[linux.git] / drivers / xen / evtchn.c

/******************************************************************************
 * evtchn.c
 *
 * Driver for receiving and demuxing event-channel signals.
 *
 * Copyright (c) 2004-2005, K A Fraser
 * Multi-process extensions Copyright (c) 2004, Steven Smith
 *
 * This program is free software; you can redistribute it and/or
 * modify it under the terms of the GNU General Public License version 2
 * as published by the Free Software Foundation; or, when distributed
 * separately from the Linux kernel or incorporated into other
 * software packages, subject to the following license:
 *
 * Permission is hereby granted, free of charge, to any person obtaining a copy
 * of this source file (the "Software"), to deal in the Software without
 * restriction, including without limitation the rights to use, copy, modify,
 * merge, publish, distribute, sublicense, and/or sell copies of the Software,
 * and to permit persons to whom the Software is furnished to do so, subject to
 * the following conditions:
 *
 * The above copyright notice and this permission notice shall be included in
 * all copies or substantial portions of the Software.
 *
 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
 * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
 * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
 * AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
 * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
 * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
 * IN THE SOFTWARE.
 */

#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt

#include <linux/module.h>
#include <linux/kernel.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/miscdevice.h>
#include <linux/major.h>
#include <linux/proc_fs.h>
#include <linux/stat.h>
#include <linux/poll.h>
#include <linux/irq.h>
#include <linux/init.h>
#include <linux/mutex.h>
#include <linux/cpu.h>
#include <linux/mm.h>
#include <linux/vmalloc.h>

#include <xen/xen.h>
#include <xen/events.h>
#include <xen/evtchn.h>
#include <xen/xen-ops.h>
#include <asm/xen/hypervisor.h>

struct per_user_data {
	struct mutex bind_mutex; /* serialize bind/unbind operations */
	struct rb_root evtchns;
	unsigned int nr_evtchns;

	/* Notification ring, accessed via /dev/xen/evtchn. */
	unsigned int ring_size;
	evtchn_port_t *ring;
	unsigned int ring_cons, ring_prod, ring_overflow;
	struct mutex ring_cons_mutex; /* protect against concurrent readers */
	spinlock_t ring_prod_lock; /* product against concurrent interrupts */

	/* Processes wait on this queue when ring is empty. */
	wait_queue_head_t evtchn_wait;
	struct fasync_struct *evtchn_async_queue;
	const char *name;

	domid_t restrict_domid;
};

#define UNRESTRICTED_DOMID ((domid_t)-1)

struct user_evtchn {
	struct rb_node node;
	struct per_user_data *user;
	unsigned port;
	bool enabled;
};

static void evtchn_free_ring(evtchn_port_t *ring)
{
	kvfree(ring);
}

static unsigned int evtchn_ring_offset(struct per_user_data *u,
				       unsigned int idx)
{
	return idx & (u->ring_size - 1);
}

static evtchn_port_t *evtchn_ring_entry(struct per_user_data *u,
					unsigned int idx)
{
	return u->ring + evtchn_ring_offset(u, idx);
}

static int add_evtchn(struct per_user_data *u, struct user_evtchn *evtchn)
{
	struct rb_node **new = &(u->evtchns.rb_node), *parent = NULL;

	u->nr_evtchns++;

	while (*new) {
		struct user_evtchn *this;

		this = rb_entry(*new, struct user_evtchn, node);

		parent = *new;
		if (this->port < evtchn->port)
			new = &((*new)->rb_left);
		else if (this->port > evtchn->port)
			new = &((*new)->rb_right);
		else
			return -EEXIST;
	}

	/* Add new node and rebalance tree. */
	rb_link_node(&evtchn->node, parent, new);
	rb_insert_color(&evtchn->node, &u->evtchns);

	return 0;
}

static void del_evtchn(struct per_user_data *u, struct user_evtchn *evtchn)
{
	u->nr_evtchns--;
	rb_erase(&evtchn->node, &u->evtchns);
	kfree(evtchn);
}

static struct user_evtchn *find_evtchn(struct per_user_data *u, unsigned port)
{
	struct rb_node *node = u->evtchns.rb_node;

	while (node) {
		struct user_evtchn *evtchn;

		evtchn = rb_entry(node, struct user_evtchn, node);

		if (evtchn->port < port)
			node = node->rb_left;
		else if (evtchn->port > port)
			node = node->rb_right;
		else
			return evtchn;
	}
	return NULL;
}

static irqreturn_t evtchn_interrupt(int irq, void *data)
{
	struct user_evtchn *evtchn = data;
	struct per_user_data *u = evtchn->user;

	WARN(!evtchn->enabled,
	     "Interrupt for port %d, 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++) {
			wake_up_interruptible(&u->evtchn_wait);
			kill_fasync(&u->evtchn_async_queue,
				    SIGIO, POLL_IN);
		}
	} else
		u->ring_overflow = 1;

	spin_unlock(&u->ring_prod_lock);

	return IRQ_HANDLED;
}

static ssize_t evtchn_read(struct file *file, char __user *buf,
			   size_t count, loff_t *ppos)
{
	int rc;
	unsigned int c, p, bytes1 = 0, bytes2 = 0;
	struct per_user_data *u = file->private_data;

	/* Whole number of ports. */
	count &= ~(sizeof(evtchn_port_t)-1);

	if (count == 0)
		return 0;

	if (count > PAGE_SIZE)
		count = PAGE_SIZE;

	for (;;) {
		mutex_lock(&u->ring_cons_mutex);

		rc = -EFBIG;
		if (u->ring_overflow)
			goto unlock_out;

		c = u->ring_cons;
		p = u->ring_prod;
		if (c != p)
			break;

		mutex_unlock(&u->ring_cons_mutex);

		if (file->f_flags & O_NONBLOCK)
			return -EAGAIN;

		rc = wait_event_interruptible(u->evtchn_wait,
					      u->ring_cons != u->ring_prod);
		if (rc)
			return rc;
	}

