blob: 64ee720b75c7ac4a80c4e1c06cd5cacf0a3fa961 [file] [log] [blame]
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 Grafa725d562013-04-17 13:29:30 +020038#ifdef CONFIG_HAVE_KVM_IRQ_ROUTING
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) {
Yang Zhangaa2fbe62013-04-11 19:21:40 +0800103 kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 1,
104 false);
105 kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 0,
106 false);
Alex Williamson7a844282012-09-21 11:58:03 -0600107 } else
108 kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID,
Yang Zhangaa2fbe62013-04-11 19:21:40 +0800109 irqfd->gsi, 1, false);
Alex Williamson7a844282012-09-21 11:58:03 -0600110}
111
112/*
113 * Since resampler irqfds share an IRQ source ID, we de-assert once
114 * then notify all of the resampler irqfds using this GSI. We can't
115 * do multiple de-asserts or we risk racing with incoming re-asserts.
116 */
117static void
118irqfd_resampler_ack(struct kvm_irq_ack_notifier *kian)
119{
120 struct _irqfd_resampler *resampler;
121 struct _irqfd *irqfd;
122
123 resampler = container_of(kian, struct _irqfd_resampler, notifier);
124
125 kvm_set_irq(resampler->kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID,
Yang Zhangaa2fbe62013-04-11 19:21:40 +0800126 resampler->notifier.gsi, 0, false);
Alex Williamson7a844282012-09-21 11:58:03 -0600127
128 rcu_read_lock();
129
130 list_for_each_entry_rcu(irqfd, &resampler->list, resampler_link)
131 eventfd_signal(irqfd->resamplefd, 1);
132
133 rcu_read_unlock();
134}
135
136static void
137irqfd_resampler_shutdown(struct _irqfd *irqfd)
138{
139 struct _irqfd_resampler *resampler = irqfd->resampler;
140 struct kvm *kvm = resampler->kvm;
141
142 mutex_lock(&kvm->irqfds.resampler_lock);
143
144 list_del_rcu(&irqfd->resampler_link);
145 synchronize_rcu();
146
147 if (list_empty(&resampler->list)) {
148 list_del(&resampler->link);
149 kvm_unregister_irq_ack_notifier(kvm, &resampler->notifier);
150 kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID,
Yang Zhangaa2fbe62013-04-11 19:21:40 +0800151 resampler->notifier.gsi, 0, false);
Alex Williamson7a844282012-09-21 11:58:03 -0600152 kfree(resampler);
153 }
154
155 mutex_unlock(&kvm->irqfds.resampler_lock);
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400156}
157
158/*
159 * Race-free decouple logic (ordering is critical)
160 */
161static void
162irqfd_shutdown(struct work_struct *work)
163{
164 struct _irqfd *irqfd = container_of(work, struct _irqfd, shutdown);
Michael S. Tsirkinb6a114d2010-01-13 19:12:30 +0200165 u64 cnt;
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400166
167 /*
168 * Synchronize with the wait-queue and unhook ourselves to prevent
169 * further events.
170 */
Michael S. Tsirkinb6a114d2010-01-13 19:12:30 +0200171 eventfd_ctx_remove_wait_queue(irqfd->eventfd, &irqfd->wait, &cnt);
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400172
173 /*
174 * We know no new events will be scheduled at this point, so block
175 * until all previously outstanding events have completed
176 */
Tejun Heo43829732012-08-20 14:51:24 -0700177 flush_work(&irqfd->inject);
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400178
Alex Williamson7a844282012-09-21 11:58:03 -0600179 if (irqfd->resampler) {
180 irqfd_resampler_shutdown(irqfd);
181 eventfd_ctx_put(irqfd->resamplefd);
182 }
183
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400184 /*
185 * It is now safe to release the object's resources
186 */
187 eventfd_ctx_put(irqfd->eventfd);
188 kfree(irqfd);
189}
190
191
192/* assumes kvm->irqfds.lock is held */
193static bool
194irqfd_is_active(struct _irqfd *irqfd)
195{
196 return list_empty(&irqfd->list) ? false : true;
197}
198
199/*
200 * Mark the irqfd as inactive and schedule it for removal
201 *
202 * assumes kvm->irqfds.lock is held
203 */
204static void
205irqfd_deactivate(struct _irqfd *irqfd)
206{
207 BUG_ON(!irqfd_is_active(irqfd));
208
209 list_del_init(&irqfd->list);
210
211 queue_work(irqfd_cleanup_wq, &irqfd->shutdown);
212}
213
214/*
215 * Called with wqh->lock held and interrupts disabled
216 */
217static int
218irqfd_wakeup(wait_queue_t *wait, unsigned mode, int sync, void *key)
219{
220 struct _irqfd *irqfd = container_of(wait, struct _irqfd, wait);
221 unsigned long flags = (unsigned long)key;
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200222 struct kvm_kernel_irq_routing_entry *irq;
223 struct kvm *kvm = irqfd->kvm;
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400224
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200225 if (flags & POLLIN) {
226 rcu_read_lock();
227 irq = rcu_dereference(irqfd->irq_entry);
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400228 /* An event has been signaled, inject an interrupt */
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200229 if (irq)
Yang Zhangaa2fbe62013-04-11 19:21:40 +0800230 kvm_set_msi(irq, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1,
231 false);
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200232 else
233 schedule_work(&irqfd->inject);
234 rcu_read_unlock();
235 }
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400236
237 if (flags & POLLHUP) {
238 /* The eventfd is closing, detach from KVM */
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400239 unsigned long flags;
240
241 spin_lock_irqsave(&kvm->irqfds.lock, flags);
242
243 /*
244 * We must check if someone deactivated the irqfd before
245 * we could acquire the irqfds.lock since the item is
246 * deactivated from the KVM side before it is unhooked from
247 * the wait-queue. If it is already deactivated, we can
248 * simply return knowing the other side will cleanup for us.
