/*
   * 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
   */
  
  #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 <asm/hw_irq.h>

  /*
   * 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};

  /* Interrupt types. */
  enum xen_irq_type {

  	IRQT_UNBOUND = 0,

  	IRQT_PIRQ,
  	IRQT_VIRQ,
  	IRQT_IPI,
  	IRQT_EVTCHN
  };

  /*
   * Packed IRQ information:
   * type - enum xen_irq_type
   * event channel - irq->event channel mapping
   * cpu - cpu this event channel is bound to
   * index - type-specific information:

   *    PIRQ - physical IRQ, GSI, flags, and owner domain

   *    VIRQ - virq number
   *    IPI - IPI vector
   *    EVTCHN -
   */

  struct irq_info {

  	struct list_head list;

  	int refcnt;

  	enum xen_irq_type type;	/* type */

  	unsigned irq;

  	unsigned short evtchn;	/* event channel */
  	unsigned short cpu;	/* cpu bound */
  
  	union {
  		unsigned short virq;
  		enum ipi_vector ipi;
  		struct {

  			unsigned short pirq;

  			unsigned short gsi;

  			unsigned char flags;

  			uint16_t domid;

  		} pirq;
  	} u;
  };

  #define PIRQ_NEEDS_EOI	(1 << 0)

  #define PIRQ_SHAREABLE	(1 << 1)

  static int *evtchn_to_irq;

  #ifdef CONFIG_X86

  static unsigned long *pirq_eoi_map;

  #endif

  static bool (*pirq_needs_eoi)(unsigned irq);

  /*
   * Note sizeof(xen_ulong_t) can be more than sizeof(unsigned long). Be
   * careful to only use bitops which allow for this (e.g
   * test_bit/find_first_bit and friends but not __ffs) and to pass
   * BITS_PER_EVTCHN_WORD as the bitmask length.
   */
  #define BITS_PER_EVTCHN_WORD (sizeof(xen_ulong_t)*8)
  /*
   * Make a bitmask (i.e. unsigned long *) of a xen_ulong_t
   * array. Primarily to avoid long lines (hence the terse name).
   */
  #define BM(x) (unsigned long *)(x)
  /* Find the first set bit in a evtchn mask */
  #define EVTCHN_FIRST_BIT(w) find_first_bit(BM(&(w)), BITS_PER_EVTCHN_WORD)
  
  static DEFINE_PER_CPU(xen_ulong_t [NR_EVENT_CHANNELS/BITS_PER_EVTCHN_WORD],

  		      cpu_evtchn_mask);

  /* 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);

  /* Get info for IRQ */
  static struct irq_info *info_for_irq(unsigned irq)

  {

  	return irq_get_handler_data(irq);

  }

  /* Constructors for packed IRQ information. */
  static void xen_irq_info_common_init(struct irq_info *info,

  				     unsigned irq,

  				     enum xen_irq_type type,
  				     unsigned short evtchn,
  				     unsigned short cpu)

  {

  
  	BUG_ON(info->type != IRQT_UNBOUND && info->type != type);
  
  	info->type = type;

  	info->irq = irq;

  	info->evtchn = evtchn;
  	info->cpu = cpu;

  
  	evtchn_to_irq[evtchn] = irq;

  
  	irq_clear_status_flags(irq, IRQ_NOREQUEST|IRQ_NOAUTOEN);

  }

  static void xen_irq_info_evtchn_init(unsigned irq,
  				     unsigned short evtchn)

  {

  	struct irq_info *info = info_for_irq(irq);

  	xen_irq_info_common_init(info, irq, IRQT_EVTCHN, evtchn, 0);

  }

  static void xen_irq_info_ipi_init(unsigned cpu,
  				  unsigned irq,

  				  unsigned short evtchn,
  				  enum ipi_vector ipi)

