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Gregory Haskins721eecbf2009-05-20 10:30:49 -04001/*
2 * kvm eventfd support - use eventfd objects to signal various KVM events
3 *
4 * Copyright 2009 Novell. All Rights Reserved.
Avi Kivity221d0592010-05-23 18:37:00 +03005 * Copyright 2010 Red Hat, Inc. and/or its affiliates.
Gregory Haskins721eecbf2009-05-20 10:30:49 -04006 *
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>
Gregory Haskinsd34e6b12009-07-07 17:08:49 -040025#include <linux/kvm.h>
Gregory Haskins721eecbf2009-05-20 10:30:49 -040026#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>
Gregory Haskinsd34e6b12009-07-07 17:08:49 -040033#include <linux/kernel.h>
Tejun Heo5a0e3ad2010-03-24 17:04:11 +090034#include <linux/slab.h>
Gregory Haskinsd34e6b12009-07-07 17:08:49 -040035
36#include "iodev.h"
Gregory Haskins721eecbf2009-05-20 10:30:49 -040037
Alexander Graf914daba2012-10-09 00:22:59 +020038#ifdef __KVM_HAVE_IOAPIC
Gregory Haskins721eecbf2009-05-20 10:30:49 -040039/*
40 * --------------------------------------------------------------------
41 * irqfd: Allows an fd to be used to inject an interrupt to the guest
42 *
43 * Credit goes to Avi Kivity for the original idea.
44 * --------------------------------------------------------------------
45 */
46
Alex Williamson7a844282012-09-21 11:58:03 -060047/*
48 * Resampling irqfds are a special variety of irqfds used to emulate
49 * level triggered interrupts. The interrupt is asserted on eventfd
50 * trigger. On acknowledgement through the irq ack notifier, the
51 * interrupt is de-asserted and userspace is notified through the
52 * resamplefd. All resamplers on the same gsi are de-asserted
53 * together, so we don't need to track the state of each individual
54 * user. We can also therefore share the same irq source ID.
55 */
56struct _irqfd_resampler {
57 struct kvm *kvm;
58 /*
59 * List of resampling struct _irqfd objects sharing this gsi.
60 * RCU list modified under kvm->irqfds.resampler_lock
61 */
62 struct list_head list;
63 struct kvm_irq_ack_notifier notifier;
64 /*
65 * Entry in list of kvm->irqfd.resampler_list. Use for sharing
66 * resamplers among irqfds on the same gsi.
67 * Accessed and modified under kvm->irqfds.resampler_lock
68 */
69 struct list_head link;
70};
71
Gregory Haskins721eecbf2009-05-20 10:30:49 -040072struct _irqfd {
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +020073 /* Used for MSI fast-path */
74 struct kvm *kvm;
75 wait_queue_t wait;
76 /* Update side is protected by irqfds.lock */
77 struct kvm_kernel_irq_routing_entry __rcu *irq_entry;
78 /* Used for level IRQ fast-path */
79 int gsi;
80 struct work_struct inject;
Alex Williamson7a844282012-09-21 11:58:03 -060081 /* The resampler used by this irqfd (resampler-only) */
82 struct _irqfd_resampler *resampler;
83 /* Eventfd notified on resample (resampler-only) */
84 struct eventfd_ctx *resamplefd;
85 /* Entry in list of irqfds for a resampler (resampler-only) */
86 struct list_head resampler_link;
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +020087 /* Used for setup/shutdown */
88 struct eventfd_ctx *eventfd;
89 struct list_head list;
90 poll_table pt;
91 struct work_struct shutdown;
Gregory Haskins721eecbf2009-05-20 10:30:49 -040092};
93
94static struct workqueue_struct *irqfd_cleanup_wq;
95
96static void
97irqfd_inject(struct work_struct *work)
98{
99 struct _irqfd *irqfd = container_of(work, struct _irqfd, inject);
100 struct kvm *kvm = irqfd->kvm;
101
Alex Williamson7a844282012-09-21 11:58:03 -0600102 if (!irqfd->resampler) {
103 kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 1);
104 kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 0);
105 } else
106 kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID,
107 irqfd->gsi, 1);
108}
109
110/*
111 * Since resampler irqfds share an IRQ source ID, we de-assert once
112 * then notify all of the resampler irqfds using this GSI. We can't
113 * do multiple de-asserts or we risk racing with incoming re-asserts.
