--- a/Documentation/admin-guide/kernel-parameters.txt
+++ b/Documentation/admin-guide/kernel-parameters.txt
@@ -5270,6 +5270,14 @@
 			with /sys/devices/system/xen_memory/xen_memory0/scrub_pages.
 			Default value controlled with CONFIG_XEN_SCRUB_PAGES_DEFAULT.
 
+	xen.event_eoi_delay=	[XEN]
+			How long to delay EOI handling in case of event
+			storms (jiffies). Default is 10.
+
+	xen.event_loop_timeout=	[XEN]
+			After which time (jiffies) the event handling loop
+			should start to delay EOI handling. Default is 2.
+
 	xirc2ps_cs=	[NET,PCMCIA]
 			Format:
 			<irq>,<irq_mask>,<io>,<full_duplex>,<do_sound>,<lockup_hack>[,<irq2>[,<irq3>[,<irq4>]]]
--- a/drivers/xen/events/events_2l.c
+++ b/drivers/xen/events/events_2l.c
@@ -161,7 +161,7 @@ static inline xen_ulong_t active_evtchns
  * 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)
+static void evtchn_2l_handle_events(unsigned cpu, struct evtchn_loop_ctrl *ctrl)
 {
 	int irq;
 	xen_ulong_t pending_words;
@@ -242,10 +242,7 @@ static void evtchn_2l_handle_events(unsi
 
 			/* Process port. */
 			port = (word_idx * BITS_PER_EVTCHN_WORD) + bit_idx;
-			irq = get_evtchn_to_irq(port);
-
-			if (irq != -1)
-				generic_handle_irq(irq);
+			handle_irq_for_port(port, ctrl);
 
 			bit_idx = (bit_idx + 1) % BITS_PER_EVTCHN_WORD;
 
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -34,6 +34,8 @@
 #include <linux/pci.h>
 #include <linux/spinlock.h>
 #include <linux/cpuhotplug.h>
+#include <linux/atomic.h>
+#include <linux/ktime.h>
 
 #ifdef CONFIG_X86
 #include <asm/desc.h>
@@ -63,6 +65,15 @@
 
 #include "events_internal.h"
 
+#undef MODULE_PARAM_PREFIX
+#define MODULE_PARAM_PREFIX "xen."
+
+static uint __read_mostly event_loop_timeout = 2;
+module_param(event_loop_timeout, uint, 0644);
+
+static uint __read_mostly event_eoi_delay = 10;
+module_param(event_eoi_delay, uint, 0644);
+
 const struct evtchn_ops *evtchn_ops;
 
 /*
@@ -86,6 +97,7 @@ static DEFINE_RWLOCK(evtchn_rwlock);
  * irq_mapping_update_lock
  *   evtchn_rwlock
  *     IRQ-desc lock
+ *       percpu eoi_list_lock
  */
 
 static LIST_HEAD(xen_irq_list_head);
@@ -118,6 +130,8 @@ static struct irq_chip xen_pirq_chip;
 static void enable_dynirq(struct irq_data *data);
 static void disable_dynirq(struct irq_data *data);
 
+static DEFINE_PER_CPU(unsigned int, irq_epoch);
+
 static void clear_evtchn_to_irq_row(unsigned row)
 {
 	unsigned col;
@@ -397,17 +411,120 @@ void notify_remote_via_irq(int irq)
 }
 EXPORT_SYMBOL_GPL(notify_remote_via_irq);
 