	/* Byte lengths of two chunks. Chunk split (if any) is at ring wrap. */
	if (((c ^ p) & u->ring_size) != 0) {
		bytes1 = (u->ring_size - evtchn_ring_offset(u, c)) *
			sizeof(evtchn_port_t);
		bytes2 = evtchn_ring_offset(u, p) * sizeof(evtchn_port_t);
	} else {
		bytes1 = (p - c) * sizeof(evtchn_port_t);
		bytes2 = 0;
	}

	/* Truncate chunks according to caller's maximum byte count. */
	if (bytes1 > count) {
		bytes1 = count;
		bytes2 = 0;
	} else if ((bytes1 + bytes2) > count) {
		bytes2 = count - bytes1;
	}

	rc = -EFAULT;
	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);
	rc = bytes1 + bytes2;

 unlock_out:
	mutex_unlock(&u->ring_cons_mutex);
	return rc;
}

static ssize_t evtchn_write(struct file *file, const char __user *buf,
			    size_t count, loff_t *ppos)
{
	int rc, i;
	evtchn_port_t *kbuf = (evtchn_port_t *)__get_free_page(GFP_KERNEL);
	struct per_user_data *u = file->private_data;

	if (kbuf == NULL)
		return -ENOMEM;

	/* Whole number of ports. */
	count &= ~(sizeof(evtchn_port_t)-1);

	rc = 0;
	if (count == 0)
		goto out;

	if (count > PAGE_SIZE)
		count = PAGE_SIZE;

	rc = -EFAULT;
	if (copy_from_user(kbuf, buf, count) != 0)
		goto out;

	mutex_lock(&u->bind_mutex);

	for (i = 0; i < (count/sizeof(evtchn_port_t)); i++) {
		unsigned port = kbuf[i];
		struct user_evtchn *evtchn;

		evtchn = find_evtchn(u, port);
		if (evtchn && !evtchn->enabled) {
			evtchn->enabled = true;
			enable_irq(irq_from_evtchn(port));
		}
	}

	mutex_unlock(&u->bind_mutex);

	rc = count;

 out:
	free_page((unsigned long)kbuf);
	return rc;
}

static int evtchn_resize_ring(struct per_user_data *u)
{
	unsigned int new_size;
	evtchn_port_t *new_ring, *old_ring;

	/*
	 * Ensure the ring is large enough to capture all possible
	 * events. i.e., one free slot for each bound event.
	 */
	if (u->nr_evtchns <= u->ring_size)
		return 0;

	if (u->ring_size == 0)
		new_size = 64;
	else
		new_size = 2 * u->ring_size;

	new_ring = kvmalloc(new_size * sizeof(*new_ring), GFP_KERNEL);
	if (!new_ring)
		return -ENOMEM;

	old_ring = u->ring;

	/*
	 * Access to the ring contents is serialized by either the
	 * prod /or/ cons lock so take both when resizing.
	 */
	mutex_lock(&u->ring_cons_mutex);
	spin_lock_irq(&u->ring_prod_lock);

	/*
	 * Copy the old ring contents to the new ring.
	 *
	 * To take care of wrapping, a full ring, and the new index
	 * pointing into the second half, simply copy the old contents
	 * twice.
	 *
	 * +---------+    +------------------+
	 * |34567  12| -> |34567  1234567  12|
	 * +-----p-c-+    +-------c------p---+
	 */
	memcpy(new_ring, old_ring, u->ring_size * sizeof(*u->ring));
	memcpy(new_ring + u->ring_size, old_ring,
	       u->ring_size * sizeof(*u->ring));

	u->ring = new_ring;
	u->ring_size = new_size;

	spin_unlock_irq(&u->ring_prod_lock);
	mutex_unlock(&u->ring_cons_mutex);

	evtchn_free_ring(old_ring);

	return 0;
}

static int evtchn_bind_to_user(struct per_user_data *u, int port)
{
	struct user_evtchn *evtchn;
	struct evtchn_close close;
	int rc = 0;

	/*
	 * Ports are never reused, so every caller should pass in a
	 * unique port.
	 *
	 * (Locking not necessary because we haven't registered the
	 * interrupt handler yet, and our caller has already
	 * serialized bind operations.)
	 */

	evtchn = kzalloc(sizeof(*evtchn), GFP_KERNEL);
	if (!evtchn)
		return -ENOMEM;

	evtchn->user = u;
	evtchn->port = port;
	evtchn->enabled = true; /* start enabled */

	rc = add_evtchn(u, evtchn);
	if (rc < 0)
		goto err;

	rc = evtchn_resize_ring(u);
	if (rc < 0)
		goto err;

	rc = bind_evtchn_to_irqhandler(port, evtchn_interrupt, 0,
				       u->name, evtchn);
	if (rc < 0)
		goto err;

	rc = evtchn_make_refcounted(port);
	return rc;

err:
	/* bind failed, should close the port now */
	close.port = port;
	if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
		BUG();
	del_evtchn(u, evtchn);
	return rc;
}

static void evtchn_unbind_from_user(struct per_user_data *u,
				    struct user_evtchn *evtchn)
{
	int irq = irq_from_evtchn(evtchn->port);

	BUG_ON(irq < 0);

	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(int 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_rebind_evtchn_to_cpu(evtchn, selected_cpu);
	raw_spin_unlock_irqrestore(&desc->lock, flags);
}

static long evtchn_ioctl(struct file *file,
			 unsigned int cmd, unsigned long arg)
{
	int rc;
	struct per_user_data *u = file->private_data;
	void __user *uarg = (void __user *) arg;

