Initial import

5 files changed, 2686 insertions, 0 deletions

diff --git a/drivers/xen/events/Makefile b/drivers/xen/events/Makefile
new file mode 100644
index 000000000..62be55cd9
--- /dev/null
+++ b/drivers/xen/events/Makefile
@@ -0,0 +1,5 @@
+obj-y += events.o
+
+events-y += events_base.o
+events-y += events_2l.o
+events-y += events_fifo.o
diff --git a/drivers/xen/events/events_2l.c b/drivers/xen/events/events_2l.c
new file mode 100644
index 000000000..7dd46312c
--- /dev/null
+++ b/drivers/xen/events/events_2l.c
@@ -0,0 +1,375 @@
+/*
+ * Xen event channels (2-level ABI)
+ *
+ * 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 <asm/sync_bitops.h>
+#include <asm/xen/hypercall.h>
+#include <asm/xen/hypervisor.h>
+
+#include <xen/xen.h>
+#include <xen/xen-ops.h>
+#include <xen/events.h>
+#include <xen/interface/xen.h>
+#include <xen/interface/event_channel.h>
+
+#include "events_internal.h"
+
+/*
+ * 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 [EVTCHN_2L_NR_CHANNELS/BITS_PER_EVTCHN_WORD],
+		      cpu_evtchn_mask);
+
+static unsigned evtchn_2l_max_channels(void)
+{
+	return EVTCHN_2L_NR_CHANNELS;
+}
+
+static void evtchn_2l_bind_to_cpu(struct irq_info *info, unsigned cpu)
+{
+	clear_bit(info->evtchn, BM(per_cpu(cpu_evtchn_mask, info->cpu)));
+	set_bit(info->evtchn, BM(per_cpu(cpu_evtchn_mask, cpu)));
+}
+
+static void evtchn_2l_clear_pending(unsigned port)
+{
+	struct shared_info *s = HYPERVISOR_shared_info;
+	sync_clear_bit(port, BM(&s->evtchn_pending[0]));
+}
+
+static void evtchn_2l_set_pending(unsigned port)
+{
+	struct shared_info *s = HYPERVISOR_shared_info;
+	sync_set_bit(port, BM(&s->evtchn_pending[0]));
+}
+
+static bool evtchn_2l_is_pending(unsigned port)
+{
+	struct shared_info *s = HYPERVISOR_shared_info;
+	return sync_test_bit(port, BM(&s->evtchn_pending[0]));
+}
+
+static bool evtchn_2l_test_and_set_mask(unsigned port)
+{
+	struct shared_info *s = HYPERVISOR_shared_info;
+	return sync_test_and_set_bit(port, BM(&s->evtchn_mask[0]));
+}
+
+static void evtchn_2l_mask(unsigned port)
+{
+	struct shared_info *s = HYPERVISOR_shared_info;
+	sync_set_bit(port, BM(&s->evtchn_mask[0]));
+}
+
+static void evtchn_2l_unmask(unsigned 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 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))
+
+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];
+}
+
+/*
+ * Search the CPU's 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 evtchn_2l_handle_events(unsigned cpu)
+{
+	int irq;
+	xen_ulong_t pending_words;
+	xen_ulong_t pending_bits;
+	int start_word_idx, start_bit_idx;
+	int word_idx, bit_idx;
+	int i;
+	struct shared_info *s = HYPERVISOR_shared_info;
+	struct vcpu_info *vcpu_info = __this_cpu_read(xen_vcpu);
+
+	/* Timer interrupt has highest priority. */
+	irq = irq_from_virq(cpu, VIRQ_TIMER);
+	if (irq != -1) {
+		unsigned int evtchn = evtchn_from_irq(irq);
+		word_idx = evtchn / BITS_PER_LONG;
+		bit_idx = evtchn % BITS_PER_LONG;
+		if (active_evtchns(cpu, s, word_idx) & (1ULL << bit_idx))
+			generic_handle_irq(irq);
+	}
+
+	/*
+	 * Master flag must be cleared /before/ clearing
+	 * selector flag. xchg_xen_ulong must contain an
+	 * appropriate barrier.
+	 */
+	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 */
+		/*
+		 * We scan the starting word in two parts.
+		 *
+		 * 1st time: start in the middle, scanning the
+		 * upper bits.
