Commit | Line | Data |
---|---|---|
721eecbf GH |
1 | /* |
2 | * kvm eventfd support - use eventfd objects to signal various KVM events | |
3 | * | |
4 | * Copyright 2009 Novell. All Rights Reserved. | |
221d059d | 5 | * Copyright 2010 Red Hat, Inc. and/or its affiliates. |
721eecbf GH |
6 | * |
7 | * Author: | |
8 | * Gregory Haskins <ghaskins@novell.com> | |
9 | * | |
10 | * This file is free software; you can redistribute it and/or modify | |
11 | * it under the terms of version 2 of the GNU General Public License | |
12 | * as published by the Free Software Foundation. | |
13 | * | |
14 | * This program is distributed in the hope that it will be useful, | |
15 | * but WITHOUT ANY WARRANTY; without even the implied warranty of | |
16 | * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the | |
17 | * GNU General Public License for more details. | |
18 | * | |
19 | * You should have received a copy of the GNU General Public License | |
20 | * along with this program; if not, write to the Free Software Foundation, | |
21 | * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA. | |
22 | */ | |
23 | ||
24 | #include <linux/kvm_host.h> | |
d34e6b17 | 25 | #include <linux/kvm.h> |
721eecbf GH |
26 | #include <linux/workqueue.h> |
27 | #include <linux/syscalls.h> | |
28 | #include <linux/wait.h> | |
29 | #include <linux/poll.h> | |
30 | #include <linux/file.h> | |
31 | #include <linux/list.h> | |
32 | #include <linux/eventfd.h> | |
d34e6b17 | 33 | #include <linux/kernel.h> |
719d93cd | 34 | #include <linux/srcu.h> |
5a0e3ad6 | 35 | #include <linux/slab.h> |
56f89f36 | 36 | #include <linux/seqlock.h> |
e4d57e1e | 37 | #include <trace/events/kvm.h> |
d34e6b17 GH |
38 | |
39 | #include "iodev.h" | |
721eecbf | 40 | |
297e2105 | 41 | #ifdef CONFIG_HAVE_KVM_IRQFD |
721eecbf GH |
42 | /* |
43 | * -------------------------------------------------------------------- | |
44 | * irqfd: Allows an fd to be used to inject an interrupt to the guest | |
45 | * | |
46 | * Credit goes to Avi Kivity for the original idea. | |
47 | * -------------------------------------------------------------------- | |
48 | */ | |
49 | ||
7a84428a AW |
50 | /* |
51 | * Resampling irqfds are a special variety of irqfds used to emulate | |
52 | * level triggered interrupts. The interrupt is asserted on eventfd | |
53 | * trigger. On acknowledgement through the irq ack notifier, the | |
54 | * interrupt is de-asserted and userspace is notified through the | |
55 | * resamplefd. All resamplers on the same gsi are de-asserted | |
56 | * together, so we don't need to track the state of each individual | |
57 | * user. We can also therefore share the same irq source ID. | |
58 | */ | |
59 | struct _irqfd_resampler { | |
60 | struct kvm *kvm; | |
61 | /* | |
62 | * List of resampling struct _irqfd objects sharing this gsi. | |
63 | * RCU list modified under kvm->irqfds.resampler_lock | |
64 | */ | |
65 | struct list_head list; | |
66 | struct kvm_irq_ack_notifier notifier; | |
67 | /* | |
68 | * Entry in list of kvm->irqfd.resampler_list. Use for sharing | |
69 | * resamplers among irqfds on the same gsi. | |
70 | * Accessed and modified under kvm->irqfds.resampler_lock | |
71 | */ | |
72 | struct list_head link; | |
73 | }; | |
74 | ||
721eecbf | 75 | struct _irqfd { |
bd2b53b2 MT |
76 | /* Used for MSI fast-path */ |
77 | struct kvm *kvm; | |
78 | wait_queue_t wait; | |
79 | /* Update side is protected by irqfds.lock */ | |
56f89f36 PM |
80 | struct kvm_kernel_irq_routing_entry irq_entry; |
81 | seqcount_t irq_entry_sc; | |
bd2b53b2 MT |
82 | /* Used for level IRQ fast-path */ |
83 | int gsi; | |
84 | struct work_struct inject; | |
7a84428a AW |
85 | /* The resampler used by this irqfd (resampler-only) */ |
86 | struct _irqfd_resampler *resampler; | |
87 | /* Eventfd notified on resample (resampler-only) */ | |
88 | struct eventfd_ctx *resamplefd; | |
89 | /* Entry in list of irqfds for a resampler (resampler-only) */ | |
90 | struct list_head resampler_link; | |
bd2b53b2 MT |
91 | /* Used for setup/shutdown */ |
92 | struct eventfd_ctx *eventfd; | |
93 | struct list_head list; | |
