[v2,2/8] xen/events: don't unmask an event channel when an eoi is pending

diff --git a/drivers/xen/events/events_2l.c b/drivers/xen/events/events_2l.c
index a7f413c5c190..b8f2f971c2f0 100644
--- a/drivers/xen/events/events_2l.c
+++ b/drivers/xen/events/events_2l.c
@@ -77,12 +77,6 @@  static bool evtchn_2l_is_pending(evtchn_port_t port)
 	return sync_test_bit(port, BM(&s->evtchn_pending[0]));
 }
 
-static bool evtchn_2l_test_and_set_mask(evtchn_port_t 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(evtchn_port_t port)
 {
 	struct shared_info *s = HYPERVISOR_shared_info;
@@ -376,7 +370,6 @@  static const struct evtchn_ops evtchn_ops_2l = {
 	.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,
diff --git a/drivers/xen/events/events_base.c b/drivers/xen/events/events_base.c
index 6c539db81f8f..e157e7506830 100644
--- a/drivers/xen/events/events_base.c
+++ b/drivers/xen/events/events_base.c
@@ -97,13 +97,18 @@  struct irq_info {
 	short refcnt;
 	u8 spurious_cnt;
 	u8 is_accounted;
-	enum xen_irq_type type; /* type */
+	short type;		/* type: IRQT_* */
+	u8 mask_reason;		/* Why is event channel masked */
+#define EVT_MASK_REASON_EXPLICIT	0x01
+#define EVT_MASK_REASON_TEMPORARY	0x02
+#define EVT_MASK_REASON_EOI_PENDING	0x04
 	unsigned irq;
 	evtchn_port_t evtchn;   /* event channel */
 	unsigned short cpu;     /* cpu bound */
 	unsigned short eoi_cpu; /* EOI must happen on this cpu-1 */
 	unsigned int irq_epoch; /* If eoi_cpu valid: irq_epoch of event */
 	u64 eoi_time;           /* Time in jiffies when to EOI. */
+	spinlock_t lock;
 
 	union {
 		unsigned short virq;
@@ -152,6 +157,7 @@  static DEFINE_RWLOCK(evtchn_rwlock);
  *   evtchn_rwlock
  *     IRQ-desc lock
  *       percpu eoi_list_lock
+ *         irq_info->lock
  */
 
 static LIST_HEAD(xen_irq_list_head);
@@ -302,6 +308,8 @@  static int xen_irq_info_common_setup(struct irq_info *info,
 	info->irq = irq;
 	info->evtchn = evtchn;
 	info->cpu = cpu;
+	info->mask_reason = EVT_MASK_REASON_EXPLICIT;
+	spin_lock_init(&info->lock);
 
 	ret = set_evtchn_to_irq(evtchn, irq);
 	if (ret < 0)
@@ -450,6 +458,34 @@  unsigned int cpu_from_evtchn(evtchn_port_t evtchn)
 	return ret;
 }
 
+static void do_mask(struct irq_info *info, u8 reason)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&info->lock, flags);
+
+	if (!info->mask_reason)
+		mask_evtchn(info->evtchn);
+
+	info->mask_reason |= reason;
+
+	spin_unlock_irqrestore(&info->lock, flags);
+}
+
+static void do_unmask(struct irq_info *info, u8 reason)
+{
+	unsigned long flags;
+
+	spin_lock_irqsave(&info->lock, flags);
+
+	info->mask_reason &= ~reason;
+
+	if (!info->mask_reason)
+		unmask_evtchn(info->evtchn);
+
+	spin_unlock_irqrestore(&info->lock, flags);
+}
+
 #ifdef CONFIG_X86
 static bool pirq_check_eoi_map(unsigned irq)
 {
@@ -586,7 +622,7 @@  static void xen_irq_lateeoi_locked(struct irq_info *info, bool spurious)
 	}
 
 	info->eoi_time = 0;
-	unmask_evtchn(evtchn);
+	do_unmask(info, EVT_MASK_REASON_EOI_PENDING);
 }
 
 static void xen_irq_lateeoi_worker(struct work_struct *work)
@@ -831,7 +867,8 @@  static unsigned int __startup_pirq(unsigned int irq)
 		goto err;
 
 out:
-	unmask_evtchn(evtchn);
+	do_unmask(info, EVT_MASK_REASON_EXPLICIT);
+
 	eoi_pirq(irq_get_irq_data(irq));
 
 	return 0;
@@ -858,7 +895,7 @@  static void shutdown_pirq(struct irq_data *data)
 	if (!VALID_EVTCHN(evtchn))
 		return;
 