+		 *
+		 * 2nd time: scan the whole word (not just the
+		 * parts skipped in the first pass) -- if an
+		 * event in the previously scanned bits is
+		 * pending again it would just be scanned on
+		 * the next loop anyway.
+		 */
+		if (word_idx == start_word_idx) {
+			if (i == 0)
+				bit_idx = start_bit_idx;
+		}
+
+		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 = get_evtchn_to_irq(port);
+
+			if (irq != -1)
+				generic_handle_irq(irq);
+
+			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;
+	}
+}
+
+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("\nvcpu %d\n  ", 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"\n  ", i,
+		       pending, v->evtchn_upcall_pending,
+		       (int)(sizeof(v->evtchn_pending_sel)*2),
+		       v->evtchn_pending_sel);
+	}
+	v = per_cpu(xen_vcpu, cpu);
+
+	printk("\npending:\n   ");
+	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 ? "\n   " : " ");
+	printk("\nglobal mask:\n   ");
+	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 ? "\n   " : " ");
+
+	printk("\nglobally unmasked:\n   ");
+	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 ? "\n   " : " ");
+
+	printk("\nlocal cpu%d mask:\n   ", cpu);
+	for (i = (EVTCHN_2L_NR_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 ? "\n   " : " ");
+
+	printk("\nlocally unmasked:\n   ");
+	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 ? "\n   " : " ");
+	}
+
+	printk("\npending list:\n");
+	for (i = 0; i < EVTCHN_2L_NR_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\n",
+			       cpu_from_evtchn(i), i,
+			       get_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 void evtchn_2l_resume(void)
+{
+	int i;
+
+	for_each_online_cpu(i)
+		memset(per_cpu(cpu_evtchn_mask, i), 0, sizeof(xen_ulong_t) *
+				EVTCHN_2L_NR_CHANNELS/BITS_PER_EVTCHN_WORD);
+}
+
+static const struct evtchn_ops evtchn_ops_2l = {
+	.max_channels      = evtchn_2l_max_channels,
+	.nr_channels       = evtchn_2l_max_channels,
+	.bind_to_cpu       = evtchn_2l_bind_to_cpu,
+	.clear_pending     = evtchn_2l_clear_pending,
+	.set_pending       = evtchn_2l_set_pending,
+	.is_pending        = evtchn_2l_is_pending,
+	.test_and_set_mask = evtchn_2l_test_and_set_mask,
+	.mask              = evtchn_2l_mask,
+	.unmask            = evtchn_2l_unmask,
+	.handle_events     = evtchn_2l_handle_events,
+	.resume	           = evtchn_2l_resume,
+};
+
+void __init xen_evtchn_2l_init(void)
+{
+	pr_info("Using 2-level ABI\n");
+	evtchn_ops = &evtchn_ops_2l;
+}
diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
new file mode 100644
index 000000000..383879504
--- /dev/null
+++ b/drivers/xen/events/events_base.c
@@ -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
+}
diff --git a/drivers/xen/events/events_fifo.c b/drivers/xen/events/events_fifo.c
new file mode 100644
index 000000000..417415d73
--- /dev/null
+++ b/drivers/xen/events/events_fifo.c
@@ -0,0 +1,450 @@
+/*
+ * Xen event channels (FIFO-based ABI)
+ *
+ * Copyright (C) 2013 Citrix Systems R&D ltd.
+ *
+ * This source code is free software; you can redistribute it and/or
+ * modify it under the terms of the GNU General Public License as
+ * published by the Free Software Foundation; either version 2 of the
+ * License, or (at your option) any later version.
+ *
+ * Or, when distributed separately from the Linux kernel or
+ * incorporated into other software packages, subject to the following
+ * license:
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this source file (the "Software"), to deal in the Software without
+ * restriction, including without limitation the rights to use, copy, modify,
+ * merge, publish, distribute, sublicense, and/or sell copies of the Software,
+ * and to permit persons to whom the Software is furnished to do so, subject to
+ * the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+ * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
+ * IN THE SOFTWARE.