+struct lateeoi_work {
+	struct delayed_work delayed;
+	spinlock_t eoi_list_lock;
+	struct list_head eoi_list;
+};
+
+static DEFINE_PER_CPU(struct lateeoi_work, lateeoi);
+
+static void lateeoi_list_del(struct irq_info *info)
+{
+	struct lateeoi_work *eoi = &per_cpu(lateeoi, info->eoi_cpu);
+	unsigned long flags;
+
+	spin_lock_irqsave(&eoi->eoi_list_lock, flags);
+	list_del_init(&info->eoi_list);
+	spin_unlock_irqrestore(&eoi->eoi_list_lock, flags);
+}
+
+static void lateeoi_list_add(struct irq_info *info)
+{
+	struct lateeoi_work *eoi = &per_cpu(lateeoi, info->eoi_cpu);
+	struct irq_info *elem;
+	u64 now = get_jiffies_64();
+	unsigned long delay;
+	unsigned long flags;
+
+	if (now < info->eoi_time)
+		delay = info->eoi_time - now;
+	else
+		delay = 1;
+
+	spin_lock_irqsave(&eoi->eoi_list_lock, flags);
+
+	if (list_empty(&eoi->eoi_list)) {
+		list_add(&info->eoi_list, &eoi->eoi_list);
+		mod_delayed_work_on(info->eoi_cpu, system_wq,
+				    &eoi->delayed, delay);
+	} else {
+		list_for_each_entry_reverse(elem, &eoi->eoi_list, eoi_list) {
+			if (elem->eoi_time <= info->eoi_time)
+				break;
+		}
+		list_add(&info->eoi_list, &elem->eoi_list);
+	}
+
+	spin_unlock_irqrestore(&eoi->eoi_list_lock, flags);
+}
+
 static void xen_irq_lateeoi_locked(struct irq_info *info)
 {
 	evtchn_port_t evtchn;
+	unsigned int cpu;
 
 	evtchn = info->evtchn;
-	if (!VALID_EVTCHN(evtchn))
+	if (!VALID_EVTCHN(evtchn) || !list_empty(&info->eoi_list))
+		return;
+
+	cpu = info->eoi_cpu;
+	if (info->eoi_time && info->irq_epoch == per_cpu(irq_epoch, cpu)) {
+		lateeoi_list_add(info);
 		return;
+	}
 
+	info->eoi_time = 0;
 	unmask_evtchn(evtchn);
 }
 
+static void xen_irq_lateeoi_worker(struct work_struct *work)
+{
+	struct lateeoi_work *eoi;
+	struct irq_info *info;
+	u64 now = get_jiffies_64();
+	unsigned long flags;
+
+	eoi = container_of(to_delayed_work(work), struct lateeoi_work, delayed);
+
+	read_lock_irqsave(&evtchn_rwlock, flags);
+
+	while (true) {
+		spin_lock(&eoi->eoi_list_lock);
+
+		info = list_first_entry_or_null(&eoi->eoi_list, struct irq_info,
+						eoi_list);
+
+		if (info == NULL || now < info->eoi_time) {
+			spin_unlock(&eoi->eoi_list_lock);
+			break;
+		}
+
+		list_del_init(&info->eoi_list);
+
+		spin_unlock(&eoi->eoi_list_lock);
+
+		info->eoi_time = 0;
+
+		xen_irq_lateeoi_locked(info);
+	}
+
+	if (info)
+		mod_delayed_work_on(info->eoi_cpu, system_wq,
+				    &eoi->delayed, info->eoi_time - now);
+
+	read_unlock_irqrestore(&evtchn_rwlock, flags);
+}
+
+static void xen_cpu_init_eoi(unsigned int cpu)
+{
+	struct lateeoi_work *eoi = &per_cpu(lateeoi, cpu);
+
+	INIT_DELAYED_WORK(&eoi->delayed, xen_irq_lateeoi_worker);
+	spin_lock_init(&eoi->eoi_list_lock);
+	INIT_LIST_HEAD(&eoi->eoi_list);
+}
+
 void xen_irq_lateeoi(unsigned int irq, unsigned int eoi_flags)
 {
 	struct irq_info *info;
@@ -427,6 +544,7 @@ EXPORT_SYMBOL_GPL(xen_irq_lateeoi);
 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_affinity_mask(irq), cpumask_of(0));
@@ -441,6 +559,7 @@ static void xen_irq_init(unsigned irq)
 
 	set_info_for_irq(irq, info);
 
+	INIT_LIST_HEAD(&info->eoi_list);
 	list_add_tail(&info->list, &xen_irq_list_head);
 }
 
@@ -496,6 +615,9 @@ static void xen_free_irq(unsigned irq)
 
 	write_lock_irqsave(&evtchn_rwlock, flags);
 
+	if (!list_empty(&info->eoi_list))
+		lateeoi_list_del(info);
+
 	list_del(&info->list);
 
 	set_info_for_irq(irq, NULL);
@@ -1355,6 +1477,54 @@ void xen_send_IPI_one(unsigned int cpu,
 	notify_remote_via_irq(irq);
 }
 
