[PATCH V2] Implement 3-level event channel in Linux

[PATCH V2] Implement 3-level event channel in Linux

[Wei Liu]

Changes from V1:
* separate mechanical fixes to different changesets
* close evtchn once binding to irq fails
* remove kzalloc()
* always try to register 3-level event channel

[PATCH V2 01/13] xen: add KERN_DEBUG in printk

[Wei Liu]

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
---
 drivers/xen/events.c |   28 ++++++++++++++--------------
 1 file changed, 14 insertions(+), 14 deletions(-)

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 7595581..4d9a3a6 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -1176,7 +1176,7 @@ irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
 
 	spin_lock_irqsave(&debug_lock, flags);
 
-	printk("\nvcpu %d\n  ", cpu);
+	printk(KERN_DEBUG "\nvcpu %d\n  ", cpu);
 
 	for_each_online_cpu(i) {
 		int pending;
@@ -1184,51 +1184,51 @@ irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
 		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*lx\n  ", i,
+		printk(KERN_DEBUG "%d: masked=%d pending=%d event_sel %0*lx\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   ");
+	printk(KERN_DEBUG "\npending:\n   ");
 	for (i = ARRAY_SIZE(sh->evtchn_pending)-1; i >= 0; i--)
-		printk("%0*lx%s", (int)sizeof(sh->evtchn_pending[0])*2,
+		printk(KERN_DEBUG "%0*lx%s", (int)sizeof(sh->evtchn_pending[0])*2,
 		       sh->evtchn_pending[i],
 		       i % 8 == 0 ? "\n   " : " ");
-	printk("\nglobal mask:\n   ");
+	printk(KERN_DEBUG "\nglobal mask:\n   ");
 	for (i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)
-		printk("%0*lx%s",
+		printk(KERN_DEBUG "%0*lx%s",
 		       (int)(sizeof(sh->evtchn_mask[0])*2),
 		       sh->evtchn_mask[i],
 		       i % 8 == 0 ? "\n   " : " ");
 
-	printk("\nglobally unmasked:\n   ");
+	printk(KERN_DEBUG "\nglobally unmasked:\n   ");
 	for (i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)
-		printk("%0*lx%s", (int)(sizeof(sh->evtchn_mask[0])*2),
+		printk(KERN_DEBUG "%0*lx%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);
+	printk(KERN_DEBUG "\nlocal cpu%d mask:\n   ", cpu);
 	for (i = (NR_EVENT_CHANNELS/BITS_PER_LONG)-1; i >= 0; i--)
-		printk("%0*lx%s", (int)(sizeof(cpu_evtchn[0])*2),
+		printk(KERN_DEBUG "%0*lx%s", (int)(sizeof(cpu_evtchn[0])*2),
 		       cpu_evtchn[i],
 		       i % 8 == 0 ? "\n   " : " ");
 
-	printk("\nlocally unmasked:\n   ");
+	printk(KERN_DEBUG "\nlocally unmasked:\n   ");
 	for (i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--) {
 		unsigned long pending = sh->evtchn_pending[i]
 			& ~sh->evtchn_mask[i]
 			& cpu_evtchn[i];
-		printk("%0*lx%s", (int)(sizeof(sh->evtchn_mask[0])*2),
+		printk(KERN_DEBUG "%0*lx%s", (int)(sizeof(sh->evtchn_mask[0])*2),
 		       pending, i % 8 == 0 ? "\n   " : " ");
 	}
 
-	printk("\npending list:\n");
+	printk(KERN_DEBUG "\npending list:\n");
 	for (i = 0; i < NR_EVENT_CHANNELS; i++) {
 		if (sync_test_bit(i, sh->evtchn_pending)) {
 			int word_idx = i / BITS_PER_LONG;
-			printk("  %d: event %d -> irq %d%s%s%s\n",
+			printk(KERN_DEBUG "  %d: event %d -> irq %d%s%s%s\n",
 			       cpu_from_evtchn(i), i,
 			       evtchn_to_irq[i],
 			       sync_test_bit(word_idx, &v->evtchn_pending_sel)
-- 
1.7.10.4

[PATCH V2 02/13] xen: fix output of xen_debug_interrupt

[Wei Liu]

Make the per-cpu selector L1 to be consistent with description in
__xen_evtchn_do_upcall's comment.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
---
 drivers/xen/events.c |    2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 4d9a3a6..d937bf8 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -1232,7 +1232,7 @@ irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
 			       cpu_from_evtchn(i), i,
 			       evtchn_to_irq[i],
 			       sync_test_bit(word_idx, &v->evtchn_pending_sel)
-					     ? "" : " l2-clear",
+					     ? "" : " l1-clear",
 			       !sync_test_bit(i, sh->evtchn_mask)
 					     ? "" : " globally-masked",
 			       sync_test_bit(i, cpu_evtchn)
-- 
1.7.10.4

[PATCH V2 03/13] xen: fix error handling path if xen_allocate_irq_dynamic fails

[Wei Liu]

The call to xen_allocate_irq_dynamic() might return -ev error codes, not
lietral -1.

Reviewed-by: David Vrabel <david.vrabel@citrix.com>
Signed-off-by: Wei Liu <wei.liu2@citrix.com>
---
 drivers/xen/events.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index d937bf8..96ed76f 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -820,7 +820,7 @@ int bind_evtchn_to_irq(unsigned int evtchn)
 
 	if (irq == -1) {
 		irq = xen_allocate_irq_dynamic();
-		if (irq == -1)
+		if (irq < 0)
 			goto out;
 
 		irq_set_chip_and_handler_name(irq, &xen_dynamic_chip,
@@ -923,7 +923,7 @@ int bind_virq_to_irq(unsigned int virq, unsigned int cpu)
 
 	if (irq == -1) {
 		irq = xen_allocate_irq_dynamic();
-		if (irq == -1)
+		if (irq < 0)
 			goto out;
 
 		irq_set_chip_and_handler_name(irq, &xen_percpu_chip,
-- 
1.7.10.4

[PATCH V2 04/13] xen: close evtchn port if binding to irq fails

[Wei Liu]

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
---
 drivers/xen/evtchn.c |    9 +++++++++
 1 file changed, 9 insertions(+)

diff --git a/drivers/xen/evtchn.c b/drivers/xen/evtchn.c
index b1f60a0..ef02dfa 100644
--- a/drivers/xen/evtchn.c
+++ b/drivers/xen/evtchn.c
@@ -269,6 +269,15 @@ static int evtchn_bind_to_user(struct per_user_data *u, int port)
 				       u->name, (void *)(unsigned long)port);
 	if (rc >= 0)
 		rc = evtchn_make_refcounted(port);
+	else {
+		/* bind failed, should close the port now */
+		struct evtchn_close close;
+		close.port = port;
+		if (port != 0 && /* port 0 is never used */
+		    HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
+			BUG();
+		set_port_user(port, NULL);
+	}
 
 	return rc;
 }
-- 
1.7.10.4

[PATCH V2 05/13] xen: sync public headers

[Wei Liu]

