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 | |
34 | #define pr_fmt(fmt) "xen:" KBUILD_MODNAME ": " fmt |
35 | |
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> |
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> |
50 | #include <linux/mutex.h> |
51 | #include <linux/cpu.h> |
52 | #include <linux/mm.h> |
53 | #include <linux/vmalloc.h> |
54 | |
55 | #include <xen/xen.h> |
56 | #include <xen/events.h> |
57 | #include <xen/evtchn.h> |
58 | #include <xen/xen-ops.h> |
59 | #include <asm/xen/hypervisor.h> |
60 | |
61 | struct per_user_data { |
62 | struct mutex bind_mutex; /* serialize bind/unbind operations */ |
63 | struct rb_root evtchns; |
64 | unsigned int nr_evtchns; |
65 | |
66 | /* Notification ring, accessed via /dev/xen/evtchn. */ |
67 | unsigned int ring_size; |
68 | evtchn_port_t *ring; |
69 | unsigned int ring_cons, ring_prod, ring_overflow; |
70 | struct mutex ring_cons_mutex; /* protect against concurrent readers */ |
71 | spinlock_t ring_prod_lock; /* product against concurrent interrupts */ |
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; |
77 | |
78 | domid_t restrict_domid; |
79 | }; |
80 | |
81 | #define UNRESTRICTED_DOMID ((domid_t)-1) |
82 | |
83 | struct user_evtchn { |
84 | struct rb_node node; |
85 | struct per_user_data *user; |
86 | evtchn_port_t port; |
87 | bool enabled; |
88 | }; |
89 | |
90 | static void evtchn_free_ring(evtchn_port_t *ring) |
91 | { |
92 | kvfree(addr: 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 | |
107 | static int add_evtchn(struct per_user_data *u, struct user_evtchn *evtchn) |
108 | { |
109 | struct rb_node **new = &(u->evtchns.rb_node), *parent = NULL; |
110 | |
111 | u->nr_evtchns++; |
112 | |
113 | while (*new) { |
114 | struct user_evtchn *this; |
115 | |
116 | this = rb_entry(*new, struct user_evtchn, node); |
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(node: &evtchn->node, parent, rb_link: new); |
129 | rb_insert_color(&evtchn->node, &u->evtchns); |
130 | |
131 | return 0; |
132 | } |
133 | |
134 | static void del_evtchn(struct per_user_data *u, struct user_evtchn *evtchn) |
135 | { |
136 | u->nr_evtchns--; |
137 | rb_erase(&evtchn->node, &u->evtchns); |
138 | kfree(objp: evtchn); |
139 | } |
140 | |
141 | static struct user_evtchn *find_evtchn(struct per_user_data *u, |
142 | evtchn_port_t port) |
143 | { |
144 | struct rb_node *node = u->evtchns.rb_node; |
145 | |
146 | while (node) { |
147 | struct user_evtchn *evtchn; |
148 | |
149 | evtchn = rb_entry(node, struct user_evtchn, node); |
150 | |
151 | if (evtchn->port < port) |
152 | node = node->rb_left; |
153 | else if (evtchn->port > port) |
154 | node = node->rb_right; |
155 | else |
156 | return evtchn; |
157 | } |
158 | return NULL; |
159 | } |
160 | |
161 | static irqreturn_t evtchn_interrupt(int irq, void *data) |
162 | { |
163 | struct user_evtchn *evtchn = data; |
164 | struct per_user_data *u = evtchn->user; |
165 | unsigned int prod, cons; |
166 | |
167 | WARN(!evtchn->enabled, |
168 | "Interrupt for port %u, but apparently not enabled; per-user %p\n" , |
169 | evtchn->port, u); |
170 | |
171 | evtchn->enabled = false; |
172 | |
173 | spin_lock(lock: &u->ring_prod_lock); |
174 | |