94 | poll_table pt; | |
95 | struct work_struct shutdown; | |
721eecbf GH |
96 | }; |
97 | ||
98 | static struct workqueue_struct *irqfd_cleanup_wq; | |
99 | ||
100 | static void | |
101 | irqfd_inject(struct work_struct *work) | |
102 | { | |
103 | struct _irqfd *irqfd = container_of(work, struct _irqfd, inject); | |
104 | struct kvm *kvm = irqfd->kvm; | |
105 | ||
7a84428a | 106 | if (!irqfd->resampler) { |
aa2fbe6d YZ |
107 | kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 1, |
108 | false); | |
109 | kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 0, | |
110 | false); | |
7a84428a AW |
111 | } else |
112 | kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID, | |
aa2fbe6d | 113 | irqfd->gsi, 1, false); |
7a84428a AW |
114 | } |
115 | ||
116 | /* | |
117 | * Since resampler irqfds share an IRQ source ID, we de-assert once | |
118 | * then notify all of the resampler irqfds using this GSI. We can't | |
119 | * do multiple de-asserts or we risk racing with incoming re-asserts. | |
120 | */ | |
121 | static void | |
122 | irqfd_resampler_ack(struct kvm_irq_ack_notifier *kian) | |
123 | { | |
124 | struct _irqfd_resampler *resampler; | |
719d93cd | 125 | struct kvm *kvm; |
7a84428a | 126 | struct _irqfd *irqfd; |
719d93cd | 127 | int idx; |
7a84428a AW |
128 | |
129 | resampler = container_of(kian, struct _irqfd_resampler, notifier); | |
719d93cd | 130 | kvm = resampler->kvm; |
7a84428a | 131 | |
719d93cd | 132 | kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID, |
aa2fbe6d | 133 | resampler->notifier.gsi, 0, false); |
7a84428a | 134 | |
719d93cd | 135 | idx = srcu_read_lock(&kvm->irq_srcu); |
7a84428a AW |
136 | |
137 | list_for_each_entry_rcu(irqfd, &resampler->list, resampler_link) | |
138 | eventfd_signal(irqfd->resamplefd, 1); | |
139 | ||
719d93cd | 140 | srcu_read_unlock(&kvm->irq_srcu, idx); |
7a84428a AW |
141 | } |
142 | ||
143 | static void | |
144 | irqfd_resampler_shutdown(struct _irqfd *irqfd) | |
145 | { | |
146 | struct _irqfd_resampler *resampler = irqfd->resampler; | |
147 | struct kvm *kvm = resampler->kvm; | |
148 | ||
149 | mutex_lock(&kvm->irqfds.resampler_lock); | |
150 | ||
151 | list_del_rcu(&irqfd->resampler_link); | |
719d93cd | 152 | synchronize_srcu(&kvm->irq_srcu); |
7a84428a AW |
153 | |
154 | if (list_empty(&resampler->list)) { | |
155 | list_del(&resampler->link); | |
156 | kvm_unregister_irq_ack_notifier(kvm, &resampler->notifier); | |
157 | kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID, | |
aa2fbe6d | 158 | resampler->notifier.gsi, 0, false); |
7a84428a AW |
159 | kfree(resampler); |
160 | } | |
161 | ||
162 | mutex_unlock(&kvm->irqfds.resampler_lock); | |
721eecbf GH |
163 | } |
164 | ||
165 | /* | |
166 | * Race-free decouple logic (ordering is critical) | |
167 | */ | |
168 | static void | |
169 | irqfd_shutdown(struct work_struct *work) | |
170 | { | |
171 | struct _irqfd *irqfd = container_of(work, struct _irqfd, shutdown); | |
b6a114d2 | 172 | u64 cnt; |
721eecbf GH |
173 | |
174 | /* | |
175 | * Synchronize with the wait-queue and unhook ourselves to prevent | |
176 | * further events. | |
177 | */ | |
b6a114d2 | 178 | eventfd_ctx_remove_wait_queue(irqfd->eventfd, &irqfd->wait, &cnt); |
721eecbf GH |
179 | |
180 | /* | |
181 | * We know no new events will be scheduled at this point, so block | |
182 | * until all previously outstanding events have completed | |
183 | */ | |
43829731 | 184 | flush_work(&irqfd->inject); |
721eecbf | 185 | |
7a84428a AW |
186 | if (irqfd->resampler) { |
187 | irqfd_resampler_shutdown(irqfd); | |
188 | eventfd_ctx_put(irqfd->resamplefd); | |
189 | } | |
190 | ||
721eecbf GH |
191 | /* |
192 | * It is now safe to release the object's resources | |
193 | */ | |
194 | eventfd_ctx_put(irqfd->eventfd); | |
195 | kfree(irqfd); | |
196 | } | |
197 | ||
198 | ||
199 | /* assumes kvm->irqfds.lock is held */ | |
200 | static bool | |
201 | irqfd_is_active(struct _irqfd *irqfd) | |
202 | { | |
203 | return list_empty(&irqfd->list) ? false : true; | |
204 | } | |
205 | ||
206 | /* | |
207 | * Mark the irqfd as inactive and schedule it for removal | |
