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 | bool unbinding; |
89 | }; |
90 | |
91 | static void evtchn_free_ring(evtchn_port_t *ring) |
92 | { |
93 | kvfree(addr: ring); |
94 | } |
95 | |
96 | static unsigned int evtchn_ring_offset(struct per_user_data *u, |
97 | unsigned int idx) |
98 | { |
99 | return idx & (u->ring_size - 1); |
100 | } |
101 | |
102 | static evtchn_port_t *evtchn_ring_entry(struct per_user_data *u, |
103 | unsigned int idx) |
104 | { |
105 | return u->ring + evtchn_ring_offset(u, idx); |
106 | } |
107 | |
108 | static int add_evtchn(struct per_user_data *u, struct user_evtchn *evtchn) |
109 | { |
110 | struct rb_node **new = &(u->evtchns.rb_node), *parent = NULL; |
111 | |
112 | u->nr_evtchns++; |
113 | |
114 | while (*new) { |
115 | struct user_evtchn *this; |
116 | |
117 | this = rb_entry(*new, struct user_evtchn, node); |
118 | |
119 | parent = *new; |
120 | if (this->port < evtchn->port) |
121 | new = &((*new)->rb_left); |
122 | else if (this->port > evtchn->port) |
123 | new = &((*new)->rb_right); |
124 | else |
125 | return -EEXIST; |
126 | } |
127 | |
128 | /* Add new node and rebalance tree. */ |
129 | rb_link_node(node: &evtchn->node, parent, rb_link: new); |
130 | rb_insert_color(&evtchn->node, &u->evtchns); |
131 | |
132 | return 0; |
133 | } |
134 | |
135 | static void del_evtchn(struct per_user_data *u, struct user_evtchn *evtchn) |
136 | { |
137 | u->nr_evtchns--; |
138 | rb_erase(&evtchn->node, &u->evtchns); |
139 | kfree(objp: evtchn); |
140 | } |
141 | |
142 | static struct user_evtchn *find_evtchn(struct per_user_data *u, |
143 | evtchn_port_t port) |
144 | { |
145 | struct rb_node *node = u->evtchns.rb_node; |
146 | |
147 | while (node) { |
148 | struct user_evtchn *evtchn; |
149 | |
150 | evtchn = rb_entry(node, struct user_evtchn, node); |
151 | |
152 | if (evtchn->port < port) |
153 | node = node->rb_left; |
154 | else if (evtchn->port > port) |
155 | node = node->rb_right; |
156 | else |
157 | return evtchn; |
158 | } |
159 | return NULL; |
160 | } |
161 | |
162 | static irqreturn_t evtchn_interrupt(int irq, void *data) |
163 | { |
164 | struct user_evtchn *evtchn = data; |
165 | struct per_user_data *u = evtchn->user; |
166 | unsigned int prod, cons; |
167 | |
168 | /* Handler might be called when tearing down the IRQ. */ |
169 | if (evtchn->unbinding) |
170 | return IRQ_HANDLED; |
171 | |
172 | WARN(!evtchn->enabled, |
173 | "Interrupt for port %u, but apparently not enabled; per-user %p\n" , |
174 | evtchn->port, u); |
175 | |
176 | evtchn->enabled = false; |
177 | |
178 | spin_lock(lock: &u->ring_prod_lock); |
179 | |
180 | prod = READ_ONCE(u->ring_prod); |
181 | cons = READ_ONCE(u->ring_cons); |
182 | |
183 | if ((prod - cons) < u->ring_size) { |
184 | *evtchn_ring_entry(u, idx: prod) = evtchn->port; |
185 | smp_wmb(); /* Ensure ring contents visible */ |
186 | WRITE_ONCE(u->ring_prod, prod + 1); |
187 | if (cons == prod) { |
188 | wake_up_interruptible(&u->evtchn_wait); |
189 | kill_fasync(&u->evtchn_async_queue, |
190 | SIGIO, POLL_IN); |
191 | } |
192 | } else |
193 | u->ring_overflow = 1; |