175 | prod = READ_ONCE(u->ring_prod); |
176 | cons = READ_ONCE(u->ring_cons); |
177 | |
178 | if ((prod - cons) < u->ring_size) { |
179 | *evtchn_ring_entry(u, idx: prod) = evtchn->port; |
180 | smp_wmb(); /* Ensure ring contents visible */ |
181 | WRITE_ONCE(u->ring_prod, prod + 1); |
182 | if (cons == prod) { |
183 | wake_up_interruptible(&u->evtchn_wait); |
184 | kill_fasync(&u->evtchn_async_queue, |
185 | SIGIO, POLL_IN); |
186 | } |
187 | } else |
188 | u->ring_overflow = 1; |
189 | |
190 | spin_unlock(lock: &u->ring_prod_lock); |
191 | |
192 | return IRQ_HANDLED; |
193 | } |
194 | |
195 | static ssize_t evtchn_read(struct file *file, char __user *buf, |
196 | size_t count, loff_t *ppos) |
197 | { |
198 | int rc; |
199 | unsigned int c, p, bytes1 = 0, bytes2 = 0; |
200 | struct per_user_data *u = file->private_data; |
201 | |
202 | /* Whole number of ports. */ |
203 | count &= ~(sizeof(evtchn_port_t)-1); |
204 | |
205 | if (count == 0) |
206 | return 0; |
207 | |
208 | if (count > PAGE_SIZE) |
209 | count = PAGE_SIZE; |
210 | |
211 | for (;;) { |
212 | mutex_lock(&u->ring_cons_mutex); |
213 | |
214 | rc = -EFBIG; |
215 | if (u->ring_overflow) |
216 | goto unlock_out; |
217 | |
218 | c = READ_ONCE(u->ring_cons); |
219 | p = READ_ONCE(u->ring_prod); |
220 | if (c != p) |
221 | break; |
222 | |
223 | mutex_unlock(lock: &u->ring_cons_mutex); |
224 | |
225 | if (file->f_flags & O_NONBLOCK) |
226 | return -EAGAIN; |
227 | |
228 | rc = wait_event_interruptible(u->evtchn_wait, |
229 | READ_ONCE(u->ring_cons) != READ_ONCE(u->ring_prod)); |
230 | if (rc) |
231 | return rc; |
232 | } |
233 | |
234 | /* Byte lengths of two chunks. Chunk split (if any) is at ring wrap. */ |
235 | if (((c ^ p) & u->ring_size) != 0) { |
236 | bytes1 = (u->ring_size - evtchn_ring_offset(u, idx: c)) * |
237 | sizeof(evtchn_port_t); |
238 | bytes2 = evtchn_ring_offset(u, idx: p) * sizeof(evtchn_port_t); |
239 | } else { |
240 | bytes1 = (p - c) * sizeof(evtchn_port_t); |
241 | bytes2 = 0; |
242 | } |
243 | |
244 | /* Truncate chunks according to caller's maximum byte count. */ |
245 | if (bytes1 > count) { |
246 | bytes1 = count; |
247 | bytes2 = 0; |
248 | } else if ((bytes1 + bytes2) > count) { |
249 | bytes2 = count - bytes1; |
250 | } |
251 | |
252 | rc = -EFAULT; |
253 | smp_rmb(); /* Ensure that we see the port before we copy it. */ |
254 | if (copy_to_user(to: buf, from: evtchn_ring_entry(u, idx: c), n: bytes1) || |
255 | ((bytes2 != 0) && |
256 | copy_to_user(to: &buf[bytes1], from: &u->ring[0], n: bytes2))) |
257 | goto unlock_out; |
258 | |
259 | WRITE_ONCE(u->ring_cons, c + (bytes1 + bytes2) / sizeof(evtchn_port_t)); |
260 | rc = bytes1 + bytes2; |
261 | |
262 | unlock_out: |
263 | mutex_unlock(lock: &u->ring_cons_mutex); |
264 | return rc; |
265 | } |
266 | |
267 | static ssize_t evtchn_write(struct file *file, const char __user *buf, |
268 | size_t count, loff_t *ppos) |
269 | { |
270 | int rc, i; |
271 | evtchn_port_t *kbuf = (evtchn_port_t *)__get_free_page(GFP_KERNEL); |
272 | struct per_user_data *u = file->private_data; |
273 | |
274 | if (kbuf == NULL) |
275 | return -ENOMEM; |
276 | |
277 | /* Whole number of ports. */ |
278 | count &= ~(sizeof(evtchn_port_t)-1); |
