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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 | unsigned port; | |
87 | bool enabled; | |
88 | }; | |
89 | ||
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 | ||
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(&evtchn->node, parent, 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(evtchn); | |
139 | } | |
140 | ||
141 | static struct user_evtchn *find_evtchn(struct per_user_data *u, unsigned port) | |
142 | { | |
143 | struct rb_node *node = u->evtchns.rb_node; | |
144 | ||
145 | while (node) { | |
146 | struct user_evtchn *evtchn; | |
147 | ||
148 | evtchn = rb_entry(node, struct user_evtchn, node); | |
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; | |
158 | } | |
159 | ||
160 | static irqreturn_t evtchn_interrupt(int irq, void *data) | |
161 | { | |
162 | struct user_evtchn *evtchn = data; | |
163 | struct per_user_data *u = evtchn->user; | |
164 | ||
165 | WARN(!evtchn->enabled, | |
166 | "Interrupt for port %d, but apparently not enabled; per-user %p\n", | |
167 | evtchn->port, u); | |
168 | ||
169 | disable_irq_nosync(irq); | |
170 | evtchn->enabled = false; | |
171 | ||
172 | spin_lock(&u->ring_prod_lock); | |
173 | ||
174 | if ((u->ring_prod - u->ring_cons) < u->ring_size) { | |
175 | *evtchn_ring_entry(u, u->ring_prod) = evtchn->port; | |
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 | } | |
182 | } else | |
183 | u->ring_overflow = 1; | |
184 | ||
185 | spin_unlock(&u->ring_prod_lock); | |
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. */ | |
230 | if (((c ^ p) & u->ring_size) != 0) { | |
231 | bytes1 = (u->ring_size - evtchn_ring_offset(u, c)) * | |
232 | sizeof(evtchn_port_t); | |
233 | bytes2 = evtchn_ring_offset(u, p) * sizeof(evtchn_port_t); | |
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. */ | |
249 | if (copy_to_user(buf, evtchn_ring_entry(u, c), bytes1) || | |
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 | ||
286 | mutex_lock(&u->bind_mutex); | |
287 | ||
288 | for (i = 0; i < (count/sizeof(evtchn_port_t)); i++) { | |
289 | unsigned port = kbuf[i]; | |
290 | struct user_evtchn *evtchn; | |
291 | ||
292 | evtchn = find_evtchn(u, port); | |
293 | if (evtchn && !evtchn->enabled) { | |
294 | evtchn->enabled = true; | |
295 | enable_irq(irq_from_evtchn(port)); | |
296 | } | |
297 | } | |
298 | ||
299 | mutex_unlock(&u->bind_mutex); | |
300 | ||
301 | rc = count; | |
302 | ||
303 | out: | |
304 | free_page((unsigned long)kbuf); | |
305 | return rc; | |
306 | } | |
307 | ||
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; | |
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 | ||
325 | new_ring = kvmalloc(new_size * sizeof(*new_ring), GFP_KERNEL); | |
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 | * | |
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. | |
344 | * | |
345 | * +---------+ +------------------+ | |
346 | * |34567 12| -> |34567 1234567 12| | |
347 | * +-----p-c-+ +-------c------p---+ | |
348 | */ | |
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)); | |
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 | ||
364 | static int evtchn_bind_to_user(struct per_user_data *u, int port) | |
365 | { | |
366 | struct user_evtchn *evtchn; | |
367 | struct evtchn_close close; | |
368 | int rc = 0; | |
369 | ||
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 | */ | |
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; | |
390 | ||
391 | rc = evtchn_resize_ring(u); | |
392 | if (rc < 0) | |
393 | goto err; | |
394 | ||
395 | rc = bind_evtchn_to_irqhandler(port, evtchn_interrupt, 0, | |
396 | u->name, evtchn); | |
397 | if (rc < 0) | |
398 | goto err; | |
399 | ||
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); | |
409 | return rc; | |
410 | } | |
411 | ||
412 | static void evtchn_unbind_from_user(struct per_user_data *u, | |
413 | struct user_evtchn *evtchn) | |
414 | { | |
415 | int irq = irq_from_evtchn(evtchn->port); | |
416 | ||
417 | BUG_ON(irq < 0); | |
418 | ||
419 | unbind_from_irqhandler(irq, evtchn); | |
420 | ||
421 | del_evtchn(u, evtchn); | |
422 | } | |
423 | ||