	/* Prevent bind from racing with unbind */
	mutex_lock(&u->bind_mutex);

	switch (cmd) {
	case IOCTL_EVTCHN_BIND_VIRQ: {
		struct ioctl_evtchn_bind_virq bind;
		struct evtchn_bind_virq bind_virq;

		rc = -EACCES;
		if (u->restrict_domid != UNRESTRICTED_DOMID)
			break;

		rc = -EFAULT;
		if (copy_from_user(&bind, uarg, sizeof(bind)))
			break;

		bind_virq.virq = bind.virq;
		bind_virq.vcpu = xen_vcpu_nr(0);
		rc = HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
						 &bind_virq);
		if (rc != 0)
			break;

		rc = evtchn_bind_to_user(u, bind_virq.port);
		if (rc == 0)
			rc = bind_virq.port;
		break;
	}

	case IOCTL_EVTCHN_BIND_INTERDOMAIN: {
		struct ioctl_evtchn_bind_interdomain bind;
		struct evtchn_bind_interdomain bind_interdomain;

		rc = -EFAULT;
		if (copy_from_user(&bind, uarg, sizeof(bind)))
			break;

		rc = -EACCES;
		if (u->restrict_domid != UNRESTRICTED_DOMID &&
		    u->restrict_domid != bind.remote_domain)
			break;

		bind_interdomain.remote_dom  = bind.remote_domain;
		bind_interdomain.remote_port = bind.remote_port;
		rc = HYPERVISOR_event_channel_op(EVTCHNOP_bind_interdomain,
						 &bind_interdomain);
		if (rc != 0)
			break;

		rc = evtchn_bind_to_user(u, bind_interdomain.local_port);
		if (rc == 0) {
			rc = bind_interdomain.local_port;
			evtchn_bind_interdom_next_vcpu(rc);
		}
		break;
	}

	case IOCTL_EVTCHN_BIND_UNBOUND_PORT: {
		struct ioctl_evtchn_bind_unbound_port bind;
		struct evtchn_alloc_unbound alloc_unbound;

		rc = -EACCES;
		if (u->restrict_domid != UNRESTRICTED_DOMID)
			break;

		rc = -EFAULT;
		if (copy_from_user(&bind, uarg, sizeof(bind)))
			break;

		alloc_unbound.dom        = DOMID_SELF;
		alloc_unbound.remote_dom = bind.remote_domain;
		rc = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
						 &alloc_unbound);
		if (rc != 0)
			break;

		rc = evtchn_bind_to_user(u, alloc_unbound.port);
		if (rc == 0)
			rc = alloc_unbound.port;
		break;
	}

	case IOCTL_EVTCHN_UNBIND: {
		struct ioctl_evtchn_unbind unbind;
		struct user_evtchn *evtchn;

		rc = -EFAULT;
		if (copy_from_user(&unbind, uarg, sizeof(unbind)))
			break;

		rc = -EINVAL;
		if (unbind.port >= xen_evtchn_nr_channels())
			break;

		rc = -ENOTCONN;
		evtchn = find_evtchn(u, unbind.port);
		if (!evtchn)
			break;

		disable_irq(irq_from_evtchn(unbind.port));
		evtchn_unbind_from_user(u, evtchn);
		rc = 0;
		break;
	}

	case IOCTL_EVTCHN_NOTIFY: {
		struct ioctl_evtchn_notify notify;
		struct user_evtchn *evtchn;

		rc = -EFAULT;
		if (copy_from_user(&notify, uarg, sizeof(notify)))
			break;

		rc = -ENOTCONN;
		evtchn = find_evtchn(u, notify.port);
		if (evtchn) {
			notify_remote_via_evtchn(notify.port);
			rc = 0;
		}
		break;
	}

	case IOCTL_EVTCHN_RESET: {
		/* 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;
		spin_unlock_irq(&u->ring_prod_lock);
		mutex_unlock(&u->ring_cons_mutex);
		rc = 0;
		break;
	}

	case IOCTL_EVTCHN_RESTRICT_DOMID: {
		struct ioctl_evtchn_restrict_domid ierd;

		rc = -EACCES;
		if (u->restrict_domid != UNRESTRICTED_DOMID)
			break;

		rc = -EFAULT;
		if (copy_from_user(&ierd, uarg, sizeof(ierd)))
		    break;

		rc = -EINVAL;
		if (ierd.domid == 0 || ierd.domid >= DOMID_FIRST_RESERVED)
			break;

		u->restrict_domid = ierd.domid;
		rc = 0;

		break;
	}

	default:
		rc = -ENOSYS;
		break;
	}
	mutex_unlock(&u->bind_mutex);

	return rc;
}

static unsigned int evtchn_poll(struct file *file, poll_table *wait)
{
	unsigned int mask = POLLOUT | POLLWRNORM;
	struct per_user_data *u = file->private_data;

	poll_wait(file, &u->evtchn_wait, wait);
	if (u->ring_cons != u->ring_prod)
		mask |= POLLIN | POLLRDNORM;
	if (u->ring_overflow)
		mask = POLLERR;
	return mask;
}

static int evtchn_fasync(int fd, struct file *filp, int on)
{
	struct per_user_data *u = filp->private_data;
	return fasync_helper(fd, filp, on, &u->evtchn_async_queue);
}

static int evtchn_open(struct inode *inode, struct file *filp)
{
	struct per_user_data *u;

	u = kzalloc(sizeof(*u), GFP_KERNEL);
	if (u == NULL)
		return -ENOMEM;

	u->name = kasprintf(GFP_KERNEL, "evtchn:%s", current->comm);
	if (u->name == NULL) {
		kfree(u);
		return -ENOMEM;
	}

	init_waitqueue_head(&u->evtchn_wait);

	mutex_init(&u->bind_mutex);
	mutex_init(&u->ring_cons_mutex);
	spin_lock_init(&u->ring_prod_lock);

	u->restrict_domid = UNRESTRICTED_DOMID;

	filp->private_data = u;

	return nonseekable_open(inode, filp);
}

static int evtchn_release(struct inode *inode, struct file *filp)
{
	struct per_user_data *u = filp->private_data;
	struct rb_node *node;

	while ((node = u->evtchns.rb_node)) {
		struct user_evtchn *evtchn;

		evtchn = rb_entry(node, struct user_evtchn, node);
		disable_irq(irq_from_evtchn(evtchn->port));
		evtchn_unbind_from_user(u, evtchn);
	}

	evtchn_free_ring(u->ring);
	kfree(u->name);
	kfree(u);

	return 0;
}

static const struct file_operations evtchn_fops = {
	.owner   = THIS_MODULE,
	.read    = evtchn_read,
	.write   = evtchn_write,
	.unlocked_ioctl = evtchn_ioctl,
	.poll    = evtchn_poll,
	.fasync  = evtchn_fasync,
	.open    = evtchn_open,
	.release = evtchn_release,
	.llseek	 = no_llseek,
};

static struct miscdevice evtchn_miscdev = {
	.minor        = MISC_DYNAMIC_MINOR,
	.name         = "xen/evtchn",
	.fops         = &evtchn_fops,
};
static int __init evtchn_init(void)
{
	int err;

	if (!xen_domain())
		return -ENODEV;

