
+       int ipi, irq, evtchn;
+
+       for (ipi = 0; ipi < XEN_NR_IPIS; ipi++) {
+               if ((irq = per_cpu(ipi_to_irq, cpu)[ipi]) == -1)
+                       continue;
+
+               BUG_ON(ipi_from_irq(irq) != ipi);
+
+               /* Get a new binding from Xen. */
+               bind_ipi.vcpu = cpu;
+               if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_ipi,
+                                               &bind_ipi) != 0)
+                       BUG();
+               evtchn = bind_ipi.port;
+
+               /* Record the new mapping. */
+               (void)xen_irq_info_ipi_setup(cpu, irq, evtchn, ipi);
+               bind_evtchn_to_cpu(evtchn, cpu);
+       }
+}
+
+/* Clear an irq's pending state, in preparation for polling on it */
+void xen_clear_irq_pending(int irq)
+{
+       int evtchn = evtchn_from_irq(irq);
+
+       if (VALID_EVTCHN(evtchn))
+               clear_evtchn(evtchn);
+}
+EXPORT_SYMBOL(xen_clear_irq_pending);
+void xen_set_irq_pending(int irq)
+{
+       int evtchn = evtchn_from_irq(irq);
+
+       if (VALID_EVTCHN(evtchn))
+               set_evtchn(evtchn);
+}
+
+bool xen_test_irq_pending(int irq)
+{
+       int evtchn = evtchn_from_irq(irq);
+       bool ret = false;
+
+       if (VALID_EVTCHN(evtchn))
+               ret = test_evtchn(evtchn);
+
+       return ret;
+}
+
+/* Poll waiting for an irq to become pending with timeout.  In the usual case,
+ * the irq will be disabled so it won't deliver an interrupt. */
+void xen_poll_irq_timeout(int irq, u64 timeout)
+{
+       evtchn_port_t evtchn = evtchn_from_irq(irq);
+
+       if (VALID_EVTCHN(evtchn)) {
+               struct sched_poll poll;
+
+               poll.nr_ports = 1;
+               poll.timeout = timeout;
+               set_xen_guest_handle(poll.ports, &evtchn);
+
+               if (HYPERVISOR_sched_op(SCHEDOP_poll, &poll) != 0)
+                       BUG();
+       }
+}
+EXPORT_SYMBOL(xen_poll_irq_timeout);
+/* Poll waiting for an irq to become pending.  In the usual case, the
+ * irq will be disabled so it won't deliver an interrupt. */
+void xen_poll_irq(int irq)
+{
+       xen_poll_irq_timeout(irq, 0 /* no timeout */);
+}
+
+/* Check whether the IRQ line is shared with other guests. */
+int xen_test_irq_shared(int irq)
+{
+       struct irq_info *info = info_for_irq(irq);
+       struct physdev_irq_status_query irq_status;
+
+       if (WARN_ON(!info))
+               return -ENOENT;
+
+       irq_status.irq = info->u.pirq.pirq;
+
+       if (HYPERVISOR_physdev_op(PHYSDEVOP_irq_status_query, &irq_status))
+               return 0;
+       return !(irq_status.flags & XENIRQSTAT_shared);
+}
+EXPORT_SYMBOL_GPL(xen_test_irq_shared);
+
+void xen_irq_resume(void)
+{
+       unsigned int cpu;
+       struct irq_info *info;
+
+       /* New event-channel space is not 'live' yet. */
+       xen_evtchn_mask_all();
+       xen_evtchn_resume();
+
+       /* No IRQ <-> event-channel mappings. */
+       list_for_each_entry(info, &xen_irq_list_head, list)
+               info->evtchn = 0; /* zap event-channel binding */
+
+       clear_evtchn_to_irq_all();
+
+       for_each_possible_cpu(cpu) {
+               restore_cpu_virqs(cpu);
+               restore_cpu_ipis(cpu);
+       }
+
+       restore_pirqs();
+}
+
+static struct irq_chip xen_dynamic_chip __read_mostly = {
+       .name                   = "xen-dyn",
+
+       .irq_disable            = disable_dynirq,
+       .irq_mask               = disable_dynirq,
+       .irq_unmask             = enable_dynirq,
+
+       .irq_ack                = ack_dynirq,
+       .irq_mask_ack           = mask_ack_dynirq,
+
+       .irq_set_affinity       = set_affinity_irq,
+       .irq_retrigger          = retrigger_dynirq,
+};
+
+static struct irq_chip xen_pirq_chip __read_mostly = {
+       .name                   = "xen-pirq",
+
+       .irq_startup            = startup_pirq,
+       .irq_shutdown           = shutdown_pirq,