208 | * | |
209 | * assumes kvm->irqfds.lock is held | |
210 | */ | |
211 | static void | |
212 | irqfd_deactivate(struct _irqfd *irqfd) | |
213 | { | |
214 | BUG_ON(!irqfd_is_active(irqfd)); | |
215 | ||
216 | list_del_init(&irqfd->list); | |
217 | ||
218 | queue_work(irqfd_cleanup_wq, &irqfd->shutdown); | |
219 | } | |
220 | ||
221 | /* | |
222 | * Called with wqh->lock held and interrupts disabled | |
223 | */ | |
224 | static int | |
225 | irqfd_wakeup(wait_queue_t *wait, unsigned mode, int sync, void *key) | |
226 | { | |
227 | struct _irqfd *irqfd = container_of(wait, struct _irqfd, wait); | |
228 | unsigned long flags = (unsigned long)key; | |
56f89f36 | 229 | struct kvm_kernel_irq_routing_entry irq; |
bd2b53b2 | 230 | struct kvm *kvm = irqfd->kvm; |
56f89f36 | 231 | unsigned seq; |
719d93cd | 232 | int idx; |
721eecbf | 233 | |
bd2b53b2 | 234 | if (flags & POLLIN) { |
719d93cd | 235 | idx = srcu_read_lock(&kvm->irq_srcu); |
56f89f36 PM |
236 | do { |
237 | seq = read_seqcount_begin(&irqfd->irq_entry_sc); | |
238 | irq = irqfd->irq_entry; | |
239 | } while (read_seqcount_retry(&irqfd->irq_entry_sc, seq)); | |
721eecbf | 240 | /* An event has been signaled, inject an interrupt */ |
56f89f36 PM |
241 | if (irq.type == KVM_IRQ_ROUTING_MSI) |
242 | kvm_set_msi(&irq, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1, | |
aa2fbe6d | 243 | false); |
bd2b53b2 MT |
244 | else |
245 | schedule_work(&irqfd->inject); | |
719d93cd | 246 | srcu_read_unlock(&kvm->irq_srcu, idx); |
bd2b53b2 | 247 | } |
721eecbf GH |
248 | |
249 | if (flags & POLLHUP) { | |
250 | /* The eventfd is closing, detach from KVM */ | |
721eecbf GH |
251 | unsigned long flags; |
252 | ||
253 | spin_lock_irqsave(&kvm->irqfds.lock, flags); | |
254 | ||
255 | /* | |
256 | * We must check if someone deactivated the irqfd before | |
257 | * we could acquire the irqfds.lock since the item is | |
258 | * deactivated from the KVM side before it is unhooked from | |
259 | * the wait-queue. If it is already deactivated, we can | |
260 | * simply return knowing the other side will cleanup for us. | |
261 | * We cannot race against the irqfd going away since the | |
262 | * other side is required to acquire wqh->lock, which we hold | |
263 | */ | |
264 | if (irqfd_is_active(irqfd)) | |
265 | irqfd_deactivate(irqfd); | |
266 | ||
267 | spin_unlock_irqrestore(&kvm->irqfds.lock, flags); | |
268 | } | |
269 | ||
270 | return 0; | |
271 | } | |
272 | ||
273 | static void | |
274 | irqfd_ptable_queue_proc(struct file *file, wait_queue_head_t *wqh, | |
275 | poll_table *pt) | |
276 | { | |
277 | struct _irqfd *irqfd = container_of(pt, struct _irqfd, pt); | |
721eecbf GH |
278 | add_wait_queue(wqh, &irqfd->wait); |
279 | } | |
280 | ||
bd2b53b2 | 281 | /* Must be called under irqfds.lock */ |
9957c86d | 282 | static void irqfd_update(struct kvm *kvm, struct _irqfd *irqfd) |
bd2b53b2 MT |
283 | { |
284 | struct kvm_kernel_irq_routing_entry *e; | |
8ba918d4 PM |
285 | struct kvm_kernel_irq_routing_entry entries[KVM_NR_IRQCHIPS]; |
286 | int i, n_entries; | |
287 | ||
9957c86d | 288 | n_entries = kvm_irq_map_gsi(kvm, entries, irqfd->gsi); |
bd2b53b2 | 289 | |
56f89f36 PM |
290 | write_seqcount_begin(&irqfd->irq_entry_sc); |
291 | ||
292 | irqfd->irq_entry.type = 0; | |
bd2b53b2 | 293 | |
8ba918d4 PM |
294 | e = entries; |
295 | for (i = 0; i < n_entries; ++i, ++e) { | |
bd2b53b2 MT |
296 | /* Only fast-path MSI. */ |
297 | if (e->type == KVM_IRQ_ROUTING_MSI) | |
56f89f36 | 298 | irqfd->irq_entry = *e; |
bd2b53b2 | 299 | } |
56f89f36 | 300 | |
56f89f36 | 301 | write_seqcount_end(&irqfd->irq_entry_sc); |
bd2b53b2 MT |
302 | } |
303 | ||
721eecbf | 304 | static int |
d4db2935 | 305 | kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args) |
721eecbf | 306 | { |
f1d1c309 | 307 | struct _irqfd *irqfd, *tmp; |
cffe78d9 | 308 | struct fd f; |
7a84428a | 309 | struct eventfd_ctx *eventfd = NULL, *resamplefd = NULL; |
721eecbf GH |
310 | int ret; |
311 | unsigned int events; | |
9957c86d | 312 | int idx; |
721eecbf GH |
313 | |
314 | irqfd = kzalloc(sizeof(*irqfd), GFP_KERNEL); | |