194 | |
195 | spin_unlock(lock: &u->ring_prod_lock); |
196 | |
197 | return IRQ_HANDLED; |
198 | } |
199 | |
200 | static ssize_t evtchn_read(struct file *file, char __user *buf, |
201 | size_t count, loff_t *ppos) |
202 | { |
203 | int rc; |
204 | unsigned int c, p, bytes1 = 0, bytes2 = 0; |
205 | struct per_user_data *u = file->private_data; |
206 | |
207 | /* Whole number of ports. */ |
208 | count &= ~(sizeof(evtchn_port_t)-1); |
209 | |
210 | if (count == 0) |
211 | return 0; |
212 | |
213 | if (count > PAGE_SIZE) |
214 | count = PAGE_SIZE; |
215 | |
216 | for (;;) { |
217 | mutex_lock(&u->ring_cons_mutex); |
218 | |
219 | rc = -EFBIG; |
220 | if (u->ring_overflow) |
221 | goto unlock_out; |
222 | |
223 | c = READ_ONCE(u->ring_cons); |
224 | p = READ_ONCE(u->ring_prod); |
225 | if (c != p) |
226 | break; |
227 | |
228 | mutex_unlock(lock: &u->ring_cons_mutex); |
229 | |
230 | if (file->f_flags & O_NONBLOCK) |
231 | return -EAGAIN; |
232 | |
233 | rc = wait_event_interruptible(u->evtchn_wait, |
234 | READ_ONCE(u->ring_cons) != READ_ONCE(u->ring_prod)); |
235 | if (rc) |
236 | return rc; |
237 | } |
238 | |
239 | /* Byte lengths of two chunks. Chunk split (if any) is at ring wrap. */ |
240 | if (((c ^ p) & u->ring_size) != 0) { |
241 | bytes1 = (u->ring_size - evtchn_ring_offset(u, idx: c)) * |
242 | sizeof(evtchn_port_t); |
243 | bytes2 = evtchn_ring_offset(u, idx: p) * sizeof(evtchn_port_t); |
244 | } else { |
245 | bytes1 = (p - c) * sizeof(evtchn_port_t); |
246 | bytes2 = 0; |
247 | } |
248 | |
249 | /* Truncate chunks according to caller's maximum byte count. */ |
250 | if (bytes1 > count) { |
251 | bytes1 = count; |
252 | bytes2 = 0; |
253 | } else if ((bytes1 + bytes2) > count) { |
254 | bytes2 = count - bytes1; |
255 | } |
256 | |
257 | rc = -EFAULT; |
258 | smp_rmb(); /* Ensure that we see the port before we copy it. */ |
259 | if (copy_to_user(to: buf, from: evtchn_ring_entry(u, idx: c), n: bytes1) || |
260 | ((bytes2 != 0) && |
261 | copy_to_user(to: &buf[bytes1], from: &u->ring[0], n: bytes2))) |
262 | goto unlock_out; |
263 | |
264 | WRITE_ONCE(u->ring_cons, c + (bytes1 + bytes2) / sizeof(evtchn_port_t)); |
265 | rc = bytes1 + bytes2; |
266 | |
267 | unlock_out: |
268 | mutex_unlock(lock: &u->ring_cons_mutex); |
269 | return rc; |
270 | } |
271 | |
272 | static ssize_t evtchn_write(struct file *file, const char __user *buf, |
273 | size_t count, loff_t *ppos) |
274 | { |
275 | int rc, i; |
276 | evtchn_port_t *kbuf = (evtchn_port_t *)__get_free_page(GFP_KERNEL); |
277 | struct per_user_data *u = file->private_data; |
278 | |
279 | if (kbuf == NULL) |
280 | return -ENOMEM; |
281 | |
282 | /* Whole number of ports. */ |
283 | count &= ~(sizeof(evtchn_port_t)-1); |
284 | |
285 | rc = 0; |
286 | if (count == 0) |
287 | goto out; |
288 | |
289 | if (count > PAGE_SIZE) |
290 | count = PAGE_SIZE; |
291 | |
292 | rc = -EFAULT; |
293 | if (copy_from_user(to: kbuf, from: buf, n: count) != 0) |
294 | goto out; |
295 | |
296 | mutex_lock(&u->bind_mutex); |
297 | |
298 | for (i = 0; i < (count/sizeof(evtchn_port_t)); i++) { |
299 | evtchn_port_t port = kbuf[i]; |