279 | |
280 | rc = 0; |
281 | if (count == 0) |
282 | goto out; |
283 | |
284 | if (count > PAGE_SIZE) |
285 | count = PAGE_SIZE; |
286 | |
287 | rc = -EFAULT; |
288 | if (copy_from_user(to: kbuf, from: buf, n: count) != 0) |
289 | goto out; |
290 | |
291 | mutex_lock(&u->bind_mutex); |
292 | |
293 | for (i = 0; i < (count/sizeof(evtchn_port_t)); i++) { |
294 | evtchn_port_t port = kbuf[i]; |
295 | struct user_evtchn *evtchn; |
296 | |
297 | evtchn = find_evtchn(u, port); |
298 | if (evtchn && !evtchn->enabled) { |
299 | evtchn->enabled = true; |
300 | xen_irq_lateeoi(irq: irq_from_evtchn(evtchn: port), eoi_flags: 0); |
301 | } |
302 | } |
303 | |
304 | mutex_unlock(lock: &u->bind_mutex); |
305 | |
306 | rc = count; |
307 | |
308 | out: |
309 | free_page((unsigned long)kbuf); |
310 | return rc; |
311 | } |
312 | |
313 | static int evtchn_resize_ring(struct per_user_data *u) |
314 | { |
315 | unsigned int new_size; |
316 | evtchn_port_t *new_ring, *old_ring; |
317 | |
318 | /* |
319 | * Ensure the ring is large enough to capture all possible |
320 | * events. i.e., one free slot for each bound event. |
321 | */ |
322 | if (u->nr_evtchns <= u->ring_size) |
323 | return 0; |
324 | |
325 | if (u->ring_size == 0) |
326 | new_size = 64; |
327 | else |
328 | new_size = 2 * u->ring_size; |
329 | |
330 | new_ring = kvmalloc_array(n: new_size, size: sizeof(*new_ring), GFP_KERNEL); |
331 | if (!new_ring) |
332 | return -ENOMEM; |
333 | |
334 | old_ring = u->ring; |
335 | |
336 | /* |
337 | * Access to the ring contents is serialized by either the |
338 | * prod /or/ cons lock so take both when resizing. |
339 | */ |
340 | mutex_lock(&u->ring_cons_mutex); |
341 | spin_lock_irq(lock: &u->ring_prod_lock); |
342 | |
343 | /* |
344 | * Copy the old ring contents to the new ring. |
345 | * |
346 | * To take care of wrapping, a full ring, and the new index |
347 | * pointing into the second half, simply copy the old contents |
348 | * twice. |
349 | * |
350 | * +---------+ +------------------+ |
351 | * |34567 12| -> |34567 1234567 12| |
352 | * +-----p-c-+ +-------c------p---+ |
353 | */ |
354 | memcpy(new_ring, old_ring, u->ring_size * sizeof(*u->ring)); |
355 | memcpy(new_ring + u->ring_size, old_ring, |
356 | u->ring_size * sizeof(*u->ring)); |
357 | |
358 | u->ring = new_ring; |
359 | u->ring_size = new_size; |
360 | |
361 | spin_unlock_irq(lock: &u->ring_prod_lock); |
362 | mutex_unlock(lock: &u->ring_cons_mutex); |
363 | |
364 | evtchn_free_ring(ring: old_ring); |
365 | |
366 | return 0; |
367 | } |
368 | |
369 | static int evtchn_bind_to_user(struct per_user_data *u, evtchn_port_t port, |
370 | bool is_static) |
371 | { |
372 | struct user_evtchn *evtchn; |
373 | int rc = 0; |
374 | |
375 | /* |
376 | * Ports are never reused, so every caller should pass in a |
377 | * unique port. |
378 | * |
379 | * (Locking not necessary because we haven't registered the |
380 | * interrupt handler yet, and our caller has already |
381 | * serialized bind operations.) |
382 | */ |
383 | |
384 | evtchn = kzalloc(size: sizeof(*evtchn), GFP_KERNEL); |
385 | if (!evtchn) |
386 | return -ENOMEM; |
387 | |
388 | evtchn->user = u; |
389 | evtchn->port = port; |
