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Commit | Line | Data |
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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 | 38 | |
e4d57e1e | 39 | #include "irq.h" |
d34e6b17 | 40 | #include "iodev.h" |
721eecbf | 41 | |
297e2105 | 42 | #ifdef CONFIG_HAVE_KVM_IRQFD |
721eecbf GH |
43 | /* |
44 | * -------------------------------------------------------------------- | |
45 | * irqfd: Allows an fd to be used to inject an interrupt to the guest | |
46 | * | |
47 | * Credit goes to Avi Kivity for the original idea. | |
48 | * -------------------------------------------------------------------- | |
49 | */ | |
50 | ||
7a84428a AW |
51 | /* |
52 | * Resampling irqfds are a special variety of irqfds used to emulate | |
53 | * level triggered interrupts. The interrupt is asserted on eventfd | |
54 | * trigger. On acknowledgement through the irq ack notifier, the | |
55 | * interrupt is de-asserted and userspace is notified through the | |
56 | * resamplefd. All resamplers on the same gsi are de-asserted | |
57 | * together, so we don't need to track the state of each individual | |
58 | * user. We can also therefore share the same irq source ID. | |
59 | */ | |
60 | struct _irqfd_resampler { | |
61 | struct kvm *kvm; | |
62 | /* | |
63 | * List of resampling struct _irqfd objects sharing this gsi. | |
64 | * RCU list modified under kvm->irqfds.resampler_lock | |
65 | */ | |
66 | struct list_head list; | |
67 | struct kvm_irq_ack_notifier notifier; | |
68 | /* | |
69 | * Entry in list of kvm->irqfd.resampler_list. Use for sharing | |
70 | * resamplers among irqfds on the same gsi. | |
71 | * Accessed and modified under kvm->irqfds.resampler_lock | |
72 | */ | |
73 | struct list_head link; | |
74 | }; | |
75 | ||
721eecbf | 76 | struct _irqfd { |
bd2b53b2 MT |
77 | /* Used for MSI fast-path */ |
78 | struct kvm *kvm; | |
79 | wait_queue_t wait; | |
80 | /* Update side is protected by irqfds.lock */ | |
56f89f36 PM |
81 | struct kvm_kernel_irq_routing_entry irq_entry; |
82 | seqcount_t irq_entry_sc; | |
bd2b53b2 MT |
83 | /* Used for level IRQ fast-path */ |
84 | int gsi; | |
85 | struct work_struct inject; | |
7a84428a AW |
86 | /* The resampler used by this irqfd (resampler-only) */ |
87 | struct _irqfd_resampler *resampler; | |
88 | /* Eventfd notified on resample (resampler-only) */ | |
89 | struct eventfd_ctx *resamplefd; | |
90 | /* Entry in list of irqfds for a resampler (resampler-only) */ | |
91 | struct list_head resampler_link; | |
bd2b53b2 MT |
92 | /* Used for setup/shutdown */ |
93 | struct eventfd_ctx *eventfd; | |
94 | struct list_head list; | |
95 | poll_table pt; | |
96 | struct work_struct shutdown; | |
721eecbf GH |
97 | }; |
98 | ||
99 | static struct workqueue_struct *irqfd_cleanup_wq; | |
100 | ||
101 | static void | |
102 | irqfd_inject(struct work_struct *work) | |
103 | { | |
104 | struct _irqfd *irqfd = container_of(work, struct _irqfd, inject); | |
105 | struct kvm *kvm = irqfd->kvm; | |
106 | ||
7a84428a | 107 | if (!irqfd->resampler) { |
aa2fbe6d YZ |
108 | kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 1, |
109 | false); | |
110 | kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 0, | |
111 | false); | |
7a84428a AW |
112 | } else |
113 | kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID, | |
aa2fbe6d | 114 | irqfd->gsi, 1, false); |
7a84428a AW |
115 | } |
116 | ||
117 | /* | |
118 | * Since resampler irqfds share an IRQ source ID, we de-assert once | |
119 | * then notify all of the resampler irqfds using this GSI. We can't | |
120 | * do multiple de-asserts or we risk racing with incoming re-asserts. | |
121 | */ | |
122 | static void | |
123 | irqfd_resampler_ack(struct kvm_irq_ack_notifier *kian) | |
124 | { | |
125 | struct _irqfd_resampler *resampler; | |
719d93cd | 126 | struct kvm *kvm; |
7a84428a | 127 | struct _irqfd *irqfd; |
719d93cd | 128 | int idx; |