	/* Create '/dev/xen/evtchn'. */
	err = misc_register(&evtchn_miscdev);
	if (err != 0) {
		pr_err("Could not register /dev/xen/evtchn\n");
		return err;
	}

	pr_info("Event-channel device installed\n");

	return 0;
}

static void __exit evtchn_cleanup(void)
{
	misc_deregister(&evtchn_miscdev);
}

module_init(evtchn_init);
module_exit(evtchn_cleanup);

MODULE_LICENSE("GPL");
Commit	Line	Data
f7116284 IC	1	/******************************************************************************
	2	* evtchn.c
	3	*
	4	* Driver for receiving and demuxing event-channel signals.
	5	*
	6	* Copyright (c) 2004-2005, K A Fraser
	7	* Multi-process extensions Copyright (c) 2004, Steven Smith
	8	*
	9	* This program is free software; you can redistribute it and/or
	10	* modify it under the terms of the GNU General Public License version 2
	11	* as published by the Free Software Foundation; or, when distributed
	12	* separately from the Linux kernel or incorporated into other
	13	* software packages, subject to the following license:
	14	*
	15	* Permission is hereby granted, free of charge, to any person obtaining a copy
	16	* of this source file (the "Software"), to deal in the Software without
	17	* restriction, including without limitation the rights to use, copy, modify,
	18	* merge, publish, distribute, sublicense, and/or sell copies of the Software,
	19	* and to permit persons to whom the Software is furnished to do so, subject to
	20	* the following conditions:
	21	*
	22	* The above copyright notice and this permission notice shall be included in
	23	* all copies or substantial portions of the Software.
	24	*
	25	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	26	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	27	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
	28	* AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
	29	* LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
	30	* FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS
	31	* IN THE SOFTWARE.
	32	*/
	33
283c0972 JP	34	#define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt
283c0972 JP	35
f7116284 IC	36	#include <linux/module.h>
	37	#include <linux/kernel.h>
	38	#include <linux/sched.h>
	39	#include <linux/slab.h>
	40	#include <linux/string.h>
	41	#include <linux/errno.h>
	42	#include <linux/fs.h>
f7116284 IC	43	#include <linux/miscdevice.h>
	44	#include <linux/major.h>
	45	#include <linux/proc_fs.h>
	46	#include <linux/stat.h>
	47	#include <linux/poll.h>
	48	#include <linux/irq.h>
	49	#include <linux/init.h>
f7116284 IC	50	#include <linux/mutex.h>
f7116284 IC	51	#include <linux/cpu.h>
86200154 DV	52	#include <linux/mm.h>
86200154 DV	53	#include <linux/vmalloc.h>
1ccbf534 JF	54
1ccbf534 JF	55	#include <xen/xen.h>
f7116284 IC	56	#include <xen/events.h>
f7116284 IC	57	#include <xen/evtchn.h>
cbbb4682	58	#include <xen/xen-ops.h>
f7116284 IC	59	#include <asm/xen/hypervisor.h>
	60
	61	struct per_user_data {
0a4666b5	62	struct mutex bind_mutex; /* serialize bind/unbind operations */
73cc4bb0	63	struct rb_root evtchns;
86200154	64	unsigned int nr_evtchns;
0a4666b5	65
f7116284	66	/* Notification ring, accessed via /dev/xen/evtchn. */
86200154	67	unsigned int ring_size;
f7116284 IC	68	evtchn_port_t *ring;
	69	unsigned int ring_cons, ring_prod, ring_overflow;
	70	struct mutex ring_cons_mutex; /* protect against concurrent readers */
73cc4bb0	71	spinlock_t ring_prod_lock; /* product against concurrent interrupts */
f7116284 IC	72
	73	/* Processes wait on this queue when ring is empty. */
	74	wait_queue_head_t evtchn_wait;
	75	struct fasync_struct *evtchn_async_queue;
	76	const char *name;
fbc872c3 DV	77
fbc872c3 DV	78	domid_t restrict_domid;
f7116284 IC	79	};
f7116284 IC	80
fbc872c3 DV	81	#define UNRESTRICTED_DOMID ((domid_t)-1)
fbc872c3 DV	82
73cc4bb0 DV	83	struct user_evtchn {
	84	struct rb_node node;
	85	struct per_user_data *user;
	86	unsigned port;
	87	bool enabled;
	88	};
f7116284	89
86200154 DV	90	static void evtchn_free_ring(evtchn_port_t *ring)
	91	{
	92	kvfree(ring);
	93	}
	94
	95	static unsigned int evtchn_ring_offset(struct per_user_data *u,
	96	unsigned int idx)
	97	{
	98	return idx & (u->ring_size - 1);
	99	}
	100
	101	static evtchn_port_t evtchn_ring_entry(struct per_user_data u,
	102	unsigned int idx)
	103	{
	104	return u->ring + evtchn_ring_offset(u, idx);
	105	}
	106
73cc4bb0	107	static int add_evtchn(struct per_user_data u, struct user_evtchn evtchn)