+ */
+
+#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/smp.h>
+#include <linux/percpu.h>
+#include <linux/cpu.h>
+
+#include <asm/sync_bitops.h>
+#include <asm/xen/hypercall.h>
+#include <asm/xen/hypervisor.h>
+#include <asm/xen/page.h>
+
+#include <xen/xen.h>
+#include <xen/xen-ops.h>
+#include <xen/events.h>
+#include <xen/interface/xen.h>
+#include <xen/interface/event_channel.h>
+
+#include "events_internal.h"
+
+#define EVENT_WORDS_PER_PAGE (PAGE_SIZE / sizeof(event_word_t))
+#define MAX_EVENT_ARRAY_PAGES (EVTCHN_FIFO_NR_CHANNELS / EVENT_WORDS_PER_PAGE)
+
+struct evtchn_fifo_queue {
+	uint32_t head[EVTCHN_FIFO_MAX_QUEUES];
+};
+
+static DEFINE_PER_CPU(struct evtchn_fifo_control_block *, cpu_control_block);
+static DEFINE_PER_CPU(struct evtchn_fifo_queue, cpu_queue);
+static event_word_t *event_array[MAX_EVENT_ARRAY_PAGES] __read_mostly;
+static unsigned event_array_pages __read_mostly;
+
+/*
+ * sync_set_bit() and friends must be unsigned long aligned.
+ */
+#if BITS_PER_LONG > 32
+
+#define BM(w) (unsigned long *)((unsigned long)w & ~0x7UL)
+#define EVTCHN_FIFO_BIT(b, w) \
+    (((unsigned long)w & 0x4UL) ? (EVTCHN_FIFO_ ##b + 32) : EVTCHN_FIFO_ ##b)
+
+#else
+
+#define BM(w) ((unsigned long *)(w))
+#define EVTCHN_FIFO_BIT(b, w) EVTCHN_FIFO_ ##b
+
+#endif
+
+static inline event_word_t *event_word_from_port(unsigned port)
+{
+	unsigned i = port / EVENT_WORDS_PER_PAGE;
+
+	return event_array[i] + port % EVENT_WORDS_PER_PAGE;
+}
+
+static unsigned evtchn_fifo_max_channels(void)
+{
+	return EVTCHN_FIFO_NR_CHANNELS;
+}
+
+static unsigned evtchn_fifo_nr_channels(void)
+{
+	return event_array_pages * EVENT_WORDS_PER_PAGE;
+}
+
+static int init_control_block(int cpu,
+                              struct evtchn_fifo_control_block *control_block)
+{
+	struct evtchn_fifo_queue *q = &per_cpu(cpu_queue, cpu);
+	struct evtchn_init_control init_control;
+	unsigned int i;
+
+	/* Reset the control block and the local HEADs. */
+	clear_page(control_block);
+	for (i = 0; i < EVTCHN_FIFO_MAX_QUEUES; i++)
+		q->head[i] = 0;
+
+	init_control.control_gfn = virt_to_mfn(control_block);
+	init_control.offset      = 0;
+	init_control.vcpu        = cpu;
+
+	return HYPERVISOR_event_channel_op(EVTCHNOP_init_control, &init_control);
+}
+
+static void free_unused_array_pages(void)
+{
+	unsigned i;
+
+	for (i = event_array_pages; i < MAX_EVENT_ARRAY_PAGES; i++) {
+		if (!event_array[i])
+			break;
+		free_page((unsigned long)event_array[i]);
+		event_array[i] = NULL;
+	}
+}
+
+static void init_array_page(event_word_t *array_page)
+{
+	unsigned i;
+
+	for (i = 0; i < EVENT_WORDS_PER_PAGE; i++)
+		array_page[i] = 1 << EVTCHN_FIFO_MASKED;
+}
+
+static int evtchn_fifo_setup(struct irq_info *info)
+{
+	unsigned port = info->evtchn;
+	unsigned new_array_pages;
+	int ret;
+
+	new_array_pages = port / EVENT_WORDS_PER_PAGE + 1;
+
+	if (new_array_pages > MAX_EVENT_ARRAY_PAGES)
+		return -EINVAL;
+
+	while (event_array_pages < new_array_pages) {
+		void *array_page;
+		struct evtchn_expand_array expand_array;
+
+		/* Might already have a page if we've resumed. */
+		array_page = event_array[event_array_pages];
+		if (!array_page) {
+			array_page = (void *)__get_free_page(GFP_KERNEL);
+			if (array_page == NULL) {