7a84428a AW |
129 | |
130 | resampler = container_of(kian, struct _irqfd_resampler, notifier); | |
719d93cd | 131 | kvm = resampler->kvm; |
7a84428a | 132 | |
719d93cd | 133 | kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID, |
aa2fbe6d | 134 | resampler->notifier.gsi, 0, false); |
7a84428a | 135 | |
719d93cd | 136 | idx = srcu_read_lock(&kvm->irq_srcu); |
7a84428a AW |
137 | |
138 | list_for_each_entry_rcu(irqfd, &resampler->list, resampler_link) | |
139 | eventfd_signal(irqfd->resamplefd, 1); | |
140 | ||
719d93cd | 141 | srcu_read_unlock(&kvm->irq_srcu, idx); |
7a84428a AW |
142 | } |
143 | ||
144 | static void | |
145 | irqfd_resampler_shutdown(struct _irqfd *irqfd) | |
146 | { | |
147 | struct _irqfd_resampler *resampler = irqfd->resampler; | |
148 | struct kvm *kvm = resampler->kvm; | |
149 | ||
150 | mutex_lock(&kvm->irqfds.resampler_lock); | |
151 | ||
152 | list_del_rcu(&irqfd->resampler_link); | |
719d93cd | 153 | synchronize_srcu(&kvm->irq_srcu); |
7a84428a AW |
154 | |
155 | if (list_empty(&resampler->list)) { | |
156 | list_del(&resampler->link); | |
157 | kvm_unregister_irq_ack_notifier(kvm, &resampler->notifier); | |
158 | kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID, | |
aa2fbe6d | 159 | resampler->notifier.gsi, 0, false); |
7a84428a AW |
160 | kfree(resampler); |
161 | } | |
162 | ||
163 | mutex_unlock(&kvm->irqfds.resampler_lock); | |
721eecbf GH |
164 | } |
165 | ||
166 | /* | |
167 | * Race-free decouple logic (ordering is critical) | |
168 | */ | |
169 | static void | |
170 | irqfd_shutdown(struct work_struct *work) | |
171 | { | |
172 | struct _irqfd *irqfd = container_of(work, struct _irqfd, shutdown); | |
b6a114d2 | 173 | u64 cnt; |
721eecbf GH |
174 | |
175 | /* | |
176 | * Synchronize with the wait-queue and unhook ourselves to prevent | |
177 | * further events. | |
178 | */ | |
b6a114d2 | 179 | eventfd_ctx_remove_wait_queue(irqfd->eventfd, &irqfd->wait, &cnt); |
721eecbf GH |
180 | |
181 | /* | |
182 | * We know no new events will be scheduled at this point, so block | |
183 | * until all previously outstanding events have completed | |
184 | */ | |
43829731 | 185 | flush_work(&irqfd->inject); |
721eecbf | 186 | |
7a84428a AW |
187 | if (irqfd->resampler) { |
188 | irqfd_resampler_shutdown(irqfd); | |
189 | eventfd_ctx_put(irqfd->resamplefd); | |
190 | } | |
191 | ||
721eecbf GH |
192 | /* |
193 | * It is now safe to release the object's resources | |
194 | */ | |
195 | eventfd_ctx_put(irqfd->eventfd); | |
196 | kfree(irqfd); | |
197 | } | |
198 | ||
199 | ||
200 | /* assumes kvm->irqfds.lock is held */ | |
201 | static bool | |
202 | irqfd_is_active(struct _irqfd *irqfd) | |
203 | { | |
204 | return list_empty(&irqfd->list) ? false : true; | |
205 | } | |
206 | ||
207 | /* | |
208 | * Mark the irqfd as inactive and schedule it for removal | |
209 | * | |
210 | * assumes kvm->irqfds.lock is held | |
211 | */ | |
212 | static void | |
213 | irqfd_deactivate(struct _irqfd *irqfd) | |
214 | { | |
215 | BUG_ON(!irqfd_is_active(irqfd)); | |
216 | ||
217 | list_del_init(&irqfd->list); | |
218 | ||
219 | queue_work(irqfd_cleanup_wq, &irqfd->shutdown); | |
220 | } | |
221 | ||
222 | /* | |
223 | * Called with wqh->lock held and interrupts disabled | |
224 | */ | |
225 | static int | |
226 | irqfd_wakeup(wait_queue_t *wait, unsigned mode, int sync, void *key) | |
227 | { | |
228 | struct _irqfd *irqfd = container_of(wait, struct _irqfd, wait); | |
229 | unsigned long flags = (unsigned long)key; | |
56f89f36 | 230 | struct kvm_kernel_irq_routing_entry irq; |
bd2b53b2 | 231 | struct kvm *kvm = irqfd->kvm; |
56f89f36 | 232 | unsigned seq; |
719d93cd | 233 | int idx; |
721eecbf | 234 | |
bd2b53b2 | 235 | if (flags & POLLIN) { |
719d93cd | 236 | idx = srcu_read_lock(&kvm->irq_srcu); |
56f89f36 PM |
237 | do { |
238 | seq = read_seqcount_begin(&irqfd->irq_entry_sc); | |
239 | irq = irqfd->irq_entry; | |