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
---
 include/xen/interface/event_channel.h |   33 +++++++++++++++++++++++++++++++++
 include/xen/interface/xen.h           |    9 ++++++++-
 2 files changed, 41 insertions(+), 1 deletion(-)

diff --git a/include/xen/interface/event_channel.h b/include/xen/interface/event_channel.h
index f494292..9d8b9e7 100644
--- a/include/xen/interface/event_channel.h
+++ b/include/xen/interface/event_channel.h
@@ -190,6 +190,39 @@ struct evtchn_reset {
 };
 typedef struct evtchn_reset evtchn_reset_t;
 
+/*
+ * EVTCHNOP_register_nlevel: Register N-level event channel
+ * NOTES:
+ *  1. Currently only 3-level is supported.
+ *  2. Should fall back to 2-level if this call fails.
+ */
+#define EVTCHNOP_register_nlevel 11
+/* 64 bit guests need 8 pages for evtchn_pending and evtchn_mask for
+ * 256k event channels while 32 bit ones only need 1 page for 32k
+ * event channels. */
+#define EVTCHN_MAX_L3_PAGES 8
+struct evtchn_register_3level {
+	/* IN parameters. */
+	uint32_t nr_pages; /* for evtchn_{pending,mask} */
+	uint32_t nr_vcpus; /* for l2sel_{mfns,mask} */
+	GUEST_HANDLE(ulong) evtchn_pending;
+	GUEST_HANDLE(ulong) evtchn_mask;
+	GUEST_HANDLE(ulong) l2sel_mfns;
+	GUEST_HANDLE(ulong) l2sel_offsets;
+};
+typedef struct evtchn_register_3level evtchn_register_3level_t;
+DEFINE_GUEST_HANDLE(evtchn_register_3level_t);
+
+struct evtchn_register_nlevel {
+	/* IN parameters. */
+	uint32_t level;
+	union {
+		evtchn_register_3level_t l3;
+	} u;
+};
+typedef struct evtchn_register_nlevel evtchn_register_nlevel_t;
+DEFINE_GUEST_HANDLE(evtchn_register_nlevel_t);
+
 struct evtchn_op {
 	uint32_t cmd; /* EVTCHNOP_* */
 	union {
diff --git a/include/xen/interface/xen.h b/include/xen/interface/xen.h
index a890804..5220e33 100644
--- a/include/xen/interface/xen.h
+++ b/include/xen/interface/xen.h
@@ -283,9 +283,16 @@ DEFINE_GUEST_HANDLE_STRUCT(multicall_entry);
 
 /*
  * Event channel endpoints per domain:
+ * 2-level:
  *  1024 if a long is 32 bits; 4096 if a long is 64 bits.
+ * 3-level:
+ *  32k if a long is 32 bits; 256k if a long is 64 bits.
  */
-#define NR_EVENT_CHANNELS (sizeof(unsigned long) * sizeof(unsigned long) * 64)
+#define NR_EVENT_CHANNELS_L2 (sizeof(unsigned long) * sizeof(unsigned long) * 64)
+#define NR_EVENT_CHANNELS_L3 (NR_EVENT_CHANNELS_L2 * 64)
+#if !defined(__XEN__) && !defined(__XEN_TOOLS__)
+#define NR_EVENT_CHANNELS NR_EVENT_CHANNELS_L2 /* for compatibility */
+#endif
 
 struct vcpu_time_info {
 	/*
-- 
1.7.10.4

[PATCH V2 06/13] xen: introduce test_and_set_mask

[Wei Liu]

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
---
 drivers/xen/events.c |   10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 96ed76f..2278851 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -345,6 +345,12 @@ static inline int test_evtchn(int port)
 	return sync_test_bit(port, &s->evtchn_pending[0]);
 }
 
+static inline int test_and_set_mask(int port)
+{
+	struct shared_info *s = HYPERVISOR_shared_info;
+	return sync_test_and_set_bit(port, &s->evtchn_mask[0]);
+}
+
 
 /**
  * notify_remote_via_irq - send event to remote end of event channel via irq
@@ -1464,7 +1470,7 @@ int resend_irq_on_evtchn(unsigned int irq)
 	if (!VALID_EVTCHN(evtchn))
 		return 1;
 
-	masked = sync_test_and_set_bit(evtchn, s->evtchn_mask);
+	masked = test_and_set_mask(evtchn);
 	sync_set_bit(evtchn, s->evtchn_pending);
 	if (!masked)
 		unmask_evtchn(evtchn);
@@ -1513,7 +1519,7 @@ static int retrigger_dynirq(struct irq_data *data)
 	if (VALID_EVTCHN(evtchn)) {
 		int masked;
 
-		masked = sync_test_and_set_bit(evtchn, sh->evtchn_mask);
+		masked = test_and_set_mask(evtchn);
 		sync_set_bit(evtchn, sh->evtchn_pending);
 		if (!masked)
 			unmask_evtchn(evtchn);
-- 
1.7.10.4

[PATCH V2 07/13] xen: replace raw bit ops with functions

[Wei Liu]

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
---
 drivers/xen/events.c |    4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 2278851..6019cd9 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -1471,7 +1471,7 @@ int resend_irq_on_evtchn(unsigned int irq)
 		return 1;
 
 	masked = test_and_set_mask(evtchn);
-	sync_set_bit(evtchn, s->evtchn_pending);
+	set_evtchn(evtchn);
 	if (!masked)
 		unmask_evtchn(evtchn);
 
@@ -1520,7 +1520,7 @@ static int retrigger_dynirq(struct irq_data *data)
 		int masked;
 
 		masked = test_and_set_mask(evtchn);
-		sync_set_bit(evtchn, sh->evtchn_pending);
+		set_evtchn(evtchn);
 		if (!masked)
 			unmask_evtchn(evtchn);
 		ret = 1;
-- 
1.7.10.4

[PATCH V2 08/13] xen: generalized event channel operations

[Wei Liu]

Use global pointers in common operations to allow for better code sharing
between N-level event channel.

Functions which are not suitable for sharing are also taken care of.

Also update drivers/xen/evtchn.c to use exported variable instead of macro.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
---
 drivers/xen/events.c |  180 ++++++++++++++++++++++++++++++++------------------
 drivers/xen/evtchn.c |   12 ++--
 include/xen/events.h |    2 +
 3 files changed, 123 insertions(+), 71 deletions(-)

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 6019cd9..355dbda 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -51,6 +51,16 @@
 #include <xen/interface/hvm/hvm_op.h>
 #include <xen/interface/hvm/params.h>
 
+/* N-level event channel, starting from 2 */
+unsigned int evtchn_level = 2;
+EXPORT_SYMBOL_GPL(evtchn_level);
+unsigned int nr_event_channels;
+EXPORT_SYMBOL_GPL(nr_event_channels);
+
+/* The following pointers point to pending bitmap and mask bitmap. */
+static unsigned long *evtchn_pending;
+static unsigned long *evtchn_mask;
+
 /*
  * 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.
@@ -113,7 +123,7 @@ static int *evtchn_to_irq;
 static unsigned long *pirq_eoi_map;
 static bool (*pirq_needs_eoi)(unsigned irq);
 
-static DEFINE_PER_CPU(unsigned long [NR_EVENT_CHANNELS/BITS_PER_LONG],
+static DEFINE_PER_CPU(unsigned long [NR_EVENT_CHANNELS_L2/BITS_PER_LONG],
 		      cpu_evtchn_mask);
 