315 | if (!irqfd) | |
316 | return -ENOMEM; | |
317 | ||
318 | irqfd->kvm = kvm; | |
d4db2935 | 319 | irqfd->gsi = args->gsi; |
721eecbf GH |
320 | INIT_LIST_HEAD(&irqfd->list); |
321 | INIT_WORK(&irqfd->inject, irqfd_inject); | |
322 | INIT_WORK(&irqfd->shutdown, irqfd_shutdown); | |
56f89f36 | 323 | seqcount_init(&irqfd->irq_entry_sc); |
721eecbf | 324 | |
cffe78d9 AV |
325 | f = fdget(args->fd); |
326 | if (!f.file) { | |
327 | ret = -EBADF; | |
328 | goto out; | |
721eecbf GH |
329 | } |
330 | ||
cffe78d9 | 331 | eventfd = eventfd_ctx_fileget(f.file); |
721eecbf GH |
332 | if (IS_ERR(eventfd)) { |
333 | ret = PTR_ERR(eventfd); | |
334 | goto fail; | |
335 | } | |
336 | ||
337 | irqfd->eventfd = eventfd; | |
338 | ||
7a84428a AW |
339 | if (args->flags & KVM_IRQFD_FLAG_RESAMPLE) { |
340 | struct _irqfd_resampler *resampler; | |
341 | ||
342 | resamplefd = eventfd_ctx_fdget(args->resamplefd); | |
343 | if (IS_ERR(resamplefd)) { | |
344 | ret = PTR_ERR(resamplefd); | |
345 | goto fail; | |
346 | } | |
347 | ||
348 | irqfd->resamplefd = resamplefd; | |
349 | INIT_LIST_HEAD(&irqfd->resampler_link); | |
350 | ||
351 | mutex_lock(&kvm->irqfds.resampler_lock); | |
352 | ||
353 | list_for_each_entry(resampler, | |
49f8a1a5 | 354 | &kvm->irqfds.resampler_list, link) { |
7a84428a AW |
355 | if (resampler->notifier.gsi == irqfd->gsi) { |
356 | irqfd->resampler = resampler; | |
357 | break; | |
358 | } | |
359 | } | |
360 | ||
361 | if (!irqfd->resampler) { | |
362 | resampler = kzalloc(sizeof(*resampler), GFP_KERNEL); | |
363 | if (!resampler) { | |
364 | ret = -ENOMEM; | |
365 | mutex_unlock(&kvm->irqfds.resampler_lock); | |
366 | goto fail; | |
367 | } | |
368 | ||
369 | resampler->kvm = kvm; | |
370 | INIT_LIST_HEAD(&resampler->list); | |
371 | resampler->notifier.gsi = irqfd->gsi; | |
372 | resampler->notifier.irq_acked = irqfd_resampler_ack; | |
373 | INIT_LIST_HEAD(&resampler->link); | |
374 | ||
375 | list_add(&resampler->link, &kvm->irqfds.resampler_list); | |
376 | kvm_register_irq_ack_notifier(kvm, | |
377 | &resampler->notifier); | |
378 | irqfd->resampler = resampler; | |
379 | } | |
380 | ||
381 | list_add_rcu(&irqfd->resampler_link, &irqfd->resampler->list); | |
719d93cd | 382 | synchronize_srcu(&kvm->irq_srcu); |
7a84428a AW |
383 | |
384 | mutex_unlock(&kvm->irqfds.resampler_lock); | |
385 | } | |
386 | ||
721eecbf GH |
387 | /* |
388 | * Install our own custom wake-up handling so we are notified via | |
389 | * a callback whenever someone signals the underlying eventfd | |
390 | */ | |
391 | init_waitqueue_func_entry(&irqfd->wait, irqfd_wakeup); | |
392 | init_poll_funcptr(&irqfd->pt, irqfd_ptable_queue_proc); | |
393 | ||
f1d1c309 MT |
394 | spin_lock_irq(&kvm->irqfds.lock); |
395 | ||
396 | ret = 0; | |
397 | list_for_each_entry(tmp, &kvm->irqfds.items, list) { | |
398 | if (irqfd->eventfd != tmp->eventfd) | |
399 | continue; | |
400 | /* This fd is used for another irq already. */ | |
401 | ret = -EBUSY; | |
402 | spin_unlock_irq(&kvm->irqfds.lock); | |
403 | goto fail; | |
404 | } | |
405 | ||
9957c86d PM |
406 | idx = srcu_read_lock(&kvm->irq_srcu); |
407 | irqfd_update(kvm, irqfd); | |
408 | srcu_read_unlock(&kvm->irq_srcu, idx); | |
bd2b53b2 | 409 | |
721eecbf | 410 | list_add_tail(&irqfd->list, &kvm->irqfds.items); |
721eecbf | 411 | |
684a0b71 CH |
412 | spin_unlock_irq(&kvm->irqfds.lock); |
413 | ||
721eecbf GH |
414 | /* |
415 | * Check if there was an event already pending on the eventfd | |
416 | * before we registered, and trigger it as if we didn't miss it. | |
417 | */ | |
684a0b71 CH |
418 | events = f.file->f_op->poll(f.file, &irqfd->pt); |
419 | ||
721eecbf GH |
420 | if (events & POLLIN) |
421 | schedule_work(&irqfd->inject); | |
422 | ||
423 | /* | |
424 | * do not drop the file until the irqfd is fully initialized, otherwise | |
425 | * we might race against the POLLHUP | |
426 | */ | |
cffe78d9 | 427 | fdput(f); |
721eecbf GH |
428 | |
429 | return 0; | |
430 | ||
431 | fail: | |
7a84428a AW |
432 | if (irqfd->resampler) |
433 | irqfd_resampler_shutdown(irqfd); | |
434 | ||