e3cc067b	108	{
73cc4bb0	109	struct rb_node *new = &(u->evtchns.rb_node), parent = NULL;
e3cc067b	110
86200154 DV	111	u->nr_evtchns++;
86200154 DV	112
73cc4bb0 DV	113	while (*new) {
	114	struct user_evtchn *this;
	115
2f60b288	116	this = rb_entry(*new, struct user_evtchn, node);
73cc4bb0 DV	117
	118	parent = *new;
	119	if (this->port < evtchn->port)
	120	new = &((*new)->rb_left);
	121	else if (this->port > evtchn->port)
	122	new = &((*new)->rb_right);
	123	else
	124	return -EEXIST;
	125	}
	126
	127	/* Add new node and rebalance tree. */
	128	rb_link_node(&evtchn->node, parent, new);
	129	rb_insert_color(&evtchn->node, &u->evtchns);
	130
	131	return 0;
e3cc067b JF	132	}
e3cc067b JF	133
73cc4bb0	134	static void del_evtchn(struct per_user_data u, struct user_evtchn evtchn)
e3cc067b	135	{
86200154	136	u->nr_evtchns--;
73cc4bb0 DV	137	rb_erase(&evtchn->node, &u->evtchns);
73cc4bb0 DV	138	kfree(evtchn);
e3cc067b JF	139	}
e3cc067b JF	140
73cc4bb0	141	static struct user_evtchn find_evtchn(struct per_user_data u, unsigned port)
e3cc067b	142	{
73cc4bb0 DV	143	struct rb_node *node = u->evtchns.rb_node;
	144
	145	while (node) {
	146	struct user_evtchn *evtchn;
	147
2f60b288	148	evtchn = rb_entry(node, struct user_evtchn, node);
73cc4bb0 DV	149
	150	if (evtchn->port < port)
	151	node = node->rb_left;
	152	else if (evtchn->port > port)
	153	node = node->rb_right;
	154	else
	155	return evtchn;
	156	}
	157	return NULL;
e3cc067b JF	158	}
e3cc067b JF	159
70697d54	160	static irqreturn_t evtchn_interrupt(int irq, void *data)
f7116284	161	{
73cc4bb0 DV	162	struct user_evtchn *evtchn = data;
73cc4bb0 DV	163	struct per_user_data *u = evtchn->user;
e3cc067b	164
73cc4bb0	165	WARN(!evtchn->enabled,
0edce91d	166	"Interrupt for port %d, but apparently not enabled; per-user %p\n",
73cc4bb0	167	evtchn->port, u);
f7116284 IC	168
f7116284 IC	169	disable_irq_nosync(irq);
73cc4bb0 DV	170	evtchn->enabled = false;
	171
	172	spin_lock(&u->ring_prod_lock);
f7116284	173
86200154 DV	174	if ((u->ring_prod - u->ring_cons) < u->ring_size) {
86200154 DV	175	*evtchn_ring_entry(u, u->ring_prod) = evtchn->port;
f7116284 IC	176	wmb(); /* Ensure ring contents visible */
	177	if (u->ring_cons == u->ring_prod++) {
	178	wake_up_interruptible(&u->evtchn_wait);
	179	kill_fasync(&u->evtchn_async_queue,
	180	SIGIO, POLL_IN);
	181	}
e3cc067b	182	} else
f7116284	183	u->ring_overflow = 1;
f7116284	184
73cc4bb0	185	spin_unlock(&u->ring_prod_lock);
f7116284 IC	186
	187	return IRQ_HANDLED;
	188	}
	189
	190	static ssize_t evtchn_read(struct file file, char __user buf,
	191	size_t count, loff_t *ppos)
	192	{
	193	int rc;
	194	unsigned int c, p, bytes1 = 0, bytes2 = 0;
	195	struct per_user_data *u = file->private_data;
	196
	197	/* Whole number of ports. */
	198	count &= ~(sizeof(evtchn_port_t)-1);
	199
	200	if (count == 0)
	201	return 0;
	202
	203	if (count > PAGE_SIZE)
	204	count = PAGE_SIZE;
	205
	206	for (;;) {
	207	mutex_lock(&u->ring_cons_mutex);
	208
	209	rc = -EFBIG;
	210	if (u->ring_overflow)
	211	goto unlock_out;
	212
	213	c = u->ring_cons;
	214	p = u->ring_prod;
	215	if (c != p)
	216	break;
	217
	218	mutex_unlock(&u->ring_cons_mutex);
	219
	220	if (file->f_flags & O_NONBLOCK)
	221	return -EAGAIN;
	222
	223	rc = wait_event_interruptible(u->evtchn_wait,
	224	u->ring_cons != u->ring_prod);
	225	if (rc)
	226	return rc;
	227	}
	228
	229	/* Byte lengths of two chunks. Chunk split (if any) is at ring wrap. */
86200154 DV	230	if (((c ^ p) & u->ring_size) != 0) {
86200154 DV	231	bytes1 = (u->ring_size - evtchn_ring_offset(u, c)) *
f7116284	232	sizeof(evtchn_port_t);
86200154	233	bytes2 = evtchn_ring_offset(u, p) * sizeof(evtchn_port_t);
f7116284 IC	234	} else {
	235	bytes1 = (p - c) * sizeof(evtchn_port_t);
	236	bytes2 = 0;
	237	}
	238
	239	/* Truncate chunks according to caller's maximum byte count. */
	240	if (bytes1 > count) {
	241	bytes1 = count;
	242	bytes2 = 0;
	243	} else if ((bytes1 + bytes2) > count) {
	244	bytes2 = count - bytes1;
	245	}
	246
	247	rc = -EFAULT;
	248	rmb(); /* Ensure that we see the port before we copy it. */
86200154	249	if (copy_to_user(buf, evtchn_ring_entry(u, c), bytes1) \|\|
f7116284 IC	250	((bytes2 != 0) &&
	251	copy_to_user(&buf[bytes1], &u->ring[0], bytes2)))
	252	goto unlock_out;
	253
	254	u->ring_cons += (bytes1 + bytes2) / sizeof(evtchn_port_t);
	255	rc = bytes1 + bytes2;
	256
	257	unlock_out:
	258	mutex_unlock(&u->ring_cons_mutex);
	259	return rc;
	260	}
	261
	262	static ssize_t evtchn_write(struct file file, const char __user buf,
	263	size_t count, loff_t *ppos)
	264	{
	265	int rc, i;
	266	evtchn_port_t kbuf = (evtchn_port_t )__get_free_page(GFP_KERNEL);
	267	struct per_user_data *u = file->private_data;
	268
	269	if (kbuf == NULL)
	270	return -ENOMEM;
	271
	272	/* Whole number of ports. */
	273	count &= ~(sizeof(evtchn_port_t)-1);
	274
	275	rc = 0;
	276	if (count == 0)
	277	goto out;
	278
	279	if (count > PAGE_SIZE)
	280	count = PAGE_SIZE;
	281
	282	rc = -EFAULT;
	283	if (copy_from_user(kbuf, buf, count) != 0)
	284	goto out;
	285
73cc4bb0	286	mutex_lock(&u->bind_mutex);
e3cc067b JF	287
	288	for (i = 0; i < (count/sizeof(evtchn_port_t)); i++) {
	289	unsigned port = kbuf[i];
73cc4bb0	290	struct user_evtchn *evtchn;
e3cc067b	291
73cc4bb0 DV	292	evtchn = find_evtchn(u, port);
	293	if (evtchn && !evtchn->enabled) {
	294	evtchn->enabled = true;
e3cc067b JF	295	enable_irq(irq_from_evtchn(port));
	296	}
	297	}
	298
73cc4bb0	299	mutex_unlock(&u->bind_mutex);
f7116284 IC	300
	301	rc = count;
	302
	303	out:
	304	free_page((unsigned long)kbuf);
	305	return rc;
	306	}
	307
86200154 DV	308	static int evtchn_resize_ring(struct per_user_data *u)
	309	{
	310	unsigned int new_size;
	311	evtchn_port_t new_ring, old_ring;
86200154 DV	312
	313	/*
	314	* Ensure the ring is large enough to capture all possible
	315	* events. i.e., one free slot for each bound event.
	316	*/
	317	if (u->nr_evtchns <= u->ring_size)
	318	return 0;
	319
	320	if (u->ring_size == 0)
	321	new_size = 64;
	322	else
	323	new_size = 2 * u->ring_size;
	324
752ade68	325	new_ring = kvmalloc(new_size * sizeof(*new_ring), GFP_KERNEL);
86200154 DV	326	if (!new_ring)
	327	return -ENOMEM;
	328
	329	old_ring = u->ring;
	330
	331	/*
	332	* Access to the ring contents is serialized by either the
	333	* prod /or/ cons lock so take both when resizing.
	334	*/
	335	mutex_lock(&u->ring_cons_mutex);
	336	spin_lock_irq(&u->ring_prod_lock);
	337
	338	/*
	339	* Copy the old ring contents to the new ring.
	340	*
27e0e638 JB	341	* To take care of wrapping, a full ring, and the new index
	342	* pointing into the second half, simply copy the old contents
	343	* twice.
86200154 DV	344	*
86200154 DV	345	* +---------+ +------------------+
27e0e638 JB	346	* \|34567 12\| -> \|34567 1234567 12\|
27e0e638 JB	347	* +-----p-c-+ +-------c------p---+
86200154	348	*/
27e0e638 JB	349	memcpy(new_ring, old_ring, u->ring_size * sizeof(*u->ring));
	350	memcpy(new_ring + u->ring_size, old_ring,
	351	u->ring_size * sizeof(*u->ring));
86200154 DV	352
	353	u->ring = new_ring;
	354	u->ring_size = new_size;
	355
	356	spin_unlock_irq(&u->ring_prod_lock);
	357	mutex_unlock(&u->ring_cons_mutex);
	358
	359	evtchn_free_ring(old_ring);
	360
	361	return 0;
	362	}
	363
f7116284 IC	364	static int evtchn_bind_to_user(struct per_user_data *u, int port)
f7116284 IC	365	{
73cc4bb0 DV	366	struct user_evtchn *evtchn;
73cc4bb0 DV	367	struct evtchn_close close;
f7116284 IC	368	int rc = 0;
f7116284 IC	369
0a4666b5 JF	370	/*
	371	* Ports are never reused, so every caller should pass in a
	372	* unique port.
	373	*
	374	* (Locking not necessary because we haven't registered the
	375	* interrupt handler yet, and our caller has already
	376	* serialized bind operations.)
	377	*/
73cc4bb0 DV	378
	379	evtchn = kzalloc(sizeof(*evtchn), GFP_KERNEL);
	380	if (!evtchn)
	381	return -ENOMEM;
	382
	383	evtchn->user = u;
	384	evtchn->port = port;
	385	evtchn->enabled = true; /* start enabled */
	386
	387	rc = add_evtchn(u, evtchn);
	388	if (rc < 0)
	389	goto err;
f7116284	390
86200154 DV	391	rc = evtchn_resize_ring(u);
	392	if (rc < 0)
	393	goto err;
	394
af09d1a7	395	rc = bind_evtchn_to_irqhandler(port, evtchn_interrupt, 0,
73cc4bb0 DV	396	u->name, evtchn);
	397	if (rc < 0)
	398	goto err;
0a4666b5	399
73cc4bb0 DV	400	rc = evtchn_make_refcounted(port);
	401	return rc;
	402
	403	err:
	404	/* bind failed, should close the port now */
	405	close.port = port;
	406	if (HYPERVISOR_event_channel_op(EVTCHNOP_close, &close) != 0)
	407	BUG();
	408	del_evtchn(u, evtchn);
f7116284 IC	409	return rc;
	410	}
	411
73cc4bb0 DV	412	static void evtchn_unbind_from_user(struct per_user_data *u,
73cc4bb0 DV	413	struct user_evtchn *evtchn)
f7116284	414	{
73cc4bb0	415	int irq = irq_from_evtchn(evtchn->port);
f7116284	416