+				ret = -ENOMEM;
+				goto error;
+			}
+			event_array[event_array_pages] = array_page;
+		}
+
+		/* Mask all events in this page before adding it. */
+		init_array_page(array_page);
+
+		expand_array.array_gfn = virt_to_mfn(array_page);
+
+		ret = HYPERVISOR_event_channel_op(EVTCHNOP_expand_array, &expand_array);
+		if (ret < 0)
+			goto error;
+
+		event_array_pages++;
+	}
+	return 0;
+
+  error:
+	if (event_array_pages == 0)
+		panic("xen: unable to expand event array with initial page (%d)\n", ret);
+	else
+		pr_err("unable to expand event array (%d)\n", ret);
+	free_unused_array_pages();
+	return ret;
+}
+
+static void evtchn_fifo_bind_to_cpu(struct irq_info *info, unsigned cpu)
+{
+	/* no-op */
+}
+
+static void evtchn_fifo_clear_pending(unsigned port)
+{
+	event_word_t *word = event_word_from_port(port);
+	sync_clear_bit(EVTCHN_FIFO_BIT(PENDING, word), BM(word));
+}
+
+static void evtchn_fifo_set_pending(unsigned port)
+{
+	event_word_t *word = event_word_from_port(port);
+	sync_set_bit(EVTCHN_FIFO_BIT(PENDING, word), BM(word));
+}
+
+static bool evtchn_fifo_is_pending(unsigned port)
+{
+	event_word_t *word = event_word_from_port(port);
+	return sync_test_bit(EVTCHN_FIFO_BIT(PENDING, word), BM(word));
+}
+
+static bool evtchn_fifo_test_and_set_mask(unsigned port)
+{
+	event_word_t *word = event_word_from_port(port);
+	return sync_test_and_set_bit(EVTCHN_FIFO_BIT(MASKED, word), BM(word));
+}
+
+static void evtchn_fifo_mask(unsigned port)
+{
+	event_word_t *word = event_word_from_port(port);
+	sync_set_bit(EVTCHN_FIFO_BIT(MASKED, word), BM(word));
+}
+
+static bool evtchn_fifo_is_masked(unsigned port)
+{
+	event_word_t *word = event_word_from_port(port);
+	return sync_test_bit(EVTCHN_FIFO_BIT(MASKED, word), BM(word));
+}
+/*
+ * Clear MASKED, spinning if BUSY is set.
+ */
+static void clear_masked(volatile event_word_t *word)
+{
+	event_word_t new, old, w;
+
+	w = *word;
+
+	do {
+		old = w & ~(1 << EVTCHN_FIFO_BUSY);
+		new = old & ~(1 << EVTCHN_FIFO_MASKED);
+		w = sync_cmpxchg(word, old, new);
+	} while (w != old);
+}
+
+static void evtchn_fifo_unmask(unsigned port)
+{
+	event_word_t *word = event_word_from_port(port);
+
+	BUG_ON(!irqs_disabled());
+
+	clear_masked(word);
+	if (evtchn_fifo_is_pending(port)) {
+		struct evtchn_unmask unmask = { .port = port };
+		(void)HYPERVISOR_event_channel_op(EVTCHNOP_unmask, &unmask);
+	}
+}
+
+static uint32_t clear_linked(volatile event_word_t *word)
+{
+	event_word_t new, old, w;
+
+	w = *word;
+
+	do {
+		old = w;
+		new = (w & ~((1 << EVTCHN_FIFO_LINKED)
+			     | EVTCHN_FIFO_LINK_MASK));
+	} while ((w = sync_cmpxchg(word, old, new)) != old);
+
+	return w & EVTCHN_FIFO_LINK_MASK;
+}
+
+static void handle_irq_for_port(unsigned port)
+{
+	int irq;
+
+	irq = get_evtchn_to_irq(port);
+	if (irq != -1)
+		generic_handle_irq(irq);
+}
+
+static void consume_one_event(unsigned cpu,
+			      struct evtchn_fifo_control_block *control_block,
+			      unsigned priority, unsigned long *ready)
+{
+	struct evtchn_fifo_queue *q = &per_cpu(cpu_queue, cpu);
+	uint32_t head;
+	unsigned port;
+	event_word_t *word;
+
+	head = q->head[priority];
+
+	/*
+	 * Reached the tail last time?  Read the new HEAD from the
+	 * control block.