300 | struct user_evtchn *evtchn; |
301 | |
302 | evtchn = find_evtchn(u, port); |
303 | if (evtchn && !evtchn->enabled) { |
304 | evtchn->enabled = true; |
305 | xen_irq_lateeoi(irq: irq_from_evtchn(evtchn: port), eoi_flags: 0); |
306 | } |
307 | } |
308 | |
309 | mutex_unlock(lock: &u->bind_mutex); |
310 | |
311 | rc = count; |
312 | |
313 | out: |
314 | free_page((unsigned long)kbuf); |
315 | return rc; |
316 | } |
317 | |
318 | static int evtchn_resize_ring(struct per_user_data *u) |
319 | { |
320 | unsigned int new_size; |
321 | evtchn_port_t *new_ring, *old_ring; |
322 | |
323 | /* |
324 | * Ensure the ring is large enough to capture all possible |
325 | * events. i.e., one free slot for each bound event. |
326 | */ |
327 | if (u->nr_evtchns <= u->ring_size) |
328 | return 0; |
329 | |
330 | if (u->ring_size == 0) |
331 | new_size = 64; |
332 | else |
333 | new_size = 2 * u->ring_size; |
334 | |
335 | new_ring = kvmalloc_array(n: new_size, size: sizeof(*new_ring), GFP_KERNEL); |
336 | if (!new_ring) |
337 | return -ENOMEM; |
338 | |
339 | old_ring = u->ring; |
340 | |
341 | /* |
342 | * Access to the ring contents is serialized by either the |
343 | * prod /or/ cons lock so take both when resizing. |
344 | */ |
345 | mutex_lock(&u->ring_cons_mutex); |
346 | spin_lock_irq(lock: &u->ring_prod_lock); |
347 | |
348 | /* |
349 | * Copy the old ring contents to the new ring. |
350 | * |
351 | * To take care of wrapping, a full ring, and the new index |
352 | * pointing into the second half, simply copy the old contents |
353 | * twice. |
354 | * |
355 | * +---------+ +------------------+ |
356 | * |34567 12| -> |34567 1234567 12| |
357 | * +-----p-c-+ +-------c------p---+ |
358 | */ |
359 | memcpy(new_ring, old_ring, u->ring_size * sizeof(*u->ring)); |
360 | memcpy(new_ring + u->ring_size, old_ring, |
361 | u->ring_size * sizeof(*u->ring)); |
362 | |
363 | u->ring = new_ring; |
364 | u->ring_size = new_size; |
365 | |
366 | spin_unlock_irq(lock: &u->ring_prod_lock); |
367 | mutex_unlock(lock: &u->ring_cons_mutex); |
368 | |
369 | evtchn_free_ring(ring: old_ring); |
370 | |
371 | return 0; |
372 | } |
373 | |
374 | static int evtchn_bind_to_user(struct per_user_data *u, evtchn_port_t port, |
375 | bool is_static) |
376 | { |
377 | struct user_evtchn *evtchn; |
378 | int rc = 0; |
379 | |
380 | /* |
381 | * Ports are never reused, so every caller should pass in a |
382 | * unique port. |
383 | * |
384 | * (Locking not necessary because we haven't registered the |
385 | * interrupt handler yet, and our caller has already |
386 | * serialized bind operations.) |
387 | */ |
388 | |
389 | evtchn = kzalloc(size: sizeof(*evtchn), GFP_KERNEL); |
390 | if (!evtchn) |
391 | return -ENOMEM; |
392 | |
393 | evtchn->user = u; |
394 | evtchn->port = port; |
395 | evtchn->enabled = true; /* start enabled */ |
396 | |
397 | rc = add_evtchn(u, evtchn); |
398 | if (rc < 0) |
399 | goto err; |
400 | |
401 | rc = evtchn_resize_ring(u); |
402 | if (rc < 0) |
403 | goto err; |
404 | |
405 | rc = bind_evtchn_to_irqhandler_lateeoi(evtchn: port, handler: evtchn_interrupt, IRQF_SHARED, |
