Commit | Line | Data |
---|---|---|
775c8a3d | 1 | // SPDX-License-Identifier: GPL-2.0-only |
721eecbf GH |
2 | /* |
3 | * kvm eventfd support - use eventfd objects to signal various KVM events | |
4 | * | |
5 | * Copyright 2009 Novell. All Rights Reserved. | |
221d059d | 6 | * Copyright 2010 Red Hat, Inc. and/or its affiliates. |
721eecbf GH |
7 | * |
8 | * Author: | |
9 | * Gregory Haskins <ghaskins@novell.com> | |
721eecbf GH |
10 | */ |
11 | ||
12 | #include <linux/kvm_host.h> | |
d34e6b17 | 13 | #include <linux/kvm.h> |
166c9775 | 14 | #include <linux/kvm_irqfd.h> |
721eecbf GH |
15 | #include <linux/workqueue.h> |
16 | #include <linux/syscalls.h> | |
17 | #include <linux/wait.h> | |
18 | #include <linux/poll.h> | |
19 | #include <linux/file.h> | |
20 | #include <linux/list.h> | |
21 | #include <linux/eventfd.h> | |
d34e6b17 | 22 | #include <linux/kernel.h> |
719d93cd | 23 | #include <linux/srcu.h> |
5a0e3ad6 | 24 | #include <linux/slab.h> |
56f89f36 | 25 | #include <linux/seqlock.h> |
9016cfb5 | 26 | #include <linux/irqbypass.h> |
e4d57e1e | 27 | #include <trace/events/kvm.h> |
d34e6b17 | 28 | |
af669ac6 | 29 | #include <kvm/iodev.h> |
721eecbf | 30 | |
297e2105 | 31 | #ifdef CONFIG_HAVE_KVM_IRQFD |
721eecbf | 32 | |
36343f6e | 33 | static struct workqueue_struct *irqfd_cleanup_wq; |
721eecbf | 34 | |
654f1f13 PX |
35 | bool __attribute__((weak)) |
36 | kvm_arch_irqfd_allowed(struct kvm *kvm, struct kvm_irqfd *args) | |
37 | { | |
38 | return true; | |
39 | } | |
40 | ||
721eecbf GH |
41 | static void |
42 | irqfd_inject(struct work_struct *work) | |
43 | { | |
166c9775 EA |
44 | struct kvm_kernel_irqfd *irqfd = |
45 | container_of(work, struct kvm_kernel_irqfd, inject); | |
721eecbf GH |
46 | struct kvm *kvm = irqfd->kvm; |
47 | ||
7a84428a | 48 | if (!irqfd->resampler) { |
aa2fbe6d YZ |
49 | kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 1, |
50 | false); | |
51 | kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 0, | |
52 | false); | |
7a84428a AW |
53 | } else |
54 | kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID, | |
aa2fbe6d | 55 | irqfd->gsi, 1, false); |
7a84428a AW |
56 | } |
57 | ||
58 | /* | |
59 | * Since resampler irqfds share an IRQ source ID, we de-assert once | |
60 | * then notify all of the resampler irqfds using this GSI. We can't | |
61 | * do multiple de-asserts or we risk racing with incoming re-asserts. | |
62 | */ | |
63 | static void | |
64 | irqfd_resampler_ack(struct kvm_irq_ack_notifier *kian) | |
65 | { | |
166c9775 | 66 | struct kvm_kernel_irqfd_resampler *resampler; |
719d93cd | 67 | struct kvm *kvm; |
166c9775 | 68 | struct kvm_kernel_irqfd *irqfd; |
719d93cd | 69 | int idx; |
7a84428a | 70 | |
166c9775 EA |
71 | resampler = container_of(kian, |
72 | struct kvm_kernel_irqfd_resampler, notifier); | |
719d93cd | 73 | kvm = resampler->kvm; |
7a84428a | 74 | |
719d93cd | 75 | kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID, |
aa2fbe6d | 76 | resampler->notifier.gsi, 0, false); |
7a84428a | 77 | |
719d93cd | 78 | idx = srcu_read_lock(&kvm->irq_srcu); |
7a84428a AW |
79 | |
80 | list_for_each_entry_rcu(irqfd, &resampler->list, resampler_link) | |
81 | eventfd_signal(irqfd->resamplefd, 1); | |
82 | ||
719d93cd | 83 | srcu_read_unlock(&kvm->irq_srcu, idx); |
7a84428a AW |
84 | } |
85 | ||
86 | static void | |
166c9775 | 87 | irqfd_resampler_shutdown(struct kvm_kernel_irqfd *irqfd) |
7a84428a | 88 | { |
166c9775 | 89 | struct kvm_kernel_irqfd_resampler *resampler = irqfd->resampler; |
7a84428a AW |
90 | struct kvm *kvm = resampler->kvm; |
91 | ||
92 | mutex_lock(&kvm->irqfds.resampler_lock); | |
93 | ||
94 | list_del_rcu(&irqfd->resampler_link); | |
719d93cd | 95 | synchronize_srcu(&kvm->irq_srcu); |
7a84428a AW |
96 | |
97 | if (list_empty(&resampler->list)) { | |
98 | list_del(&resampler->link); | |
99 | kvm_unregister_irq_ack_notifier(kvm, &resampler->notifier); | |
100 | kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID, | |
aa2fbe6d | 101 | resampler->notifier.gsi, 0, false); |
7a84428a AW |
102 | kfree(resampler); |
103 | } | |
104 | ||
105 | mutex_unlock(&kvm->irqfds.resampler_lock); | |
721eecbf GH |
106 | } |
107 | ||
108 | /* | |
109 | * Race-free decouple logic (ordering is critical) | |
110 | */ | |