240 | } while (read_seqcount_retry(&irqfd->irq_entry_sc, seq)); | |
721eecbf | 241 | /* An event has been signaled, inject an interrupt */ |
56f89f36 PM |
242 | if (irq.type == KVM_IRQ_ROUTING_MSI) |
243 | kvm_set_msi(&irq, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1, | |
aa2fbe6d | 244 | false); |
bd2b53b2 MT |
245 | else |
246 | schedule_work(&irqfd->inject); | |
719d93cd | 247 | srcu_read_unlock(&kvm->irq_srcu, idx); |
bd2b53b2 | 248 | } |
721eecbf GH |
249 | |
250 | if (flags & POLLHUP) { | |
251 | /* The eventfd is closing, detach from KVM */ | |
721eecbf GH |
252 | unsigned long flags; |
253 | ||
254 | spin_lock_irqsave(&kvm->irqfds.lock, flags); | |
255 | ||
256 | /* | |
257 | * We must check if someone deactivated the irqfd before | |
258 | * we could acquire the irqfds.lock since the item is | |
259 | * deactivated from the KVM side before it is unhooked from | |
260 | * the wait-queue. If it is already deactivated, we can | |
261 | * simply return knowing the other side will cleanup for us. | |
262 | * We cannot race against the irqfd going away since the | |
263 | * other side is required to acquire wqh->lock, which we hold | |
264 | */ | |
265 | if (irqfd_is_active(irqfd)) | |
266 | irqfd_deactivate(irqfd); | |
267 | ||
268 | spin_unlock_irqrestore(&kvm->irqfds.lock, flags); | |
269 | } | |
270 | ||
271 | return 0; | |
272 | } | |
273 | ||
274 | static void | |
275 | irqfd_ptable_queue_proc(struct file *file, wait_queue_head_t *wqh, | |
276 | poll_table *pt) | |
277 | { | |
278 | struct _irqfd *irqfd = container_of(pt, struct _irqfd, pt); | |
721eecbf GH |
279 | add_wait_queue(wqh, &irqfd->wait); |
280 | } | |
281 | ||
bd2b53b2 | 282 | /* Must be called under irqfds.lock */ |
9957c86d | 283 | static void irqfd_update(struct kvm *kvm, struct _irqfd *irqfd) |
bd2b53b2 MT |
284 | { |
285 | struct kvm_kernel_irq_routing_entry *e; | |
8ba918d4 PM |
286 | struct kvm_kernel_irq_routing_entry entries[KVM_NR_IRQCHIPS]; |
287 | int i, n_entries; | |
288 | ||
9957c86d | 289 | n_entries = kvm_irq_map_gsi(kvm, entries, irqfd->gsi); |
bd2b53b2 | 290 | |
56f89f36 PM |
291 | write_seqcount_begin(&irqfd->irq_entry_sc); |
292 | ||
293 | irqfd->irq_entry.type = 0; | |
bd2b53b2 | 294 | |
8ba918d4 PM |
295 | e = entries; |
296 | for (i = 0; i < n_entries; ++i, ++e) { | |
bd2b53b2 MT |
297 | /* Only fast-path MSI. */ |
298 | if (e->type == KVM_IRQ_ROUTING_MSI) | |
56f89f36 | 299 | irqfd->irq_entry = *e; |
bd2b53b2 | 300 | } |
56f89f36 | 301 | |
56f89f36 | 302 | write_seqcount_end(&irqfd->irq_entry_sc); |
bd2b53b2 MT |
303 | } |
304 | ||
721eecbf | 305 | static int |
d4db2935 | 306 | kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args) |
721eecbf | 307 | { |
f1d1c309 | 308 | struct _irqfd *irqfd, *tmp; |
cffe78d9 | 309 | struct fd f; |
7a84428a | 310 | struct eventfd_ctx *eventfd = NULL, *resamplefd = NULL; |
721eecbf GH |
311 | int ret; |
312 | unsigned int events; | |
9957c86d | 313 | int idx; |
721eecbf GH |
314 | |
315 | irqfd = kzalloc(sizeof(*irqfd), GFP_KERNEL); | |
316 | if (!irqfd) | |
317 | return -ENOMEM; | |
318 | ||
319 | irqfd->kvm = kvm; | |
d4db2935 | 320 | irqfd->gsi = args->gsi; |
721eecbf GH |
321 | INIT_LIST_HEAD(&irqfd->list); |
322 | INIT_WORK(&irqfd->inject, irqfd_inject); | |
323 | INIT_WORK(&irqfd->shutdown, irqfd_shutdown); | |
56f89f36 | 324 | seqcount_init(&irqfd->irq_entry_sc); |
721eecbf | 325 | |
cffe78d9 AV |
326 | f = fdget(args->fd); |
327 | if (!f.file) { | |
328 | ret = -EBADF; | |
329 | goto out; | |
721eecbf GH |
330 | } |
331 | ||
cffe78d9 | 332 | eventfd = eventfd_ctx_fileget(f.file); |
721eecbf GH |
333 | if (IS_ERR(eventfd)) { |
334 | ret = PTR_ERR(eventfd); | |
335 | goto fail; | |
336 | } | |
337 | ||
338 | irqfd->eventfd = eventfd; | |
339 | ||
7a84428a AW |
340 | if (args->flags & KVM_IRQFD_FLAG_RESAMPLE) { |
341 | struct _irqfd_resampler *resampler; | |
342 | ||
343 | resamplefd = eventfd_ctx_fdget(args->resamplefd); | |