390 | evtchn->enabled = true; /* start enabled */ |
391 | |
392 | rc = add_evtchn(u, evtchn); |
393 | if (rc < 0) |
394 | goto err; |
395 | |
396 | rc = evtchn_resize_ring(u); |
397 | if (rc < 0) |
398 | goto err; |
399 | |
400 | rc = bind_evtchn_to_irqhandler_lateeoi(evtchn: port, handler: evtchn_interrupt, IRQF_SHARED, |
401 | devname: u->name, dev_id: evtchn); |
402 | if (rc < 0) |
403 | goto err; |
404 | |
405 | rc = evtchn_make_refcounted(evtchn: port, is_static); |
406 | return rc; |
407 | |
408 | err: |
409 | /* bind failed, should close the port now */ |
410 | if (!is_static) |
411 | xen_evtchn_close(port); |
412 | |
413 | del_evtchn(u, evtchn); |
414 | return rc; |
415 | } |
416 | |
417 | static void evtchn_unbind_from_user(struct per_user_data *u, |
418 | struct user_evtchn *evtchn) |
419 | { |
420 | int irq = irq_from_evtchn(evtchn: evtchn->port); |
421 | |
422 | BUG_ON(irq < 0); |
423 | |
424 | unbind_from_irqhandler(irq, dev_id: evtchn); |
425 | |
426 | del_evtchn(u, evtchn); |
427 | } |
428 | |
429 | static long evtchn_ioctl(struct file *file, |
430 | unsigned int cmd, unsigned long arg) |
431 | { |
432 | int rc; |
433 | struct per_user_data *u = file->private_data; |
434 | void __user *uarg = (void __user *) arg; |
435 | |
436 | /* Prevent bind from racing with unbind */ |
437 | mutex_lock(&u->bind_mutex); |
438 | |
439 | switch (cmd) { |
440 | case IOCTL_EVTCHN_BIND_VIRQ: { |
441 | struct ioctl_evtchn_bind_virq bind; |
442 | struct evtchn_bind_virq bind_virq; |
443 | |
444 | rc = -EACCES; |
445 | if (u->restrict_domid != UNRESTRICTED_DOMID) |
446 | break; |
447 | |
448 | rc = -EFAULT; |
449 | if (copy_from_user(to: &bind, from: uarg, n: sizeof(bind))) |
450 | break; |
451 | |
452 | bind_virq.virq = bind.virq; |
453 | bind_virq.vcpu = xen_vcpu_nr(cpu: 0); |
454 | rc = HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq, |
455 | arg: &bind_virq); |
456 | if (rc != 0) |
457 | break; |
458 | |
459 | rc = evtchn_bind_to_user(u, port: bind_virq.port, is_static: false); |
460 | if (rc == 0) |
461 | rc = bind_virq.port; |
462 | break; |
463 | } |
464 | |
465 | case IOCTL_EVTCHN_BIND_INTERDOMAIN: { |
466 | struct ioctl_evtchn_bind_interdomain bind; |
467 | struct evtchn_bind_interdomain bind_interdomain; |
468 | |
469 | rc = -EFAULT; |
470 | if (copy_from_user(to: &bind, from: uarg, n: sizeof(bind))) |
471 | break; |
472 | |
473 | rc = -EACCES; |
474 | if (u->restrict_domid != UNRESTRICTED_DOMID && |
475 | u->restrict_domid != bind.remote_domain) |
476 | break; |
477 | |
478 | bind_interdomain.remote_dom = bind.remote_domain; |
479 | bind_interdomain.remote_port = bind.remote_port; |
480 | rc = HYPERVISOR_event_channel_op(EVTCHNOP_bind_interdomain, |
481 | arg: &bind_interdomain); |
482 | if (rc != 0) |
483 | break; |
484 | |
485 | rc = evtchn_bind_to_user(u, port: bind_interdomain.local_port, is_static: false); |
486 | if (rc == 0) |
487 | rc = bind_interdomain.local_port; |
488 | break; |
489 | } |
490 | |
491 | case IOCTL_EVTCHN_BIND_UNBOUND_PORT: { |
492 | struct ioctl_evtchn_bind_unbound_port bind; |
493 | struct evtchn_alloc_unbound alloc_unbound; |
494 | |
495 | rc = -EACCES; |
496 | if (u->restrict_domid != UNRESTRICTED_DOMID) |