 /* Xen will never allocate port zero for any purpose. */
@@ -286,12 +296,11 @@ static bool pirq_needs_eoi_flag(unsigned irq)
 }
 
 static inline unsigned long active_evtchns(unsigned int cpu,
-					   struct shared_info *sh,
 					   unsigned int idx)
 {
-	return sh->evtchn_pending[idx] &
+	return evtchn_pending[idx] &
 		per_cpu(cpu_evtchn_mask, cpu)[idx] &
-		~sh->evtchn_mask[idx];
+		~evtchn_mask[idx];
 }
 
 static void bind_evtchn_to_cpu(unsigned int chn, unsigned int cpu)
@@ -329,26 +338,22 @@ static void init_evtchn_cpu_bindings(void)
 
 static inline void clear_evtchn(int port)
 {
-	struct shared_info *s = HYPERVISOR_shared_info;
-	sync_clear_bit(port, &s->evtchn_pending[0]);
+	sync_clear_bit(port, &evtchn_pending[0]);
 }
 
 static inline void set_evtchn(int port)
 {
-	struct shared_info *s = HYPERVISOR_shared_info;
-	sync_set_bit(port, &s->evtchn_pending[0]);
+	sync_set_bit(port, &evtchn_pending[0]);
 }
 
 static inline int test_evtchn(int port)
 {
-	struct shared_info *s = HYPERVISOR_shared_info;
-	return sync_test_bit(port, &s->evtchn_pending[0]);
+	return sync_test_bit(port, &evtchn_pending[0]);
 }
 
 static inline int test_and_set_mask(int port)
 {
-	struct shared_info *s = HYPERVISOR_shared_info;
-	return sync_test_and_set_bit(port, &s->evtchn_mask[0]);
+	return sync_test_and_set_bit(port, &evtchn_mask[0]);
 }
 
 
@@ -371,13 +376,28 @@ EXPORT_SYMBOL_GPL(notify_remote_via_irq);
 
 static void mask_evtchn(int port)
 {
-	struct shared_info *s = HYPERVISOR_shared_info;
-	sync_set_bit(port, &s->evtchn_mask[0]);
+	sync_set_bit(port, &evtchn_mask[0]);
+}
+
+static inline void __unmask_local_port_l2(int port)
+{
+	struct vcpu_info *vcpu_info = __this_cpu_read(xen_vcpu);
+
+	sync_clear_bit(port, &evtchn_mask[0]);
+
+	/*
+	 * 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 (sync_test_bit(port, &evtchn_pending[0]) &&
+	    !sync_test_and_set_bit(port / BITS_PER_LONG,
+				   &vcpu_info->evtchn_pending_sel))
+		vcpu_info->evtchn_upcall_pending = 1;
 }
 
 static void unmask_evtchn(int port)
 {
-	struct shared_info *s = HYPERVISOR_shared_info;
 	unsigned int cpu = get_cpu();
 
 	BUG_ON(!irqs_disabled());
@@ -387,19 +407,13 @@ static void unmask_evtchn(int port)
 		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);
-
-		sync_clear_bit(port, &s->evtchn_mask[0]);
-
-		/*
-		 * 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 (sync_test_bit(port, &s->evtchn_pending[0]) &&
-		    !sync_test_and_set_bit(port / BITS_PER_LONG,
-					   &vcpu_info->evtchn_pending_sel))
-			vcpu_info->evtchn_upcall_pending = 1;
+		switch (evtchn_level) {
+		case 2:
+			__unmask_local_port_l2(port);
+			break;
+		default:
+			BUG();
+		}
 	}
 
 	put_cpu();
@@ -902,7 +916,7 @@ static int find_virq(unsigned int virq, unsigned int cpu)
 	int port, rc = -ENOENT;
 
 	memset(&status, 0, sizeof(status));
-	for (port = 0; port <= NR_EVENT_CHANNELS; port++) {
+	for (port = 0; port <= nr_event_channels; port++) {
 		status.dom = DOMID_SELF;
 		status.port = port;
 		rc = HYPERVISOR_event_channel_op(EVTCHNOP_status, &status);
@@ -1127,7 +1141,7 @@ int evtchn_get(unsigned int evtchn)
 	struct irq_info *info;
 	int err = -ENOENT;
 
-	if (evtchn >= NR_EVENT_CHANNELS)
+	if (evtchn >= nr_event_channels)
 		return -EINVAL;
 
 	mutex_lock(&irq_mapping_update_lock);
@@ -1170,15 +1184,16 @@ void xen_send_IPI_one(unsigned int cpu, enum ipi_vector vector)
 	notify_remote_via_irq(irq);
 }
 
+static irqreturn_t xen_debug_interrupt_l2(int irq, void *dev_id);
+
 irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
 {
-	struct shared_info *sh = HYPERVISOR_shared_info;
-	int cpu = smp_processor_id();
-	unsigned long *cpu_evtchn = per_cpu(cpu_evtchn_mask, cpu);
-	int i;
-	unsigned long flags;
+	irqreturn_t rc;
 	static DEFINE_SPINLOCK(debug_lock);
+	unsigned long flags;
+	int cpu = smp_processor_id();
 	struct vcpu_info *v;
+	int i;
 
 	spin_lock_irqsave(&debug_lock, flags);
 
@@ -1195,24 +1210,45 @@ irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
 		       (int)(sizeof(v->evtchn_pending_sel)*2),
 		       v->evtchn_pending_sel);
 	}
+
+	switch (evtchn_level) {
+	case 2:
+		rc = xen_debug_interrupt_l2(irq, dev_id);
+		break;
+	default:
+		BUG();
+	}
+
+	spin_unlock_irqrestore(&debug_lock, flags);
+	return rc;
+}
+
+static irqreturn_t xen_debug_interrupt_l2(int irq, void *dev_id)
+{
+	int cpu = smp_processor_id();
+	unsigned long *cpu_evtchn = per_cpu(cpu_evtchn_mask, cpu);
+	int i;
+	unsigned long nr_elems = NR_EVENT_CHANNELS_L2 / BITS_PER_LONG;
+	struct vcpu_info *v;
+
 	v = per_cpu(xen_vcpu, cpu);
 
 	printk(KERN_DEBUG "\npending:\n   ");
-	for (i = ARRAY_SIZE(sh->evtchn_pending)-1; i >= 0; i--)
-		printk(KERN_DEBUG "%0*lx%s", (int)sizeof(sh->evtchn_pending[0])*2,
-		       sh->evtchn_pending[i],
+	for (i = nr_elems; i >= 0; i--)
+		printk(KERN_DEBUG "%0*lx%s", (int)sizeof(evtchn_pending[0])*2,
+		       evtchn_pending[i],
 		       i % 8 == 0 ? "\n   " : " ");
 	printk(KERN_DEBUG "\nglobal mask:\n   ");
-	for (i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)
+	for (i = nr_elems-1; i >= 0; i--)
 		printk(KERN_DEBUG "%0*lx%s",
-		       (int)(sizeof(sh->evtchn_mask[0])*2),
-		       sh->evtchn_mask[i],
+		       (int)(sizeof(evtchn_mask[0])*2),
+		       evtchn_mask[i],
 		       i % 8 == 0 ? "\n   " : " ");
 