114 */
115static void
116irqfd_resampler_ack(struct kvm_irq_ack_notifier *kian)
117{
118 struct _irqfd_resampler *resampler;
119 struct _irqfd *irqfd;
120
121 resampler = container_of(kian, struct _irqfd_resampler, notifier);
122
123 kvm_set_irq(resampler->kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID,
124 resampler->notifier.gsi, 0);
125
126 rcu_read_lock();
127
128 list_for_each_entry_rcu(irqfd, &resampler->list, resampler_link)
129 eventfd_signal(irqfd->resamplefd, 1);
130
131 rcu_read_unlock();
132}
133
134static void
135irqfd_resampler_shutdown(struct _irqfd *irqfd)
136{
137 struct _irqfd_resampler *resampler = irqfd->resampler;
138 struct kvm *kvm = resampler->kvm;
139
140 mutex_lock(&kvm->irqfds.resampler_lock);
141
142 list_del_rcu(&irqfd->resampler_link);
143 synchronize_rcu();
144
145 if (list_empty(&resampler->list)) {
146 list_del(&resampler->link);
147 kvm_unregister_irq_ack_notifier(kvm, &resampler->notifier);
148 kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID,
149 resampler->notifier.gsi, 0);
150 kfree(resampler);
151 }
152
153 mutex_unlock(&kvm->irqfds.resampler_lock);
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400154}
155
156/*
157 * Race-free decouple logic (ordering is critical)
158 */
159static void
160irqfd_shutdown(struct work_struct *work)
161{
162 struct _irqfd *irqfd = container_of(work, struct _irqfd, shutdown);
Michael S. Tsirkinb6a114d2010-01-13 19:12:30 +0200163 u64 cnt;
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400164
165 /*
166 * Synchronize with the wait-queue and unhook ourselves to prevent
167 * further events.
168 */
Michael S. Tsirkinb6a114d2010-01-13 19:12:30 +0200169 eventfd_ctx_remove_wait_queue(irqfd->eventfd, &irqfd->wait, &cnt);
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400170
171 /*
172 * We know no new events will be scheduled at this point, so block
173 * until all previously outstanding events have completed
174 */
Tejun Heo43829732012-08-20 14:51:24 -0700175 flush_work(&irqfd->inject);
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400176
Alex Williamson7a844282012-09-21 11:58:03 -0600177 if (irqfd->resampler) {
178 irqfd_resampler_shutdown(irqfd);
179 eventfd_ctx_put(irqfd->resamplefd);
180 }
181
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400182 /*
183 * It is now safe to release the object's resources
184 */
185 eventfd_ctx_put(irqfd->eventfd);
186 kfree(irqfd);
187}
188
189
190/* assumes kvm->irqfds.lock is held */
191static bool
192irqfd_is_active(struct _irqfd *irqfd)
193{
194 return list_empty(&irqfd->list) ? false : true;
195}
196
197/*
198 * Mark the irqfd as inactive and schedule it for removal
199 *
200 * assumes kvm->irqfds.lock is held
201 */
202static void
203irqfd_deactivate(struct _irqfd *irqfd)
204{
205 BUG_ON(!irqfd_is_active(irqfd));
206
207 list_del_init(&irqfd->list);
208
209 queue_work(irqfd_cleanup_wq, &irqfd->shutdown);
210}
211
212/*
213 * Called with wqh->lock held and interrupts disabled
214 */
215static int
216irqfd_wakeup(wait_queue_t *wait, unsigned mode, int sync, void *key)
217{
218 struct _irqfd *irqfd = container_of(wait, struct _irqfd, wait);
219 unsigned long flags = (unsigned long)key;
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200220 struct kvm_kernel_irq_routing_entry *irq;
221 struct kvm *kvm = irqfd->kvm;
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400222
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200223 if (flags & POLLIN) {
224 rcu_read_lock();
225 irq = rcu_dereference(irqfd->irq_entry);
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400226 /* An event has been signaled, inject an interrupt */
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200227 if (irq)
228 kvm_set_msi(irq, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1);
229 else
230 schedule_work(&irqfd->inject);
231 rcu_read_unlock();
232 }
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400233
234 if (flags & POLLHUP) {
235 /* The eventfd is closing, detach from KVM */
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400236 unsigned long flags;
237
238 spin_lock_irqsave(&kvm->irqfds.lock, flags);
239
240 /*
241 * We must check if someone deactivated the irqfd before
242 * we could acquire the irqfds.lock since the item is
243 * deactivated from the KVM side before it is unhooked from
244 * the wait-queue. If it is already deactivated, we can
245 * simply return knowing the other side will cleanup for us.