+       .irq_enable             = enable_pirq,
+       .irq_disable            = disable_pirq,
+
+       .irq_mask               = disable_dynirq,
+       .irq_unmask             = enable_dynirq,
+
+       .irq_ack                = eoi_pirq,
+       .irq_eoi                = eoi_pirq,
+       .irq_mask_ack           = mask_ack_pirq,
+
+       .irq_set_affinity       = set_affinity_irq,
+
+       .irq_retrigger          = retrigger_dynirq,
+};
+
+static struct irq_chip xen_percpu_chip __read_mostly = {
+       .name                   = "xen-percpu",
+
+       .irq_disable            = disable_dynirq,
+       .irq_mask               = disable_dynirq,
+       .irq_unmask             = enable_dynirq,
+
+       .irq_ack                = ack_dynirq,
+};
+
+int xen_set_callback_via(uint64_t via)
+{
+       struct xen_hvm_param a;
+       a.domid = DOMID_SELF;
+       a.index = HVM_PARAM_CALLBACK_IRQ;
+       a.value = via;
+       return HYPERVISOR_hvm_op(HVMOP_set_param, &a);
+}
+EXPORT_SYMBOL_GPL(xen_set_callback_via);
+
+#ifdef CONFIG_XEN_PVHVM
+/* Vector callbacks are better than PCI interrupts to receive event
+ * channel notifications because we can receive vector callbacks on any
+ * vcpu and we don't need PCI support or APIC interactions. */
+void xen_callback_vector(void)
+{
+       int rc;
+       uint64_t callback_via;
+       if (xen_have_vector_callback) {
+               callback_via = HVM_CALLBACK_VECTOR(HYPERVISOR_CALLBACK_VECTOR);
+               rc = xen_set_callback_via(callback_via);
+               if (rc) {
+                       pr_err("Request for Xen HVM callback vector failed\n");
+                       xen_have_vector_callback = 0;
+                       return;
+               }
+               pr_info("Xen HVM callback vector for event delivery is enabled\n");
+               /* in the restore case the vector has already been allocated */
+               if (!test_bit(HYPERVISOR_CALLBACK_VECTOR, used_vectors))
+                       alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR,
+                                       xen_hvm_callback_vector);
+       }
+}
+#else
+void xen_callback_vector(void) {}
+#endif
+
+#undef MODULE_PARAM_PREFIX
+#define MODULE_PARAM_PREFIX "xen."
+
+static bool fifo_events = true;
+module_param(fifo_events, bool, 0);
+
+void __init xen_init_IRQ(void)
+{
+       int ret = -EINVAL;
+
+       if (fifo_events)
+               ret = xen_evtchn_fifo_init();
+       if (ret < 0)
+               xen_evtchn_2l_init();
+
+       evtchn_to_irq = kcalloc(EVTCHN_ROW(xen_evtchn_max_channels()),
+                               sizeof(*evtchn_to_irq), GFP_KERNEL);
+       BUG_ON(!evtchn_to_irq);
+
+       /* No event channels are 'live' right now. */
+       xen_evtchn_mask_all();
+
+       pirq_needs_eoi = pirq_needs_eoi_flag;
+
+#ifdef CONFIG_X86
+       if (xen_pv_domain()) {
+               irq_ctx_init(smp_processor_id());
+               if (xen_initial_domain())
+                       pci_xen_initial_domain();
+       }
+       if (xen_feature(XENFEAT_hvm_callback_vector))
+               xen_callback_vector();
+
+       if (xen_hvm_domain()) {
+               native_init_IRQ();
+               /* pci_xen_hvm_init must be called after native_init_IRQ so that
+                * __acpi_register_gsi can point at the right function */
+               pci_xen_hvm_init();
+       } else {
+               int rc;
+               struct physdev_pirq_eoi_gmfn eoi_gmfn;
+
+               pirq_eoi_map = (void *)__get_free_page(GFP_KERNEL|__GFP_ZERO);
+               eoi_gmfn.gmfn = virt_to_mfn(pirq_eoi_map);
+               rc = HYPERVISOR_physdev_op(PHYSDEVOP_pirq_eoi_gmfn_v2, &eoi_gmfn);
+               /* TODO: No PVH support for PIRQ EOI */
+               if (rc != 0) {
+                       free_page((unsigned long) pirq_eoi_map);
+                       pirq_eoi_map = NULL;
+               } else
+                       pirq_needs_eoi = pirq_check_eoi_map;
+       }
+#endif
+}