e7e44e44 WL	417	BUG_ON(irq < 0);
e7e44e44 WL	418
73cc4bb0	419	unbind_from_irqhandler(irq, evtchn);
0a4666b5	420
73cc4bb0	421	del_evtchn(u, evtchn);
f7116284 IC	422	}
f7116284 IC	423
c48f64ab AS	424	static DEFINE_PER_CPU(int, bind_last_selected_cpu);
	425
	426	static void evtchn_bind_interdom_next_vcpu(int evtchn)
	427	{
	428	unsigned int selected_cpu, irq;
	429	struct irq_desc *desc;
	430	unsigned long flags;
	431
	432	irq = irq_from_evtchn(evtchn);
	433	desc = irq_to_desc(irq);
	434
	435	if (!desc)
	436	return;
	437
	438	raw_spin_lock_irqsave(&desc->lock, flags);
	439	selected_cpu = this_cpu_read(bind_last_selected_cpu);
	440	selected_cpu = cpumask_next_and(selected_cpu,
	441	desc->irq_common_data.affinity, cpu_online_mask);
	442
	443	if (unlikely(selected_cpu >= nr_cpu_ids))
	444	selected_cpu = cpumask_first_and(desc->irq_common_data.affinity,
	445	cpu_online_mask);
	446
	447	this_cpu_write(bind_last_selected_cpu, selected_cpu);
	448
	449	/* unmask expects irqs to be disabled */
	450	xen_rebind_evtchn_to_cpu(evtchn, selected_cpu);
	451	raw_spin_unlock_irqrestore(&desc->lock, flags);
	452	}
	453
f7116284 IC	454	static long evtchn_ioctl(struct file *file,
	455	unsigned int cmd, unsigned long arg)
	456	{
	457	int rc;
	458	struct per_user_data *u = file->private_data;
	459	void __user uarg = (void __user ) arg;
	460
0a4666b5 JF	461	/* Prevent bind from racing with unbind */
	462	mutex_lock(&u->bind_mutex);
	463
f7116284 IC	464	switch (cmd) {
	465	case IOCTL_EVTCHN_BIND_VIRQ: {
	466	struct ioctl_evtchn_bind_virq bind;
	467	struct evtchn_bind_virq bind_virq;
	468
fbc872c3 DV	469	rc = -EACCES;
	470	if (u->restrict_domid != UNRESTRICTED_DOMID)
	471	break;
	472
f7116284 IC	473	rc = -EFAULT;
	474	if (copy_from_user(&bind, uarg, sizeof(bind)))
	475	break;
	476
	477	bind_virq.virq = bind.virq;
cbbb4682	478	bind_virq.vcpu = xen_vcpu_nr(0);
f7116284 IC	479	rc = HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq,
	480	&bind_virq);
	481	if (rc != 0)
	482	break;
	483
	484	rc = evtchn_bind_to_user(u, bind_virq.port);
	485	if (rc == 0)
	486	rc = bind_virq.port;
	487	break;
	488	}
	489
	490	case IOCTL_EVTCHN_BIND_INTERDOMAIN: {
	491	struct ioctl_evtchn_bind_interdomain bind;
	492	struct evtchn_bind_interdomain bind_interdomain;
	493
	494	rc = -EFAULT;
	495	if (copy_from_user(&bind, uarg, sizeof(bind)))
	496	break;
	497
fbc872c3 DV	498	rc = -EACCES;
	499	if (u->restrict_domid != UNRESTRICTED_DOMID &&
	500	u->restrict_domid != bind.remote_domain)
	501	break;
	502
f7116284 IC	503	bind_interdomain.remote_dom = bind.remote_domain;
	504	bind_interdomain.remote_port = bind.remote_port;
	505	rc = HYPERVISOR_event_channel_op(EVTCHNOP_bind_interdomain,
	506	&bind_interdomain);
	507	if (rc != 0)
	508	break;
	509
	510	rc = evtchn_bind_to_user(u, bind_interdomain.local_port);
c48f64ab	511	if (rc == 0) {
f7116284	512	rc = bind_interdomain.local_port;
c48f64ab AS	513	evtchn_bind_interdom_next_vcpu(rc);
c48f64ab AS	514	}
f7116284 IC	515	break;
	516	}
	517
	518	case IOCTL_EVTCHN_BIND_UNBOUND_PORT: {
	519	struct ioctl_evtchn_bind_unbound_port bind;
	520	struct evtchn_alloc_unbound alloc_unbound;
	521
fbc872c3 DV	522	rc = -EACCES;
	523	if (u->restrict_domid != UNRESTRICTED_DOMID)
	524	break;
	525
f7116284 IC	526	rc = -EFAULT;
	527	if (copy_from_user(&bind, uarg, sizeof(bind)))
	528	break;
	529
	530	alloc_unbound.dom = DOMID_SELF;
	531	alloc_unbound.remote_dom = bind.remote_domain;
	532	rc = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound,
	533	&alloc_unbound);
	534	if (rc != 0)
	535	break;
	536
	537	rc = evtchn_bind_to_user(u, alloc_unbound.port);
	538	if (rc == 0)
	539	rc = alloc_unbound.port;
	540	break;
	541	}
	542
	543	case IOCTL_EVTCHN_UNBIND: {
	544	struct ioctl_evtchn_unbind unbind;
73cc4bb0	545	struct user_evtchn *evtchn;
f7116284 IC	546
	547	rc = -EFAULT;
	548	if (copy_from_user(&unbind, uarg, sizeof(unbind)))
	549	break;
	550
	551	rc = -EINVAL;
0dc0064a	552	if (unbind.port >= xen_evtchn_nr_channels())
f7116284 IC	553	break;
f7116284 IC	554
f7116284	555	rc = -ENOTCONN;
73cc4bb0 DV	556	evtchn = find_evtchn(u, unbind.port);
73cc4bb0 DV	557	if (!evtchn)
f7116284	558	break;
f7116284	559
3f5e554f	560	disable_irq(irq_from_evtchn(unbind.port));
73cc4bb0	561	evtchn_unbind_from_user(u, evtchn);
f7116284 IC	562	rc = 0;
	563	break;
	564	}
	565
	566	case IOCTL_EVTCHN_NOTIFY: {
	567	struct ioctl_evtchn_notify notify;
73cc4bb0	568	struct user_evtchn *evtchn;