246 * We cannot race against the irqfd going away since the
247 * other side is required to acquire wqh->lock, which we hold
248 */
249 if (irqfd_is_active(irqfd))
250 irqfd_deactivate(irqfd);
251
252 spin_unlock_irqrestore(&kvm->irqfds.lock, flags);
253 }
254
255 return 0;
256}
257
258static void
259irqfd_ptable_queue_proc(struct file *file, wait_queue_head_t *wqh,
260 poll_table *pt)
261{
262 struct _irqfd *irqfd = container_of(pt, struct _irqfd, pt);
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400263 add_wait_queue(wqh, &irqfd->wait);
264}
265
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200266/* Must be called under irqfds.lock */
267static void irqfd_update(struct kvm *kvm, struct _irqfd *irqfd,
268 struct kvm_irq_routing_table *irq_rt)
269{
270 struct kvm_kernel_irq_routing_entry *e;
271 struct hlist_node *n;
272
273 if (irqfd->gsi >= irq_rt->nr_rt_entries) {
274 rcu_assign_pointer(irqfd->irq_entry, NULL);
275 return;
276 }
277
278 hlist_for_each_entry(e, n, &irq_rt->map[irqfd->gsi], link) {
279 /* Only fast-path MSI. */
280 if (e->type == KVM_IRQ_ROUTING_MSI)
281 rcu_assign_pointer(irqfd->irq_entry, e);
282 else
283 rcu_assign_pointer(irqfd->irq_entry, NULL);
284 }
285}
286
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400287static int
Alex Williamsond4db2932012-06-29 09:56:08 -0600288kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400289{
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200290 struct kvm_irq_routing_table *irq_rt;
Michael S. Tsirkinf1d1c302010-01-13 18:58:09 +0200291 struct _irqfd *irqfd, *tmp;
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400292 struct file *file = NULL;
Alex Williamson7a844282012-09-21 11:58:03 -0600293 struct eventfd_ctx *eventfd = NULL, *resamplefd = NULL;
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400294 int ret;
295 unsigned int events;
296
297 irqfd = kzalloc(sizeof(*irqfd), GFP_KERNEL);
298 if (!irqfd)
299 return -ENOMEM;
300
301 irqfd->kvm = kvm;
Alex Williamsond4db2932012-06-29 09:56:08 -0600302 irqfd->gsi = args->gsi;
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400303 INIT_LIST_HEAD(&irqfd->list);
304 INIT_WORK(&irqfd->inject, irqfd_inject);
305 INIT_WORK(&irqfd->shutdown, irqfd_shutdown);
306
Alex Williamsond4db2932012-06-29 09:56:08 -0600307 file = eventfd_fget(args->fd);
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400308 if (IS_ERR(file)) {
309 ret = PTR_ERR(file);
310 goto fail;
311 }
312
313 eventfd = eventfd_ctx_fileget(file);
314 if (IS_ERR(eventfd)) {
315 ret = PTR_ERR(eventfd);
316 goto fail;
317 }
318
319 irqfd->eventfd = eventfd;
320
Alex Williamson7a844282012-09-21 11:58:03 -0600321 if (args->flags & KVM_IRQFD_FLAG_RESAMPLE) {
322 struct _irqfd_resampler *resampler;
323
324 resamplefd = eventfd_ctx_fdget(args->resamplefd);
325 if (IS_ERR(resamplefd)) {
326 ret = PTR_ERR(resamplefd);
327 goto fail;
328 }
329
330 irqfd->resamplefd = resamplefd;
331 INIT_LIST_HEAD(&irqfd->resampler_link);
332
333 mutex_lock(&kvm->irqfds.resampler_lock);
334
335 list_for_each_entry(resampler,
Alex Williamson49f8a1a2012-12-06 14:44:59 -0700336 &kvm->irqfds.resampler_list, link) {
Alex Williamson7a844282012-09-21 11:58:03 -0600337 if (resampler->notifier.gsi == irqfd->gsi) {
338 irqfd->resampler = resampler;
339 break;
340 }
341 }
342
343 if (!irqfd->resampler) {
344 resampler = kzalloc(sizeof(*resampler), GFP_KERNEL);
345 if (!resampler) {
346 ret = -ENOMEM;
347 mutex_unlock(&kvm->irqfds.resampler_lock);
348 goto fail;
349 }
350
351 resampler->kvm = kvm;
352 INIT_LIST_HEAD(&resampler->list);
353 resampler->notifier.gsi = irqfd->gsi;
354 resampler->notifier.irq_acked = irqfd_resampler_ack;
355 INIT_LIST_HEAD(&resampler->link);