111 | static void | |
112 | irqfd_shutdown(struct work_struct *work) | |
113 | { | |
166c9775 EA |
114 | struct kvm_kernel_irqfd *irqfd = |
115 | container_of(work, struct kvm_kernel_irqfd, shutdown); | |
b5020a8e | 116 | struct kvm *kvm = irqfd->kvm; |
b6a114d2 | 117 | u64 cnt; |
721eecbf | 118 | |
b5020a8e LT |
119 | /* Make sure irqfd has been initalized in assign path. */ |
120 | synchronize_srcu(&kvm->irq_srcu); | |
121 | ||
721eecbf GH |
122 | /* |
123 | * Synchronize with the wait-queue and unhook ourselves to prevent | |
124 | * further events. | |
125 | */ | |
b6a114d2 | 126 | eventfd_ctx_remove_wait_queue(irqfd->eventfd, &irqfd->wait, &cnt); |
721eecbf GH |
127 | |
128 | /* | |
129 | * We know no new events will be scheduled at this point, so block | |
130 | * until all previously outstanding events have completed | |
131 | */ | |
43829731 | 132 | flush_work(&irqfd->inject); |
721eecbf | 133 | |
7a84428a AW |
134 | if (irqfd->resampler) { |
135 | irqfd_resampler_shutdown(irqfd); | |
136 | eventfd_ctx_put(irqfd->resamplefd); | |
137 | } | |
138 | ||
721eecbf GH |
139 | /* |
140 | * It is now safe to release the object's resources | |
141 | */ | |
9016cfb5 EA |
142 | #ifdef CONFIG_HAVE_KVM_IRQ_BYPASS |
143 | irq_bypass_unregister_consumer(&irqfd->consumer); | |
144 | #endif | |
721eecbf GH |
145 | eventfd_ctx_put(irqfd->eventfd); |
146 | kfree(irqfd); | |
147 | } | |
148 | ||
149 | ||
150 | /* assumes kvm->irqfds.lock is held */ | |
151 | static bool | |
166c9775 | 152 | irqfd_is_active(struct kvm_kernel_irqfd *irqfd) |
721eecbf GH |
153 | { |
154 | return list_empty(&irqfd->list) ? false : true; | |
155 | } | |
156 | ||
157 | /* | |
158 | * Mark the irqfd as inactive and schedule it for removal | |
159 | * | |
160 | * assumes kvm->irqfds.lock is held | |
161 | */ | |
162 | static void | |
166c9775 | 163 | irqfd_deactivate(struct kvm_kernel_irqfd *irqfd) |
721eecbf GH |
164 | { |
165 | BUG_ON(!irqfd_is_active(irqfd)); | |
166 | ||
167 | list_del_init(&irqfd->list); | |
168 | ||
36343f6e | 169 | queue_work(irqfd_cleanup_wq, &irqfd->shutdown); |
721eecbf GH |
170 | } |
171 | ||
b97e6de9 | 172 | int __attribute__((weak)) kvm_arch_set_irq_inatomic( |
c9a5ecca AS |
173 | struct kvm_kernel_irq_routing_entry *irq, |
174 | struct kvm *kvm, int irq_source_id, | |
175 | int level, | |
176 | bool line_status) | |
177 | { | |
178 | return -EWOULDBLOCK; | |
179 | } | |
180 | ||
721eecbf GH |
181 | /* |
182 | * Called with wqh->lock held and interrupts disabled | |
183 | */ | |
184 | static int | |
ac6424b9 | 185 | irqfd_wakeup(wait_queue_entry_t *wait, unsigned mode, int sync, void *key) |
721eecbf | 186 | { |
166c9775 EA |
187 | struct kvm_kernel_irqfd *irqfd = |
188 | container_of(wait, struct kvm_kernel_irqfd, wait); | |
3ad6f93e | 189 | __poll_t flags = key_to_poll(key); |
56f89f36 | 190 | struct kvm_kernel_irq_routing_entry irq; |
bd2b53b2 | 191 | struct kvm *kvm = irqfd->kvm; |
56f89f36 | 192 | unsigned seq; |
719d93cd | 193 | int idx; |
721eecbf | 194 | |
a9a08845 | 195 | if (flags & EPOLLIN) { |
719d93cd | 196 | idx = srcu_read_lock(&kvm->irq_srcu); |
56f89f36 PM |
197 | do { |
198 | seq = read_seqcount_begin(&irqfd->irq_entry_sc); | |
199 | irq = irqfd->irq_entry; | |
200 | } while (read_seqcount_retry(&irqfd->irq_entry_sc, seq)); | |
721eecbf | 201 | /* An event has been signaled, inject an interrupt */ |
b97e6de9 PB |
202 | if (kvm_arch_set_irq_inatomic(&irq, kvm, |
203 | KVM_USERSPACE_IRQ_SOURCE_ID, 1, | |
204 | false) == -EWOULDBLOCK) | |
bd2b53b2 | 205 | schedule_work(&irqfd->inject); |
719d93cd | 206 | srcu_read_unlock(&kvm->irq_srcu, idx); |
bd2b53b2 | 207 | } |
721eecbf | 208 | |
a9a08845 | 209 | if (flags & EPOLLHUP) { |
721eecbf | 210 | /* The eventfd is closing, detach from KVM */ |
ca0488aa | 211 | unsigned long iflags; |
721eecbf | 212 | |
ca0488aa | 213 | spin_lock_irqsave(&kvm->irqfds.lock, iflags); |
721eecbf GH |
214 | |
215 | /* | |
216 | * We must check if someone deactivated the irqfd before | |
217 | * we could acquire the irqfds.lock since the item is | |
218 | * deactivated from the KVM side before it is unhooked from | |
219 | * the wait-queue. If it is already deactivated, we can | |
220 | * simply return knowing the other side will cleanup for us. | |