  {

  	struct irq_info *info = info_for_irq(irq);

  	xen_irq_info_common_init(info, irq, IRQT_IPI, evtchn, 0);

  
  	info->u.ipi = ipi;

  
  	per_cpu(ipi_to_irq, cpu)[ipi] = irq;

  }

  static void xen_irq_info_virq_init(unsigned cpu,
  				   unsigned irq,

  				   unsigned short evtchn,
  				   unsigned short virq)

  {

  	struct irq_info *info = info_for_irq(irq);

  	xen_irq_info_common_init(info, irq, IRQT_VIRQ, evtchn, 0);

  
  	info->u.virq = virq;

  
  	per_cpu(virq_to_irq, cpu)[virq] = irq;

  }

  static void xen_irq_info_pirq_init(unsigned irq,
  				   unsigned short evtchn,
  				   unsigned short pirq,
  				   unsigned short gsi,

  				   uint16_t domid,

  				   unsigned char flags)

  {

  	struct irq_info *info = info_for_irq(irq);

  	xen_irq_info_common_init(info, irq, IRQT_PIRQ, evtchn, 0);

  
  	info->u.pirq.pirq = pirq;
  	info->u.pirq.gsi = gsi;

  	info->u.pirq.domid = domid;

  	info->u.pirq.flags = flags;

  }
  
  /*
   * Accessors for packed IRQ information.
   */

  static unsigned int evtchn_from_irq(unsigned irq)

  {

  	if (unlikely(WARN(irq < 0 || irq >= nr_irqs, "Invalid irq %d!
  ", irq)))
  		return 0;

  	return info_for_irq(irq)->evtchn;

  }

  unsigned irq_from_evtchn(unsigned int evtchn)
  {
  	return evtchn_to_irq[evtchn];
  }
  EXPORT_SYMBOL_GPL(irq_from_evtchn);

  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;
  }
  
  static unsigned cpu_from_irq(unsigned irq)
  {
  	return info_for_irq(irq)->cpu;
  }
  
  static unsigned int cpu_from_evtchn(unsigned int evtchn)
  {
  	int irq = 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 inline xen_ulong_t active_evtchns(unsigned int cpu,
  					 struct shared_info *sh,
  					 unsigned int idx)

  {

  	return sh->evtchn_pending[idx] &

  		per_cpu(cpu_evtchn_mask, cpu)[idx] &

  		~sh->evtchn_mask[idx];

  }
  
  static void bind_evtchn_to_cpu(unsigned int chn, unsigned int cpu)
  {
  	int irq = evtchn_to_irq[chn];
  
  	BUG_ON(irq == -1);
  #ifdef CONFIG_SMP

  	cpumask_copy(irq_to_desc(irq)->irq_data.affinity, cpumask_of(cpu));

  #endif

  	clear_bit(chn, BM(per_cpu(cpu_evtchn_mask, cpu_from_irq(irq))));
  	set_bit(chn, BM(per_cpu(cpu_evtchn_mask, cpu)));

  	info_for_irq(irq)->cpu = cpu;

  }
  
  static void init_evtchn_cpu_bindings(void)
  {

  	int i;

  #ifdef CONFIG_SMP

  	struct irq_info *info;

  	/* By default all event channels notify CPU#0. */

  	list_for_each_entry(info, &xen_irq_list_head, list) {
  		struct irq_desc *desc = irq_to_desc(info->irq);

  		cpumask_copy(desc->irq_data.affinity, cpumask_of(0));

  	}

  #endif

  	for_each_possible_cpu(i)

  		memset(per_cpu(cpu_evtchn_mask, i),

  		       (i == 0) ? ~0 : 0, NR_EVENT_CHANNELS/8);

  }

  static inline void clear_evtchn(int port)
  {
  	struct shared_info *s = HYPERVISOR_shared_info;

  	sync_clear_bit(port, BM(&s->evtchn_pending[0]));

  }
  
  static inline void set_evtchn(int port)
  {
  	struct shared_info *s = HYPERVISOR_shared_info;

  	sync_set_bit(port, BM(&s->evtchn_pending[0]));