+	 */
+	if (head == 0) {
+		rmb(); /* Ensure word is up-to-date before reading head. */
+		head = control_block->head[priority];
+	}
+
+	port = head;
+	word = event_word_from_port(port);
+	head = clear_linked(word);
+
+	/*
+	 * If the link is non-zero, there are more events in the
+	 * queue, otherwise the queue is empty.
+	 *
+	 * If the queue is empty, clear this priority from our local
+	 * copy of the ready word.
+	 */
+	if (head == 0)
+		clear_bit(priority, ready);
+
+	if (evtchn_fifo_is_pending(port) && !evtchn_fifo_is_masked(port))
+		handle_irq_for_port(port);
+
+	q->head[priority] = head;
+}
+
+static void evtchn_fifo_handle_events(unsigned cpu)
+{
+	struct evtchn_fifo_control_block *control_block;
+	unsigned long ready;
+	unsigned q;
+
+	control_block = per_cpu(cpu_control_block, cpu);
+
+	ready = xchg(&control_block->ready, 0);
+
+	while (ready) {
+		q = find_first_bit(&ready, EVTCHN_FIFO_MAX_QUEUES);
+		consume_one_event(cpu, control_block, q, &ready);
+		ready |= xchg(&control_block->ready, 0);
+	}
+}
+
+static void evtchn_fifo_resume(void)
+{
+	unsigned cpu;
+
+	for_each_possible_cpu(cpu) {
+		void *control_block = per_cpu(cpu_control_block, cpu);
+		int ret;
+
+		if (!control_block)
+			continue;
+
+		/*
+		 * If this CPU is offline, take the opportunity to
+		 * free the control block while it is not being
+		 * used.
+		 */
+		if (!cpu_online(cpu)) {
+			free_page((unsigned long)control_block);
+			per_cpu(cpu_control_block, cpu) = NULL;
+			continue;
+		}
+
+		ret = init_control_block(cpu, control_block);
+		if (ret < 0)
+			BUG();
+	}
+
+	/*
+	 * The event array starts out as empty again and is extended
+	 * as normal when events are bound.  The existing pages will
+	 * be reused.
+	 */
+	event_array_pages = 0;
+}
+
+static const struct evtchn_ops evtchn_ops_fifo = {
+	.max_channels      = evtchn_fifo_max_channels,
+	.nr_channels       = evtchn_fifo_nr_channels,
+	.setup             = evtchn_fifo_setup,
+	.bind_to_cpu       = evtchn_fifo_bind_to_cpu,
+	.clear_pending     = evtchn_fifo_clear_pending,
+	.set_pending       = evtchn_fifo_set_pending,
+	.is_pending        = evtchn_fifo_is_pending,
+	.test_and_set_mask = evtchn_fifo_test_and_set_mask,
+	.mask              = evtchn_fifo_mask,
+	.unmask            = evtchn_fifo_unmask,
+	.handle_events     = evtchn_fifo_handle_events,
+	.resume            = evtchn_fifo_resume,
+};
+
+static int evtchn_fifo_alloc_control_block(unsigned cpu)
+{
+	void *control_block = NULL;
+	int ret = -ENOMEM;
+
+	control_block = (void *)__get_free_page(GFP_KERNEL);
+	if (control_block == NULL)
+		goto error;
+
+	ret = init_control_block(cpu, control_block);
+	if (ret < 0)
+		goto error;
+
+	per_cpu(cpu_control_block, cpu) = control_block;
+
+	return 0;
+
+  error:
+	free_page((unsigned long)control_block);
+	return ret;
+}
+
+static int evtchn_fifo_cpu_notification(struct notifier_block *self,
+						  unsigned long action,
+						  void *hcpu)
+{
+	int cpu = (long)hcpu;
+	int ret = 0;
+
+	switch (action) {
+	case CPU_UP_PREPARE:
+		if (!per_cpu(cpu_control_block, cpu))
+			ret = evtchn_fifo_alloc_control_block(cpu);
+		break;
+	default:
+		break;
+	}
+	return ret < 0 ? NOTIFY_BAD : NOTIFY_OK;
+}
+
+static struct notifier_block evtchn_fifo_cpu_notifier = {
+	.notifier_call	= evtchn_fifo_cpu_notification,
+};
+
+int __init xen_evtchn_fifo_init(void)
+{
+	int cpu = get_cpu();
+	int ret;
+
+	ret = evtchn_fifo_alloc_control_block(cpu);
+	if (ret < 0)
+		goto out;
+
+	pr_info("Using FIFO-based ABI\n");
+
+	evtchn_ops = &evtchn_ops_fifo;
+
+	register_cpu_notifier(&evtchn_fifo_cpu_notifier);
+out:
+	put_cpu();
+	return ret;
+}
diff --git a/drivers/xen/events/events_internal.h b/drivers/xen/events/events_internal.h
new file mode 100644
index 000000000..50c2050a1
--- /dev/null
+++ b/drivers/xen/events/events_internal.h
@@ -0,0 +1,151 @@
+/*
+ * Xen Event Channels (internal header)
+ *
+ * Copyright (C) 2013 Citrix Systems R&D Ltd.