 	printk(KERN_DEBUG "\nglobally unmasked:\n   ");
-	for (i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--)
-		printk(KERN_DEBUG "%0*lx%s", (int)(sizeof(sh->evtchn_mask[0])*2),
-		       sh->evtchn_pending[i] & ~sh->evtchn_mask[i],
+	for (i = nr_elems-1; i >= 0; i--)
+		printk(KERN_DEBUG "%0*lx%s", (int)(sizeof(evtchn_mask[0])*2),
+		       evtchn_pending[i] & ~evtchn_mask[i],
 		       i % 8 == 0 ? "\n   " : " ");
 
 	printk(KERN_DEBUG "\nlocal cpu%d mask:\n   ", cpu);
@@ -1222,32 +1258,30 @@ irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
 		       i % 8 == 0 ? "\n   " : " ");
 
 	printk(KERN_DEBUG "\nlocally unmasked:\n   ");
-	for (i = ARRAY_SIZE(sh->evtchn_mask)-1; i >= 0; i--) {
-		unsigned long pending = sh->evtchn_pending[i]
-			& ~sh->evtchn_mask[i]
+	for (i = nr_elems-1; i >= 0; i--) {
+		unsigned long pending = evtchn_pending[i]
+			& ~evtchn_mask[i]
 			& cpu_evtchn[i];
-		printk(KERN_DEBUG "%0*lx%s", (int)(sizeof(sh->evtchn_mask[0])*2),
+		printk(KERN_DEBUG "%0*lx%s", (int)(sizeof(evtchn_mask[0])*2),
 		       pending, i % 8 == 0 ? "\n   " : " ");
 	}
 
 	printk(KERN_DEBUG "\npending list:\n");
-	for (i = 0; i < NR_EVENT_CHANNELS; i++) {
-		if (sync_test_bit(i, sh->evtchn_pending)) {
+	for (i = 0; i < NR_EVENT_CHANNELS_L2; i++) {
+		if (sync_test_bit(i, evtchn_pending)) {
 			int word_idx = i / BITS_PER_LONG;
 			printk(KERN_DEBUG "  %d: event %d -> irq %d%s%s%s\n",
 			       cpu_from_evtchn(i), i,
 			       evtchn_to_irq[i],
 			       sync_test_bit(word_idx, &v->evtchn_pending_sel)
 					     ? "" : " l1-clear",
-			       !sync_test_bit(i, sh->evtchn_mask)
+			       !sync_test_bit(i, evtchn_mask)
 					     ? "" : " globally-masked",
 			       sync_test_bit(i, cpu_evtchn)
 					     ? "" : " locally-masked");
 		}
 	}
 
-	spin_unlock_irqrestore(&debug_lock, flags);
-
 	return IRQ_HANDLED;
 }
 
@@ -1269,13 +1303,12 @@ static DEFINE_PER_CPU(unsigned int, current_bit_idx);
  * 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)
+static void __xen_evtchn_do_upcall_l2(void)
 {
 	int start_word_idx, start_bit_idx;
 	int word_idx, bit_idx;
 	int i;
 	int cpu = get_cpu();
-	struct shared_info *s = HYPERVISOR_shared_info;
 	struct vcpu_info *vcpu_info = __this_cpu_read(xen_vcpu);
 	unsigned count;
 
@@ -1314,7 +1347,7 @@ static void __xen_evtchn_do_upcall(void)
 			}
 			word_idx = __ffs(words);
 
-			pending_bits = active_evtchns(cpu, s, word_idx);
+			pending_bits = active_evtchns(cpu, 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 */
@@ -1383,7 +1416,13 @@ void xen_evtchn_do_upcall(struct pt_regs *regs)
 	exit_idle();
 	irq_enter();
 
-	__xen_evtchn_do_upcall();
+	switch (evtchn_level) {
+	case 2:
+		__xen_evtchn_do_upcall_l2();
+		break;
+	default:
+		BUG();
+	}
 
 	irq_exit();
 	set_irq_regs(old_regs);
@@ -1391,7 +1430,13 @@ void xen_evtchn_do_upcall(struct pt_regs *regs)
 
 void xen_hvm_evtchn_do_upcall(void)
 {
-	__xen_evtchn_do_upcall();
+	switch (evtchn_level) {
+	case 2:
+		__xen_evtchn_do_upcall_l2();
+		break;
+	default:
+		BUG();
+	}
 }
 EXPORT_SYMBOL_GPL(xen_hvm_evtchn_do_upcall);
 
@@ -1465,7 +1510,6 @@ static int set_affinity_irq(struct irq_data *data, const struct cpumask *dest,
 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;
@@ -1513,7 +1557,6 @@ static void mask_ack_dynirq(struct irq_data *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)) {
@@ -1689,14 +1732,14 @@ void xen_irq_resume(void)
 	init_evtchn_cpu_bindings();
 
 	/* New event-channel space is not 'live' yet. */
-	for (evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++)
+	for (evtchn = 0; evtchn < nr_event_channels; evtchn++)
 		mask_evtchn(evtchn);
 
 	/* No IRQ <-> event-channel mappings. */
 	list_for_each_entry(info, &xen_irq_list_head, list)
 		info->evtchn = 0; /* zap event-channel binding */
 
-	for (evtchn = 0; evtchn < NR_EVENT_CHANNELS; evtchn++)
+	for (evtchn = 0; evtchn < nr_event_channels; evtchn++)
 		evtchn_to_irq[evtchn] = -1;
 
 	for_each_possible_cpu(cpu) {
@@ -1792,17 +1835,24 @@ void xen_callback_vector(void) {}
 void __init xen_init_IRQ(void)
 {
 	int i, rc;
+	struct shared_info *s = HYPERVISOR_shared_info;
+
+	evtchn_pending = s->evtchn_pending;
+	evtchn_mask = s->evtchn_mask;
+
+	evtchn_level = 2;
+	nr_event_channels = NR_EVENT_CHANNELS_L2;
 
-	evtchn_to_irq = kcalloc(NR_EVENT_CHANNELS, sizeof(*evtchn_to_irq),
+	evtchn_to_irq = kcalloc(nr_event_channels, sizeof(*evtchn_to_irq),
 				    GFP_KERNEL);
 	BUG_ON(!evtchn_to_irq);
-	for (i = 0; i < NR_EVENT_CHANNELS; i++)
+	for (i = 0; i < nr_event_channels; i++)
 		evtchn_to_irq[i] = -1;
 
 	init_evtchn_cpu_bindings();
 
 	/* No event channels are 'live' right now. */
-	for (i = 0; i < NR_EVENT_CHANNELS; i++)
+	for (i = 0; i < nr_event_channels; i++)
 		mask_evtchn(i);
 
 	pirq_needs_eoi = pirq_needs_eoi_flag;
diff --git a/drivers/xen/evtchn.c b/drivers/xen/evtchn.c
index ef02dfa..3eecdd7 100644
--- a/drivers/xen/evtchn.c
+++ b/drivers/xen/evtchn.c
@@ -232,7 +232,7 @@ static ssize_t evtchn_write(struct file *file, const char __user *buf,
 	for (i = 0; i < (count/sizeof(evtchn_port_t)); i++) {
 		unsigned port = kbuf[i];
 