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 | ||
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 | ||
461 | /* Prevent bind from racing with unbind */ | |
462 | mutex_lock(&u->bind_mutex); | |
463 | ||
464 | switch (cmd) { | |
465 | case IOCTL_EVTCHN_BIND_VIRQ: { | |
466 | struct ioctl_evtchn_bind_virq bind; | |
467 | struct evtchn_bind_virq bind_virq; | |
468 | ||
469 | rc = -EACCES; | |
470 | if (u->restrict_domid != UNRESTRICTED_DOMID) | |
471 | break; | |
472 | ||
473 | rc = -EFAULT; | |
474 | if (copy_from_user(&bind, uarg, sizeof(bind))) | |
475 | break; | |
476 | ||
477 | bind_virq.virq = bind.virq; | |
478 | bind_virq.vcpu = xen_vcpu_nr(0); | |
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 | ||
498 | rc = -EACCES; | |
499 | if (u->restrict_domid != UNRESTRICTED_DOMID && | |
500 | u->restrict_domid != bind.remote_domain) | |
501 | break; | |
502 | ||
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); | |
511 | if (rc == 0) { | |
512 | rc = bind_interdomain.local_port; | |
513 | evtchn_bind_interdom_next_vcpu(rc); | |
514 | } | |
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 | ||
522 | rc = -EACCES; | |
523 | if (u->restrict_domid != UNRESTRICTED_DOMID) | |
524 | break; | |
525 | ||
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; | |
545 | struct user_evtchn *evtchn; | |
546 | ||
547 | rc = -EFAULT; | |
548 | if (copy_from_user(&unbind, uarg, sizeof(unbind))) | |
549 | break; | |
550 | ||
551 | rc = -EINVAL; | |
552 | if (unbind.port >= xen_evtchn_nr_channels()) | |
553 | break; | |
554 | ||
555 | rc = -ENOTCONN; | |
556 | evtchn = find_evtchn(u, unbind.port); | |
557 | if (!evtchn) | |
558 | break; | |
559 | ||
560 | disable_irq(irq_from_evtchn(unbind.port)); | |
561 | evtchn_unbind_from_user(u, evtchn); | |
562 | rc = 0; | |
563 | break; | |
564 | } | |
565 | ||
566 | case IOCTL_EVTCHN_NOTIFY: { | |
567 | struct ioctl_evtchn_notify notify; | |
568 | struct user_evtchn *evtchn; | |
569 | ||
570 | rc = -EFAULT; | |
571 | if (copy_from_user(¬ify, uarg, sizeof(notify))) | |
572 | break; | |
573 | ||
574 | rc = -ENOTCONN; | |
575 | evtchn = find_evtchn(u, notify.port); | |
576 | if (evtchn) { | |
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); | |
586 | spin_lock_irq(&u->ring_prod_lock); | |
587 | u->ring_cons = u->ring_prod = u->ring_overflow = 0; | |
588 | spin_unlock_irq(&u->ring_prod_lock); | |
589 | mutex_unlock(&u->ring_cons_mutex); | |
590 | rc = 0; | |
591 | break; | |
592 | } | |
593 | ||
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 | ||
615 | default: | |
616 | rc = -ENOSYS; | |
617 | break; | |
618 | } | |
619 | mutex_unlock(&u->bind_mutex); | |
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 | ||
659 | mutex_init(&u->bind_mutex); | |
660 | mutex_init(&u->ring_cons_mutex); | |
661 | spin_lock_init(&u->ring_prod_lock); | |
662 | ||
663 | u->restrict_domid = UNRESTRICTED_DOMID; | |
664 | ||
665 | filp->private_data = u; | |
666 | ||
667 | return nonseekable_open(inode, filp); | |
668 | } | |
669 | ||
670 | static int evtchn_release(struct inode *inode, struct file *filp) | |
671 | { | |
672 | struct per_user_data *u = filp->private_data; | |
673 | struct rb_node *node; | |
674 | ||
675 | while ((node = u->evtchns.rb_node)) { | |
676 | struct user_evtchn *evtchn; | |
677 | ||
678 | evtchn = rb_entry(node, struct user_evtchn, node); | |
679 | disable_irq(irq_from_evtchn(evtchn->port)); | |
680 | evtchn_unbind_from_user(u, evtchn); | |
681 | } | |
682 | ||
683 | evtchn_free_ring(u->ring); | |
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, | |
699 | .llseek = no_llseek, | |
700 | }; | |
701 | ||
702 | static struct miscdevice evtchn_miscdev = { | |
703 | .minor = MISC_DYNAMIC_MINOR, | |
704 | .name = "xen/evtchn", | |
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 | ||
714 | /* Create '/dev/xen/evtchn'. */ | |
715 | err = misc_register(&evtchn_miscdev); | |
716 | if (err != 0) { | |
717 | pr_err("Could not register /dev/xen/evtchn\n"); | |
718 | return err; | |
719 | } | |
720 | ||
721 | pr_info("Event-channel device installed\n"); | |
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"); |