497 | break; |
498 | |
499 | rc = -EFAULT; |
500 | if (copy_from_user(to: &bind, from: uarg, n: sizeof(bind))) |
501 | break; |
502 | |
503 | alloc_unbound.dom = DOMID_SELF; |
504 | alloc_unbound.remote_dom = bind.remote_domain; |
505 | rc = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound, |
506 | arg: &alloc_unbound); |
507 | if (rc != 0) |
508 | break; |
509 | |
510 | rc = evtchn_bind_to_user(u, port: alloc_unbound.port, is_static: false); |
511 | if (rc == 0) |
512 | rc = alloc_unbound.port; |
513 | break; |
514 | } |
515 | |
516 | case IOCTL_EVTCHN_UNBIND: { |
517 | struct ioctl_evtchn_unbind unbind; |
518 | struct user_evtchn *evtchn; |
519 | |
520 | rc = -EFAULT; |
521 | if (copy_from_user(to: &unbind, from: uarg, n: sizeof(unbind))) |
522 | break; |
523 | |
524 | rc = -EINVAL; |
525 | if (unbind.port >= xen_evtchn_nr_channels()) |
526 | break; |
527 | |
528 | rc = -ENOTCONN; |
529 | evtchn = find_evtchn(u, port: unbind.port); |
530 | if (!evtchn) |
531 | break; |
532 | |
533 | disable_irq(irq: irq_from_evtchn(evtchn: unbind.port)); |
534 | evtchn_unbind_from_user(u, evtchn); |
535 | rc = 0; |
536 | break; |
537 | } |
538 | |
539 | case IOCTL_EVTCHN_BIND_STATIC: { |
540 | struct ioctl_evtchn_bind bind; |
541 | struct user_evtchn *evtchn; |
542 | |
543 | rc = -EFAULT; |
544 | if (copy_from_user(to: &bind, from: uarg, n: sizeof(bind))) |
545 | break; |
546 | |
547 | rc = -EISCONN; |
548 | evtchn = find_evtchn(u, port: bind.port); |
549 | if (evtchn) |
550 | break; |
551 | |
552 | rc = evtchn_bind_to_user(u, port: bind.port, is_static: true); |
553 | break; |
554 | } |
555 | |
556 | case IOCTL_EVTCHN_NOTIFY: { |
557 | struct ioctl_evtchn_notify notify; |
558 | struct user_evtchn *evtchn; |
559 | |
560 | rc = -EFAULT; |
561 | if (copy_from_user(to: ¬ify, from: uarg, n: sizeof(notify))) |
562 | break; |
563 | |
564 | rc = -ENOTCONN; |
565 | evtchn = find_evtchn(u, port: notify.port); |
566 | if (evtchn) { |
567 | notify_remote_via_evtchn(port: notify.port); |
568 | rc = 0; |
569 | } |
570 | break; |
571 | } |
572 | |
573 | case IOCTL_EVTCHN_RESET: { |
574 | /* Initialise the ring to empty. Clear errors. */ |
575 | mutex_lock(&u->ring_cons_mutex); |
576 | spin_lock_irq(lock: &u->ring_prod_lock); |
577 | WRITE_ONCE(u->ring_cons, 0); |
578 | WRITE_ONCE(u->ring_prod, 0); |
579 | u->ring_overflow = 0; |
580 | spin_unlock_irq(lock: &u->ring_prod_lock); |
581 | mutex_unlock(lock: &u->ring_cons_mutex); |
582 | rc = 0; |
583 | break; |
584 | } |
585 | |
586 | case IOCTL_EVTCHN_RESTRICT_DOMID: { |
587 | struct ioctl_evtchn_restrict_domid ierd; |
588 | |
589 | rc = -EACCES; |
590 | if (u->restrict_domid != UNRESTRICTED_DOMID) |
591 | break; |
592 | |
593 | rc = -EFAULT; |
594 | if (copy_from_user(to: &ierd, from: uarg, n: sizeof(ierd))) |
595 | break; |
596 | |
597 | rc = -EINVAL; |
598 | if (ierd.domid == 0 || ierd.domid >= DOMID_FIRST_RESERVED) |
599 | break; |
600 | |
601 | u->restrict_domid = ierd.domid; |
602 | rc = 0; |
603 | |
604 | break; |
605 | } |
606 | |
607 | default: |
608 | rc = -ENOSYS; |
609 | break; |
610 | } |
611 | mutex_unlock(lock: &u->bind_mutex); |
612 | |
613 | return rc; |
614 | } |
615 | |