406 | devname: u->name, dev_id: evtchn); |
407 | if (rc < 0) |
408 | goto err; |
409 | |
410 | rc = evtchn_make_refcounted(evtchn: port, is_static); |
411 | return rc; |
412 | |
413 | err: |
414 | /* bind failed, should close the port now */ |
415 | if (!is_static) |
416 | xen_evtchn_close(port); |
417 | |
418 | del_evtchn(u, evtchn); |
419 | return rc; |
420 | } |
421 | |
422 | static void evtchn_unbind_from_user(struct per_user_data *u, |
423 | struct user_evtchn *evtchn) |
424 | { |
425 | int irq = irq_from_evtchn(evtchn: evtchn->port); |
426 | |
427 | BUG_ON(irq < 0); |
428 | |
429 | evtchn->unbinding = true; |
430 | unbind_from_irqhandler(irq, dev_id: evtchn); |
431 | |
432 | del_evtchn(u, evtchn); |
433 | } |
434 | |
435 | static long evtchn_ioctl(struct file *file, |
436 | unsigned int cmd, unsigned long arg) |
437 | { |
438 | int rc; |
439 | struct per_user_data *u = file->private_data; |
440 | void __user *uarg = (void __user *) arg; |
441 | |
442 | /* Prevent bind from racing with unbind */ |
443 | mutex_lock(&u->bind_mutex); |
444 | |
445 | switch (cmd) { |
446 | case IOCTL_EVTCHN_BIND_VIRQ: { |
447 | struct ioctl_evtchn_bind_virq bind; |
448 | struct evtchn_bind_virq bind_virq; |
449 | |
450 | rc = -EACCES; |
451 | if (u->restrict_domid != UNRESTRICTED_DOMID) |
452 | break; |
453 | |
454 | rc = -EFAULT; |
455 | if (copy_from_user(to: &bind, from: uarg, n: sizeof(bind))) |
456 | break; |
457 | |
458 | bind_virq.virq = bind.virq; |
459 | bind_virq.vcpu = xen_vcpu_nr(cpu: 0); |
460 | rc = HYPERVISOR_event_channel_op(EVTCHNOP_bind_virq, |
461 | arg: &bind_virq); |
462 | if (rc != 0) |
463 | break; |
464 | |
465 | rc = evtchn_bind_to_user(u, port: bind_virq.port, is_static: false); |
466 | if (rc == 0) |
467 | rc = bind_virq.port; |
468 | break; |
469 | } |
470 | |
471 | case IOCTL_EVTCHN_BIND_INTERDOMAIN: { |
472 | struct ioctl_evtchn_bind_interdomain bind; |
473 | struct evtchn_bind_interdomain bind_interdomain; |
474 | |
475 | rc = -EFAULT; |
476 | if (copy_from_user(to: &bind, from: uarg, n: sizeof(bind))) |
477 | break; |
478 | |
479 | rc = -EACCES; |
480 | if (u->restrict_domid != UNRESTRICTED_DOMID && |
481 | u->restrict_domid != bind.remote_domain) |
482 | break; |
483 | |
484 | bind_interdomain.remote_dom = bind.remote_domain; |
485 | bind_interdomain.remote_port = bind.remote_port; |
486 | rc = HYPERVISOR_event_channel_op(EVTCHNOP_bind_interdomain, |
487 | arg: &bind_interdomain); |
488 | if (rc != 0) |
489 | break; |
490 | |
491 | rc = evtchn_bind_to_user(u, port: bind_interdomain.local_port, is_static: false); |
492 | if (rc == 0) |
493 | rc = bind_interdomain.local_port; |
494 | break; |
495 | } |
496 | |
497 | case IOCTL_EVTCHN_BIND_UNBOUND_PORT: { |
498 | struct ioctl_evtchn_bind_unbound_port bind; |
499 | struct evtchn_alloc_unbound alloc_unbound; |
500 | |
501 | rc = -EACCES; |
502 | if (u->restrict_domid != UNRESTRICTED_DOMID) |
503 | break; |
504 | |
505 | rc = -EFAULT; |
506 | if (copy_from_user(to: &bind, from: uarg, n: sizeof(bind))) |
507 | break; |
508 | |
509 | alloc_unbound.dom = DOMID_SELF; |