221 | * We cannot race against the irqfd going away since the | |
222 | * other side is required to acquire wqh->lock, which we hold | |
223 | */ | |
224 | if (irqfd_is_active(irqfd)) | |
225 | irqfd_deactivate(irqfd); | |
226 | ||
ca0488aa | 227 | spin_unlock_irqrestore(&kvm->irqfds.lock, iflags); |
721eecbf GH |
228 | } |
229 | ||
230 | return 0; | |
231 | } | |
232 | ||
233 | static void | |
234 | irqfd_ptable_queue_proc(struct file *file, wait_queue_head_t *wqh, | |
235 | poll_table *pt) | |
236 | { | |
166c9775 EA |
237 | struct kvm_kernel_irqfd *irqfd = |
238 | container_of(pt, struct kvm_kernel_irqfd, pt); | |
721eecbf GH |
239 | add_wait_queue(wqh, &irqfd->wait); |
240 | } | |
241 | ||
bd2b53b2 | 242 | /* Must be called under irqfds.lock */ |
166c9775 | 243 | static void irqfd_update(struct kvm *kvm, struct kvm_kernel_irqfd *irqfd) |
bd2b53b2 MT |
244 | { |
245 | struct kvm_kernel_irq_routing_entry *e; | |
8ba918d4 | 246 | struct kvm_kernel_irq_routing_entry entries[KVM_NR_IRQCHIPS]; |
351dc647 | 247 | int n_entries; |
8ba918d4 | 248 | |
9957c86d | 249 | n_entries = kvm_irq_map_gsi(kvm, entries, irqfd->gsi); |
bd2b53b2 | 250 | |
56f89f36 PM |
251 | write_seqcount_begin(&irqfd->irq_entry_sc); |
252 | ||
8ba918d4 | 253 | e = entries; |
351dc647 AS |
254 | if (n_entries == 1) |
255 | irqfd->irq_entry = *e; | |
256 | else | |
257 | irqfd->irq_entry.type = 0; | |
56f89f36 | 258 | |
56f89f36 | 259 | write_seqcount_end(&irqfd->irq_entry_sc); |
bd2b53b2 MT |
260 | } |
261 | ||
1a02b270 EA |
262 | #ifdef CONFIG_HAVE_KVM_IRQ_BYPASS |
263 | void __attribute__((weak)) kvm_arch_irq_bypass_stop( | |
264 | struct irq_bypass_consumer *cons) | |
265 | { | |
266 | } | |
267 | ||
268 | void __attribute__((weak)) kvm_arch_irq_bypass_start( | |
269 | struct irq_bypass_consumer *cons) | |
270 | { | |
271 | } | |
f70c20aa FW |
272 | |
273 | int __attribute__((weak)) kvm_arch_update_irqfd_routing( | |
274 | struct kvm *kvm, unsigned int host_irq, | |
275 | uint32_t guest_irq, bool set) | |
276 | { | |
277 | return 0; | |
278 | } | |
1a02b270 EA |
279 | #endif |
280 | ||
721eecbf | 281 | static int |
d4db2935 | 282 | kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args) |
721eecbf | 283 | { |
166c9775 | 284 | struct kvm_kernel_irqfd *irqfd, *tmp; |
cffe78d9 | 285 | struct fd f; |
7a84428a | 286 | struct eventfd_ctx *eventfd = NULL, *resamplefd = NULL; |
721eecbf | 287 | int ret; |
e6c8adca | 288 | __poll_t events; |
9957c86d | 289 | int idx; |
721eecbf | 290 | |
01c94e64 EA |
291 | if (!kvm_arch_intc_initialized(kvm)) |
292 | return -EAGAIN; | |
293 | ||
654f1f13 PX |
294 | if (!kvm_arch_irqfd_allowed(kvm, args)) |
295 | return -EINVAL; | |
296 | ||
b12ce36a | 297 | irqfd = kzalloc(sizeof(*irqfd), GFP_KERNEL_ACCOUNT); |
721eecbf GH |
298 | if (!irqfd) |
299 | return -ENOMEM; | |
300 | ||
301 | irqfd->kvm = kvm; | |
d4db2935 | 302 | irqfd->gsi = args->gsi; |
721eecbf GH |
303 | INIT_LIST_HEAD(&irqfd->list); |
304 | INIT_WORK(&irqfd->inject, irqfd_inject); | |
305 | INIT_WORK(&irqfd->shutdown, irqfd_shutdown); | |
56f89f36 | 306 | seqcount_init(&irqfd->irq_entry_sc); |
721eecbf | 307 | |
cffe78d9 AV |
308 | f = fdget(args->fd); |
309 | if (!f.file) { | |
310 | ret = -EBADF; | |
311 | goto out; | |
721eecbf GH |
312 | } |
313 | ||
cffe78d9 | 314 | eventfd = eventfd_ctx_fileget(f.file); |
721eecbf GH |
315 | if (IS_ERR(eventfd)) { |
316 | ret = PTR_ERR(eventfd); | |
317 | goto fail; | |
318 | } | |
319 | ||
320 | irqfd->eventfd = eventfd; | |
321 | ||
7a84428a | 322 | if (args->flags & KVM_IRQFD_FLAG_RESAMPLE) { |
166c9775 | 323 | struct kvm_kernel_irqfd_resampler *resampler; |
7a84428a AW |
324 | |
325 | resamplefd = eventfd_ctx_fdget(args->resamplefd); | |
326 | if (IS_ERR(resamplefd)) { | |
327 | ret = PTR_ERR(resamplefd); | |
328 | goto fail; | |
329 | } | |
330 | ||
331 | irqfd->resamplefd = resamplefd; | |
332 | INIT_LIST_HEAD(&irqfd->resampler_link); | |
333 | ||
334 | mutex_lock(&kvm->irqfds.resampler_lock); | |
335 | ||
336 | list_for_each_entry(resampler, | |
49f8a1a5 | 337 | &kvm->irqfds.resampler_list, link) { |
7a84428a AW |
338 | if (resampler->notifier.gsi == irqfd->gsi) { |
339 | irqfd->resampler = resampler; | |
340 | break; | |
341 | } | |
342 | } | |