435 | if (resamplefd && !IS_ERR(resamplefd)) | |
436 | eventfd_ctx_put(resamplefd); | |
437 | ||
721eecbf GH |
438 | if (eventfd && !IS_ERR(eventfd)) |
439 | eventfd_ctx_put(eventfd); | |
440 | ||
cffe78d9 | 441 | fdput(f); |
721eecbf | 442 | |
cffe78d9 | 443 | out: |
721eecbf GH |
444 | kfree(irqfd); |
445 | return ret; | |
446 | } | |
c77dcacb PB |
447 | |
448 | bool kvm_irq_has_notifier(struct kvm *kvm, unsigned irqchip, unsigned pin) | |
449 | { | |
450 | struct kvm_irq_ack_notifier *kian; | |
451 | int gsi, idx; | |
452 | ||
453 | idx = srcu_read_lock(&kvm->irq_srcu); | |
454 | gsi = kvm_irq_map_chip_pin(kvm, irqchip, pin); | |
455 | if (gsi != -1) | |
456 | hlist_for_each_entry_rcu(kian, &kvm->irq_ack_notifier_list, | |
457 | link) | |
458 | if (kian->gsi == gsi) { | |
459 | srcu_read_unlock(&kvm->irq_srcu, idx); | |
460 | return true; | |
461 | } | |
462 | ||
463 | srcu_read_unlock(&kvm->irq_srcu, idx); | |
464 | ||
465 | return false; | |
466 | } | |
467 | EXPORT_SYMBOL_GPL(kvm_irq_has_notifier); | |
468 | ||
469 | void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin) | |
470 | { | |
471 | struct kvm_irq_ack_notifier *kian; | |
472 | int gsi, idx; | |
473 | ||
474 | trace_kvm_ack_irq(irqchip, pin); | |
475 | ||
476 | idx = srcu_read_lock(&kvm->irq_srcu); | |
477 | gsi = kvm_irq_map_chip_pin(kvm, irqchip, pin); | |
478 | if (gsi != -1) | |
479 | hlist_for_each_entry_rcu(kian, &kvm->irq_ack_notifier_list, | |
480 | link) | |
481 | if (kian->gsi == gsi) | |
482 | kian->irq_acked(kian); | |
483 | srcu_read_unlock(&kvm->irq_srcu, idx); | |
484 | } | |
485 | ||
486 | void kvm_register_irq_ack_notifier(struct kvm *kvm, | |
487 | struct kvm_irq_ack_notifier *kian) | |
488 | { | |
489 | mutex_lock(&kvm->irq_lock); | |
490 | hlist_add_head_rcu(&kian->link, &kvm->irq_ack_notifier_list); | |
491 | mutex_unlock(&kvm->irq_lock); | |
c77dcacb | 492 | kvm_vcpu_request_scan_ioapic(kvm); |
c77dcacb PB |
493 | } |
494 | ||
495 | void kvm_unregister_irq_ack_notifier(struct kvm *kvm, | |
496 | struct kvm_irq_ack_notifier *kian) | |
497 | { | |
498 | mutex_lock(&kvm->irq_lock); | |
499 | hlist_del_init_rcu(&kian->link); | |
500 | mutex_unlock(&kvm->irq_lock); | |
501 | synchronize_srcu(&kvm->irq_srcu); | |
c77dcacb | 502 | kvm_vcpu_request_scan_ioapic(kvm); |
c77dcacb | 503 | } |
914daba8 | 504 | #endif |
721eecbf GH |
505 | |
506 | void | |
d34e6b17 | 507 | kvm_eventfd_init(struct kvm *kvm) |
721eecbf | 508 | { |
297e2105 | 509 | #ifdef CONFIG_HAVE_KVM_IRQFD |
721eecbf GH |
510 | spin_lock_init(&kvm->irqfds.lock); |
511 | INIT_LIST_HEAD(&kvm->irqfds.items); | |
7a84428a AW |
512 | INIT_LIST_HEAD(&kvm->irqfds.resampler_list); |
513 | mutex_init(&kvm->irqfds.resampler_lock); | |
914daba8 | 514 | #endif |
d34e6b17 | 515 | INIT_LIST_HEAD(&kvm->ioeventfds); |
721eecbf GH |
516 | } |
517 | ||
297e2105 | 518 | #ifdef CONFIG_HAVE_KVM_IRQFD |
721eecbf GH |
519 | /* |
520 | * shutdown any irqfd's that match fd+gsi | |
521 | */ | |
522 | static int | |
d4db2935 | 523 | kvm_irqfd_deassign(struct kvm *kvm, struct kvm_irqfd *args) |
721eecbf GH |
524 | { |
525 | struct _irqfd *irqfd, *tmp; | |
526 | struct eventfd_ctx *eventfd; | |
527 | ||
d4db2935 | 528 | eventfd = eventfd_ctx_fdget(args->fd); |
721eecbf GH |
529 | if (IS_ERR(eventfd)) |
530 | return PTR_ERR(eventfd); | |
531 | ||
532 | spin_lock_irq(&kvm->irqfds.lock); | |
533 | ||
534 | list_for_each_entry_safe(irqfd, tmp, &kvm->irqfds.items, list) { | |
d4db2935 | 535 | if (irqfd->eventfd == eventfd && irqfd->gsi == args->gsi) { |
bd2b53b2 | 536 | /* |
56f89f36 | 537 | * This clearing of irq_entry.type is needed for when |
c8ce057e MT |
538 | * another thread calls kvm_irq_routing_update before |
539 | * we flush workqueue below (we synchronize with | |
540 | * kvm_irq_routing_update using irqfds.lock). | |
bd2b53b2 | 541 | */ |
56f89f36 PM |
542 | write_seqcount_begin(&irqfd->irq_entry_sc); |
543 | irqfd->irq_entry.type = 0; | |
544 | write_seqcount_end(&irqfd->irq_entry_sc); | |
721eecbf | 545 | irqfd_deactivate(irqfd); |
bd2b53b2 | 546 | } |
721eecbf GH |
547 | } |
548 | ||
549 | spin_unlock_irq(&kvm->irqfds.lock); | |