+ *
+ * This source code is licensed under the GNU General Public License,
+ * Version 2 or later.  See the file COPYING for more details.
+ */
+#ifndef __EVENTS_INTERNAL_H__
+#define __EVENTS_INTERNAL_H__
+
+/* 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 - vector, with MSB being "needs EIO", or physical IRQ of the HVM
+ *           guest, or GSI (real passthrough IRQ) of the device.
+ *    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 int 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 vector;
+			unsigned char flags;
+			uint16_t domid;
+		} pirq;
+	} u;
+};
+
+#define PIRQ_NEEDS_EOI	(1 << 0)
+#define PIRQ_SHAREABLE	(1 << 1)
+#define PIRQ_MSI_GROUP	(1 << 2)
+
+struct evtchn_ops {
+	unsigned (*max_channels)(void);
+	unsigned (*nr_channels)(void);
+
+	int (*setup)(struct irq_info *info);
+	void (*bind_to_cpu)(struct irq_info *info, unsigned cpu);
+
+	void (*clear_pending)(unsigned port);
+	void (*set_pending)(unsigned port);
+	bool (*is_pending)(unsigned port);
+	bool (*test_and_set_mask)(unsigned port);
+	void (*mask)(unsigned port);
+	void (*unmask)(unsigned port);
+
+	void (*handle_events)(unsigned cpu);
+	void (*resume)(void);
+};
+
+extern const struct evtchn_ops *evtchn_ops;
+
+extern int **evtchn_to_irq;
+int get_evtchn_to_irq(unsigned int evtchn);
+
+struct irq_info *info_for_irq(unsigned irq);
+unsigned cpu_from_irq(unsigned irq);
+unsigned cpu_from_evtchn(unsigned int evtchn);
+
+static inline unsigned xen_evtchn_max_channels(void)
+{
+	return evtchn_ops->max_channels();
+}
+
+/*
+ * Do any ABI specific setup for a bound event channel before it can
+ * be unmasked and used.
+ */
+static inline int xen_evtchn_port_setup(struct irq_info *info)
+{
+	if (evtchn_ops->setup)
+		return evtchn_ops->setup(info);
+	return 0;
+}
+
+static inline void xen_evtchn_port_bind_to_cpu(struct irq_info *info,
+					       unsigned cpu)
+{
+	evtchn_ops->bind_to_cpu(info, cpu);
+}
+
+static inline void clear_evtchn(unsigned port)
+{
+	evtchn_ops->clear_pending(port);
+}
+
+static inline void set_evtchn(unsigned port)
+{
+	evtchn_ops->set_pending(port);
+}
+
+static inline bool test_evtchn(unsigned port)
+{
+	return evtchn_ops->is_pending(port);
+}
+
+static inline bool test_and_set_mask(unsigned port)
+{
+	return evtchn_ops->test_and_set_mask(port);
+}
+
+static inline void mask_evtchn(unsigned port)
+{
+	return evtchn_ops->mask(port);
+}
+
+static inline void unmask_evtchn(unsigned port)
+{
+	return evtchn_ops->unmask(port);
+}
+
+static inline void xen_evtchn_handle_events(unsigned cpu)
+{
+	return evtchn_ops->handle_events(cpu);
+}
+
+static inline void xen_evtchn_resume(void)
+{
+	if (evtchn_ops->resume)
+		evtchn_ops->resume();
+}
+
+void xen_evtchn_2l_init(void);
+int xen_evtchn_fifo_init(void);
+
+#endif /* #ifndef __EVENTS_INTERNAL_H__ */