-	mask_evtchn(evtchn);
+	do_mask(info, EVT_MASK_REASON_EXPLICIT);
 	xen_evtchn_close(evtchn);
 	xen_irq_info_cleanup(info);
 }
@@ -1691,10 +1728,10 @@  void rebind_evtchn_irq(evtchn_port_t evtchn, int irq)
 }
 
 /* Rebind an evtchn so that it gets delivered to a specific cpu */
-static int xen_rebind_evtchn_to_cpu(evtchn_port_t evtchn, unsigned int tcpu)
+static int xen_rebind_evtchn_to_cpu(struct irq_info *info, unsigned int tcpu)
 {
 	struct evtchn_bind_vcpu bind_vcpu;
-	int masked;
+	evtchn_port_t evtchn = info ? info->evtchn : 0;
 
 	if (!VALID_EVTCHN(evtchn))
 		return -1;
@@ -1710,7 +1747,7 @@  static int xen_rebind_evtchn_to_cpu(evtchn_port_t evtchn, unsigned int tcpu)
 	 * Mask the event while changing the VCPU binding to prevent
 	 * it being delivered on an unexpected VCPU.
 	 */
-	masked = test_and_set_mask(evtchn);
+	do_mask(info, EVT_MASK_REASON_TEMPORARY);
 
 	/*
 	 * If this fails, it usually just indicates that we're dealing with a
@@ -1720,8 +1757,7 @@  static int xen_rebind_evtchn_to_cpu(evtchn_port_t evtchn, unsigned int tcpu)
 	if (HYPERVISOR_event_channel_op(EVTCHNOP_bind_vcpu, &bind_vcpu) >= 0)
 		bind_evtchn_to_cpu(evtchn, tcpu, false);
 
-	if (!masked)
-		unmask_evtchn(evtchn);
+	do_unmask(info, EVT_MASK_REASON_TEMPORARY);
 
 	return 0;
 }
@@ -1760,7 +1796,7 @@  static int set_affinity_irq(struct irq_data *data, const struct cpumask *dest,
 	unsigned int tcpu = select_target_cpu(dest);
 	int ret;
 
-	ret = xen_rebind_evtchn_to_cpu(evtchn_from_irq(data->irq), tcpu);
+	ret = xen_rebind_evtchn_to_cpu(info_for_irq(data->irq), tcpu);
 	if (!ret)
 		irq_data_update_effective_affinity(data, cpumask_of(tcpu));
 
@@ -1769,18 +1805,20 @@  static int set_affinity_irq(struct irq_data *data, const struct cpumask *dest,
 
 static void enable_dynirq(struct irq_data *data)
 {
-	evtchn_port_t evtchn = evtchn_from_irq(data->irq);
+	struct irq_info *info = info_for_irq(data->irq);
+	evtchn_port_t evtchn = info ? info->evtchn : 0;
 
 	if (VALID_EVTCHN(evtchn))
-		unmask_evtchn(evtchn);
+		do_unmask(info, EVT_MASK_REASON_EXPLICIT);
 }
 
 static void disable_dynirq(struct irq_data *data)
 {
-	evtchn_port_t evtchn = evtchn_from_irq(data->irq);
+	struct irq_info *info = info_for_irq(data->irq);
+	evtchn_port_t evtchn = info ? info->evtchn : 0;
 
 	if (VALID_EVTCHN(evtchn))
-		mask_evtchn(evtchn);
+		do_mask(info, EVT_MASK_REASON_EXPLICIT);
 }
 
 static void ack_dynirq(struct irq_data *data)
@@ -1799,18 +1837,40 @@  static void mask_ack_dynirq(struct irq_data *data)
 	ack_dynirq(data);
 }
 