344 | if (IS_ERR(resamplefd)) { | |
345 | ret = PTR_ERR(resamplefd); | |
346 | goto fail; | |
347 | } | |
348 | ||
349 | irqfd->resamplefd = resamplefd; | |
350 | INIT_LIST_HEAD(&irqfd->resampler_link); | |
351 | ||
352 | mutex_lock(&kvm->irqfds.resampler_lock); | |
353 | ||
354 | list_for_each_entry(resampler, | |
49f8a1a5 | 355 | &kvm->irqfds.resampler_list, link) { |
7a84428a AW |
356 | if (resampler->notifier.gsi == irqfd->gsi) { |
357 | irqfd->resampler = resampler; | |
358 | break; | |
359 | } | |
360 | } | |
361 | ||
362 | if (!irqfd->resampler) { | |
363 | resampler = kzalloc(sizeof(*resampler), GFP_KERNEL); | |
364 | if (!resampler) { | |
365 | ret = -ENOMEM; | |
366 | mutex_unlock(&kvm->irqfds.resampler_lock); | |
367 | goto fail; | |
368 | } | |
369 | ||
370 | resampler->kvm = kvm; | |
371 | INIT_LIST_HEAD(&resampler->list); | |
372 | resampler->notifier.gsi = irqfd->gsi; | |
373 | resampler->notifier.irq_acked = irqfd_resampler_ack; | |
374 | INIT_LIST_HEAD(&resampler->link); | |
375 | ||
376 | list_add(&resampler->link, &kvm->irqfds.resampler_list); | |
377 | kvm_register_irq_ack_notifier(kvm, | |
378 | &resampler->notifier); | |
379 | irqfd->resampler = resampler; | |
380 | } | |
381 | ||
382 | list_add_rcu(&irqfd->resampler_link, &irqfd->resampler->list); | |
719d93cd | 383 | synchronize_srcu(&kvm->irq_srcu); |
7a84428a AW |
384 | |
385 | mutex_unlock(&kvm->irqfds.resampler_lock); | |
386 | } | |
387 | ||
721eecbf GH |
388 | /* |
389 | * Install our own custom wake-up handling so we are notified via | |
390 | * a callback whenever someone signals the underlying eventfd | |
391 | */ | |
392 | init_waitqueue_func_entry(&irqfd->wait, irqfd_wakeup); | |
393 | init_poll_funcptr(&irqfd->pt, irqfd_ptable_queue_proc); | |
394 | ||
f1d1c309 MT |
395 | spin_lock_irq(&kvm->irqfds.lock); |
396 | ||
397 | ret = 0; | |
398 | list_for_each_entry(tmp, &kvm->irqfds.items, list) { | |
399 | if (irqfd->eventfd != tmp->eventfd) | |
400 | continue; | |
401 | /* This fd is used for another irq already. */ | |
402 | ret = -EBUSY; | |
403 | spin_unlock_irq(&kvm->irqfds.lock); | |
404 | goto fail; | |
405 | } | |
406 | ||
9957c86d PM |
407 | idx = srcu_read_lock(&kvm->irq_srcu); |
408 | irqfd_update(kvm, irqfd); | |
409 | srcu_read_unlock(&kvm->irq_srcu, idx); | |
bd2b53b2 | 410 | |
721eecbf | 411 | list_add_tail(&irqfd->list, &kvm->irqfds.items); |
721eecbf | 412 | |
684a0b71 CH |
413 | spin_unlock_irq(&kvm->irqfds.lock); |
414 | ||
721eecbf GH |
415 | /* |
416 | * Check if there was an event already pending on the eventfd | |
417 | * before we registered, and trigger it as if we didn't miss it. | |
418 | */ | |
684a0b71 CH |
419 | events = f.file->f_op->poll(f.file, &irqfd->pt); |
420 | ||
721eecbf GH |
421 | if (events & POLLIN) |
422 | schedule_work(&irqfd->inject); | |
423 | ||
424 | /* | |
425 | * do not drop the file until the irqfd is fully initialized, otherwise | |
426 | * we might race against the POLLHUP | |
427 | */ | |
cffe78d9 | 428 | fdput(f); |
721eecbf GH |
429 | |
430 | return 0; | |
431 | ||
432 | fail: | |
7a84428a AW |
433 | if (irqfd->resampler) |
434 | irqfd_resampler_shutdown(irqfd); | |
435 | ||
436 | if (resamplefd && !IS_ERR(resamplefd)) | |
437 | eventfd_ctx_put(resamplefd); | |
438 | ||
721eecbf GH |
439 | if (eventfd && !IS_ERR(eventfd)) |
440 | eventfd_ctx_put(eventfd); | |
441 | ||
cffe78d9 | 442 | fdput(f); |
721eecbf | 443 | |
cffe78d9 | 444 | out: |
721eecbf GH |
445 | kfree(irqfd); |
446 | return ret; | |
447 | } | |
c77dcacb PB |
448 | |
449 | bool kvm_irq_has_notifier(struct kvm *kvm, unsigned irqchip, unsigned pin) | |
450 | { | |
451 | struct kvm_irq_ack_notifier *kian; | |
452 | int gsi, idx; | |
453 | ||
454 | idx = srcu_read_lock(&kvm->irq_srcu); | |
455 | gsi = kvm_irq_map_chip_pin(kvm, irqchip, pin); | |
456 | if (gsi != -1) | |
457 | hlist_for_each_entry_rcu(kian, &kvm->irq_ack_notifier_list, | |
458 | link) | |
459 | if (kian->gsi == gsi) { | |