+struct evtchn_loop_ctrl {
+	ktime_t timeout;
+	unsigned count;
+	bool defer_eoi;
+};
+
+void handle_irq_for_port(evtchn_port_t port, struct evtchn_loop_ctrl *ctrl)
+{
+	int irq;
+	struct irq_info *info;
+
+	irq = get_evtchn_to_irq(port);
+	if (irq == -1)
+		return;
+
+	/*
+	 * Check for timeout every 256 events.
+	 * We are setting the timeout value only after the first 256
+	 * events in order to not hurt the common case of few loop
+	 * iterations. The 256 is basically an arbitrary value.
+	 *
+	 * In case we are hitting the timeout we need to defer all further
+	 * EOIs in order to ensure to leave the event handling loop rather
+	 * sooner than later.
+	 */
+	if (!ctrl->defer_eoi && !(++ctrl->count & 0xff)) {
+		ktime_t kt = ktime_get();
+
+		if (!ctrl->timeout) {
+			kt = ktime_add_ms(kt,
+					  jiffies_to_msecs(event_loop_timeout));
+			ctrl->timeout = kt;
+		} else if (kt > ctrl->timeout) {
+			ctrl->defer_eoi = true;
+		}
+	}
+
+	info = info_for_irq(irq);
+
+	if (ctrl->defer_eoi) {
+		info->eoi_cpu = smp_processor_id();
+		info->irq_epoch = __this_cpu_read(irq_epoch);
+		info->eoi_time = get_jiffies_64() + event_eoi_delay;
+	}
+
+	generic_handle_irq(irq);
+}
+
 static DEFINE_PER_CPU(unsigned, xed_nesting_count);
 
 static void __xen_evtchn_do_upcall(void)
@@ -1362,6 +1532,7 @@ static void __xen_evtchn_do_upcall(void)
 	struct vcpu_info *vcpu_info = __this_cpu_read(xen_vcpu);
 	int cpu = get_cpu();
 	unsigned count;
+	struct evtchn_loop_ctrl ctrl = { 0 };
 
 	read_lock(&evtchn_rwlock);
 
@@ -1371,7 +1542,7 @@ static void __xen_evtchn_do_upcall(void)
 		if (__this_cpu_inc_return(xed_nesting_count) - 1)
 			goto out;
 
-		xen_evtchn_handle_events(cpu);
+		xen_evtchn_handle_events(cpu, &ctrl);
 
 		BUG_ON(!irqs_disabled());
 
@@ -1382,6 +1553,13 @@ static void __xen_evtchn_do_upcall(void)
 out:
 	read_unlock(&evtchn_rwlock);
 
+	/*
+	 * Increment irq_epoch only now to defer EOIs only for
+	 * xen_irq_lateeoi() invocations occurring from inside the loop
+	 * above.
+	 */
+	__this_cpu_inc(irq_epoch);
+
 	put_cpu();
 }
 
@@ -1828,9 +2006,6 @@ void xen_callback_vector(void)
 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);
 
@@ -1838,6 +2013,8 @@ static int xen_evtchn_cpu_prepare(unsign
 {
 	int ret = 0;
 
+	xen_cpu_init_eoi(cpu);
+
 	if (evtchn_ops->percpu_init)
 		ret = evtchn_ops->percpu_init(cpu);
 
@@ -1864,6 +2041,8 @@ void __init xen_init_IRQ(void)
 	if (ret < 0)
 		xen_evtchn_2l_init();
 
+	xen_cpu_init_eoi(smp_processor_id());
+
 	cpuhp_setup_state_nocalls(CPUHP_XEN_EVTCHN_PREPARE,
 				  "xen/evtchn:prepare",
 				  xen_evtchn_cpu_prepare, xen_evtchn_cpu_dead);
--- a/drivers/xen/events/events_fifo.c
+++ b/drivers/xen/events/events_fifo.c
@@ -275,19 +275,9 @@ static uint32_t clear_linked(volatile ev
 	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,
+static void consume_one_event(unsigned cpu, struct evtchn_loop_ctrl *ctrl,
 			      struct evtchn_fifo_control_block *control_block,
-			      unsigned priority, unsigned long *ready,
-			      bool drop)
+			      unsigned priority, unsigned long *ready)
 {
 	struct evtchn_fifo_queue *q = &per_cpu(cpu_queue, cpu);
 	uint32_t head;
@@ -320,16 +310,17 @@ static void consume_one_event(unsigned c
 		clear_bit(priority, ready);
 