343 | ||
344 | if (!irqfd->resampler) { | |
b12ce36a BG |
345 | resampler = kzalloc(sizeof(*resampler), |
346 | GFP_KERNEL_ACCOUNT); | |
7a84428a AW |
347 | if (!resampler) { |
348 | ret = -ENOMEM; | |
349 | mutex_unlock(&kvm->irqfds.resampler_lock); | |
350 | goto fail; | |
351 | } | |
352 | ||
353 | resampler->kvm = kvm; | |
354 | INIT_LIST_HEAD(&resampler->list); | |
355 | resampler->notifier.gsi = irqfd->gsi; | |
356 | resampler->notifier.irq_acked = irqfd_resampler_ack; | |
357 | INIT_LIST_HEAD(&resampler->link); | |
358 | ||
359 | list_add(&resampler->link, &kvm->irqfds.resampler_list); | |
360 | kvm_register_irq_ack_notifier(kvm, | |
361 | &resampler->notifier); | |
362 | irqfd->resampler = resampler; | |
363 | } | |
364 | ||
365 | list_add_rcu(&irqfd->resampler_link, &irqfd->resampler->list); | |
719d93cd | 366 | synchronize_srcu(&kvm->irq_srcu); |
7a84428a AW |
367 | |
368 | mutex_unlock(&kvm->irqfds.resampler_lock); | |
369 | } | |
370 | ||
721eecbf GH |
371 | /* |
372 | * Install our own custom wake-up handling so we are notified via | |
373 | * a callback whenever someone signals the underlying eventfd | |
374 | */ | |
375 | init_waitqueue_func_entry(&irqfd->wait, irqfd_wakeup); | |
376 | init_poll_funcptr(&irqfd->pt, irqfd_ptable_queue_proc); | |
377 | ||
f1d1c309 MT |
378 | spin_lock_irq(&kvm->irqfds.lock); |
379 | ||
380 | ret = 0; | |
381 | list_for_each_entry(tmp, &kvm->irqfds.items, list) { | |
382 | if (irqfd->eventfd != tmp->eventfd) | |
383 | continue; | |
384 | /* This fd is used for another irq already. */ | |
385 | ret = -EBUSY; | |
386 | spin_unlock_irq(&kvm->irqfds.lock); | |
387 | goto fail; | |
388 | } | |
389 | ||
9957c86d PM |
390 | idx = srcu_read_lock(&kvm->irq_srcu); |
391 | irqfd_update(kvm, irqfd); | |
bd2b53b2 | 392 | |
721eecbf | 393 | list_add_tail(&irqfd->list, &kvm->irqfds.items); |
721eecbf | 394 | |
684a0b71 CH |
395 | spin_unlock_irq(&kvm->irqfds.lock); |
396 | ||
721eecbf GH |
397 | /* |
398 | * Check if there was an event already pending on the eventfd | |
399 | * before we registered, and trigger it as if we didn't miss it. | |
400 | */ | |
9965ed17 | 401 | events = vfs_poll(f.file, &irqfd->pt); |
684a0b71 | 402 | |
a9a08845 | 403 | if (events & EPOLLIN) |
721eecbf GH |
404 | schedule_work(&irqfd->inject); |
405 | ||
9016cfb5 | 406 | #ifdef CONFIG_HAVE_KVM_IRQ_BYPASS |
14717e20 AW |
407 | if (kvm_arch_has_irq_bypass()) { |
408 | irqfd->consumer.token = (void *)irqfd->eventfd; | |
409 | irqfd->consumer.add_producer = kvm_arch_irq_bypass_add_producer; | |
410 | irqfd->consumer.del_producer = kvm_arch_irq_bypass_del_producer; | |
411 | irqfd->consumer.stop = kvm_arch_irq_bypass_stop; | |
412 | irqfd->consumer.start = kvm_arch_irq_bypass_start; | |
413 | ret = irq_bypass_register_consumer(&irqfd->consumer); | |
414 | if (ret) | |
415 | pr_info("irq bypass consumer (token %p) registration fails: %d\n", | |
9016cfb5 | 416 | irqfd->consumer.token, ret); |
14717e20 | 417 | } |
9016cfb5 | 418 | #endif |
721eecbf | 419 | |
b5020a8e | 420 | srcu_read_unlock(&kvm->irq_srcu, idx); |
9432a317 PB |
421 | |
422 | /* | |
423 | * do not drop the file until the irqfd is fully initialized, otherwise | |
424 | * we might race against the EPOLLHUP | |
425 | */ | |
426 | fdput(f); | |
721eecbf GH |
427 | return 0; |
428 | ||
429 | fail: | |
7a84428a AW |
430 | if (irqfd->resampler) |
431 | irqfd_resampler_shutdown(irqfd); | |
432 | ||
433 | if (resamplefd && !IS_ERR(resamplefd)) | |
434 | eventfd_ctx_put(resamplefd); | |
435 | ||
721eecbf GH |
436 | if (eventfd && !IS_ERR(eventfd)) |
437 | eventfd_ctx_put(eventfd); | |
438 | ||
cffe78d9 | 439 | fdput(f); |
721eecbf | 440 | |
cffe78d9 | 441 | out: |
721eecbf GH |
442 | kfree(irqfd); |
443 | return ret; | |
444 | } | |
c77dcacb PB |
445 | |
446 | bool kvm_irq_has_notifier(struct kvm *kvm, unsigned irqchip, unsigned pin) | |
447 | { | |
448 | struct kvm_irq_ack_notifier *kian; | |
449 | int gsi, idx; | |
450 | ||
451 | idx = srcu_read_lock(&kvm->irq_srcu); | |
452 | gsi = kvm_irq_map_chip_pin(kvm, irqchip, pin); | |
453 | if (gsi != -1) | |
454 | hlist_for_each_entry_rcu(kian, &kvm->irq_ack_notifier_list, | |
455 | link) | |
456 | if (kian->gsi == gsi) { | |
457 | srcu_read_unlock(&kvm->irq_srcu, idx); | |