460 | srcu_read_unlock(&kvm->irq_srcu, idx); | |
461 | return true; | |
462 | } | |
463 | ||
464 | srcu_read_unlock(&kvm->irq_srcu, idx); | |
465 | ||
466 | return false; | |
467 | } | |
468 | EXPORT_SYMBOL_GPL(kvm_irq_has_notifier); | |
469 | ||
470 | void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin) | |
471 | { | |
472 | struct kvm_irq_ack_notifier *kian; | |
473 | int gsi, idx; | |
474 | ||
475 | trace_kvm_ack_irq(irqchip, pin); | |
476 | ||
477 | idx = srcu_read_lock(&kvm->irq_srcu); | |
478 | gsi = kvm_irq_map_chip_pin(kvm, irqchip, pin); | |
479 | if (gsi != -1) | |
480 | hlist_for_each_entry_rcu(kian, &kvm->irq_ack_notifier_list, | |
481 | link) | |
482 | if (kian->gsi == gsi) | |
483 | kian->irq_acked(kian); | |
484 | srcu_read_unlock(&kvm->irq_srcu, idx); | |
485 | } | |
486 | ||
487 | void kvm_register_irq_ack_notifier(struct kvm *kvm, | |
488 | struct kvm_irq_ack_notifier *kian) | |
489 | { | |
490 | mutex_lock(&kvm->irq_lock); | |
491 | hlist_add_head_rcu(&kian->link, &kvm->irq_ack_notifier_list); | |
492 | mutex_unlock(&kvm->irq_lock); | |
493 | #ifdef __KVM_HAVE_IOAPIC | |
494 | kvm_vcpu_request_scan_ioapic(kvm); | |
495 | #endif | |
496 | } | |
497 | ||
498 | void kvm_unregister_irq_ack_notifier(struct kvm *kvm, | |
499 | struct kvm_irq_ack_notifier *kian) | |
500 | { | |
501 | mutex_lock(&kvm->irq_lock); | |
502 | hlist_del_init_rcu(&kian->link); | |
503 | mutex_unlock(&kvm->irq_lock); | |
504 | synchronize_srcu(&kvm->irq_srcu); | |
505 | #ifdef __KVM_HAVE_IOAPIC | |
506 | kvm_vcpu_request_scan_ioapic(kvm); | |
507 | #endif | |
508 | } | |
914daba8 | 509 | #endif |
721eecbf GH |
510 | |
511 | void | |
d34e6b17 | 512 | kvm_eventfd_init(struct kvm *kvm) |
721eecbf | 513 | { |
297e2105 | 514 | #ifdef CONFIG_HAVE_KVM_IRQFD |
721eecbf GH |
515 | spin_lock_init(&kvm->irqfds.lock); |
516 | INIT_LIST_HEAD(&kvm->irqfds.items); | |
7a84428a AW |
517 | INIT_LIST_HEAD(&kvm->irqfds.resampler_list); |
518 | mutex_init(&kvm->irqfds.resampler_lock); | |
914daba8 | 519 | #endif |
d34e6b17 | 520 | INIT_LIST_HEAD(&kvm->ioeventfds); |
721eecbf GH |
521 | } |
522 | ||
297e2105 | 523 | #ifdef CONFIG_HAVE_KVM_IRQFD |
721eecbf GH |
524 | /* |
525 | * shutdown any irqfd's that match fd+gsi | |
526 | */ | |
527 | static int | |
d4db2935 | 528 | kvm_irqfd_deassign(struct kvm *kvm, struct kvm_irqfd *args) |
721eecbf GH |
529 | { |
530 | struct _irqfd *irqfd, *tmp; | |
531 | struct eventfd_ctx *eventfd; | |
532 | ||
d4db2935 | 533 | eventfd = eventfd_ctx_fdget(args->fd); |
721eecbf GH |
534 | if (IS_ERR(eventfd)) |
535 | return PTR_ERR(eventfd); | |
536 | ||
537 | spin_lock_irq(&kvm->irqfds.lock); | |
538 | ||
539 | list_for_each_entry_safe(irqfd, tmp, &kvm->irqfds.items, list) { | |
d4db2935 | 540 | if (irqfd->eventfd == eventfd && irqfd->gsi == args->gsi) { |
bd2b53b2 | 541 | /* |
56f89f36 | 542 | * This clearing of irq_entry.type is needed for when |
c8ce057e MT |
543 | * another thread calls kvm_irq_routing_update before |
544 | * we flush workqueue below (we synchronize with | |
545 | * kvm_irq_routing_update using irqfds.lock). | |
bd2b53b2 | 546 | */ |
56f89f36 PM |
547 | write_seqcount_begin(&irqfd->irq_entry_sc); |
548 | irqfd->irq_entry.type = 0; | |
549 | write_seqcount_end(&irqfd->irq_entry_sc); | |
721eecbf | 550 | irqfd_deactivate(irqfd); |
bd2b53b2 | 551 | } |
721eecbf GH |
552 | } |
553 | ||
554 | spin_unlock_irq(&kvm->irqfds.lock); | |
555 | eventfd_ctx_put(eventfd); | |
556 | ||
557 | /* | |
558 | * Block until we know all outstanding shutdown jobs have completed | |
559 | * so that we guarantee there will not be any more interrupts on this | |
560 | * gsi once this deassign function returns. | |
561 | */ | |
562 | flush_workqueue(irqfd_cleanup_wq); | |
563 | ||
564 | return 0; | |
565 | } | |
566 | ||
567 | int | |
d4db2935 | 568 | kvm_irqfd(struct kvm *kvm, struct kvm_irqfd *args) |
721eecbf | 569 | { |