-		if (port < NR_EVENT_CHANNELS &&
+		if (port < nr_event_channels &&
 		    get_port_user(port) == u &&
 		    !get_port_enabled(port)) {
 			set_port_enabled(port, true);
@@ -373,7 +373,7 @@ static long evtchn_ioctl(struct file *file,
 			break;
 
 		rc = -EINVAL;
-		if (unbind.port >= NR_EVENT_CHANNELS)
+		if (unbind.port >= nr_event_channels)
 			break;
 
 		spin_lock_irq(&port_user_lock);
@@ -401,7 +401,7 @@ static long evtchn_ioctl(struct file *file,
 		if (copy_from_user(&notify, uarg, sizeof(notify)))
 			break;
 
-		if (notify.port >= NR_EVENT_CHANNELS) {
+		if (notify.port >= nr_event_channels) {
 			rc = -EINVAL;
 		} else if (get_port_user(notify.port) != u) {
 			rc = -ENOTCONN;
@@ -491,7 +491,7 @@ static int evtchn_release(struct inode *inode, struct file *filp)
 
 	free_page((unsigned long)u->ring);
 
-	for (i = 0; i < NR_EVENT_CHANNELS; i++) {
+	for (i = 0; i < nr_event_channels; i++) {
 		if (get_port_user(i) != u)
 			continue;
 
@@ -500,7 +500,7 @@ static int evtchn_release(struct inode *inode, struct file *filp)
 
 	spin_unlock_irq(&port_user_lock);
 
-	for (i = 0; i < NR_EVENT_CHANNELS; i++) {
+	for (i = 0; i < nr_event_channels; i++) {
 		if (get_port_user(i) != u)
 			continue;
 
@@ -537,7 +537,7 @@ static int __init evtchn_init(void)
 	if (!xen_domain())
 		return -ENODEV;
 
-	port_user = kcalloc(NR_EVENT_CHANNELS, sizeof(*port_user), GFP_KERNEL);
+	port_user = kcalloc(nr_event_channels, sizeof(*port_user), GFP_KERNEL);
 	if (port_user == NULL)
 		return -ENOMEM;
 
diff --git a/include/xen/events.h b/include/xen/events.h
index 04399b2..6b117ac 100644
--- a/include/xen/events.h
+++ b/include/xen/events.h
@@ -109,4 +109,6 @@ int xen_irq_from_gsi(unsigned gsi);
 /* Determine whether to ignore this IRQ if it is passed to a guest. */
 int xen_test_irq_shared(int irq);
 
+extern unsigned int nr_event_channels;
+
 #endif	/* _XEN_EVENTS_H */
-- 
1.7.10.4

[PATCH V2 09/13] xen: dynamically allocate cpu_evtchn_mask

[Wei Liu]

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
---
 drivers/xen/events.c |   18 +++++++++++++++---
 1 file changed, 15 insertions(+), 3 deletions(-)

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 355dbda..94d6570 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -123,8 +123,7 @@ static int *evtchn_to_irq;
 static unsigned long *pirq_eoi_map;
 static bool (*pirq_needs_eoi)(unsigned irq);
 
-static DEFINE_PER_CPU(unsigned long [NR_EVENT_CHANNELS_L2/BITS_PER_LONG],
-		      cpu_evtchn_mask);
+static DEFINE_PER_CPU(unsigned long *, cpu_evtchn_mask);
 
 /* Xen will never allocate port zero for any purpose. */
 #define VALID_EVTCHN(chn)	((chn) != 0)
@@ -333,7 +332,8 @@ static void init_evtchn_cpu_bindings(void)
 
 	for_each_possible_cpu(i)
 		memset(per_cpu(cpu_evtchn_mask, i),
-		       (i == 0) ? ~0 : 0, sizeof(*per_cpu(cpu_evtchn_mask, i)));
+		       (i == 0) ? ~0 : 0,
+		       sizeof(unsigned long)*(nr_event_channels/BITS_PER_LONG));
 }
 
 static inline void clear_evtchn(int port)
@@ -1835,6 +1835,7 @@ void xen_callback_vector(void) {}
 void __init xen_init_IRQ(void)
 {
 	int i, rc;
+	int cpu;
 	struct shared_info *s = HYPERVISOR_shared_info;
 
 	evtchn_pending = s->evtchn_pending;
@@ -1849,6 +1850,17 @@ void __init xen_init_IRQ(void)
 	for (i = 0; i < nr_event_channels; i++)
 		evtchn_to_irq[i] = -1;
 
+	for_each_possible_cpu(cpu) {
+		void *p;
+		unsigned int nr = nr_event_channels / BITS_PER_LONG;
+
+		p = kzalloc_node(sizeof(unsigned long) * nr,
+				 GFP_KERNEL,
+				 cpu_to_node(cpu));
+		BUG_ON(!p);
+		per_cpu(cpu_evtchn_mask, cpu) = p;
+	}
+
 	init_evtchn_cpu_bindings();
 
 	/* No event channels are 'live' right now. */
-- 
1.7.10.4

[PATCH V2 10/13] xen: implement 3-level event channel routines

[Wei Liu]

Only do_upcall, debug_interrupt and unmask_evtchn are required.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
---
 drivers/xen/events.c |  291 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 291 insertions(+)

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 94d6570..f3f0fdc 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -51,6 +51,9 @@
 #include <xen/interface/hvm/hvm_op.h>
 #include <xen/interface/hvm/params.h>
 
+/* Helper macro(s) */
+#define LONG_BITORDER (BITS_PER_LONG == 64 ? 6 : 5)
+
 /* N-level event channel, starting from 2 */
 unsigned int evtchn_level = 2;
 EXPORT_SYMBOL_GPL(evtchn_level);
@@ -61,6 +64,9 @@ EXPORT_SYMBOL_GPL(nr_event_channels);
 static unsigned long *evtchn_pending;
 static unsigned long *evtchn_mask;
 
+/* 2nd level selector for 3-level event channel */
+static DEFINE_PER_CPU(unsigned long[sizeof(unsigned long) * 8], evtchn_sel_l2);
+
 /*
  * 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.
@@ -396,6 +402,28 @@ static inline void __unmask_local_port_l2(int port)
 		vcpu_info->evtchn_upcall_pending = 1;
 }
 
+static inline void __unmask_local_port_l3(int port)
+{
+	struct vcpu_info *vcpu_info = __this_cpu_read(xen_vcpu);
+	int cpu = smp_processor_id();
+	unsigned int l1bit = port >> (LONG_BITORDER << 1);
+	unsigned int l2bit = port >> LONG_BITORDER;
+
+	sync_clear_bit(port, &evtchn_mask[0]);
+
+	/*
+	 * 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 (sync_test_bit(port, &evtchn_pending[0]) &&
+	    !sync_test_and_set_bit(l2bit,
+				   &per_cpu(evtchn_sel_l2, cpu)[0]) &&
+	    !sync_test_and_set_bit(l1bit,
+				   &vcpu_info->evtchn_pending_sel))
+		vcpu_info->evtchn_upcall_pending = 1;
+}
+
 static void unmask_evtchn(int port)
 {
 	unsigned int cpu = get_cpu();
@@ -411,6 +439,9 @@ static void unmask_evtchn(int port)
 		case 2:
 			__unmask_local_port_l2(port);
 			break;
+		case 3:
+			__unmask_local_port_l3(port);
+			break;
 		default:
 			BUG();
 		}
@@ -1185,6 +1216,7 @@ void xen_send_IPI_one(unsigned int cpu, enum ipi_vector vector)
 }
 
 static irqreturn_t xen_debug_interrupt_l2(int irq, void *dev_id);
+static irqreturn_t xen_debug_interrupt_l3(int irq, void *dev_id);
 
 irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
 {
@@ -1215,6 +1247,9 @@ irqreturn_t xen_debug_interrupt(int irq, void *dev_id)
 	case 2:
 		rc = xen_debug_interrupt_l2(irq, dev_id);
 		break;
+	case 3:
+		rc = xen_debug_interrupt_l3(irq, dev_id);
+		break;
 	default:
 		BUG();
 	}
@@ -1285,8 +1320,109 @@ static irqreturn_t xen_debug_interrupt_l2(int irq, void *dev_id)
 	return IRQ_HANDLED;
 }
 