458 | return true; | |
459 | } | |
460 | ||
461 | srcu_read_unlock(&kvm->irq_srcu, idx); | |
462 | ||
463 | return false; | |
464 | } | |
465 | EXPORT_SYMBOL_GPL(kvm_irq_has_notifier); | |
466 | ||
ba1aefcd | 467 | void kvm_notify_acked_gsi(struct kvm *kvm, int gsi) |
c77dcacb PB |
468 | { |
469 | struct kvm_irq_ack_notifier *kian; | |
ba1aefcd AS |
470 | |
471 | hlist_for_each_entry_rcu(kian, &kvm->irq_ack_notifier_list, | |
472 | link) | |
473 | if (kian->gsi == gsi) | |
474 | kian->irq_acked(kian); | |
475 | } | |
476 | ||
477 | void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin) | |
478 | { | |
c77dcacb PB |
479 | int gsi, idx; |
480 | ||
481 | trace_kvm_ack_irq(irqchip, pin); | |
482 | ||
483 | idx = srcu_read_lock(&kvm->irq_srcu); | |
484 | gsi = kvm_irq_map_chip_pin(kvm, irqchip, pin); | |
485 | if (gsi != -1) | |
ba1aefcd | 486 | kvm_notify_acked_gsi(kvm, gsi); |
c77dcacb PB |
487 | srcu_read_unlock(&kvm->irq_srcu, idx); |
488 | } | |
489 | ||
490 | void kvm_register_irq_ack_notifier(struct kvm *kvm, | |
491 | struct kvm_irq_ack_notifier *kian) | |
492 | { | |
493 | mutex_lock(&kvm->irq_lock); | |
494 | hlist_add_head_rcu(&kian->link, &kvm->irq_ack_notifier_list); | |
495 | mutex_unlock(&kvm->irq_lock); | |
993225ad | 496 | kvm_arch_post_irq_ack_notifier_list_update(kvm); |
c77dcacb PB |
497 | } |
498 | ||
499 | void kvm_unregister_irq_ack_notifier(struct kvm *kvm, | |
500 | struct kvm_irq_ack_notifier *kian) | |
501 | { | |
502 | mutex_lock(&kvm->irq_lock); | |
503 | hlist_del_init_rcu(&kian->link); | |
504 | mutex_unlock(&kvm->irq_lock); | |
505 | synchronize_srcu(&kvm->irq_srcu); | |
993225ad | 506 | kvm_arch_post_irq_ack_notifier_list_update(kvm); |
c77dcacb | 507 | } |
914daba8 | 508 | #endif |
721eecbf GH |
509 | |
510 | void | |
d34e6b17 | 511 | kvm_eventfd_init(struct kvm *kvm) |
721eecbf | 512 | { |
297e2105 | 513 | #ifdef CONFIG_HAVE_KVM_IRQFD |
721eecbf GH |
514 | spin_lock_init(&kvm->irqfds.lock); |
515 | INIT_LIST_HEAD(&kvm->irqfds.items); | |
7a84428a AW |
516 | INIT_LIST_HEAD(&kvm->irqfds.resampler_list); |
517 | mutex_init(&kvm->irqfds.resampler_lock); | |
914daba8 | 518 | #endif |
d34e6b17 | 519 | INIT_LIST_HEAD(&kvm->ioeventfds); |
721eecbf GH |
520 | } |
521 | ||
297e2105 | 522 | #ifdef CONFIG_HAVE_KVM_IRQFD |
721eecbf GH |
523 | /* |
524 | * shutdown any irqfd's that match fd+gsi | |
525 | */ | |
526 | static int | |
d4db2935 | 527 | kvm_irqfd_deassign(struct kvm *kvm, struct kvm_irqfd *args) |
721eecbf | 528 | { |
166c9775 | 529 | struct kvm_kernel_irqfd *irqfd, *tmp; |
721eecbf GH |
530 | struct eventfd_ctx *eventfd; |
531 | ||
d4db2935 | 532 | eventfd = eventfd_ctx_fdget(args->fd); |
721eecbf GH |
533 | if (IS_ERR(eventfd)) |
534 | return PTR_ERR(eventfd); | |
535 | ||
536 | spin_lock_irq(&kvm->irqfds.lock); | |
537 | ||
538 | list_for_each_entry_safe(irqfd, tmp, &kvm->irqfds.items, list) { | |
d4db2935 | 539 | if (irqfd->eventfd == eventfd && irqfd->gsi == args->gsi) { |
bd2b53b2 | 540 | /* |
56f89f36 | 541 | * This clearing of irq_entry.type is needed for when |
c8ce057e MT |
542 | * another thread calls kvm_irq_routing_update before |
543 | * we flush workqueue below (we synchronize with | |
544 | * kvm_irq_routing_update using irqfds.lock). | |
bd2b53b2 | 545 | */ |
56f89f36 PM |
546 | write_seqcount_begin(&irqfd->irq_entry_sc); |
547 | irqfd->irq_entry.type = 0; | |
548 | write_seqcount_end(&irqfd->irq_entry_sc); | |
721eecbf | 549 | irqfd_deactivate(irqfd); |
bd2b53b2 | 550 | } |
721eecbf GH |
551 | } |
552 | ||
553 | spin_unlock_irq(&kvm->irqfds.lock); | |
554 | eventfd_ctx_put(eventfd); | |
555 | ||
556 | /* | |
557 | * Block until we know all outstanding shutdown jobs have completed | |
558 | * so that we guarantee there will not be any more interrupts on this | |
559 | * gsi once this deassign function returns. | |
560 | */ | |
36343f6e | 561 | flush_workqueue(irqfd_cleanup_wq); |
721eecbf GH |
562 | |
563 | return 0; | |
564 | } | |
565 | ||
566 | int | |
d4db2935 | 567 | kvm_irqfd(struct kvm *kvm, struct kvm_irqfd *args) |
721eecbf | 568 | { |
7a84428a | 569 | if (args->flags & ~(KVM_IRQFD_FLAG_DEASSIGN | KVM_IRQFD_FLAG_RESAMPLE)) |
326cf033 AW |
570 | return -EINVAL; |
571 | ||
d4db2935 AW |
572 | if (args->flags & KVM_IRQFD_FLAG_DEASSIGN) |