356
357 list_add(&resampler->link, &kvm->irqfds.resampler_list);
358 kvm_register_irq_ack_notifier(kvm,
359 &resampler->notifier);
360 irqfd->resampler = resampler;
361 }
362
363 list_add_rcu(&irqfd->resampler_link, &irqfd->resampler->list);
364 synchronize_rcu();
365
366 mutex_unlock(&kvm->irqfds.resampler_lock);
367 }
368
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400369 /*
370 * Install our own custom wake-up handling so we are notified via
371 * a callback whenever someone signals the underlying eventfd
372 */
373 init_waitqueue_func_entry(&irqfd->wait, irqfd_wakeup);
374 init_poll_funcptr(&irqfd->pt, irqfd_ptable_queue_proc);
375
Michael S. Tsirkinf1d1c302010-01-13 18:58:09 +0200376 spin_lock_irq(&kvm->irqfds.lock);
377
378 ret = 0;
379 list_for_each_entry(tmp, &kvm->irqfds.items, list) {
380 if (irqfd->eventfd != tmp->eventfd)
381 continue;
382 /* This fd is used for another irq already. */
383 ret = -EBUSY;
384 spin_unlock_irq(&kvm->irqfds.lock);
385 goto fail;
386 }
387
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200388 irq_rt = rcu_dereference_protected(kvm->irq_routing,
389 lockdep_is_held(&kvm->irqfds.lock));
390 irqfd_update(kvm, irqfd, irq_rt);
391
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400392 events = file->f_op->poll(file, &irqfd->pt);
393
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400394 list_add_tail(&irqfd->list, &kvm->irqfds.items);
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400395
396 /*
397 * Check if there was an event already pending on the eventfd
398 * before we registered, and trigger it as if we didn't miss it.
399 */
400 if (events & POLLIN)
401 schedule_work(&irqfd->inject);
402
Michael S. Tsirkin6bbfb262010-09-19 19:02:31 +0200403 spin_unlock_irq(&kvm->irqfds.lock);
404
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400405 /*
406 * do not drop the file until the irqfd is fully initialized, otherwise
407 * we might race against the POLLHUP
408 */
409 fput(file);
410
411 return 0;
412
413fail:
Alex Williamson7a844282012-09-21 11:58:03 -0600414 if (irqfd->resampler)
415 irqfd_resampler_shutdown(irqfd);
416
417 if (resamplefd && !IS_ERR(resamplefd))
418 eventfd_ctx_put(resamplefd);
419
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400420 if (eventfd && !IS_ERR(eventfd))
421 eventfd_ctx_put(eventfd);
422
Julia Lawall62230112009-07-28 17:53:24 +0200423 if (!IS_ERR(file))
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400424 fput(file);
425
426 kfree(irqfd);
427 return ret;
428}
Alexander Graf914daba2012-10-09 00:22:59 +0200429#endif
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400430
431void
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400432kvm_eventfd_init(struct kvm *kvm)
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400433{
Alexander Graf914daba2012-10-09 00:22:59 +0200434#ifdef __KVM_HAVE_IOAPIC
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400435 spin_lock_init(&kvm->irqfds.lock);
436 INIT_LIST_HEAD(&kvm->irqfds.items);
Alex Williamson7a844282012-09-21 11:58:03 -0600437 INIT_LIST_HEAD(&kvm->irqfds.resampler_list);
438 mutex_init(&kvm->irqfds.resampler_lock);
Alexander Graf914daba2012-10-09 00:22:59 +0200439#endif
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400440 INIT_LIST_HEAD(&kvm->ioeventfds);
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400441}
442
Alexander Graf914daba2012-10-09 00:22:59 +0200443#ifdef __KVM_HAVE_IOAPIC
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400444/*
445 * shutdown any irqfd's that match fd+gsi
446 */
447static int
Alex Williamsond4db2932012-06-29 09:56:08 -0600448kvm_irqfd_deassign(struct kvm *kvm, struct kvm_irqfd *args)