+static irqreturn_t xen_debug_interrupt_l3(int irq, void *dev_id)
+{
+	int cpu = smp_processor_id();
+	unsigned long *cpu_evtchn = per_cpu(cpu_evtchn_mask, cpu);
+	unsigned long nr_elems = NR_EVENT_CHANNELS_L3 / BITS_PER_LONG;
+	int i;
+	struct vcpu_info *v;
+
+	v = per_cpu(xen_vcpu, cpu);
+
+	printk(KERN_DEBUG "\npending (only show words which have bits set to 1):\n   ");
+	for (i = nr_elems-1; i >= 0; i--)
+		if (evtchn_pending[i] != 0UL) {
+			printk(KERN_DEBUG " word index %d %0*lx\n",
+			       i,
+			       (int)sizeof(evtchn_pending[0])*2,
+			       evtchn_pending[i]);
+		}
+
+	printk(KERN_DEBUG "\nglobal mask (only show words which have bits set to 0):\n   ");
+	for (i = nr_elems-1; i >= 0; i--)
+		if (evtchn_mask[i] != ~0UL) {
+			printk(KERN_DEBUG " word index %d %0*lx\n",
+			       i,
+			       (int)sizeof(evtchn_mask[0])*2,
+			       evtchn_mask[i]);
+		}
+
+	printk(KERN_DEBUG "\nglobally unmasked (only show result words which have bits set to 1):\n   ");
+	for (i = nr_elems-1; i >= 0; i--)
+		if ((evtchn_pending[i] & ~evtchn_mask[i]) != 0UL) {
+			printk(KERN_DEBUG " word index %d %0*lx\n",
+			       i,
+			       (int)(sizeof(evtchn_mask[0])*2),
+			       evtchn_pending[i] & ~evtchn_mask[i]);
+		}
+
+	printk(KERN_DEBUG "\nlocal cpu%d mask (only show words which have bits set to 1):\n   ", cpu);
+	for (i = (NR_EVENT_CHANNELS_L3/BITS_PER_LONG)-1; i >= 0; i--)
+		if (cpu_evtchn[i] != 0UL) {
+			printk(KERN_DEBUG " word index %d %0*lx\n",
+			       i,
+			       (int)(sizeof(cpu_evtchn[0])*2),
+			       cpu_evtchn[i]);
+		}
+
+	printk(KERN_DEBUG "\nlocally unmasked (only show result words which have bits set to 1):\n   ");
+	for (i = nr_elems-1; i >= 0; i--) {
+		unsigned long pending = evtchn_pending[i]
+			& ~evtchn_mask[i]
+			& cpu_evtchn[i];
+		if (pending != 0UL) {
+			printk(KERN_DEBUG " word index %d %0*lx\n",
+			       i,
+			       (int)(sizeof(evtchn_mask[0])*2),
+			       pending);
+		}
+	}
+
+	printk(KERN_DEBUG "\npending list:\n");
+	for (i = 0; i < NR_EVENT_CHANNELS_L3; i++) {
+		if (sync_test_bit(i, evtchn_pending)) {
+			int word_idx = i / (BITS_PER_LONG * BITS_PER_LONG);
+			int word_idx_l2 = i / BITS_PER_LONG;
+			printk(KERN_DEBUG "  %d: event %d -> irq %d%s%s%s%s\n",
+			       cpu_from_evtchn(i), i,
+			       evtchn_to_irq[i],
+			       !sync_test_bit(word_idx, &v->evtchn_pending_sel)
+			       ? "" : " l1-clear",
+			       !sync_test_bit(word_idx_l2, per_cpu(evtchn_sel_l2, cpu))
+			       ? "" : " l2-clear",
+			       sync_test_bit(i, evtchn_mask)
+			       ? "" : " globally-masked",
+			       sync_test_bit(i, cpu_evtchn)
+			       ? "" : " locally-masked");
+		}
+	}
+
+	return IRQ_HANDLED;
+}
+
+/* The following per-cpu variables are used to save current state of event
+ * processing loop.
+ *
+ * 2-level event channel:
+ *  current_word_idx is the bit index in L1 selector indicating the currently
+ *  processing word in shared bitmap.
+ *  current_bit_idx is the bit index in the currently processing word in shared
+ *  bitmap.
+ *  N.B. current_word_idx_l2 is not used.
+ *
+ * 3-level event channel:
+ *  current_word_idx is the bit index in L1 selector indicating the currently
+ *  processing word in L2 selector.
+ *  current_word_idx_l2 is the bit index in L2 selector word indicating the
+ *  currently processing word in shared bitmap.
+ *  current_bit_idx is the bit index in the currently processing word in shared
+ *  bitmap.
+ *
+ */
 static DEFINE_PER_CPU(unsigned, xed_nesting_count);
 static DEFINE_PER_CPU(unsigned int, current_word_idx);
+static DEFINE_PER_CPU(unsigned int, current_word_idx_l2);
 static DEFINE_PER_CPU(unsigned int, current_bit_idx);
 
