[RFC PATCH 2/3] Xen: rework NR_EVENT_CHANNELS related stuffs.

[Wei Liu <wei.liu2@citrix.com>]

Signed-off-by: Wei Liu <wei.liu2@citrix.com>
---
 drivers/xen/events.c        |   44 +++++++++++++++++++++++++++++--------------
 drivers/xen/evtchn.c        |   16 +++++++++-------
 include/xen/events.h        |    3 +++
 include/xen/interface/xen.h |   17 ++++++++++++++++-
 4 files changed, 58 insertions(+), 22 deletions(-)

diff --git a/drivers/xen/events.c b/drivers/xen/events.c
index 835101f..f60ba76 100644
--- a/drivers/xen/events.c
+++ b/drivers/xen/events.c
@@ -52,7 +52,8 @@
 #include <xen/interface/hvm/params.h>
 
 /* N-level event channel, starting from 2 */
-static unsigned int evtchn_level = 2;
+unsigned int evtchn_level = 2;
+EXPORT_SYMBOL_GPL(evtchn_level);
 
 struct evtchn_ops {
 	unsigned long (*active_evtchns)(unsigned int,
@@ -130,8 +131,7 @@ 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],
-		      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)
@@ -913,7 +913,7 @@ 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(evtchn_level); port++) {
 		status.dom = DOMID_SELF;
 		status.port = port;
 		rc = HYPERVISOR_event_channel_op(EVTCHNOP_status, &status);
@@ -1138,7 +1138,7 @@ int evtchn_get(unsigned int evtchn)
 	struct irq_info *info;
 	int err = -ENOENT;
 
-	if (evtchn >= NR_EVENT_CHANNELS)
+	if (evtchn >= NR_EVENT_CHANNELS(evtchn_level))
 		return -EINVAL;
 
 	mutex_lock(&irq_mapping_update_lock);
@@ -1227,7 +1227,7 @@ static irqreturn_t __xen_debug_interrupt_l2(int irq, void *dev_id)
 		       i % 8 == 0 ? "\n   " : " ");
 
 	printk("\nlocal cpu%d mask:\n   ", cpu);
-	for (i = (NR_EVENT_CHANNELS/BITS_PER_LONG)-1; i >= 0; i--)
+	for (i = (NR_EVENT_CHANNELS(evtchn_level)/BITS_PER_LONG)-1; i >= 0; i--)
 		printk("%0*lx%s", (int)(sizeof(cpu_evtchn[0])*2),
 		       cpu_evtchn[i],
 		       i % 8 == 0 ? "\n   " : " ");
@@ -1242,7 +1242,7 @@ static irqreturn_t __xen_debug_interrupt_l2(int irq, void *dev_id)
 	}
 
 	printk("\npending list:\n");
-	for (i = 0; i < NR_EVENT_CHANNELS; i++) {
+	for (i = 0; i < NR_EVENT_CHANNELS(evtchn_level); 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",
@@ -1709,14 +1709,14 @@ 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_level); evtchn++)
 		eops->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_level); evtchn++)
 		evtchn_to_irq[evtchn] = -1;
 
 	for_each_possible_cpu(cpu) {
@@ -1824,21 +1824,37 @@ static struct evtchn_ops evtchn_ops_l2 __read_mostly = {
 void __init xen_init_IRQ(void)
 {
 	int i, rc;
+	int cpu;
 
-	evtchn_level = 2;
+	/* Setup 2-level event channel */
 	eops = &evtchn_ops_l2;
+	evtchn_level = 2;
 
-	/* Setup 2-level event channel */
-	evtchn_to_irq = kcalloc(NR_EVENT_CHANNELS, sizeof(*evtchn_to_irq),
+	evtchn_to_irq = kcalloc(NR_EVENT_CHANNELS(evtchn_level),
+				sizeof(*evtchn_to_irq),
 				GFP_KERNEL);
 	BUG_ON(!evtchn_to_irq);
-	for (i = 0; i < NR_EVENT_CHANNELS; i++)
+
+	for_each_possible_cpu(cpu) {
+		void *p;
+		unsigned int nr = NR_EVENT_CHANNELS(evtchn_level)/BITS_PER_LONG;
+		p = kzalloc_node(sizeof(unsigned long) * nr,
+				 GFP_KERNEL,
+				 cpu_to_node(cpu));
+		if (!p)
+			p = kzalloc(sizeof(unsigned long) * nr,
+				    GFP_KERNEL);
+		BUG_ON(!p);
+		per_cpu(cpu_evtchn_mask, cpu) = p;
+	}
+
+	for (i = 0; i < NR_EVENT_CHANNELS(evtchn_level); 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(evtchn_level); i++)
 		eops->mask_evtchn(i);
 
 	pirq_needs_eoi = pirq_needs_eoi_flag;
diff --git a/drivers/xen/evtchn.c b/drivers/xen/evtchn.c
index b1f60a0..cb45ecf 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(evtchn_level) &&
 		    get_port_user(port) == u &&
 		    !get_port_enabled(port)) {
 			set_port_enabled(port, true);
@@ -364,7 +364,7 @@ static long evtchn_ioctl(struct file *file,
 			break;
 
 		rc = -EINVAL;
-		if (unbind.port >= NR_EVENT_CHANNELS)
+		if (unbind.port >= NR_EVENT_CHANNELS(evtchn_level))
 			break;
 
 		spin_lock_irq(&port_user_lock);
@@ -392,7 +392,7 @@ 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(evtchn_level)) {
 			rc = -EINVAL;
 		} else if (get_port_user(notify.port) != u) {
 			rc = -ENOTCONN;
@@ -482,7 +482,7 @@ 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(evtchn_level); i++) {
 		if (get_port_user(i) != u)
 			continue;
 
@@ -491,7 +491,7 @@ 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(evtchn_level); i++) {
 		if (get_port_user(i) != u)
 			continue;
 
@@ -528,7 +528,8 @@ 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(evtchn_level),
+			    sizeof(*port_user), GFP_KERNEL);
 	if (port_user == NULL)
 		return -ENOMEM;
 
@@ -541,7 +542,8 @@ static int __init evtchn_init(void)
 		return err;
 	}
 
-	printk(KERN_INFO "Event-channel device installed.\n");
+	printk(KERN_INFO "Event-channel device installed."
+	       " Event-channel level: %d\n", evtchn_level);
 
 	return 0;
 }
diff --git a/include/xen/events.h b/include/xen/events.h
index 04399b2..bc10f22 100644
--- a/include/xen/events.h
+++ b/include/xen/events.h
@@ -109,4 +109,7 @@ 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);
 
+/* N-level event channels */
+extern unsigned int evtchn_level;
+
 #endif	/* _XEN_EVENTS_H */
diff --git a/include/xen/interface/xen.h b/include/xen/interface/xen.h
index a890804..c66e1ff 100644
--- a/include/xen/interface/xen.h
+++ b/include/xen/interface/xen.h
@@ -283,9 +283,24 @@ 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 * sizeof(unsigned long))
+#define NR_EVENT_CHANNELS(x) ({ unsigned int __v = 0;	\
+	switch (x) {					\
+	case 2:						\
+		__v = NR_EVENT_CHANNELS_L2; break;	\
+	case 3:						\
+		__v = NR_EVENT_CHANNELS_L3; break;	\
+	default:					\
+		BUG();					\
+	}						\
+	__v; })
+
 
 struct vcpu_time_info {
 	/*
-- 
1.7.10.4