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400449{
450 struct _irqfd *irqfd, *tmp;
451 struct eventfd_ctx *eventfd;
452
Alex Williamsond4db2932012-06-29 09:56:08 -0600453 eventfd = eventfd_ctx_fdget(args->fd);
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400454 if (IS_ERR(eventfd))
455 return PTR_ERR(eventfd);
456
457 spin_lock_irq(&kvm->irqfds.lock);
458
459 list_for_each_entry_safe(irqfd, tmp, &kvm->irqfds.items, list) {
Alex Williamsond4db2932012-06-29 09:56:08 -0600460 if (irqfd->eventfd == eventfd && irqfd->gsi == args->gsi) {
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200461 /*
462 * This rcu_assign_pointer is needed for when
Michael S. Tsirkinc8ce0572011-03-06 13:03:26 +0200463 * another thread calls kvm_irq_routing_update before
464 * we flush workqueue below (we synchronize with
465 * kvm_irq_routing_update using irqfds.lock).
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200466 * It is paired with synchronize_rcu done by caller
467 * of that function.
468 */
469 rcu_assign_pointer(irqfd->irq_entry, NULL);
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400470 irqfd_deactivate(irqfd);
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200471 }
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400472 }
473
474 spin_unlock_irq(&kvm->irqfds.lock);
475 eventfd_ctx_put(eventfd);
476
477 /*
478 * Block until we know all outstanding shutdown jobs have completed
479 * so that we guarantee there will not be any more interrupts on this
480 * gsi once this deassign function returns.
481 */
482 flush_workqueue(irqfd_cleanup_wq);
483
484 return 0;
485}
486
487int
Alex Williamsond4db2932012-06-29 09:56:08 -0600488kvm_irqfd(struct kvm *kvm, struct kvm_irqfd *args)
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400489{
Alex Williamson7a844282012-09-21 11:58:03 -0600490 if (args->flags & ~(KVM_IRQFD_FLAG_DEASSIGN | KVM_IRQFD_FLAG_RESAMPLE))
Alex Williamson326cf032012-06-29 09:56:24 -0600491 return -EINVAL;
492
Alex Williamsond4db2932012-06-29 09:56:08 -0600493 if (args->flags & KVM_IRQFD_FLAG_DEASSIGN)
494 return kvm_irqfd_deassign(kvm, args);
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400495
Alex Williamsond4db2932012-06-29 09:56:08 -0600496 return kvm_irqfd_assign(kvm, args);
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400497}
498
499/*
500 * This function is called as the kvm VM fd is being released. Shutdown all
501 * irqfds that still remain open
502 */
503void
504kvm_irqfd_release(struct kvm *kvm)
505{
506 struct _irqfd *irqfd, *tmp;
507
508 spin_lock_irq(&kvm->irqfds.lock);
509
510 list_for_each_entry_safe(irqfd, tmp, &kvm->irqfds.items, list)
511 irqfd_deactivate(irqfd);
512
513 spin_unlock_irq(&kvm->irqfds.lock);
514
515 /*
516 * Block until we know all outstanding shutdown jobs have completed
517 * since we do not take a kvm* reference.
518 */
519 flush_workqueue(irqfd_cleanup_wq);
520
521}
522
523/*
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200524 * Change irq_routing and irqfd.
525 * Caller must invoke synchronize_rcu afterwards.
526 */
527void kvm_irq_routing_update(struct kvm *kvm,
528 struct kvm_irq_routing_table *irq_rt)
529{
530 struct _irqfd *irqfd;
531
532 spin_lock_irq(&kvm->irqfds.lock);
533
534 rcu_assign_pointer(kvm->irq_routing, irq_rt);
535
536 list_for_each_entry(irqfd, &kvm->irqfds.items, list)
537 irqfd_update(kvm, irqfd, irq_rt);
538
539 spin_unlock_irq(&kvm->irqfds.lock);
540}
541
542/*
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400543 * create a host-wide workqueue for issuing deferred shutdown requests
544 * aggregated from all vm* instances. We need our own isolated single-thread
545 * queue to prevent deadlock against flushing the normal work-queue.