  }

  static inline int test_evtchn(int port)
  {
  	struct shared_info *s = HYPERVISOR_shared_info;

  	return sync_test_bit(port, BM(&s->evtchn_pending[0]));

  }

  
  /**
   * 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 mask_evtchn(int port)
  {
  	struct shared_info *s = HYPERVISOR_shared_info;

  	sync_set_bit(port, BM(&s->evtchn_mask[0]));

  }
  
  static void unmask_evtchn(int port)
  {
  	struct shared_info *s = HYPERVISOR_shared_info;
  	unsigned int cpu = get_cpu();

  	int do_hypercall = 0, evtchn_pending = 0;

  
  	BUG_ON(!irqs_disabled());

  	if (unlikely((cpu != cpu_from_evtchn(port))))
  		do_hypercall = 1;

  	else {
  		/*
  		 * Need to clear the mask before checking pending to
  		 * avoid a race with an event becoming pending.
  		 *
  		 * EVTCHNOP_unmask will only trigger an upcall if the
  		 * mask bit was set, so if a hypercall is needed
  		 * remask the event.
  		 */
  		sync_clear_bit(port, BM(&s->evtchn_mask[0]));

  		evtchn_pending = sync_test_bit(port, BM(&s->evtchn_pending[0]));

  		if (unlikely(evtchn_pending && xen_hvm_domain())) {
  			sync_set_bit(port, BM(&s->evtchn_mask[0]));
  			do_hypercall = 1;
  		}
  	}

  
  	/* Slow path (hypercall) if this is a non-local port or if this is
  	 * an hvm domain and an event is pending (hvm domains don't have
  	 * their own implementation of irq_enable). */
  	if (do_hypercall) {

  		struct evtchn_unmask unmask = { .port = port };
  		(void)HYPERVISOR_event_channel_op(EVTCHNOP_unmask, &unmask);
  	} else {

  		struct vcpu_info *vcpu_info = __this_cpu_read(xen_vcpu);

  		/*
  		 * The following is basically the equivalent of
  		 * 'hw_resend_irq'. Just like a real IO-APIC we 'lose
  		 * the interrupt edge' if the channel is masked.
  		 */

  		if (evtchn_pending &&

  		    !sync_test_and_set_bit(port / BITS_PER_EVTCHN_WORD,
  					   BM(&vcpu_info->evtchn_pending_sel)))

  			vcpu_info->evtchn_upcall_pending = 1;
  	}
  
  	put_cpu();
  }

  static void xen_irq_init(unsigned irq)
  {
  	struct irq_info *info;

  #ifdef CONFIG_SMP

  	struct irq_desc *desc = irq_to_desc(irq);
  
  	/* By default all event channels notify CPU#0. */
  	cpumask_copy(desc->irq_data.affinity, cpumask_of(0));

  #endif

  	info = kzalloc(sizeof(*info), GFP_KERNEL);
  	if (info == NULL)
  		panic("Unable to allocate metadata for IRQ%d
  ", 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_irq_dynamic(void)

  {

  	int first = 0;
  	int irq;

  
  #ifdef CONFIG_X86_IO_APIC

  	/*
  	 * For an HVM guest or domain 0 which see "real" (emulated or

  	 * actual respectively) GSIs we allocate dynamic IRQs

  	 * e.g. those corresponding to event channels or MSIs
  	 * etc. from the range above those "real" GSIs to avoid
  	 * collisions.
  	 */
  	if (xen_initial_domain() || xen_hvm_domain())
  		first = get_nr_irqs_gsi();

  #endif

  	irq = irq_alloc_desc_from(first, -1);

  	if (irq >= 0)
  		xen_irq_init(irq);

  	return irq;

