1 files changed, 55 insertions, 58 deletions

diff --git a/drivers/xen/evtchn.c b/drivers/xen/evtchn.c
index 6e0b1dd5573c..7e4a13e632dc 100644
--- a/drivers/xen/evtchn.c
+++ b/drivers/xen/evtchn.c
@@ -85,6 +85,7 @@ struct user_evtchn {
 	struct per_user_data *user;
 	evtchn_port_t port;
 	bool enabled;
+	bool unbinding;
 };
 
 static void evtchn_free_ring(evtchn_port_t *ring)
@@ -162,20 +163,28 @@ static irqreturn_t evtchn_interrupt(int irq, void *data)
 {
 	struct user_evtchn *evtchn = data;
 	struct per_user_data *u = evtchn->user;
+	unsigned int prod, cons;
+
+	/* Handler might be called when tearing down the IRQ. */
+	if (evtchn->unbinding)
+		return IRQ_HANDLED;
 
 	WARN(!evtchn->enabled,
 	     "Interrupt for port %u, but apparently not enabled; per-user %p\n",
 	     evtchn->port, u);
 
-	disable_irq_nosync(irq);
 	evtchn->enabled = false;
 
 	spin_lock(&u->ring_prod_lock);
 
-	if ((u->ring_prod - u->ring_cons) < u->ring_size) {
-		*evtchn_ring_entry(u, u->ring_prod) = evtchn->port;
-		wmb(); /* Ensure ring contents visible */
-		if (u->ring_cons == u->ring_prod++) {
+	prod = READ_ONCE(u->ring_prod);
+	cons = READ_ONCE(u->ring_cons);
+
+	if ((prod - cons) < u->ring_size) {
+		*evtchn_ring_entry(u, prod) = evtchn->port;
+		smp_wmb(); /* Ensure ring contents visible */
+		WRITE_ONCE(u->ring_prod, prod + 1);
+		if (cons == prod) {
 			wake_up_interruptible(&u->evtchn_wait);
 			kill_fasync(&u->evtchn_async_queue,
 				    SIGIO, POLL_IN);
@@ -211,8 +220,8 @@ static ssize_t evtchn_read(struct file *file, char __user *buf,
 		if (u->ring_overflow)
 			goto unlock_out;
 
-		c = u->ring_cons;
-		p = u->ring_prod;
+		c = READ_ONCE(u->ring_cons);
+		p = READ_ONCE(u->ring_prod);
 		if (c != p)
 			break;
 
@@ -222,7 +231,7 @@ static ssize_t evtchn_read(struct file *file, char __user *buf,
 			return -EAGAIN;
 
 		rc = wait_event_interruptible(u->evtchn_wait,
-					      u->ring_cons != u->ring_prod);
+			READ_ONCE(u->ring_cons) != READ_ONCE(u->ring_prod));
 		if (rc)
 			return rc;
 	}
@@ -246,13 +255,13 @@ static ssize_t evtchn_read(struct file *file, char __user *buf,
 	}
 
 	rc = -EFAULT;
-	rmb(); /* Ensure that we see the port before we copy it. */
+	smp_rmb(); /* Ensure that we see the port before we copy it. */
 	if (copy_to_user(buf, evtchn_ring_entry(u, c), bytes1) ||
 	    ((bytes2 != 0) &&
 	     copy_to_user(&buf[bytes1], &u->ring[0], bytes2)))
 		goto unlock_out;
 
-	u->ring_cons += (bytes1 + bytes2) / sizeof(evtchn_port_t);
+	WRITE_ONCE(u->ring_cons, c + (bytes1 + bytes2) / sizeof(evtchn_port_t));
 	rc = bytes1 + bytes2;
 
  unlock_out:
@@ -293,7 +302,7 @@ static ssize_t evtchn_write(struct file *file, const char __user *buf,
 		evtchn = find_evtchn(u, port);
 		if (evtchn && !evtchn->enabled) {
 			evtchn->enabled = true;
-			enable_irq(irq_from_evtchn(port));
+			xen_irq_lateeoi(irq_from_evtchn(port), 0);
 		}
 	}
 
@@ -362,10 +371,10 @@ static int evtchn_resize_ring(struct per_user_data *u)
 	return 0;
 }
 
-static int evtchn_bind_to_user(struct per_user_data *u, evtchn_port_t port)
+static int evtchn_bind_to_user(struct per_user_data *u, evtchn_port_t port,
+			       bool is_static)
 {
 	struct user_evtchn *evtchn;
-	struct evtchn_close close;
 	int rc = 0;
 
 	/*
@@ -393,19 +402,19 @@ static int evtchn_bind_to_user(struct per_user_data *u, evtchn_port_t port)
 	if (rc < 0)
 		goto err;
 
-	rc = bind_evtchn_to_irqhandler(port, evtchn_interrupt, 0,
-				       u->name, evtchn);
+	rc = bind_evtchn_to_irqhandler_lateeoi(port, evtchn_interrupt, IRQF_SHARED,
+					       u->name, evtchn);
 	if (rc < 0)
 		goto err;
 
-	rc = evtchn_make_refcounted(port);
+	rc = evtchn_make_refcounted(port, is_static);
 	return rc;
 
 err:
 	/* bind failed, should close the port now */
-	close.port = port;
-	if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
-		BUG();
+	if (!is_static)
+		xen_evtchn_close(port);
+
 	del_evtchn(u, evtchn);
 	return rc;
 }
@@ -417,41 +426,12 @@ static void evtchn_unbind_from_user(struct per_user_data *u,
 