546 */
547static int __init irqfd_module_init(void)
548{
549 irqfd_cleanup_wq = create_singlethread_workqueue("kvm-irqfd-cleanup");
550 if (!irqfd_cleanup_wq)
551 return -ENOMEM;
552
553 return 0;
554}
555
556static void __exit irqfd_module_exit(void)
557{
558 destroy_workqueue(irqfd_cleanup_wq);
559}
560
561module_init(irqfd_module_init);
562module_exit(irqfd_module_exit);
Alexander Graf914daba2012-10-09 00:22:59 +0200563#endif
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400564
565/*
566 * --------------------------------------------------------------------
567 * ioeventfd: translate a PIO/MMIO memory write to an eventfd signal.
568 *
569 * userspace can register a PIO/MMIO address with an eventfd for receiving
570 * notification when the memory has been touched.
571 * --------------------------------------------------------------------
572 */
573
574struct _ioeventfd {
575 struct list_head list;
576 u64 addr;
577 int length;
578 struct eventfd_ctx *eventfd;
579 u64 datamatch;
580 struct kvm_io_device dev;
581 bool wildcard;
582};
583
584static inline struct _ioeventfd *
585to_ioeventfd(struct kvm_io_device *dev)
586{
587 return container_of(dev, struct _ioeventfd, dev);
588}
589
590static void
591ioeventfd_release(struct _ioeventfd *p)
592{
593 eventfd_ctx_put(p->eventfd);
594 list_del(&p->list);
595 kfree(p);
596}
597
598static bool
599ioeventfd_in_range(struct _ioeventfd *p, gpa_t addr, int len, const void *val)
600{
601 u64 _val;
602
603 if (!(addr == p->addr && len == p->length))
604 /* address-range must be precise for a hit */
605 return false;
606
607 if (p->wildcard)
608 /* all else equal, wildcard is always a hit */
609 return true;
610
611 /* otherwise, we have to actually compare the data */
612
613 BUG_ON(!IS_ALIGNED((unsigned long)val, len));
614
615 switch (len) {
616 case 1:
617 _val = *(u8 *)val;
618 break;
619 case 2:
620 _val = *(u16 *)val;
621 break;
622 case 4:
623 _val = *(u32 *)val;
624 break;
625 case 8:
626 _val = *(u64 *)val;
627 break;
628 default:
629 return false;
630 }
631
632 return _val == p->datamatch ? true : false;
633}
634
635/* MMIO/PIO writes trigger an event if the addr/val match */
636static int
637ioeventfd_write(struct kvm_io_device *this, gpa_t addr, int len,
638 const void *val)
639{
640 struct _ioeventfd *p = to_ioeventfd(this);
641
642 if (!ioeventfd_in_range(p, addr, len, val))
643 return -EOPNOTSUPP;
644
645 eventfd_signal(p->eventfd, 1);
646 return 0;
647}
648
649/*
650 * This function is called as KVM is completely shutting down. We do not
651 * need to worry about locking just nuke anything we have as quickly as possible
652 */
653static void
654ioeventfd_destructor(struct kvm_io_device *this)
655{
656 struct _ioeventfd *p = to_ioeventfd(this);
657
658 ioeventfd_release(p);
659}
660
661static const struct kvm_io_device_ops ioeventfd_ops = {
662 .write = ioeventfd_write,
663 .destructor = ioeventfd_destructor,
664};
665
666/* assumes kvm->slots_lock held */
667static bool
668ioeventfd_check_collision(struct kvm *kvm, struct _ioeventfd *p)
669{
670 struct _ioeventfd *_p;
671
672 list_for_each_entry(_p, &kvm->ioeventfds, list)
673 if (_p->addr == p->addr && _p->length == p->length &&
674 (_p->wildcard || p->wildcard ||
675 _p->datamatch == p->datamatch))
676 return true;
677
678 return false;
679}
680
681static int
682kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
683{
684 int pio = args->flags & KVM_IOEVENTFD_FLAG_PIO;
Marcelo Tosattie93f8a02009-12-23 14:35:24 -0200685 enum kvm_bus bus_idx = pio ? KVM_PIO_BUS : KVM_MMIO_BUS;
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400686 struct _ioeventfd *p;
687 struct eventfd_ctx *eventfd;
688 int ret;
689