7a84428a | 570 | if (args->flags & ~(KVM_IRQFD_FLAG_DEASSIGN | KVM_IRQFD_FLAG_RESAMPLE)) |
326cf033 AW |
571 | return -EINVAL; |
572 | ||
d4db2935 AW |
573 | if (args->flags & KVM_IRQFD_FLAG_DEASSIGN) |
574 | return kvm_irqfd_deassign(kvm, args); | |
721eecbf | 575 | |
d4db2935 | 576 | return kvm_irqfd_assign(kvm, args); |
721eecbf GH |
577 | } |
578 | ||
579 | /* | |
580 | * This function is called as the kvm VM fd is being released. Shutdown all | |
581 | * irqfds that still remain open | |
582 | */ | |
583 | void | |
584 | kvm_irqfd_release(struct kvm *kvm) | |
585 | { | |
586 | struct _irqfd *irqfd, *tmp; | |
587 | ||
588 | spin_lock_irq(&kvm->irqfds.lock); | |
589 | ||
590 | list_for_each_entry_safe(irqfd, tmp, &kvm->irqfds.items, list) | |
591 | irqfd_deactivate(irqfd); | |
592 | ||
593 | spin_unlock_irq(&kvm->irqfds.lock); | |
594 | ||
595 | /* | |
596 | * Block until we know all outstanding shutdown jobs have completed | |
597 | * since we do not take a kvm* reference. | |
598 | */ | |
599 | flush_workqueue(irqfd_cleanup_wq); | |
600 | ||
601 | } | |
602 | ||
bd2b53b2 | 603 | /* |
9957c86d | 604 | * Take note of a change in irq routing. |
719d93cd | 605 | * Caller must invoke synchronize_srcu(&kvm->irq_srcu) afterwards. |
bd2b53b2 | 606 | */ |
9957c86d | 607 | void kvm_irq_routing_update(struct kvm *kvm) |
bd2b53b2 MT |
608 | { |
609 | struct _irqfd *irqfd; | |
610 | ||
611 | spin_lock_irq(&kvm->irqfds.lock); | |
612 | ||
bd2b53b2 | 613 | list_for_each_entry(irqfd, &kvm->irqfds.items, list) |
9957c86d | 614 | irqfd_update(kvm, irqfd); |
bd2b53b2 MT |
615 | |
616 | spin_unlock_irq(&kvm->irqfds.lock); | |
617 | } | |
618 | ||
721eecbf GH |
619 | /* |
620 | * create a host-wide workqueue for issuing deferred shutdown requests | |
621 | * aggregated from all vm* instances. We need our own isolated single-thread | |
622 | * queue to prevent deadlock against flushing the normal work-queue. | |
623 | */ | |
a0f155e9 | 624 | int kvm_irqfd_init(void) |
721eecbf GH |
625 | { |
626 | irqfd_cleanup_wq = create_singlethread_workqueue("kvm-irqfd-cleanup"); | |
627 | if (!irqfd_cleanup_wq) | |
628 | return -ENOMEM; | |
629 | ||
630 | return 0; | |
631 | } | |
632 | ||
a0f155e9 | 633 | void kvm_irqfd_exit(void) |
721eecbf GH |
634 | { |
635 | destroy_workqueue(irqfd_cleanup_wq); | |
636 | } | |
914daba8 | 637 | #endif |
d34e6b17 GH |
638 | |
639 | /* | |
640 | * -------------------------------------------------------------------- | |
641 | * ioeventfd: translate a PIO/MMIO memory write to an eventfd signal. | |
642 | * | |
643 | * userspace can register a PIO/MMIO address with an eventfd for receiving | |
644 | * notification when the memory has been touched. | |
645 | * -------------------------------------------------------------------- | |
646 | */ | |
647 | ||
648 | struct _ioeventfd { | |
649 | struct list_head list; | |
650 | u64 addr; | |
651 | int length; | |
652 | struct eventfd_ctx *eventfd; | |
653 | u64 datamatch; | |
654 | struct kvm_io_device dev; | |
05e07f9b | 655 | u8 bus_idx; |
d34e6b17 GH |
656 | bool wildcard; |
657 | }; | |
658 | ||
659 | static inline struct _ioeventfd * | |
660 | to_ioeventfd(struct kvm_io_device *dev) | |
661 | { | |
662 | return container_of(dev, struct _ioeventfd, dev); | |
663 | } | |
664 | ||
665 | static void | |
666 | ioeventfd_release(struct _ioeventfd *p) | |
667 | { | |
668 | eventfd_ctx_put(p->eventfd); | |
669 | list_del(&p->list); | |
670 | kfree(p); | |
671 | } | |
672 | ||
673 | static bool | |
674 | ioeventfd_in_range(struct _ioeventfd *p, gpa_t addr, int len, const void *val) | |
675 | { | |
676 | u64 _val; | |
677 | ||
f848a5a8 MT |
678 | if (addr != p->addr) |
679 | /* address must be precise for a hit */ | |
680 | return false; | |
681 | ||
682 | if (!p->length) | |
683 | /* length = 0 means only look at the address, so always a hit */ | |
684 | return true; | |
685 | ||
686 | if (len != p->length) | |
d34e6b17 GH |