510 | alloc_unbound.remote_dom = bind.remote_domain; |
511 | rc = HYPERVISOR_event_channel_op(EVTCHNOP_alloc_unbound, |
512 | arg: &alloc_unbound); |
513 | if (rc != 0) |
514 | break; |
515 | |
516 | rc = evtchn_bind_to_user(u, port: alloc_unbound.port, is_static: false); |
517 | if (rc == 0) |
518 | rc = alloc_unbound.port; |
519 | break; |
520 | } |
521 | |
522 | case IOCTL_EVTCHN_UNBIND: { |
523 | struct ioctl_evtchn_unbind unbind; |
524 | struct user_evtchn *evtchn; |
525 | |
526 | rc = -EFAULT; |
527 | if (copy_from_user(to: &unbind, from: uarg, n: sizeof(unbind))) |
528 | break; |
529 | |
530 | rc = -EINVAL; |
531 | if (unbind.port >= xen_evtchn_nr_channels()) |
532 | break; |
533 | |
534 | rc = -ENOTCONN; |
535 | evtchn = find_evtchn(u, port: unbind.port); |
536 | if (!evtchn) |
537 | break; |
538 | |
539 | disable_irq(irq: irq_from_evtchn(evtchn: unbind.port)); |
540 | evtchn_unbind_from_user(u, evtchn); |
541 | rc = 0; |
542 | break; |
543 | } |
544 | |
545 | case IOCTL_EVTCHN_BIND_STATIC: { |
546 | struct ioctl_evtchn_bind bind; |
547 | struct user_evtchn *evtchn; |
548 | |
549 | rc = -EFAULT; |
550 | if (copy_from_user(to: &bind, from: uarg, n: sizeof(bind))) |
551 | break; |
552 | |
553 | rc = -EISCONN; |
554 | evtchn = find_evtchn(u, port: bind.port); |
555 | if (evtchn) |
556 | break; |
557 | |
558 | rc = evtchn_bind_to_user(u, port: bind.port, is_static: true); |
559 | break; |
560 | } |
561 | |
562 | case IOCTL_EVTCHN_NOTIFY: { |
563 | struct ioctl_evtchn_notify notify; |
564 | struct user_evtchn *evtchn; |
565 | |
566 | rc = -EFAULT; |
567 | if (copy_from_user(to: ¬ify, from: uarg, n: sizeof(notify))) |
568 | break; |
569 | |
570 | rc = -ENOTCONN; |
571 | evtchn = find_evtchn(u, port: notify.port); |
572 | if (evtchn) { |
573 | notify_remote_via_evtchn(port: notify.port); |
574 | rc = 0; |
575 | } |
576 | break; |
577 | } |
578 | |
579 | case IOCTL_EVTCHN_RESET: { |
580 | /* Initialise the ring to empty. Clear errors. */ |
581 | mutex_lock(&u->ring_cons_mutex); |
582 | spin_lock_irq(lock: &u->ring_prod_lock); |
583 | WRITE_ONCE(u->ring_cons, 0); |
584 | WRITE_ONCE(u->ring_prod, 0); |
585 | u->ring_overflow = 0; |
586 | spin_unlock_irq(lock: &u->ring_prod_lock); |
587 | mutex_unlock(lock: &u->ring_cons_mutex); |
588 | rc = 0; |
589 | break; |
590 | } |
591 | |
592 | case IOCTL_EVTCHN_RESTRICT_DOMID: { |
593 | struct ioctl_evtchn_restrict_domid ierd; |
594 | |
595 | rc = -EACCES; |
596 | if (u->restrict_domid != UNRESTRICTED_DOMID) |
597 | break; |
598 | |
599 | rc = -EFAULT; |
600 | if (copy_from_user(to: &ierd, from: uarg, n: sizeof(ierd))) |
601 | break; |
602 | |
603 | rc = -EINVAL; |
604 | if (ierd.domid == 0 || ierd.domid >= DOMID_FIRST_RESERVED) |
605 | break; |
606 | |
607 | u->restrict_domid = ierd.domid; |
608 | rc = 0; |
609 | |
610 | break; |
611 | } |
612 | |
613 | default: |
614 | rc = -ENOSYS; |
615 | break; |
616 | } |
617 | mutex_unlock(lock: &u->bind_mutex); |
618 | |
619 | return rc; |
620 | } |
621 | |
622 | static __poll_t evtchn_poll(struct file *file, poll_table *wait) |
623 | { |
624 | __poll_t mask = EPOLLOUT | EPOLLWRNORM; |