573 | return kvm_irqfd_deassign(kvm, args); | |
721eecbf | 574 | |
d4db2935 | 575 | return kvm_irqfd_assign(kvm, args); |
721eecbf GH |
576 | } |
577 | ||
578 | /* | |
579 | * This function is called as the kvm VM fd is being released. Shutdown all | |
580 | * irqfds that still remain open | |
581 | */ | |
582 | void | |
583 | kvm_irqfd_release(struct kvm *kvm) | |
584 | { | |
166c9775 | 585 | struct kvm_kernel_irqfd *irqfd, *tmp; |
721eecbf GH |
586 | |
587 | spin_lock_irq(&kvm->irqfds.lock); | |
588 | ||
589 | list_for_each_entry_safe(irqfd, tmp, &kvm->irqfds.items, list) | |
590 | irqfd_deactivate(irqfd); | |
591 | ||
592 | spin_unlock_irq(&kvm->irqfds.lock); | |
593 | ||
594 | /* | |
595 | * Block until we know all outstanding shutdown jobs have completed | |
596 | * since we do not take a kvm* reference. | |
597 | */ | |
36343f6e | 598 | flush_workqueue(irqfd_cleanup_wq); |
721eecbf GH |
599 | |
600 | } | |
601 | ||
bd2b53b2 | 602 | /* |
9957c86d | 603 | * Take note of a change in irq routing. |
719d93cd | 604 | * Caller must invoke synchronize_srcu(&kvm->irq_srcu) afterwards. |
bd2b53b2 | 605 | */ |
9957c86d | 606 | void kvm_irq_routing_update(struct kvm *kvm) |
bd2b53b2 | 607 | { |
166c9775 | 608 | struct kvm_kernel_irqfd *irqfd; |
bd2b53b2 MT |
609 | |
610 | spin_lock_irq(&kvm->irqfds.lock); | |
611 | ||
f70c20aa | 612 | list_for_each_entry(irqfd, &kvm->irqfds.items, list) { |
9957c86d | 613 | irqfd_update(kvm, irqfd); |
bd2b53b2 | 614 | |
f70c20aa FW |
615 | #ifdef CONFIG_HAVE_KVM_IRQ_BYPASS |
616 | if (irqfd->producer) { | |
617 | int ret = kvm_arch_update_irqfd_routing( | |
618 | irqfd->kvm, irqfd->producer->irq, | |
619 | irqfd->gsi, 1); | |
620 | WARN_ON(ret); | |
621 | } | |
622 | #endif | |
623 | } | |
624 | ||
bd2b53b2 MT |
625 | spin_unlock_irq(&kvm->irqfds.lock); |
626 | } | |
627 | ||
36343f6e PB |
628 | /* |
629 | * create a host-wide workqueue for issuing deferred shutdown requests | |
630 | * aggregated from all vm* instances. We need our own isolated | |
631 | * queue to ease flushing work items when a VM exits. | |
632 | */ | |
633 | int kvm_irqfd_init(void) | |
634 | { | |
635 | irqfd_cleanup_wq = alloc_workqueue("kvm-irqfd-cleanup", 0, 0); | |
636 | if (!irqfd_cleanup_wq) | |
637 | return -ENOMEM; | |
638 | ||
639 | return 0; | |
640 | } | |
641 | ||
a0f155e9 | 642 | void kvm_irqfd_exit(void) |
721eecbf | 643 | { |
36343f6e | 644 | destroy_workqueue(irqfd_cleanup_wq); |
721eecbf | 645 | } |
914daba8 | 646 | #endif |
d34e6b17 GH |
647 | |
648 | /* | |
649 | * -------------------------------------------------------------------- | |
650 | * ioeventfd: translate a PIO/MMIO memory write to an eventfd signal. | |
651 | * | |
652 | * userspace can register a PIO/MMIO address with an eventfd for receiving | |
653 | * notification when the memory has been touched. | |
654 | * -------------------------------------------------------------------- | |
655 | */ | |
656 | ||
657 | struct _ioeventfd { | |
658 | struct list_head list; | |
659 | u64 addr; | |
660 | int length; | |
661 | struct eventfd_ctx *eventfd; | |
662 | u64 datamatch; | |
663 | struct kvm_io_device dev; | |
05e07f9b | 664 | u8 bus_idx; |
d34e6b17 GH |
665 | bool wildcard; |
666 | }; | |
667 | ||
668 | static inline struct _ioeventfd * | |
669 | to_ioeventfd(struct kvm_io_device *dev) | |
670 | { | |
671 | return container_of(dev, struct _ioeventfd, dev); | |
672 | } | |
673 | ||
674 | static void | |
675 | ioeventfd_release(struct _ioeventfd *p) | |
676 | { | |
677 | eventfd_ctx_put(p->eventfd); | |
678 | list_del(&p->list); | |
679 | kfree(p); | |
680 | } | |
681 | ||
682 | static bool | |
683 | ioeventfd_in_range(struct _ioeventfd *p, gpa_t addr, int len, const void *val) | |
684 | { | |
685 | u64 _val; | |
686 | ||
f848a5a8 MT |
687 | if (addr != p->addr) |
688 | /* address must be precise for a hit */ | |
689 | return false; | |
690 | ||
691 | if (!p->length) | |
692 | /* length = 0 means only look at the address, so always a hit */ | |
693 | return true; | |
694 | ||
695 | if (len != p->length) | |
d34e6b17 GH |
696 | /* address-range must be precise for a hit */ |
697 | return false; | |
698 | ||
699 | if (p->wildcard) | |
700 | /* all else equal, wildcard is always a hit */ | |