616 | static __poll_t evtchn_poll(struct file *file, poll_table *wait) |
617 | { |
618 | __poll_t mask = EPOLLOUT | EPOLLWRNORM; |
619 | struct per_user_data *u = file->private_data; |
620 | |
621 | poll_wait(filp: file, wait_address: &u->evtchn_wait, p: wait); |
622 | if (READ_ONCE(u->ring_cons) != READ_ONCE(u->ring_prod)) |
623 | mask |= EPOLLIN | EPOLLRDNORM; |
624 | if (u->ring_overflow) |
625 | mask = EPOLLERR; |
626 | return mask; |
627 | } |
628 | |
629 | static int evtchn_fasync(int fd, struct file *filp, int on) |
630 | { |
631 | struct per_user_data *u = filp->private_data; |
632 | return fasync_helper(fd, filp, on, &u->evtchn_async_queue); |
633 | } |
634 | |
635 | static int evtchn_open(struct inode *inode, struct file *filp) |
636 | { |
637 | struct per_user_data *u; |
638 | |
639 | u = kzalloc(size: sizeof(*u), GFP_KERNEL); |
640 | if (u == NULL) |
641 | return -ENOMEM; |
642 | |
643 | u->name = kasprintf(GFP_KERNEL, fmt: "evtchn:%s" , current->comm); |
644 | if (u->name == NULL) { |
645 | kfree(objp: u); |
646 | return -ENOMEM; |
647 | } |
648 | |
649 | init_waitqueue_head(&u->evtchn_wait); |
650 | |
651 | mutex_init(&u->bind_mutex); |
652 | mutex_init(&u->ring_cons_mutex); |
653 | spin_lock_init(&u->ring_prod_lock); |
654 | |
655 | u->restrict_domid = UNRESTRICTED_DOMID; |
656 | |
657 | filp->private_data = u; |
658 | |
659 | return stream_open(inode, filp); |
660 | } |
661 | |
662 | static int evtchn_release(struct inode *inode, struct file *filp) |
663 | { |
664 | struct per_user_data *u = filp->private_data; |
665 | struct rb_node *node; |
666 | |
667 | while ((node = u->evtchns.rb_node)) { |
668 | struct user_evtchn *evtchn; |
669 | |
670 | evtchn = rb_entry(node, struct user_evtchn, node); |
671 | disable_irq(irq: irq_from_evtchn(evtchn: evtchn->port)); |
672 | evtchn_unbind_from_user(u, evtchn); |
673 | } |
674 | |
675 | evtchn_free_ring(ring: u->ring); |
676 | kfree(objp: u->name); |
677 | kfree(objp: u); |
678 | |
679 | return 0; |
680 | } |
681 | |
682 | static const struct file_operations evtchn_fops = { |
683 | .owner = THIS_MODULE, |
684 | .read = evtchn_read, |
685 | .write = evtchn_write, |
686 | .unlocked_ioctl = evtchn_ioctl, |
687 | .poll = evtchn_poll, |
688 | .fasync = evtchn_fasync, |
689 | .open = evtchn_open, |
690 | .release = evtchn_release, |
691 | .llseek = no_llseek, |
692 | }; |
693 | |
694 | static struct miscdevice evtchn_miscdev = { |
695 | .minor = MISC_DYNAMIC_MINOR, |
696 | .name = "xen/evtchn" , |
697 | .fops = &evtchn_fops, |
698 | }; |
699 | static int __init evtchn_init(void) |
700 | { |
701 | int err; |
702 | |
703 | if (!xen_domain()) |
704 | return -ENODEV; |
705 | |
706 | /* Create '/dev/xen/evtchn'. */ |
707 | err = misc_register(misc: &evtchn_miscdev); |
708 | if (err != 0) { |
709 | pr_err("Could not register /dev/xen/evtchn\n" ); |
710 | return err; |
711 | } |
712 | |
713 | pr_info("Event-channel device installed\n" ); |
714 | |
715 | return 0; |
716 | } |
717 | |
718 | static void __exit evtchn_cleanup(void) |
719 | { |
720 | misc_deregister(misc: &evtchn_miscdev); |
721 | } |
722 | |
723 | module_init(evtchn_init); |
724 | module_exit(evtchn_cleanup); |
725 | |
726 | MODULE_LICENSE("GPL" ); |
727 | |