550 | eventfd_ctx_put(eventfd); | |
551 | ||
552 | /* | |
553 | * Block until we know all outstanding shutdown jobs have completed | |
554 | * so that we guarantee there will not be any more interrupts on this | |
555 | * gsi once this deassign function returns. | |
556 | */ | |
557 | flush_workqueue(irqfd_cleanup_wq); | |
558 | ||
559 | return 0; | |
560 | } | |
561 | ||
562 | int | |
d4db2935 | 563 | kvm_irqfd(struct kvm *kvm, struct kvm_irqfd *args) |
721eecbf | 564 | { |
7a84428a | 565 | if (args->flags & ~(KVM_IRQFD_FLAG_DEASSIGN | KVM_IRQFD_FLAG_RESAMPLE)) |
326cf033 AW |
566 | return -EINVAL; |
567 | ||
d4db2935 AW |
568 | if (args->flags & KVM_IRQFD_FLAG_DEASSIGN) |
569 | return kvm_irqfd_deassign(kvm, args); | |
721eecbf | 570 | |
d4db2935 | 571 | return kvm_irqfd_assign(kvm, args); |
721eecbf GH |
572 | } |
573 | ||
574 | /* | |
575 | * This function is called as the kvm VM fd is being released. Shutdown all | |
576 | * irqfds that still remain open | |
577 | */ | |
578 | void | |
579 | kvm_irqfd_release(struct kvm *kvm) | |
580 | { | |
581 | struct _irqfd *irqfd, *tmp; | |
582 | ||
583 | spin_lock_irq(&kvm->irqfds.lock); | |
584 | ||
585 | list_for_each_entry_safe(irqfd, tmp, &kvm->irqfds.items, list) | |
586 | irqfd_deactivate(irqfd); | |
587 | ||
588 | spin_unlock_irq(&kvm->irqfds.lock); | |
589 | ||
590 | /* | |
591 | * Block until we know all outstanding shutdown jobs have completed | |
592 | * since we do not take a kvm* reference. | |
593 | */ | |
594 | flush_workqueue(irqfd_cleanup_wq); | |
595 | ||
596 | } | |
597 | ||
bd2b53b2 | 598 | /* |
9957c86d | 599 | * Take note of a change in irq routing. |
719d93cd | 600 | * Caller must invoke synchronize_srcu(&kvm->irq_srcu) afterwards. |
bd2b53b2 | 601 | */ |
9957c86d | 602 | void kvm_irq_routing_update(struct kvm *kvm) |
bd2b53b2 MT |
603 | { |
604 | struct _irqfd *irqfd; | |
605 | ||
606 | spin_lock_irq(&kvm->irqfds.lock); | |
607 | ||
bd2b53b2 | 608 | list_for_each_entry(irqfd, &kvm->irqfds.items, list) |
9957c86d | 609 | irqfd_update(kvm, irqfd); |
bd2b53b2 MT |
610 | |
611 | spin_unlock_irq(&kvm->irqfds.lock); | |
612 | } | |
613 | ||
721eecbf GH |
614 | /* |
615 | * create a host-wide workqueue for issuing deferred shutdown requests | |
616 | * aggregated from all vm* instances. We need our own isolated single-thread | |
617 | * queue to prevent deadlock against flushing the normal work-queue. | |
618 | */ | |
a0f155e9 | 619 | int kvm_irqfd_init(void) |
721eecbf GH |
620 | { |
621 | irqfd_cleanup_wq = create_singlethread_workqueue("kvm-irqfd-cleanup"); | |
622 | if (!irqfd_cleanup_wq) | |
623 | return -ENOMEM; | |
624 | ||
625 | return 0; | |
626 | } | |
627 | ||
a0f155e9 | 628 | void kvm_irqfd_exit(void) |
721eecbf GH |
629 | { |
630 | destroy_workqueue(irqfd_cleanup_wq); | |
631 | } | |
914daba8 | 632 | #endif |
d34e6b17 GH |
633 | |
634 | /* | |
635 | * -------------------------------------------------------------------- | |
636 | * ioeventfd: translate a PIO/MMIO memory write to an eventfd signal. | |
637 | * | |
638 | * userspace can register a PIO/MMIO address with an eventfd for receiving | |
639 | * notification when the memory has been touched. | |
640 | * -------------------------------------------------------------------- | |
641 | */ | |
642 | ||
643 | struct _ioeventfd { | |
644 | struct list_head list; | |
645 | u64 addr; | |
646 | int length; | |
647 | struct eventfd_ctx *eventfd; | |
648 | u64 datamatch; | |
649 | struct kvm_io_device dev; | |
05e07f9b | 650 | u8 bus_idx; |
d34e6b17 GH |
651 | bool wildcard; |
652 | }; | |
653 | ||
654 | static inline struct _ioeventfd * | |
655 | to_ioeventfd(struct kvm_io_device *dev) | |
656 | { | |
657 | return container_of(dev, struct _ioeventfd, dev); | |
658 | } | |
659 | ||
660 | static void | |
661 | ioeventfd_release(struct _ioeventfd *p) | |
662 | { | |
663 | eventfd_ctx_put(p->eventfd); | |
664 | list_del(&p->list); | |
665 | kfree(p); | |
666 | } | |
667 | ||
668 | static bool | |
669 | ioeventfd_in_range(struct _ioeventfd *p, gpa_t addr, int len, const void *val) | |
670 | { | |