687 | /* address-range must be precise for a hit */ |
688 | return false; | |
689 | ||
690 | if (p->wildcard) | |
691 | /* all else equal, wildcard is always a hit */ | |
692 | return true; | |
693 | ||
694 | /* otherwise, we have to actually compare the data */ | |
695 | ||
696 | BUG_ON(!IS_ALIGNED((unsigned long)val, len)); | |
697 | ||
698 | switch (len) { | |
699 | case 1: | |
700 | _val = *(u8 *)val; | |
701 | break; | |
702 | case 2: | |
703 | _val = *(u16 *)val; | |
704 | break; | |
705 | case 4: | |
706 | _val = *(u32 *)val; | |
707 | break; | |
708 | case 8: | |
709 | _val = *(u64 *)val; | |
710 | break; | |
711 | default: | |
712 | return false; | |
713 | } | |
714 | ||
715 | return _val == p->datamatch ? true : false; | |
716 | } | |
717 | ||
718 | /* MMIO/PIO writes trigger an event if the addr/val match */ | |
719 | static int | |
720 | ioeventfd_write(struct kvm_io_device *this, gpa_t addr, int len, | |
721 | const void *val) | |
722 | { | |
723 | struct _ioeventfd *p = to_ioeventfd(this); | |
724 | ||
725 | if (!ioeventfd_in_range(p, addr, len, val)) | |
726 | return -EOPNOTSUPP; | |
727 | ||
728 | eventfd_signal(p->eventfd, 1); | |
729 | return 0; | |
730 | } | |
731 | ||
732 | /* | |
733 | * This function is called as KVM is completely shutting down. We do not | |
734 | * need to worry about locking just nuke anything we have as quickly as possible | |
735 | */ | |
736 | static void | |
737 | ioeventfd_destructor(struct kvm_io_device *this) | |
738 | { | |
739 | struct _ioeventfd *p = to_ioeventfd(this); | |
740 | ||
741 | ioeventfd_release(p); | |
742 | } | |
743 | ||
744 | static const struct kvm_io_device_ops ioeventfd_ops = { | |
745 | .write = ioeventfd_write, | |
746 | .destructor = ioeventfd_destructor, | |
747 | }; | |
748 | ||
749 | /* assumes kvm->slots_lock held */ | |
750 | static bool | |
751 | ioeventfd_check_collision(struct kvm *kvm, struct _ioeventfd *p) | |
752 | { | |
753 | struct _ioeventfd *_p; | |
754 | ||
755 | list_for_each_entry(_p, &kvm->ioeventfds, list) | |
05e07f9b | 756 | if (_p->bus_idx == p->bus_idx && |
f848a5a8 MT |
757 | _p->addr == p->addr && |
758 | (!_p->length || !p->length || | |
759 | (_p->length == p->length && | |
760 | (_p->wildcard || p->wildcard || | |
761 | _p->datamatch == p->datamatch)))) | |
d34e6b17 GH |
762 | return true; |
763 | ||
764 | return false; | |
765 | } | |
766 | ||
2b83451b CH |
767 | static enum kvm_bus ioeventfd_bus_from_flags(__u32 flags) |
768 | { | |
769 | if (flags & KVM_IOEVENTFD_FLAG_PIO) | |
770 | return KVM_PIO_BUS; | |
771 | if (flags & KVM_IOEVENTFD_FLAG_VIRTIO_CCW_NOTIFY) | |
772 | return KVM_VIRTIO_CCW_NOTIFY_BUS; | |
773 | return KVM_MMIO_BUS; | |
774 | } | |
775 | ||
d34e6b17 GH |
776 | static int |
777 | kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args) | |
778 | { | |
2b83451b | 779 | enum kvm_bus bus_idx; |
d34e6b17 GH |
780 | struct _ioeventfd *p; |
781 | struct eventfd_ctx *eventfd; | |
782 | int ret; | |
783 | ||
2b83451b | 784 | bus_idx = ioeventfd_bus_from_flags(args->flags); |
f848a5a8 | 785 | /* must be natural-word sized, or 0 to ignore length */ |
d34e6b17 | 786 | switch (args->len) { |
f848a5a8 | 787 | case 0: |
d34e6b17 GH |
788 | case 1: |
789 | case 2: | |
790 | case 4: | |
791 | case 8: | |
792 | break; | |
793 | default: | |
794 | return -EINVAL; | |
795 | } | |
796 | ||
797 | /* check for range overflow */ | |
798 | if (args->addr + args->len < args->addr) | |
799 | return -EINVAL; | |
800 | ||
801 | /* check for extra flags that we don't understand */ | |
802 | if (args->flags & ~KVM_IOEVENTFD_VALID_FLAG_MASK) | |
803 | return -EINVAL; | |
804 | ||
f848a5a8 MT |
805 | /* ioeventfd with no length can't be combined with DATAMATCH */ |
806 | if (!args->len && | |
807 | args->flags & (KVM_IOEVENTFD_FLAG_PIO | | |
808 | KVM_IOEVENTFD_FLAG_DATAMATCH)) | |
809 | return -EINVAL; | |
810 | ||
d34e6b17 GH |
811 | eventfd = eventfd_ctx_fdget(args->fd); |