  }

  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 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 bool probing_irq(int irq)
  {
  	struct irq_desc *desc = irq_to_desc(irq);
  
  	return desc && desc->action == NULL;
  }

  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) {

  		if (!probing_irq(irq))
  			printk(KERN_INFO "Failed to obtain physical IRQ %d
  ",
  			       irq);
  		return 0;
  	}
  	evtchn = bind_pirq.port;
  
  	pirq_query_unmask(irq);
  
  	evtchn_to_irq[evtchn] = irq;
  	bind_evtchn_to_cpu(evtchn, 0);
  	info->evtchn = evtchn;
  
  out:
  	unmask_evtchn(evtchn);

  	eoi_pirq(irq_get_irq_data(irq));

  
  	return 0;
  }

  static unsigned int startup_pirq(struct irq_data *data)
  {
  	return __startup_pirq(data->irq);
  }
  
  static void shutdown_pirq(struct irq_data *data)

  {
  	struct evtchn_close close;

  	unsigned int irq = data->irq;

  	struct irq_info *info = info_for_irq(irq);
  	int evtchn = evtchn_from_irq(irq);
  
  	BUG_ON(info->type != IRQT_PIRQ);
  
  	if (!VALID_EVTCHN(evtchn))
  		return;
  
  	mask_evtchn(evtchn);
  
  	close.port = evtchn;
  	if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
  		BUG();
  
  	bind_evtchn_to_cpu(evtchn, 0);
  	evtchn_to_irq[evtchn] = -1;
  	info->evtchn = 0;
  }

  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);

  /*
   * 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;

  	mutex_lock(&irq_mapping_update_lock);

  	irq = xen_irq_from_gsi(gsi);

  	if (irq != -1) {

  		printk(KERN_INFO "xen_map_pirq_gsi: returning irq %d for gsi %u
  ",

  		       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;
  	}

  	xen_irq_info_pirq_init(irq, 0, pirq, gsi, DOMID_SELF,

  			       shareable ? PIRQ_SHAREABLE : 0);

  	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
  ");
  
  	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, const char *name, domid_t domid)

  {

  	int irq, ret;

  	mutex_lock(&irq_mapping_update_lock);

  	irq = xen_allocate_irq_dynamic();

  	if (irq < 0)

  		goto out;

  	irq_set_chip_and_handler_name(irq, &xen_pirq_chip, handle_edge_irq,
  			name);

  	xen_irq_info_pirq_init(irq, 0, pirq, 0, domid, 0);

  	ret = irq_set_msi_desc(irq, msidesc);

  	if (ret < 0)
  		goto error_irq;

  out:

  	mutex_unlock(&irq_mapping_update_lock);

  	return irq;

  error_irq:

  	mutex_unlock(&irq_mapping_update_lock);

  	xen_free_irq(irq);

  	return ret;

  }

  #endif

  int xen_destroy_irq(int irq)
  {
  	struct irq_desc *desc;

  	struct physdev_unmap_pirq unmap_irq;
  	struct irq_info *info = info_for_irq(irq);

  	int rc = -ENOENT;

  	mutex_lock(&irq_mapping_update_lock);

  
  	desc = irq_to_desc(irq);
  	if (!desc)
  		goto out;

  	if (xen_initial_domain()) {

  		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))
  			printk(KERN_INFO "domain %d does not have %d anymore
  ",
  				info->u.pirq.domid, info->u.pirq.pirq);
  		else if (rc) {

  			printk(KERN_WARNING "unmap irq failed %d
  ", 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;

  	mutex_lock(&irq_mapping_update_lock);

  
  	irq = 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");

  		xen_irq_info_evtchn_init(irq, evtchn);

  	} 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;

  	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;

  		xen_irq_info_ipi_init(cpu, irq, evtchn, ipi);

  
  		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;
  }

  static 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);
  }

  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 <= NR_EVENT_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;
  }

  int bind_virq_to_irq(unsigned int virq, unsigned int cpu)