671 | u64 _val; | |
672 | ||
f848a5a8 MT |
673 | if (addr != p->addr) |
674 | /* address must be precise for a hit */ | |
675 | return false; | |
676 | ||
677 | if (!p->length) | |
678 | /* length = 0 means only look at the address, so always a hit */ | |
679 | return true; | |
680 | ||
681 | if (len != p->length) | |
d34e6b17 GH |
682 | /* address-range must be precise for a hit */ |
683 | return false; | |
684 | ||
685 | if (p->wildcard) | |
686 | /* all else equal, wildcard is always a hit */ | |
687 | return true; | |
688 | ||
689 | /* otherwise, we have to actually compare the data */ | |
690 | ||
691 | BUG_ON(!IS_ALIGNED((unsigned long)val, len)); | |
692 | ||
693 | switch (len) { | |
694 | case 1: | |
695 | _val = *(u8 *)val; | |
696 | break; | |
697 | case 2: | |
698 | _val = *(u16 *)val; | |
699 | break; | |
700 | case 4: | |
701 | _val = *(u32 *)val; | |
702 | break; | |
703 | case 8: | |
704 | _val = *(u64 *)val; | |
705 | break; | |
706 | default: | |
707 | return false; | |
708 | } | |
709 | ||
710 | return _val == p->datamatch ? true : false; | |
711 | } | |
712 | ||
713 | /* MMIO/PIO writes trigger an event if the addr/val match */ | |
714 | static int | |
715 | ioeventfd_write(struct kvm_io_device *this, gpa_t addr, int len, | |
716 | const void *val) | |
717 | { | |
718 | struct _ioeventfd *p = to_ioeventfd(this); | |
719 | ||
720 | if (!ioeventfd_in_range(p, addr, len, val)) | |
721 | return -EOPNOTSUPP; | |
722 | ||
723 | eventfd_signal(p->eventfd, 1); | |
724 | return 0; | |
725 | } | |
726 | ||
727 | /* | |
728 | * This function is called as KVM is completely shutting down. We do not | |
729 | * need to worry about locking just nuke anything we have as quickly as possible | |
730 | */ | |
731 | static void | |
732 | ioeventfd_destructor(struct kvm_io_device *this) | |
733 | { | |
734 | struct _ioeventfd *p = to_ioeventfd(this); | |
735 | ||
736 | ioeventfd_release(p); | |
737 | } | |
738 | ||
739 | static const struct kvm_io_device_ops ioeventfd_ops = { | |
740 | .write = ioeventfd_write, | |
741 | .destructor = ioeventfd_destructor, | |
742 | }; | |
743 | ||
744 | /* assumes kvm->slots_lock held */ | |
745 | static bool | |
746 | ioeventfd_check_collision(struct kvm *kvm, struct _ioeventfd *p) | |
747 | { | |
748 | struct _ioeventfd *_p; | |
749 | ||
750 | list_for_each_entry(_p, &kvm->ioeventfds, list) | |
05e07f9b | 751 | if (_p->bus_idx == p->bus_idx && |
f848a5a8 MT |
752 | _p->addr == p->addr && |
753 | (!_p->length || !p->length || | |
754 | (_p->length == p->length && | |
755 | (_p->wildcard || p->wildcard || | |
756 | _p->datamatch == p->datamatch)))) | |
d34e6b17 GH |
757 | return true; |
758 | ||
759 | return false; | |
760 | } | |
761 | ||
2b83451b CH |
762 | static enum kvm_bus ioeventfd_bus_from_flags(__u32 flags) |
763 | { | |
764 | if (flags & KVM_IOEVENTFD_FLAG_PIO) | |
765 | return KVM_PIO_BUS; | |
766 | if (flags & KVM_IOEVENTFD_FLAG_VIRTIO_CCW_NOTIFY) | |
767 | return KVM_VIRTIO_CCW_NOTIFY_BUS; | |
768 | return KVM_MMIO_BUS; | |
769 | } | |
770 | ||
d34e6b17 GH |
771 | static int |
772 | kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args) | |
773 | { | |
2b83451b | 774 | enum kvm_bus bus_idx; |
d34e6b17 GH |
775 | struct _ioeventfd *p; |
776 | struct eventfd_ctx *eventfd; | |
777 | int ret; | |
778 | ||
2b83451b | 779 | bus_idx = ioeventfd_bus_from_flags(args->flags); |
f848a5a8 | 780 | /* must be natural-word sized, or 0 to ignore length */ |
d34e6b17 | 781 | switch (args->len) { |
f848a5a8 | 782 | case 0: |
d34e6b17 GH |
783 | case 1: |
784 | case 2: | |
785 | case 4: | |
786 | case 8: | |
787 | break; | |
788 | default: | |
789 | return -EINVAL; | |
790 | } | |
791 | ||
792 | /* check for range overflow */ | |
793 | if (args->addr + args->len < args->addr) | |
794 | return -EINVAL; | |
795 | ||
796 | /* check for extra flags that we don't understand */ | |
797 | if (args->flags & ~KVM_IOEVENTFD_VALID_FLAG_MASK) | |
798 | return -EINVAL; | |
799 | ||
f848a5a8 MT |
800 | /* ioeventfd with no length can't be combined with DATAMATCH */ |
801 | if (!args->len && | |