812 | if (IS_ERR(eventfd)) | |
813 | return PTR_ERR(eventfd); | |
814 | ||
815 | p = kzalloc(sizeof(*p), GFP_KERNEL); | |
816 | if (!p) { | |
817 | ret = -ENOMEM; | |
818 | goto fail; | |
819 | } | |
820 | ||
821 | INIT_LIST_HEAD(&p->list); | |
822 | p->addr = args->addr; | |
05e07f9b | 823 | p->bus_idx = bus_idx; |
d34e6b17 GH |
824 | p->length = args->len; |
825 | p->eventfd = eventfd; | |
826 | ||
827 | /* The datamatch feature is optional, otherwise this is a wildcard */ | |
828 | if (args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH) | |
829 | p->datamatch = args->datamatch; | |
830 | else | |
831 | p->wildcard = true; | |
832 | ||
79fac95e | 833 | mutex_lock(&kvm->slots_lock); |
d34e6b17 | 834 | |
25985edc | 835 | /* Verify that there isn't a match already */ |
d34e6b17 GH |
836 | if (ioeventfd_check_collision(kvm, p)) { |
837 | ret = -EEXIST; | |
838 | goto unlock_fail; | |
839 | } | |
840 | ||
841 | kvm_iodevice_init(&p->dev, &ioeventfd_ops); | |
842 | ||
743eeb0b SL |
843 | ret = kvm_io_bus_register_dev(kvm, bus_idx, p->addr, p->length, |
844 | &p->dev); | |
d34e6b17 GH |
845 | if (ret < 0) |
846 | goto unlock_fail; | |
847 | ||
68c3b4d1 MT |
848 | /* When length is ignored, MMIO is also put on a separate bus, for |
849 | * faster lookups. | |
850 | */ | |
851 | if (!args->len && !(args->flags & KVM_IOEVENTFD_FLAG_PIO)) { | |
852 | ret = kvm_io_bus_register_dev(kvm, KVM_FAST_MMIO_BUS, | |
853 | p->addr, 0, &p->dev); | |
854 | if (ret < 0) | |
855 | goto register_fail; | |
856 | } | |
857 | ||
6ea34c9b | 858 | kvm->buses[bus_idx]->ioeventfd_count++; |
d34e6b17 GH |
859 | list_add_tail(&p->list, &kvm->ioeventfds); |
860 | ||
79fac95e | 861 | mutex_unlock(&kvm->slots_lock); |
d34e6b17 GH |
862 | |
863 | return 0; | |
864 | ||
68c3b4d1 MT |
865 | register_fail: |
866 | kvm_io_bus_unregister_dev(kvm, bus_idx, &p->dev); | |
d34e6b17 | 867 | unlock_fail: |
79fac95e | 868 | mutex_unlock(&kvm->slots_lock); |
d34e6b17 GH |
869 | |
870 | fail: | |
871 | kfree(p); | |
872 | eventfd_ctx_put(eventfd); | |
873 | ||
874 | return ret; | |
875 | } | |
876 | ||
877 | static int | |
878 | kvm_deassign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args) | |
879 | { | |
2b83451b | 880 | enum kvm_bus bus_idx; |
d34e6b17 GH |
881 | struct _ioeventfd *p, *tmp; |
882 | struct eventfd_ctx *eventfd; | |
883 | int ret = -ENOENT; | |
884 | ||
2b83451b | 885 | bus_idx = ioeventfd_bus_from_flags(args->flags); |
d34e6b17 GH |
886 | eventfd = eventfd_ctx_fdget(args->fd); |
887 | if (IS_ERR(eventfd)) | |
888 | return PTR_ERR(eventfd); | |
889 | ||
79fac95e | 890 | mutex_lock(&kvm->slots_lock); |
d34e6b17 GH |
891 | |
892 | list_for_each_entry_safe(p, tmp, &kvm->ioeventfds, list) { | |
893 | bool wildcard = !(args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH); | |
894 | ||
05e07f9b MT |
895 | if (p->bus_idx != bus_idx || |
896 | p->eventfd != eventfd || | |
d34e6b17 GH |
897 | p->addr != args->addr || |
898 | p->length != args->len || | |
899 | p->wildcard != wildcard) | |
900 | continue; | |
901 | ||
902 | if (!p->wildcard && p->datamatch != args->datamatch) | |
903 | continue; | |
904 | ||
e93f8a0f | 905 | kvm_io_bus_unregister_dev(kvm, bus_idx, &p->dev); |
68c3b4d1 MT |
906 | if (!p->length) { |
907 | kvm_io_bus_unregister_dev(kvm, KVM_FAST_MMIO_BUS, | |
908 | &p->dev); | |
909 | } | |
6ea34c9b | 910 | kvm->buses[bus_idx]->ioeventfd_count--; |
d34e6b17 GH |
911 | ioeventfd_release(p); |
912 | ret = 0; | |
913 | break; | |
914 | } | |
915 | ||
79fac95e | 916 | mutex_unlock(&kvm->slots_lock); |
d34e6b17 GH |
917 | |
918 | eventfd_ctx_put(eventfd); | |
919 | ||
920 | return ret; | |
921 | } | |
922 | ||
923 | int | |
924 | kvm_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args) | |
925 | { | |
926 | if (args->flags & KVM_IOEVENTFD_FLAG_DEASSIGN) | |
927 | return kvm_deassign_ioeventfd(kvm, args); | |
928 | ||
929 | return kvm_assign_ioeventfd(kvm, args); | |
930 | } |