 /*
@@ -1409,6 +1545,155 @@ out:
 	put_cpu();
 }
 
+/*
+ * In the 3-level event channel implementation, the first level is a
+ * bitset of words which contain pending bits in the second level.
+ * The second level is another bitsets which contain pending bits in
+ * the third level.  The third level is a bit set of pending events
+ * themselves.
+ */
+static void __xen_evtchn_do_upcall_l3(void)
+{
+	struct vcpu_info *vcpu_info = __this_cpu_read(xen_vcpu);
+	unsigned count;
+	int start_word_idx_l1, start_word_idx_l2, start_bit_idx;
+	int word_idx_l1, word_idx_l2, bit_idx;
+	int i, j;
+	int cpu = get_cpu();
+
+	do {
+		unsigned long pending_words_l1;
+
+		vcpu_info->evtchn_upcall_pending = 0;
+
+		if (__this_cpu_inc_return(xed_nesting_count) - 1)
+			goto out;
+#ifndef CONFIG_X86
+		/* No need for a barrier -- XCHG is a barrier on x86. */
+		/* Clear master flag /before/ clearing selector flag. */
+		wmb();
+#endif
+		/* here we get l1 pending selector */
+		pending_words_l1 = xchg(&vcpu_info->evtchn_pending_sel, 0);
+
+		start_word_idx_l1 = __this_cpu_read(current_word_idx);
+		start_word_idx_l2 = __this_cpu_read(current_word_idx_l2);
+		start_bit_idx = __this_cpu_read(current_bit_idx);
+
+		word_idx_l1 = start_word_idx_l1;
+
+		/* loop through l1, try to pick up l2 */
+		for (i = 0; pending_words_l1 != 0; i++) {
+			unsigned long words_l1;
+			unsigned long pending_words_l2;
+
+			words_l1 = MASK_LSBS(pending_words_l1, word_idx_l1);
+
+			if (words_l1 == 0) {
+				word_idx_l1 = 0;
+				start_word_idx_l2 = 0;
+				continue;
+			}
+
+			word_idx_l1 = __ffs(words_l1);
+
+			pending_words_l2 =
+				xchg(&per_cpu(evtchn_sel_l2, cpu)[word_idx_l1],
+				     0);
+
+			word_idx_l2 = 0;
+			if (word_idx_l1 == start_word_idx_l1) {
+				if (i == 0)
+					word_idx_l2 = start_word_idx_l2;
+				else
+					word_idx_l2 &= (1UL << start_word_idx_l2) - 1;
+			}
+
+			for (j = 0; pending_words_l2 != 0; j++) {
+				unsigned long pending_bits;
+				unsigned long words_l2;
+				unsigned long idx;
+
+				words_l2 = MASK_LSBS(pending_words_l2,
+						     word_idx_l2);
+
+				if (words_l2 == 0) {
+					word_idx_l2 = 0;
+					bit_idx = 0;
+					continue;
+				}
+
+				word_idx_l2 = __ffs(words_l2);
+
+				idx = word_idx_l1*BITS_PER_LONG+word_idx_l2;
+				pending_bits =
+					active_evtchns(cpu, idx);
+
+				bit_idx = 0;
+				if (word_idx_l2 == start_word_idx_l2) {
+					if (j == 0)
+						bit_idx = start_bit_idx;
+					else
+						bit_idx &= (1UL<<start_bit_idx)-1;
+				}
+
+				/* process port */
+				do {
+					unsigned long bits;
+					int port, irq;
+					struct irq_desc *desc;
+
+					bits = MASK_LSBS(pending_bits, bit_idx);
+
+					if (bits == 0)
+						break;
+
+					bit_idx = __ffs(bits);
+
+					port = (word_idx_l1 << (LONG_BITORDER << 1)) +
+						(word_idx_l2 << LONG_BITORDER) +
+						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_LONG;
+
+					__this_cpu_write(current_bit_idx, bit_idx);
+					__this_cpu_write(current_word_idx_l2,
+							 bit_idx ? word_idx_l2 :
+							 (word_idx_l2+1) % BITS_PER_LONG);
+					__this_cpu_write(current_word_idx_l2,
+							 word_idx_l2 ? word_idx_l1 :
+							 (word_idx_l1+1) % BITS_PER_LONG);
+				} while (bit_idx != 0);
+
+				if ((word_idx_l2 != start_word_idx_l2) || (j != 0))
+					pending_words_l2 &= ~(1UL << word_idx_l2);
+
+				word_idx_l2 = (word_idx_l2 + 1) % BITS_PER_LONG;
+			}
+
+			if ((word_idx_l1 != start_word_idx_l1) || (i != 0))
+				pending_words_l1 &= ~(1UL << word_idx_l1);
+
+			word_idx_l1 = (word_idx_l1 + 1) % BITS_PER_LONG;
+		}
+
+		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);
@@ -1420,6 +1705,9 @@ void xen_evtchn_do_upcall(struct pt_regs *regs)
 	case 2:
 		__xen_evtchn_do_upcall_l2();
 		break;
+	case 3:
+		__xen_evtchn_do_upcall_l3();
+		break;
 	default:
 		BUG();
 	}
@@ -1434,6 +1722,9 @@ void xen_hvm_evtchn_do_upcall(void)
 	case 2:
 		__xen_evtchn_do_upcall_l2();
 		break;
+	case 3:
+		__xen_evtchn_do_upcall_l3();
+		break;
 	default:
 		BUG();
 	}
-- 
1.7.10.4

[PATCH V2 11/13] xen: introduce xen_event_channel_register_3level

[Wei Liu]

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
---
 drivers/xen/events.c |   94 ++++++++++++++++++++++++++++++++++++++++++++++++++
 1 file changed, 94 insertions(+)

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index f3f0fdc..6e0283c 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -53,6 +53,9 @@
 
 /* Helper macro(s) */
 #define LONG_BITORDER (BITS_PER_LONG == 64 ? 6 : 5)
+/* event bitmap size: 1 page for 32 bit and 8 pages for 64 bit */
+#define BITMAP_PG_ORDER (BITS_PER_LONG == 64 ? 3 : 1)
+#define BITMAP_NR_PAGES (BITMAP_PG_ORDER == 3 ? 8 : 1)
 
 /* N-level event channel, starting from 2 */
 unsigned int evtchn_level = 2;
@@ -2123,6 +2126,97 @@ void xen_callback_vector(void)
 void xen_callback_vector(void) {}
 #endif
 
+static int xen_event_channel_register_3level(void)
+{
+	evtchn_register_nlevel_t reg;
+	int i, cpu;
+	unsigned long *_evtchn_pending = NULL;
+	unsigned long *_evtchn_mask = NULL;
+	unsigned long *l2sel_mfns = NULL;
+	unsigned long *l2sel_offsets = NULL;
+	int rc;
+
+	/* If we come from restore path, we don't need to allocate
+	 * pages.
+	 */
+	if (!evtchn_pending && !evtchn_mask) {
+		evtchn_pending =
+			(unsigned long *)__get_free_pages(GFP_KERNEL,
+							  BITMAP_PG_ORDER);
+		evtchn_mask =
+			(unsigned long *)__get_free_pages(GFP_KERNEL,
+							  BITMAP_PG_ORDER);
+		if (!evtchn_pending || !evtchn_mask) {
+			free_pages((unsigned long)evtchn_pending, BITMAP_PG_ORDER);
+			free_pages((unsigned long)evtchn_mask, BITMAP_PG_ORDER);
+			evtchn_pending = NULL;
+			evtchn_mask = NULL;
+			rc = -ENOMEM;
+			goto err;
+		}
+	}
+
+	rc = -ENOMEM; /* Common error code for following operations */
+#define __ALLOC_ARRAY(_ptr, _nr)					\
+	do {								\
+		(_ptr) = kzalloc(sizeof(unsigned long) * (_nr),		\
+				 GFP_KERNEL);				\
+		if (!(_ptr))						\
+			goto out;					\
+	} while (0)
+
+	__ALLOC_ARRAY(_evtchn_pending, BITMAP_NR_PAGES);
+	__ALLOC_ARRAY(_evtchn_mask, BITMAP_NR_PAGES);
+	__ALLOC_ARRAY(l2sel_mfns, nr_cpu_ids);
+	__ALLOC_ARRAY(l2sel_offsets, nr_cpu_ids);
+#undef __ALLOC_ARRAY
+
+	memset(&reg, 0, sizeof(reg));
+
+	for (i = 0; i < BITMAP_NR_PAGES; i++) {
+		unsigned long offset = PAGE_SIZE * i;
+		_evtchn_pending[i] =
+			arbitrary_virt_to_mfn(
+				(void *)((unsigned long)evtchn_pending+offset));
+		_evtchn_mask[i] =
+			arbitrary_virt_to_mfn(
+				(void *)((unsigned long)evtchn_mask+offset));
+	}
+
+	for_each_possible_cpu(cpu) {
+		l2sel_mfns[cpu] =
+			arbitrary_virt_to_mfn(&per_cpu(evtchn_sel_l2, cpu));
+		l2sel_offsets[cpu] =
+			offset_in_page(&per_cpu(evtchn_sel_l2, cpu));
+	}
+
+	reg.u.l3.nr_pages = BITMAP_NR_PAGES;
+	reg.u.l3.evtchn_pending = _evtchn_pending;
+	reg.u.l3.evtchn_mask = _evtchn_mask;
+
+	reg.u.l3.nr_vcpus = nr_cpu_ids;
+	reg.u.l3.l2sel_mfns = l2sel_mfns;
+	reg.u.l3.l2sel_offsets = l2sel_offsets;
+
+	reg.level = 3;
+
+	rc = HYPERVISOR_event_channel_op(EVTCHNOP_register_nlevel, &reg);
+	if (rc) {
+		free_pages((unsigned long)evtchn_pending, BITMAP_PG_ORDER);
+		free_pages((unsigned long)evtchn_mask, BITMAP_PG_ORDER);
+		evtchn_pending = NULL;
+		evtchn_mask = NULL;
+	}
+
+out:
+	kfree(_evtchn_pending);
+	kfree(_evtchn_mask);
+	kfree(l2sel_mfns);
+	kfree(l2sel_offsets);
+err:
+	return rc;
+}
+
 void __init xen_init_IRQ(void)
 {
 	int i, rc;
-- 
1.7.10.4