+static void lateeoi_ack_dynirq(struct irq_data *data)
+{
+	struct irq_info *info = info_for_irq(data->irq);
+	evtchn_port_t evtchn = info ? info->evtchn : 0;
+
+	if (VALID_EVTCHN(evtchn)) {
+		do_mask(info, EVT_MASK_REASON_EOI_PENDING);
+		clear_evtchn(evtchn);
+	}
+}
+
+static void lateeoi_mask_ack_dynirq(struct irq_data *data)
+{
+	struct irq_info *info = info_for_irq(data->irq);
+	evtchn_port_t evtchn = info ? info->evtchn : 0;
+
+	if (VALID_EVTCHN(evtchn)) {
+		do_mask(info, EVT_MASK_REASON_EXPLICIT |
+			      EVT_MASK_REASON_EOI_PENDING);
+		clear_evtchn(evtchn);
+	}
+}
+
 static int retrigger_dynirq(struct irq_data *data)
 {
-	evtchn_port_t evtchn = evtchn_from_irq(data->irq);
-	int masked;
+	struct irq_info *info = info_for_irq(data->irq);
+	evtchn_port_t evtchn = info ? info->evtchn : 0;
 
 	if (!VALID_EVTCHN(evtchn))
 		return 0;
 
-	masked = test_and_set_mask(evtchn);
+	do_mask(info, EVT_MASK_REASON_TEMPORARY);
 	set_evtchn(evtchn);
-	if (!masked)
-		unmask_evtchn(evtchn);
+	do_unmask(info, EVT_MASK_REASON_TEMPORARY);
 
 	return 1;
 }
@@ -2024,8 +2084,8 @@  static struct irq_chip xen_lateeoi_chip __read_mostly = {
 	.irq_mask		= disable_dynirq,
 	.irq_unmask		= enable_dynirq,
 
-	.irq_ack		= mask_ack_dynirq,
-	.irq_mask_ack		= mask_ack_dynirq,
+	.irq_ack		= lateeoi_ack_dynirq,
+	.irq_mask_ack		= lateeoi_mask_ack_dynirq,
 
 	.irq_set_affinity	= set_affinity_irq,
 	.irq_retrigger		= retrigger_dynirq,
diff --git a/drivers/xen/events/events_fifo.c b/drivers/xen/events/events_fifo.c
index b234f1766810..ad9fe51d3fb3 100644
--- a/drivers/xen/events/events_fifo.c
+++ b/drivers/xen/events/events_fifo.c
@@ -209,12 +209,6 @@  static bool evtchn_fifo_is_pending(evtchn_port_t port)
 	return sync_test_bit(EVTCHN_FIFO_BIT(PENDING, word), BM(word));
 }
 
-static bool evtchn_fifo_test_and_set_mask(evtchn_port_t 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(evtchn_port_t port)
 {
 	event_word_t *word = event_word_from_port(port);
@@ -423,7 +417,6 @@  static const struct evtchn_ops evtchn_ops_fifo = {
 	.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,
diff --git a/drivers/xen/events/events_internal.h b/drivers/xen/events/events_internal.h
index 18a4090d0709..4d3398eff9cd 100644
--- a/drivers/xen/events/events_internal.h
+++ b/drivers/xen/events/events_internal.h
@@ -21,7 +21,6 @@  struct evtchn_ops {
 	void (*clear_pending)(evtchn_port_t port);
 	void (*set_pending)(evtchn_port_t port);
 	bool (*is_pending)(evtchn_port_t port);
-	bool (*test_and_set_mask)(evtchn_port_t port);
 	void (*mask)(evtchn_port_t port);
 	void (*unmask)(evtchn_port_t port);
 
@@ -84,11 +83,6 @@  static inline bool test_evtchn(evtchn_port_t port)
 	return evtchn_ops->is_pending(port);
 }
 
-static inline bool test_and_set_mask(evtchn_port_t port)
-{
-	return evtchn_ops->test_and_set_mask(port);
-}
-
 static inline void mask_evtchn(evtchn_port_t port)
 {
 	return evtchn_ops->mask(port);