625 | struct per_user_data *u = file->private_data; |
626 | |
627 | poll_wait(filp: file, wait_address: &u->evtchn_wait, p: wait); |
628 | if (READ_ONCE(u->ring_cons) != READ_ONCE(u->ring_prod)) |
629 | mask |= EPOLLIN | EPOLLRDNORM; |
630 | if (u->ring_overflow) |
631 | mask = EPOLLERR; |
632 | return mask; |
633 | } |
634 | |
635 | static int evtchn_fasync(int fd, struct file *filp, int on) |
636 | { |
637 | struct per_user_data *u = filp->private_data; |
638 | return fasync_helper(fd, filp, on, &u->evtchn_async_queue); |
639 | } |
640 | |
641 | static int evtchn_open(struct inode *inode, struct file *filp) |
642 | { |
643 | struct per_user_data *u; |
644 | |
645 | u = kzalloc(size: sizeof(*u), GFP_KERNEL); |
646 | if (u == NULL) |
647 | return -ENOMEM; |
648 | |
649 | u->name = kasprintf(GFP_KERNEL, fmt: "evtchn:%s" , current->comm); |
650 | if (u->name == NULL) { |
651 | kfree(objp: u); |
652 | return -ENOMEM; |
653 | } |
654 | |
655 | init_waitqueue_head(&u->evtchn_wait); |
656 | |
657 | mutex_init(&u->bind_mutex); |
658 | mutex_init(&u->ring_cons_mutex); |
659 | spin_lock_init(&u->ring_prod_lock); |
660 | |
661 | u->restrict_domid = UNRESTRICTED_DOMID; |
662 | |
663 | filp->private_data = u; |
664 | |
665 | return stream_open(inode, filp); |
666 | } |
667 | |
668 | static int evtchn_release(struct inode *inode, struct file *filp) |
669 | { |
670 | struct per_user_data *u = filp->private_data; |
671 | struct rb_node *node; |
672 | |
673 | while ((node = u->evtchns.rb_node)) { |
674 | struct user_evtchn *evtchn; |
675 | |
676 | evtchn = rb_entry(node, struct user_evtchn, node); |
677 | disable_irq(irq: irq_from_evtchn(evtchn: evtchn->port)); |
678 | evtchn_unbind_from_user(u, evtchn); |
679 | } |
680 | |
681 | evtchn_free_ring(ring: u->ring); |
682 | kfree(objp: u->name); |
683 | kfree(objp: u); |
684 | |
685 | return 0; |
686 | } |
687 | |
688 | static const struct file_operations evtchn_fops = { |
689 | .owner = THIS_MODULE, |
690 | .read = evtchn_read, |
691 | .write = evtchn_write, |
692 | .unlocked_ioctl = evtchn_ioctl, |
693 | .poll = evtchn_poll, |
694 | .fasync = evtchn_fasync, |
695 | .open = evtchn_open, |
696 | .release = evtchn_release, |
697 | .llseek = no_llseek, |
698 | }; |
699 | |
700 | static struct miscdevice evtchn_miscdev = { |
701 | .minor = MISC_DYNAMIC_MINOR, |
702 | .name = "xen/evtchn" , |
703 | .fops = &evtchn_fops, |
704 | }; |
705 | static int __init evtchn_init(void) |
706 | { |
707 | int err; |
708 | |
709 | if (!xen_domain()) |
710 | return -ENODEV; |
711 | |
712 | /* Create '/dev/xen/evtchn'. */ |
713 | err = misc_register(misc: &evtchn_miscdev); |
714 | if (err != 0) { |
715 | pr_err("Could not register /dev/xen/evtchn\n" ); |
716 | return err; |
717 | } |
718 | |
719 | pr_info("Event-channel device installed\n" ); |
720 | |
721 | return 0; |
722 | } |
723 | |
724 | static void __exit evtchn_cleanup(void) |
725 | { |
726 | misc_deregister(misc: &evtchn_miscdev); |
727 | } |
728 | |
729 | module_init(evtchn_init); |
730 | module_exit(evtchn_cleanup); |
731 | |
732 | MODULE_LICENSE("GPL" ); |
733 | |