802 | args->flags & (KVM_IOEVENTFD_FLAG_PIO | | |
803 | KVM_IOEVENTFD_FLAG_DATAMATCH)) | |
804 | return -EINVAL; | |
805 | ||
d34e6b17 GH |
806 | eventfd = eventfd_ctx_fdget(args->fd); |
807 | if (IS_ERR(eventfd)) | |
808 | return PTR_ERR(eventfd); | |
809 | ||
810 | p = kzalloc(sizeof(*p), GFP_KERNEL); | |
811 | if (!p) { | |
812 | ret = -ENOMEM; | |
813 | goto fail; | |
814 | } | |
815 | ||
816 | INIT_LIST_HEAD(&p->list); | |
817 | p->addr = args->addr; | |
05e07f9b | 818 | p->bus_idx = bus_idx; |
d34e6b17 GH |
819 | p->length = args->len; |
820 | p->eventfd = eventfd; | |
821 | ||
822 | /* The datamatch feature is optional, otherwise this is a wildcard */ | |
823 | if (args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH) | |
824 | p->datamatch = args->datamatch; | |
825 | else | |
826 | p->wildcard = true; | |
827 | ||
79fac95e | 828 | mutex_lock(&kvm->slots_lock); |
d34e6b17 | 829 | |
25985edc | 830 | /* Verify that there isn't a match already */ |
d34e6b17 GH |
831 | if (ioeventfd_check_collision(kvm, p)) { |
832 | ret = -EEXIST; | |
833 | goto unlock_fail; | |
834 | } | |
835 | ||
836 | kvm_iodevice_init(&p->dev, &ioeventfd_ops); | |
837 | ||
743eeb0b SL |
838 | ret = kvm_io_bus_register_dev(kvm, bus_idx, p->addr, p->length, |
839 | &p->dev); | |
d34e6b17 GH |
840 | if (ret < 0) |
841 | goto unlock_fail; | |
842 | ||
68c3b4d1 MT |
843 | /* When length is ignored, MMIO is also put on a separate bus, for |
844 | * faster lookups. | |
845 | */ | |
846 | if (!args->len && !(args->flags & KVM_IOEVENTFD_FLAG_PIO)) { | |
847 | ret = kvm_io_bus_register_dev(kvm, KVM_FAST_MMIO_BUS, | |
848 | p->addr, 0, &p->dev); | |
849 | if (ret < 0) | |
850 | goto register_fail; | |
851 | } | |
852 | ||
6ea34c9b | 853 | kvm->buses[bus_idx]->ioeventfd_count++; |
d34e6b17 GH |
854 | list_add_tail(&p->list, &kvm->ioeventfds); |
855 | ||
79fac95e | 856 | mutex_unlock(&kvm->slots_lock); |
d34e6b17 GH |
857 | |
858 | return 0; | |
859 | ||
68c3b4d1 MT |
860 | register_fail: |
861 | kvm_io_bus_unregister_dev(kvm, bus_idx, &p->dev); | |
d34e6b17 | 862 | unlock_fail: |
79fac95e | 863 | mutex_unlock(&kvm->slots_lock); |
d34e6b17 GH |
864 | |
865 | fail: | |
866 | kfree(p); | |
867 | eventfd_ctx_put(eventfd); | |
868 | ||
869 | return ret; | |
870 | } | |
871 | ||
872 | static int | |
873 | kvm_deassign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args) | |
874 | { | |
2b83451b | 875 | enum kvm_bus bus_idx; |
d34e6b17 GH |
876 | struct _ioeventfd *p, *tmp; |
877 | struct eventfd_ctx *eventfd; | |
878 | int ret = -ENOENT; | |
879 | ||
2b83451b | 880 | bus_idx = ioeventfd_bus_from_flags(args->flags); |
d34e6b17 GH |
881 | eventfd = eventfd_ctx_fdget(args->fd); |
882 | if (IS_ERR(eventfd)) | |
883 | return PTR_ERR(eventfd); | |
884 | ||
79fac95e | 885 | mutex_lock(&kvm->slots_lock); |
d34e6b17 GH |
886 | |
887 | list_for_each_entry_safe(p, tmp, &kvm->ioeventfds, list) { | |
888 | bool wildcard = !(args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH); | |
889 | ||
05e07f9b MT |
890 | if (p->bus_idx != bus_idx || |
891 | p->eventfd != eventfd || | |
d34e6b17 GH |
892 | p->addr != args->addr || |
893 | p->length != args->len || | |
894 | p->wildcard != wildcard) | |
895 | continue; | |
896 | ||
897 | if (!p->wildcard && p->datamatch != args->datamatch) | |
898 | continue; | |
899 | ||
e93f8a0f | 900 | kvm_io_bus_unregister_dev(kvm, bus_idx, &p->dev); |
68c3b4d1 MT |
901 | if (!p->length) { |
902 | kvm_io_bus_unregister_dev(kvm, KVM_FAST_MMIO_BUS, | |
903 | &p->dev); | |
904 | } | |
6ea34c9b | 905 | kvm->buses[bus_idx]->ioeventfd_count--; |
d34e6b17 GH |
906 | ioeventfd_release(p); |
907 | ret = 0; | |
908 | break; | |
909 | } | |
910 | ||
79fac95e | 911 | mutex_unlock(&kvm->slots_lock); |
d34e6b17 GH |
912 | |
913 | eventfd_ctx_put(eventfd); | |
914 | ||
915 | return ret; | |
916 | } | |
917 | ||
918 | int | |
919 | kvm_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args) | |
920 | { | |
921 | if (args->flags & KVM_IOEVENTFD_FLAG_DEASSIGN) | |
922 | return kvm_deassign_ioeventfd(kvm, args); | |
923 | ||
924 | return kvm_assign_ioeventfd(kvm, args); | |
925 | } |