701 | return true; | |
702 | ||
703 | /* otherwise, we have to actually compare the data */ | |
704 | ||
705 | BUG_ON(!IS_ALIGNED((unsigned long)val, len)); | |
706 | ||
707 | switch (len) { | |
708 | case 1: | |
709 | _val = *(u8 *)val; | |
710 | break; | |
711 | case 2: | |
712 | _val = *(u16 *)val; | |
713 | break; | |
714 | case 4: | |
715 | _val = *(u32 *)val; | |
716 | break; | |
717 | case 8: | |
718 | _val = *(u64 *)val; | |
719 | break; | |
720 | default: | |
721 | return false; | |
722 | } | |
723 | ||
724 | return _val == p->datamatch ? true : false; | |
725 | } | |
726 | ||
727 | /* MMIO/PIO writes trigger an event if the addr/val match */ | |
728 | static int | |
e32edf4f NN |
729 | ioeventfd_write(struct kvm_vcpu *vcpu, struct kvm_io_device *this, gpa_t addr, |
730 | int len, const void *val) | |
d34e6b17 GH |
731 | { |
732 | struct _ioeventfd *p = to_ioeventfd(this); | |
733 | ||
734 | if (!ioeventfd_in_range(p, addr, len, val)) | |
735 | return -EOPNOTSUPP; | |
736 | ||
737 | eventfd_signal(p->eventfd, 1); | |
738 | return 0; | |
739 | } | |
740 | ||
741 | /* | |
742 | * This function is called as KVM is completely shutting down. We do not | |
743 | * need to worry about locking just nuke anything we have as quickly as possible | |
744 | */ | |
745 | static void | |
746 | ioeventfd_destructor(struct kvm_io_device *this) | |
747 | { | |
748 | struct _ioeventfd *p = to_ioeventfd(this); | |
749 | ||
750 | ioeventfd_release(p); | |
751 | } | |
752 | ||
753 | static const struct kvm_io_device_ops ioeventfd_ops = { | |
754 | .write = ioeventfd_write, | |
755 | .destructor = ioeventfd_destructor, | |
756 | }; | |
757 | ||
758 | /* assumes kvm->slots_lock held */ | |
759 | static bool | |
760 | ioeventfd_check_collision(struct kvm *kvm, struct _ioeventfd *p) | |
761 | { | |
762 | struct _ioeventfd *_p; | |
763 | ||
764 | list_for_each_entry(_p, &kvm->ioeventfds, list) | |
05e07f9b | 765 | if (_p->bus_idx == p->bus_idx && |
f848a5a8 MT |
766 | _p->addr == p->addr && |
767 | (!_p->length || !p->length || | |
768 | (_p->length == p->length && | |
769 | (_p->wildcard || p->wildcard || | |
770 | _p->datamatch == p->datamatch)))) | |
d34e6b17 GH |
771 | return true; |
772 | ||
773 | return false; | |
774 | } | |
775 | ||
2b83451b CH |
776 | static enum kvm_bus ioeventfd_bus_from_flags(__u32 flags) |
777 | { | |
778 | if (flags & KVM_IOEVENTFD_FLAG_PIO) | |
779 | return KVM_PIO_BUS; | |
780 | if (flags & KVM_IOEVENTFD_FLAG_VIRTIO_CCW_NOTIFY) | |
781 | return KVM_VIRTIO_CCW_NOTIFY_BUS; | |
782 | return KVM_MMIO_BUS; | |
783 | } | |
784 | ||
85da11ca JW |
785 | static int kvm_assign_ioeventfd_idx(struct kvm *kvm, |
786 | enum kvm_bus bus_idx, | |
787 | struct kvm_ioeventfd *args) | |
d34e6b17 | 788 | { |
d34e6b17 | 789 | |
85da11ca JW |
790 | struct eventfd_ctx *eventfd; |
791 | struct _ioeventfd *p; | |
792 | int ret; | |
f848a5a8 | 793 | |
d34e6b17 GH |
794 | eventfd = eventfd_ctx_fdget(args->fd); |
795 | if (IS_ERR(eventfd)) | |
796 | return PTR_ERR(eventfd); | |
797 | ||
b12ce36a | 798 | p = kzalloc(sizeof(*p), GFP_KERNEL_ACCOUNT); |
d34e6b17 GH |
799 | if (!p) { |
800 | ret = -ENOMEM; | |
801 | goto fail; | |
802 | } | |
803 | ||
804 | INIT_LIST_HEAD(&p->list); | |
805 | p->addr = args->addr; | |
05e07f9b | 806 | p->bus_idx = bus_idx; |
d34e6b17 GH |
807 | p->length = args->len; |
808 | p->eventfd = eventfd; | |
809 | ||
810 | /* The datamatch feature is optional, otherwise this is a wildcard */ | |
811 | if (args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH) | |
812 | p->datamatch = args->datamatch; | |
813 | else | |
814 | p->wildcard = true; | |
815 | ||
79fac95e | 816 | mutex_lock(&kvm->slots_lock); |
d34e6b17 | 817 | |
25985edc | 818 | /* Verify that there isn't a match already */ |
d34e6b17 GH |
819 | if (ioeventfd_check_collision(kvm, p)) { |
820 | ret = -EEXIST; | |
821 | goto unlock_fail; | |
822 | } | |
823 | ||
824 | kvm_iodevice_init(&p->dev, &ioeventfd_ops); | |
825 | ||
743eeb0b SL |
826 | ret = kvm_io_bus_register_dev(kvm, bus_idx, p->addr, p->length, |
827 | &p->dev); | |
d34e6b17 GH |
828 | if (ret < 0) |
829 | goto unlock_fail; | |
830 | ||
4a12f951 | 831 | kvm_get_bus(kvm, bus_idx)->ioeventfd_count++; |
d34e6b17 GH |