 	if (evtchn_fifo_is_pending(port) && !evtchn_fifo_is_masked(port)) {
-		if (unlikely(drop))
+		if (unlikely(!ctrl))
 			pr_warn("Dropping pending event for port %u\n", port);
 		else
-			handle_irq_for_port(port);
+			handle_irq_for_port(port, ctrl);
 	}
 
 	q->head[priority] = head;
 }
 
-static void __evtchn_fifo_handle_events(unsigned cpu, bool drop)
+static void __evtchn_fifo_handle_events(unsigned cpu,
+					struct evtchn_loop_ctrl *ctrl)
 {
 	struct evtchn_fifo_control_block *control_block;
 	unsigned long ready;
@@ -341,14 +332,15 @@ static void __evtchn_fifo_handle_events(
 
 	while (ready) {
 		q = find_first_bit(&ready, EVTCHN_FIFO_MAX_QUEUES);
-		consume_one_event(cpu, control_block, q, &ready, drop);
+		consume_one_event(cpu, ctrl, control_block, q, &ready);
 		ready |= xchg(&control_block->ready, 0);
 	}
 }
 
-static void evtchn_fifo_handle_events(unsigned cpu)
+static void evtchn_fifo_handle_events(unsigned cpu,
+				      struct evtchn_loop_ctrl *ctrl)
 {
-	__evtchn_fifo_handle_events(cpu, false);
+	__evtchn_fifo_handle_events(cpu, ctrl);
 }
 
 static void evtchn_fifo_resume(void)
@@ -416,7 +408,7 @@ static int evtchn_fifo_percpu_init(unsig
 
 static int evtchn_fifo_percpu_deinit(unsigned int cpu)
 {
-	__evtchn_fifo_handle_events(cpu, true);
+	__evtchn_fifo_handle_events(cpu, NULL);
 	return 0;
 }
 
--- a/drivers/xen/events/events_internal.h
+++ b/drivers/xen/events/events_internal.h
@@ -32,11 +32,15 @@ enum xen_irq_type {
  */
 struct irq_info {
 	struct list_head list;
+	struct list_head eoi_list;
 	int refcnt;
 	enum xen_irq_type type;	/* type */
 	unsigned irq;
 	unsigned int evtchn;	/* event channel */
 	unsigned short cpu;	/* cpu bound */
+	unsigned short eoi_cpu;	/* EOI must happen on this cpu */
+	unsigned int irq_epoch;	/* If eoi_cpu valid: irq_epoch of event */
+	u64 eoi_time;		/* Time in jiffies when to EOI. */
 
 	union {
 		unsigned short virq;
@@ -55,6 +59,8 @@ struct irq_info {
 #define PIRQ_SHAREABLE	(1 << 1)
 #define PIRQ_MSI_GROUP	(1 << 2)
 
+struct evtchn_loop_ctrl;
+
 struct evtchn_ops {
 	unsigned (*max_channels)(void);
 	unsigned (*nr_channels)(void);
@@ -69,7 +75,7 @@ struct evtchn_ops {
 	void (*mask)(unsigned port);
 	void (*unmask)(unsigned port);
 
-	void (*handle_events)(unsigned cpu);
+	void (*handle_events)(unsigned cpu, struct evtchn_loop_ctrl *ctrl);
 	void (*resume)(void);
 
 	int (*percpu_init)(unsigned int cpu);
@@ -80,6 +86,7 @@ extern const struct evtchn_ops *evtchn_o
 
 extern int **evtchn_to_irq;
 int get_evtchn_to_irq(unsigned int evtchn);
+void handle_irq_for_port(evtchn_port_t port, struct evtchn_loop_ctrl *ctrl);
 
 struct irq_info *info_for_irq(unsigned irq);
 unsigned cpu_from_irq(unsigned irq);
@@ -137,9 +144,10 @@ static inline void unmask_evtchn(unsigne
 	return evtchn_ops->unmask(port);
 }
 
-static inline void xen_evtchn_handle_events(unsigned cpu)
+static inline void xen_evtchn_handle_events(unsigned cpu,
+					    struct evtchn_loop_ctrl *ctrl)
 {
-	return evtchn_ops->handle_events(cpu);
+	return evtchn_ops->handle_events(cpu, ctrl);
 }
 
 static inline void xen_evtchn_resume(void)