f7116284 IC	569
	570	rc = -EFAULT;
	571	if (copy_from_user(&notify, uarg, sizeof(notify)))
	572	break;
	573
73cc4bb0 DV	574	rc = -ENOTCONN;
	575	evtchn = find_evtchn(u, notify.port);
	576	if (evtchn) {
f7116284 IC	577	notify_remote_via_evtchn(notify.port);
	578	rc = 0;
	579	}
	580	break;
	581	}
	582
	583	case IOCTL_EVTCHN_RESET: {
	584	/* Initialise the ring to empty. Clear errors. */
	585	mutex_lock(&u->ring_cons_mutex);
73cc4bb0	586	spin_lock_irq(&u->ring_prod_lock);
f7116284	587	u->ring_cons = u->ring_prod = u->ring_overflow = 0;
73cc4bb0	588	spin_unlock_irq(&u->ring_prod_lock);
f7116284 IC	589	mutex_unlock(&u->ring_cons_mutex);
	590	rc = 0;
	591	break;
	592	}
	593
fbc872c3 DV	594	case IOCTL_EVTCHN_RESTRICT_DOMID: {
	595	struct ioctl_evtchn_restrict_domid ierd;
	596
	597	rc = -EACCES;
	598	if (u->restrict_domid != UNRESTRICTED_DOMID)
	599	break;
	600
	601	rc = -EFAULT;
	602	if (copy_from_user(&ierd, uarg, sizeof(ierd)))
	603	break;
	604
	605	rc = -EINVAL;
	606	if (ierd.domid == 0 \|\| ierd.domid >= DOMID_FIRST_RESERVED)
	607	break;
	608
	609	u->restrict_domid = ierd.domid;
	610	rc = 0;
	611
	612	break;
	613	}
	614
f7116284 IC	615	default:
	616	rc = -ENOSYS;
	617	break;
	618	}
0a4666b5	619	mutex_unlock(&u->bind_mutex);
f7116284 IC	620
	621	return rc;
	622	}
	623
	624	static unsigned int evtchn_poll(struct file file, poll_table wait)
	625	{
	626	unsigned int mask = POLLOUT \| POLLWRNORM;
	627	struct per_user_data *u = file->private_data;
	628
	629	poll_wait(file, &u->evtchn_wait, wait);
	630	if (u->ring_cons != u->ring_prod)
	631	mask \|= POLLIN \| POLLRDNORM;
	632	if (u->ring_overflow)
	633	mask = POLLERR;
	634	return mask;
	635	}
	636
	637	static int evtchn_fasync(int fd, struct file *filp, int on)
	638	{
	639	struct per_user_data *u = filp->private_data;
	640	return fasync_helper(fd, filp, on, &u->evtchn_async_queue);
	641	}
	642
	643	static int evtchn_open(struct inode inode, struct file filp)
	644	{
	645	struct per_user_data *u;
	646
	647	u = kzalloc(sizeof(*u), GFP_KERNEL);
	648	if (u == NULL)
	649	return -ENOMEM;
	650
	651	u->name = kasprintf(GFP_KERNEL, "evtchn:%s", current->comm);
	652	if (u->name == NULL) {
	653	kfree(u);
	654	return -ENOMEM;
	655	}
	656
	657	init_waitqueue_head(&u->evtchn_wait);
	658
0a4666b5	659	mutex_init(&u->bind_mutex);
f7116284	660	mutex_init(&u->ring_cons_mutex);
73cc4bb0	661	spin_lock_init(&u->ring_prod_lock);
f7116284	662
fbc872c3 DV	663	u->restrict_domid = UNRESTRICTED_DOMID;
fbc872c3 DV	664
f7116284 IC	665	filp->private_data = u;
f7116284 IC	666
6eab04a8	667	return nonseekable_open(inode, filp);
f7116284 IC	668	}
	669
	670	static int evtchn_release(struct inode inode, struct file filp)
	671	{
f7116284	672	struct per_user_data *u = filp->private_data;
73cc4bb0	673	struct rb_node *node;
f7116284	674
73cc4bb0 DV	675	while ((node = u->evtchns.rb_node)) {
73cc4bb0 DV	676	struct user_evtchn *evtchn;
f7116284	677
73cc4bb0 DV	678	evtchn = rb_entry(node, struct user_evtchn, node);
	679	disable_irq(irq_from_evtchn(evtchn->port));
	680	evtchn_unbind_from_user(u, evtchn);
3f5e554f JF	681	}
3f5e554f JF	682
86200154	683	evtchn_free_ring(u->ring);
f7116284 IC	684	kfree(u->name);
	685	kfree(u);
	686
	687	return 0;
	688	}
	689
	690	static const struct file_operations evtchn_fops = {
	691	.owner = THIS_MODULE,
	692	.read = evtchn_read,
	693	.write = evtchn_write,
	694	.unlocked_ioctl = evtchn_ioctl,
	695	.poll = evtchn_poll,
	696	.fasync = evtchn_fasync,
	697	.open = evtchn_open,
	698	.release = evtchn_release,
bc7fc5e3	699	.llseek = no_llseek,
f7116284 IC	700	};
	701
	702	static struct miscdevice evtchn_miscdev = {
	703	.minor = MISC_DYNAMIC_MINOR,
376d908f	704	.name = "xen/evtchn",
f7116284 IC	705	.fops = &evtchn_fops,
	706	};
	707	static int __init evtchn_init(void)
	708	{
	709	int err;
	710
	711	if (!xen_domain())
	712	return -ENODEV;
	713
18283ea7	714	/* Create '/dev/xen/evtchn'. */
f7116284 IC	715	err = misc_register(&evtchn_miscdev);
f7116284 IC	716	if (err != 0) {
283c0972	717	pr_err("Could not register /dev/xen/evtchn\n");
f7116284 IC	718	return err;
	719	}
	720
283c0972	721	pr_info("Event-channel device installed\n");
f7116284 IC	722
	723	return 0;
	724	}
	725
	726	static void __exit evtchn_cleanup(void)
	727	{
	728	misc_deregister(&evtchn_miscdev);
	729	}
	730
	731	module_init(evtchn_init);
	732	module_exit(evtchn_cleanup);
	733
	734	MODULE_LICENSE("GPL");