  {
  	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;

  		irq_set_chip_and_handler_name(irq, &xen_percpu_chip,

  					      handle_percpu_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;
  		}

  		xen_irq_info_virq_init(cpu, irq, evtchn, virq);

  
  		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)
  {
  	struct evtchn_close close;
  	int evtchn = evtchn_from_irq(irq);

  	struct irq_info *info = irq_get_handler_data(irq);

  	if (WARN_ON(!info))
  		return;

  	mutex_lock(&irq_mapping_update_lock);

  	if (info->refcnt > 0) {
  		info->refcnt--;
  		if (info->refcnt != 0)
  			goto done;
  	}

  	if (VALID_EVTCHN(evtchn)) {

  		close.port = evtchn;
  		if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
  			BUG();
  
  		switch (type_from_irq(irq)) {
  		case IRQT_VIRQ:
  			per_cpu(virq_to_irq, cpu_from_evtchn(evtchn))

  				[virq_from_irq(irq)] = -1;

  			break;

  		case IRQT_IPI:
  			per_cpu(ipi_to_irq, cpu_from_evtchn(evtchn))

  				[ipi_from_irq(irq)] = -1;

  			break;

  		default:
  			break;
  		}
  
  		/* Closed ports are implicitly re-bound to VCPU0. */
  		bind_evtchn_to_cpu(evtchn, 0);
  
  		evtchn_to_irq[evtchn] = -1;

  	}

  	BUG_ON(info_for_irq(irq)->type == IRQT_UNBOUND);

  	xen_free_irq(irq);

   done:

  	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);

  	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);

  int evtchn_make_refcounted(unsigned int evtchn)
  {
  	int irq = 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 >= NR_EVENT_CHANNELS)
  		return -EINVAL;

  	mutex_lock(&irq_mapping_update_lock);
  
  	irq = 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 = 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 = per_cpu(ipi_to_irq, cpu)[vector];
  	BUG_ON(irq < 0);
  	notify_remote_via_irq(irq);
  }

  irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
  {
  	struct shared_info *sh = HYPERVISOR_shared_info;
  	int cpu = smp_processor_id();

  	xen_ulong_t *cpu_evtchn = per_cpu(cpu_evtchn_mask, cpu);

  	int i;
  	unsigned long flags;
  	static DEFINE_SPINLOCK(debug_lock);

  	struct vcpu_info *v;

  
  	spin_lock_irqsave(&debug_lock, flags);

  	printk("
  vcpu %d
    ", cpu);

  
  	for_each_online_cpu(i) {

  		int pending;
  		v = per_cpu(xen_vcpu, i);
  		pending = (get_irq_regs() && i == cpu)
  			? xen_irqs_disabled(get_irq_regs())
  			: v->evtchn_upcall_mask;

  		printk("%d: masked=%d pending=%d event_sel %0*"PRI_xen_ulong"
    ", i,

  		       pending, v->evtchn_upcall_pending,
  		       (int)(sizeof(v->evtchn_pending_sel)*2),
  		       v->evtchn_pending_sel);
  	}
  	v = per_cpu(xen_vcpu, cpu);
  
  	printk("
  pending:
     ");
  	for (i = ARRAY_SIZE(sh->evtchn_pending)-1; i >= 0; i--)

  		printk("%0*"PRI_xen_ulong"%s",
  		       (int)sizeof(sh->evtchn_pending[0])*2,

  		       sh->evtchn_pending[i],
  		       i % 8 == 0 ? "
     " : " ");
  	printk("
  global mask:
     ");
  	for (i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)

  		printk("%0*"PRI_xen_ulong"%s",

  		       (int)(sizeof(sh->evtchn_mask[0])*2),
  		       sh->evtchn_mask[i],
  		       i % 8 == 0 ? "
     " : " ");
  
  	printk("
  globally unmasked:
     ");
  	for (i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)