 	BUG_ON(irq < 0);
 
+	evtchn->unbinding = true;
 	unbind_from_irqhandler(irq, evtchn);
 
 	del_evtchn(u, evtchn);
 }
 
-static DEFINE_PER_CPU(int, bind_last_selected_cpu);
-
-static void evtchn_bind_interdom_next_vcpu(evtchn_port_t evtchn)
-{
-	unsigned int selected_cpu, irq;
-	struct irq_desc *desc;
-	unsigned long flags;
-
-	irq = irq_from_evtchn(evtchn);
-	desc = irq_to_desc(irq);
-
-	if (!desc)
-		return;
-
-	raw_spin_lock_irqsave(&desc->lock, flags);
-	selected_cpu = this_cpu_read(bind_last_selected_cpu);
-	selected_cpu = cpumask_next_and(selected_cpu,
-			desc->irq_common_data.affinity, cpu_online_mask);
-
-	if (unlikely(selected_cpu >= nr_cpu_ids))
-		selected_cpu = cpumask_first_and(desc->irq_common_data.affinity,
-				cpu_online_mask);
-
-	this_cpu_write(bind_last_selected_cpu, selected_cpu);
-
-	/* unmask expects irqs to be disabled */
-	xen_set_affinity_evtchn(desc, selected_cpu);
-	raw_spin_unlock_irqrestore(&desc->lock, flags);
-}
-
 static long evtchn_ioctl(struct file *file,
 			 unsigned int cmd, unsigned long arg)
 {
@@ -482,7 +462,7 @@ static long evtchn_ioctl(struct file *file,
 		if (rc != 0)
 			break;
 
-		rc = evtchn_bind_to_user(u, bind_virq.port);
+		rc = evtchn_bind_to_user(u, bind_virq.port, false);
 		if (rc == 0)
 			rc = bind_virq.port;
 		break;
@@ -508,11 +488,9 @@ static long evtchn_ioctl(struct file *file,
 		if (rc != 0)
 			break;
 
-		rc = evtchn_bind_to_user(u, bind_interdomain.local_port);
-		if (rc == 0) {
+		rc = evtchn_bind_to_user(u, bind_interdomain.local_port, false);
+		if (rc == 0)
 			rc = bind_interdomain.local_port;
-			evtchn_bind_interdom_next_vcpu(rc);
-		}
 		break;
 	}
 
@@ -535,7 +513,7 @@ static long evtchn_ioctl(struct file *file,
 		if (rc != 0)
 			break;
 
-		rc = evtchn_bind_to_user(u, alloc_unbound.port);
+		rc = evtchn_bind_to_user(u, alloc_unbound.port, false);
 		if (rc == 0)
 			rc = alloc_unbound.port;
 		break;
@@ -564,6 +542,23 @@ static long evtchn_ioctl(struct file *file,
 		break;
 	}
 
+	case IOCTL_EVTCHN_BIND_STATIC: {
+		struct ioctl_evtchn_bind bind;
+		struct user_evtchn *evtchn;
+
+		rc = -EFAULT;
+		if (copy_from_user(&bind, uarg, sizeof(bind)))
+			break;
+
+		rc = -EISCONN;
+		evtchn = find_evtchn(u, bind.port);
+		if (evtchn)
+			break;
+
+		rc = evtchn_bind_to_user(u, bind.port, true);
+		break;
+	}
+
 	case IOCTL_EVTCHN_NOTIFY: {
 		struct ioctl_evtchn_notify notify;
 		struct user_evtchn *evtchn;
@@ -585,7 +580,9 @@ static long evtchn_ioctl(struct file *file,
 		/* Initialise the ring to empty. Clear errors. */
 		mutex_lock(&u->ring_cons_mutex);
 		spin_lock_irq(&u->ring_prod_lock);
-		u->ring_cons = u->ring_prod = u->ring_overflow = 0;
+		WRITE_ONCE(u->ring_cons, 0);
+		WRITE_ONCE(u->ring_prod, 0);
+		u->ring_overflow = 0;
 		spin_unlock_irq(&u->ring_prod_lock);
 		mutex_unlock(&u->ring_cons_mutex);
 		rc = 0;
@@ -628,7 +625,7 @@ static __poll_t evtchn_poll(struct file *file, poll_table *wait)
 	struct per_user_data *u = file->private_data;
 
 	poll_wait(file, &u->evtchn_wait, wait);
-	if (u->ring_cons != u->ring_prod)
+	if (READ_ONCE(u->ring_cons) != READ_ONCE(u->ring_prod))
 		mask |= EPOLLIN | EPOLLRDNORM;
 	if (u->ring_overflow)
 		mask = EPOLLERR;
@@ -697,7 +694,6 @@ static const struct file_operations evtchn_fops = {
 	.fasync  = evtchn_fasync,
 	.open    = evtchn_open,
 	.release = evtchn_release,
-	.llseek	 = no_llseek,
 };
 
 static struct miscdevice evtchn_miscdev = {
@@ -732,4 +728,5 @@ static void __exit evtchn_cleanup(void)
 module_init(evtchn_init);
 module_exit(evtchn_cleanup);
 
+MODULE_DESCRIPTION("Xen /dev/xen/evtchn device driver");
 MODULE_LICENSE("GPL");