[PATCH V2 12/13] xen: introduce xen_event_channel_register_nlevel

[Wei Liu]

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
---
 drivers/xen/events.c |   55 ++++++++++++++++++++++++++++++++++++++++++++------
 include/xen/events.h |    7 +++++++
 2 files changed, 56 insertions(+), 6 deletions(-)

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 6e0283c..6a0307c 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -2217,17 +2217,60 @@ err:
 	return rc;
 }
 
+void xen_event_channel_register_nlevel(unsigned int highest_level)
+{
+	int rc;
+
+	switch (highest_level) {
+	case 3:
+		rc = xen_event_channel_register_3level();
+		if (rc == 0) {
+			printk(KERN_INFO "Register 3-level event channel succeed.\n");
+			xen_set_event_channel_nlevel(3);
+			break;
+		} else {
+			printk(KERN_INFO "Regsiter 3-level event channel failed with %d\n",
+			       rc);
+		}
+		/* fall through */
+	case 2:
+		printk(KERN_INFO "Using 2-level event channel\n");
+		xen_set_event_channel_nlevel(2);
+		break;
+	default:
+		printk(KERN_INFO "Trying to register unsupported %d-level event channel\n",
+		       highest_level);
+	}
+}
+
+void xen_set_event_channel_nlevel(unsigned int level)
+{
+	struct shared_info *s = HYPERVISOR_shared_info;
+	switch (level) {
+	case 2:
+		evtchn_pending = s->evtchn_pending;
+		evtchn_mask = s->evtchn_mask;
+		evtchn_level = 2;
+		nr_event_channels = NR_EVENT_CHANNELS_L2;
+		break;
+	case 3:
+		/* evtchn_pending/mask already set */
+		evtchn_level = 3;
+		nr_event_channels = NR_EVENT_CHANNELS_L3;
+		break;
+	default:
+		printk(KERN_EMERG "Trying to set unsupported %d-level event channel\n",
+		       level);
+		BUG();
+	}
+}
+
 void __init xen_init_IRQ(void)
 {
 	int i, rc;
 	int cpu;
-	struct shared_info *s = HYPERVISOR_shared_info;
-
-	evtchn_pending = s->evtchn_pending;
-	evtchn_mask = s->evtchn_mask;
 
-	evtchn_level = 2;
-	nr_event_channels = NR_EVENT_CHANNELS_L2;
+	xen_set_event_channel_nlevel(2);
 
 	evtchn_to_irq = kcalloc(nr_event_channels, sizeof(*evtchn_to_irq),
 				    GFP_KERNEL);
diff --git a/include/xen/events.h b/include/xen/events.h
index 6b117ac..6b6c4fb 100644
--- a/include/xen/events.h
+++ b/include/xen/events.h
@@ -111,4 +111,11 @@ int xen_test_irq_shared(int irq);
 
 extern unsigned int nr_event_channels;
 
+/* Register N-level event channel. If register N-level fails, it will try to
+ * register N-1 level, until it reaches the default 2-level event channel. */
+void xen_event_channel_register_nlevel(unsigned int highest_level);
+
+/* Set event channel to N-level if registration succeed */
+void xen_set_event_channel_nlevel(unsigned int level);
+
 #endif	/* _XEN_EVENTS_H */
-- 
1.7.10.4

[PATCH V2 13/13] xen: register 3-level event channel

[Wei Liu]

3-level event channel is registered in
 a) xen_init_IRQ(), when the guest is fresh started;
 b) xen_vcpu_restore(), when the guest is restored.

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
---
 arch/x86/xen/enlighten.c |    3 +++
 drivers/xen/events.c     |    2 +-
 2 files changed, 4 insertions(+), 1 deletion(-)

diff --git a/arch/x86/xen/enlighten.c b/arch/x86/xen/enlighten.c
index bc893e7..722a994 100644
--- a/arch/x86/xen/enlighten.c
+++ b/arch/x86/xen/enlighten.c
@@ -43,6 +43,7 @@
 #include <xen/hvm.h>
 #include <xen/hvc-console.h>
 #include <xen/acpi.h>
+#include <xen/events.h>
 
 #include <asm/paravirt.h>
 #include <asm/apic.h>
@@ -195,6 +196,8 @@ void xen_vcpu_restore(void)
 		    HYPERVISOR_vcpu_op(VCPUOP_up, cpu, NULL))
 			BUG();
 	}
+
+	xen_event_channel_register_nlevel(3);
 }
 
 static void __init xen_banner(void)
diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 6a0307c..849d049 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -2270,7 +2270,7 @@ void __init xen_init_IRQ(void)
 	int i, rc;
 	int cpu;
 
-	xen_set_event_channel_nlevel(2);
+	xen_event_channel_register_nlevel(3);
 
 	evtchn_to_irq = kcalloc(nr_event_channels, sizeof(*evtchn_to_irq),
 				    GFP_KERNEL);
-- 
1.7.10.4

Re: [PATCH V2 04/13] xen: close evtchn port if binding to irq fails

[Jan Beulich]

>>> On 04.02.13 at 18:23, Wei Liu <wei.liu2@citrix.com> wrote:
> --- a/drivers/xen/evtchn.c
> +++ b/drivers/xen/evtchn.c
> @@ -269,6 +269,15 @@ static int evtchn_bind_to_user(struct per_user_data *u, 
> int port)
>  				       u->name, (void *)(unsigned long)port);
>  	if (rc >= 0)
>  		rc = evtchn_make_refcounted(port);
> +	else {
> +		/* bind failed, should close the port now */
> +		struct evtchn_close close;
> +		close.port = port;
> +		if (port != 0 && /* port 0 is never used */

If the port == 0 case really needs handling here (didn't look at
the surrounding code), this ought to be done with a "else if()"
at the top of this change imo.

Jan

> +		    HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
> +			BUG();
> +		set_port_user(port, NULL);
> +	}
>  
>  	return rc;
>  }