  		printk("%0*"PRI_xen_ulong"%s",
  		       (int)(sizeof(sh->evtchn_mask[0])*2),

  		       sh->evtchn_pending[i] & ~sh->evtchn_mask[i],
  		       i % 8 == 0 ? "
     " : " ");
  
  	printk("
  local cpu%d mask:
     ", cpu);

  	for (i = (NR_EVENT_CHANNELS/BITS_PER_EVTCHN_WORD)-1; i >= 0; i--)
  		printk("%0*"PRI_xen_ulong"%s", (int)(sizeof(cpu_evtchn[0])*2),

  		       cpu_evtchn[i],
  		       i % 8 == 0 ? "
     " : " ");
  
  	printk("
  locally unmasked:
     ");
  	for (i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--) {

  		xen_ulong_t pending = sh->evtchn_pending[i]

  			& ~sh->evtchn_mask[i]
  			& cpu_evtchn[i];

  		printk("%0*"PRI_xen_ulong"%s",
  		       (int)(sizeof(sh->evtchn_mask[0])*2),

  		       pending, i % 8 == 0 ? "
     " : " ");

  	}

  
  	printk("
  pending list:
  ");

  	for (i = 0; i < NR_EVENT_CHANNELS; i++) {

  		if (sync_test_bit(i, BM(sh->evtchn_pending))) {
  			int word_idx = i / BITS_PER_EVTCHN_WORD;

  			printk("  %d: event %d -> irq %d%s%s%s
  ",

  			       cpu_from_evtchn(i), i,

  			       evtchn_to_irq[i],

  			       sync_test_bit(word_idx, BM(&v->evtchn_pending_sel))

  					     ? "" : " l2-clear",

  			       !sync_test_bit(i, BM(sh->evtchn_mask))

  					     ? "" : " globally-masked",

  			       sync_test_bit(i, BM(cpu_evtchn))

  					     ? "" : " locally-masked");

  		}
  	}
  
  	spin_unlock_irqrestore(&debug_lock, flags);
  
  	return IRQ_HANDLED;
  }

  static DEFINE_PER_CPU(unsigned, xed_nesting_count);

  static DEFINE_PER_CPU(unsigned int, current_word_idx);
  static DEFINE_PER_CPU(unsigned int, current_bit_idx);

  /*

   * Mask out the i least significant bits of w
   */

  #define MASK_LSBS(w, i) (w & ((~((xen_ulong_t)0UL)) << i))

  /*
   * Search the CPUs pending events bitmasks.  For each one found, map
   * the event number to an irq, and feed it into do_IRQ() for
   * handling.
   *
   * Xen uses a two-level bitmap to speed searching.  The first level is
   * a bitset of words which contain pending event bits.  The second
   * level is a bitset of pending events themselves.
   */

  static void __xen_evtchn_do_upcall(void)

  {

  	int start_word_idx, start_bit_idx;

  	int word_idx, bit_idx;

  	int i, irq;

  	int cpu = get_cpu();
  	struct shared_info *s = HYPERVISOR_shared_info;

  	struct vcpu_info *vcpu_info = __this_cpu_read(xen_vcpu);

  	unsigned count;

  	do {

  		xen_ulong_t pending_words;

  		xen_ulong_t pending_bits;
  		struct irq_desc *desc;

  		vcpu_info->evtchn_upcall_pending = 0;

  		if (__this_cpu_inc_return(xed_nesting_count) - 1)

  			goto out;

  		/*
  		 * Master flag must be cleared /before/ clearing
  		 * selector flag. xchg_xen_ulong must contain an
  		 * appropriate barrier.
  		 */

  		if ((irq = per_cpu(virq_to_irq, cpu)[VIRQ_TIMER]) != -1) {
  			int evtchn = evtchn_from_irq(irq);
  			word_idx = evtchn / BITS_PER_LONG;
  			pending_bits = evtchn % BITS_PER_LONG;
  			if (active_evtchns(cpu, s, word_idx) & (1ULL << pending_bits)) {
  				desc = irq_to_desc(irq);
  				if (desc)
  					generic_handle_irq_desc(irq, desc);
  			}
  		}

  		pending_words = xchg_xen_ulong(&vcpu_info->evtchn_pending_sel, 0);

  		start_word_idx = __this_cpu_read(current_word_idx);
  		start_bit_idx = __this_cpu_read(current_bit_idx);
  
  		word_idx = start_word_idx;

  		for (i = 0; pending_words != 0; i++) {

  			xen_ulong_t words;

  			words = MASK_LSBS(pending_words, word_idx);
  