832 | list_add_tail(&p->list, &kvm->ioeventfds); |
833 | ||
79fac95e | 834 | mutex_unlock(&kvm->slots_lock); |
d34e6b17 GH |
835 | |
836 | return 0; | |
837 | ||
838 | unlock_fail: | |
79fac95e | 839 | mutex_unlock(&kvm->slots_lock); |
d34e6b17 GH |
840 | |
841 | fail: | |
842 | kfree(p); | |
843 | eventfd_ctx_put(eventfd); | |
844 | ||
845 | return ret; | |
846 | } | |
847 | ||
848 | static int | |
85da11ca JW |
849 | kvm_deassign_ioeventfd_idx(struct kvm *kvm, enum kvm_bus bus_idx, |
850 | struct kvm_ioeventfd *args) | |
d34e6b17 | 851 | { |
d34e6b17 GH |
852 | struct _ioeventfd *p, *tmp; |
853 | struct eventfd_ctx *eventfd; | |
4a12f951 | 854 | struct kvm_io_bus *bus; |
d34e6b17 GH |
855 | int ret = -ENOENT; |
856 | ||
857 | eventfd = eventfd_ctx_fdget(args->fd); | |
858 | if (IS_ERR(eventfd)) | |
859 | return PTR_ERR(eventfd); | |
860 | ||
79fac95e | 861 | mutex_lock(&kvm->slots_lock); |
d34e6b17 GH |
862 | |
863 | list_for_each_entry_safe(p, tmp, &kvm->ioeventfds, list) { | |
864 | bool wildcard = !(args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH); | |
865 | ||
05e07f9b MT |
866 | if (p->bus_idx != bus_idx || |
867 | p->eventfd != eventfd || | |
d34e6b17 GH |
868 | p->addr != args->addr || |
869 | p->length != args->len || | |
870 | p->wildcard != wildcard) | |
871 | continue; | |
872 | ||
873 | if (!p->wildcard && p->datamatch != args->datamatch) | |
874 | continue; | |
875 | ||
e93f8a0f | 876 | kvm_io_bus_unregister_dev(kvm, bus_idx, &p->dev); |
4a12f951 CB |
877 | bus = kvm_get_bus(kvm, bus_idx); |
878 | if (bus) | |
879 | bus->ioeventfd_count--; | |
d34e6b17 GH |
880 | ioeventfd_release(p); |
881 | ret = 0; | |
882 | break; | |
883 | } | |
884 | ||
79fac95e | 885 | mutex_unlock(&kvm->slots_lock); |
d34e6b17 GH |
886 | |
887 | eventfd_ctx_put(eventfd); | |
888 | ||
889 | return ret; | |
890 | } | |
891 | ||
85da11ca JW |
892 | static int kvm_deassign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args) |
893 | { | |
894 | enum kvm_bus bus_idx = ioeventfd_bus_from_flags(args->flags); | |
eefd6b06 JW |
895 | int ret = kvm_deassign_ioeventfd_idx(kvm, bus_idx, args); |
896 | ||
897 | if (!args->len && bus_idx == KVM_MMIO_BUS) | |
898 | kvm_deassign_ioeventfd_idx(kvm, KVM_FAST_MMIO_BUS, args); | |
85da11ca | 899 | |
eefd6b06 | 900 | return ret; |
85da11ca JW |
901 | } |
902 | ||
903 | static int | |
904 | kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args) | |
905 | { | |
906 | enum kvm_bus bus_idx; | |
eefd6b06 | 907 | int ret; |
85da11ca JW |
908 | |
909 | bus_idx = ioeventfd_bus_from_flags(args->flags); | |
910 | /* must be natural-word sized, or 0 to ignore length */ | |
911 | switch (args->len) { | |
912 | case 0: | |
913 | case 1: | |
914 | case 2: | |
915 | case 4: | |
916 | case 8: | |
917 | break; | |
918 | default: | |
919 | return -EINVAL; | |
920 | } | |
921 | ||
922 | /* check for range overflow */ | |
923 | if (args->addr + args->len < args->addr) | |
924 | return -EINVAL; | |
925 | ||
926 | /* check for extra flags that we don't understand */ | |
927 | if (args->flags & ~KVM_IOEVENTFD_VALID_FLAG_MASK) | |
928 | return -EINVAL; | |
929 | ||
930 | /* ioeventfd with no length can't be combined with DATAMATCH */ | |
e9ea5069 | 931 | if (!args->len && (args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH)) |
85da11ca JW |
932 | return -EINVAL; |
933 | ||
eefd6b06 JW |
934 | ret = kvm_assign_ioeventfd_idx(kvm, bus_idx, args); |
935 | if (ret) | |
936 | goto fail; | |
937 | ||
938 | /* When length is ignored, MMIO is also put on a separate bus, for | |
939 | * faster lookups. | |
940 | */ | |
941 | if (!args->len && bus_idx == KVM_MMIO_BUS) { | |
942 | ret = kvm_assign_ioeventfd_idx(kvm, KVM_FAST_MMIO_BUS, args); | |
943 | if (ret < 0) | |
944 | goto fast_fail; | |
945 | } | |
946 | ||
947 | return 0; | |
948 | ||
949 | fast_fail: | |
950 | kvm_deassign_ioeventfd_idx(kvm, bus_idx, args); | |
951 | fail: | |
952 | return ret; | |
85da11ca JW |
953 | } |
954 | ||
d34e6b17 GH |
955 | int |
956 | kvm_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args) | |
957 | { | |
958 | if (args->flags & KVM_IOEVENTFD_FLAG_DEASSIGN) | |
959 | return kvm_deassign_ioeventfd(kvm, args); | |
960 | ||
961 | return kvm_assign_ioeventfd(kvm, args); | |
962 | } |