690 /* must be natural-word sized */
691 switch (args->len) {
692 case 1:
693 case 2:
694 case 4:
695 case 8:
696 break;
697 default:
698 return -EINVAL;
699 }
700
701 /* check for range overflow */
702 if (args->addr + args->len < args->addr)
703 return -EINVAL;
704
705 /* check for extra flags that we don't understand */
706 if (args->flags & ~KVM_IOEVENTFD_VALID_FLAG_MASK)
707 return -EINVAL;
708
709 eventfd = eventfd_ctx_fdget(args->fd);
710 if (IS_ERR(eventfd))
711 return PTR_ERR(eventfd);
712
713 p = kzalloc(sizeof(*p), GFP_KERNEL);
714 if (!p) {
715 ret = -ENOMEM;
716 goto fail;
717 }
718
719 INIT_LIST_HEAD(&p->list);
720 p->addr = args->addr;
721 p->length = args->len;
722 p->eventfd = eventfd;
723
724 /* The datamatch feature is optional, otherwise this is a wildcard */
725 if (args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH)
726 p->datamatch = args->datamatch;
727 else
728 p->wildcard = true;
729
Marcelo Tosatti79fac952009-12-23 14:35:26 -0200730 mutex_lock(&kvm->slots_lock);
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400731
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300732 /* Verify that there isn't a match already */
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400733 if (ioeventfd_check_collision(kvm, p)) {
734 ret = -EEXIST;
735 goto unlock_fail;
736 }
737
738 kvm_iodevice_init(&p->dev, &ioeventfd_ops);
739
Sasha Levin743eeb02011-07-27 16:00:48 +0300740 ret = kvm_io_bus_register_dev(kvm, bus_idx, p->addr, p->length,
741 &p->dev);
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400742 if (ret < 0)
743 goto unlock_fail;
744
745 list_add_tail(&p->list, &kvm->ioeventfds);
746
Marcelo Tosatti79fac952009-12-23 14:35:26 -0200747 mutex_unlock(&kvm->slots_lock);
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400748
749 return 0;
750
751unlock_fail:
Marcelo Tosatti79fac952009-12-23 14:35:26 -0200752 mutex_unlock(&kvm->slots_lock);
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400753
754fail:
755 kfree(p);
756 eventfd_ctx_put(eventfd);
757
758 return ret;
759}
760
761static int
762kvm_deassign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
763{
764 int pio = args->flags & KVM_IOEVENTFD_FLAG_PIO;
Marcelo Tosattie93f8a02009-12-23 14:35:24 -0200765 enum kvm_bus bus_idx = pio ? KVM_PIO_BUS : KVM_MMIO_BUS;
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400766 struct _ioeventfd *p, *tmp;
767 struct eventfd_ctx *eventfd;
768 int ret = -ENOENT;
769
770 eventfd = eventfd_ctx_fdget(args->fd);
771 if (IS_ERR(eventfd))
772 return PTR_ERR(eventfd);
773
Marcelo Tosatti79fac952009-12-23 14:35:26 -0200774 mutex_lock(&kvm->slots_lock);
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400775
776 list_for_each_entry_safe(p, tmp, &kvm->ioeventfds, list) {
777 bool wildcard = !(args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH);
778
779 if (p->eventfd != eventfd ||
780 p->addr != args->addr ||
781 p->length != args->len ||
782 p->wildcard != wildcard)
783 continue;
784
785 if (!p->wildcard && p->datamatch != args->datamatch)
786 continue;
787
Marcelo Tosattie93f8a02009-12-23 14:35:24 -0200788 kvm_io_bus_unregister_dev(kvm, bus_idx, &p->dev);
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400789 ioeventfd_release(p);
790 ret = 0;
791 break;
792 }
793
Marcelo Tosatti79fac952009-12-23 14:35:26 -0200794 mutex_unlock(&kvm->slots_lock);
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400795
796 eventfd_ctx_put(eventfd);
797
798 return ret;
799}
800
801int
802kvm_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
803{
804 if (args->flags & KVM_IOEVENTFD_FLAG_DEASSIGN)
805 return kvm_deassign_ioeventfd(kvm, args);
806
807 return kvm_assign_ioeventfd(kvm, args);
808}