  			/*

  			 * If we masked out all events, wrap to beginning.

  			 */
  			if (words == 0) {

  				word_idx = 0;
  				bit_idx = 0;

  				continue;
  			}

  			word_idx = EVTCHN_FIRST_BIT(words);

  			pending_bits = active_evtchns(cpu, s, word_idx);
  			bit_idx = 0; /* usually scan entire word from start */
  			if (word_idx == start_word_idx) {
  				/* We scan the starting word in two parts */
  				if (i == 0)
  					/* 1st time: start in the middle */
  					bit_idx = start_bit_idx;
  				else
  					/* 2nd time: mask bits done already */
  					bit_idx &= (1UL << start_bit_idx) - 1;
  			}

  			do {

  				xen_ulong_t bits;

  				int port;

  				bits = MASK_LSBS(pending_bits, bit_idx);
  
  				/* If we masked out all events, move on. */

  				if (bits == 0)

  					break;

  				bit_idx = EVTCHN_FIRST_BIT(bits);

  
  				/* Process port. */

  				port = (word_idx * BITS_PER_EVTCHN_WORD) + bit_idx;

  				irq = evtchn_to_irq[port];

  				if (irq != -1) {
  					desc = irq_to_desc(irq);
  					if (desc)
  						generic_handle_irq_desc(irq, desc);
  				}

  				bit_idx = (bit_idx + 1) % BITS_PER_EVTCHN_WORD;

  
  				/* Next caller starts at last processed + 1 */
  				__this_cpu_write(current_word_idx,
  						 bit_idx ? word_idx :

  						 (word_idx+1) % BITS_PER_EVTCHN_WORD);

  				__this_cpu_write(current_bit_idx, bit_idx);
  			} while (bit_idx != 0);

  			/* Scan start_l1i twice; all others once. */
  			if ((word_idx != start_word_idx) || (i != 0))

  				pending_words &= ~(1UL << word_idx);

  			word_idx = (word_idx + 1) % BITS_PER_EVTCHN_WORD;

  		}

  		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();

  #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(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);

  	xen_irq_info_evtchn_init(irq, evtchn);

  	mutex_unlock(&irq_mapping_update_lock);

  
  	/* new event channels are always bound to cpu 0 */

  	irq_set_affinity(irq, cpumask_of(0));

  
  	/* 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 shared_info *s = HYPERVISOR_shared_info;

  	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 = sync_test_and_set_bit(evtchn, BM(s->evtchn_mask));
  
  	/*

  	 * 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(dest);

  	return rebind_irq_to_cpu(data->irq, tcpu);

  }

  int resend_irq_on_evtchn(unsigned int irq)
  {
  	int masked, evtchn = evtchn_from_irq(irq);
  	struct shared_info *s = HYPERVISOR_shared_info;
  
  	if (!VALID_EVTCHN(evtchn))
  		return 1;

  	masked = sync_test_and_set_bit(evtchn, BM(s->evtchn_mask));
  	sync_set_bit(evtchn, BM(s->evtchn_pending));

  	if (!masked)
  		unmask_evtchn(evtchn);
  
  	return 1;
  }

  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)

  {

  	int evtchn = evtchn_from_irq(data->irq);

  	struct shared_info *sh = HYPERVISOR_shared_info;

  	int ret = 0;
  
  	if (VALID_EVTCHN(evtchn)) {