249 * We cannot race against the irqfd going away since the
250 * other side is required to acquire wqh->lock, which we hold
251 */
252 if (irqfd_is_active(irqfd))
253 irqfd_deactivate(irqfd);
254
255 spin_unlock_irqrestore(&kvm->irqfds.lock, flags);
256 }
257
258 return 0;
259}
260
261static void
262irqfd_ptable_queue_proc(struct file *file, wait_queue_head_t *wqh,
263 poll_table *pt)
264{
265 struct _irqfd *irqfd = container_of(pt, struct _irqfd, pt);
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400266 add_wait_queue(wqh, &irqfd->wait);
267}
268
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200269/* Must be called under irqfds.lock */
270static void irqfd_update(struct kvm *kvm, struct _irqfd *irqfd,
271 struct kvm_irq_routing_table *irq_rt)
272{
273 struct kvm_kernel_irq_routing_entry *e;
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200274
275 if (irqfd->gsi >= irq_rt->nr_rt_entries) {
276 rcu_assign_pointer(irqfd->irq_entry, NULL);
277 return;
278 }
279
Sasha Levinb67bfe02013-02-27 17:06:00 -0800280 hlist_for_each_entry(e, &irq_rt->map[irqfd->gsi], link) {
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200281 /* Only fast-path MSI. */
282 if (e->type == KVM_IRQ_ROUTING_MSI)
283 rcu_assign_pointer(irqfd->irq_entry, e);
284 else
285 rcu_assign_pointer(irqfd->irq_entry, NULL);
286 }
287}
288
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400289static int
Alex Williamsond4db2932012-06-29 09:56:08 -0600290kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400291{
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200292 struct kvm_irq_routing_table *irq_rt;
Michael S. Tsirkinf1d1c302010-01-13 18:58:09 +0200293 struct _irqfd *irqfd, *tmp;
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400294 struct file *file = NULL;
Alex Williamson7a844282012-09-21 11:58:03 -0600295 struct eventfd_ctx *eventfd = NULL, *resamplefd = NULL;
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400296 int ret;
297 unsigned int events;
298
299 irqfd = kzalloc(sizeof(*irqfd), GFP_KERNEL);
300 if (!irqfd)
301 return -ENOMEM;
302
303 irqfd->kvm = kvm;
Alex Williamsond4db2932012-06-29 09:56:08 -0600304 irqfd->gsi = args->gsi;
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400305 INIT_LIST_HEAD(&irqfd->list);
306 INIT_WORK(&irqfd->inject, irqfd_inject);
307 INIT_WORK(&irqfd->shutdown, irqfd_shutdown);
308
Alex Williamsond4db2932012-06-29 09:56:08 -0600309 file = eventfd_fget(args->fd);
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400310 if (IS_ERR(file)) {
311 ret = PTR_ERR(file);
312 goto fail;
313 }
314
315 eventfd = eventfd_ctx_fileget(file);
316 if (IS_ERR(eventfd)) {
317 ret = PTR_ERR(eventfd);
318 goto fail;
319 }
320
321 irqfd->eventfd = eventfd;
322
Alex Williamson7a844282012-09-21 11:58:03 -0600323 if (args->flags & KVM_IRQFD_FLAG_RESAMPLE) {
324 struct _irqfd_resampler *resampler;
325
326 resamplefd = eventfd_ctx_fdget(args->resamplefd);
327 if (IS_ERR(resamplefd)) {
328 ret = PTR_ERR(resamplefd);
329 goto fail;
330 }
331
332 irqfd->resamplefd = resamplefd;
333 INIT_LIST_HEAD(&irqfd->resampler_link);
334
335 mutex_lock(&kvm->irqfds.resampler_lock);
336
337 list_for_each_entry(resampler,
Alex Williamson49f8a1a2012-12-06 14:44:59 -0700338 &kvm->irqfds.resampler_list, link) {
Alex Williamson7a844282012-09-21 11:58:03 -0600339 if (resampler->notifier.gsi == irqfd->gsi) {
340 irqfd->resampler = resampler;
341 break;
342 }
343 }
344
345 if (!irqfd->resampler) {
346 resampler = kzalloc(sizeof(*resampler), GFP_KERNEL);
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);
366 synchronize_rcu();
367
368 mutex_unlock(&kvm->irqfds.resampler_lock);
369 }
370
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400371 /*
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
Michael S. Tsirkinf1d1c302010-01-13 18:58:09 +0200378 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
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200390 irq_rt = rcu_dereference_protected(kvm->irq_routing,
391 lockdep_is_held(&kvm->irqfds.lock));
392 irqfd_update(kvm, irqfd, irq_rt);
393
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400394 events = file->f_op->poll(file, &irqfd->pt);
395
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400396 list_add_tail(&irqfd->list, &kvm->irqfds.items);
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400397
398 /*
399 * Check if there was an event already pending on the eventfd
400 * before we registered, and trigger it as if we didn't miss it.
401 */
402 if (events & POLLIN)
403 schedule_work(&irqfd->inject);
404
Michael S. Tsirkin6bbfb262010-09-19 19:02:31 +0200405 spin_unlock_irq(&kvm->irqfds.lock);
406
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400407 /*
408 * do not drop the file until the irqfd is fully initialized, otherwise
409 * we might race against the POLLHUP
410 */
411 fput(file);
412
413 return 0;
414
415fail:
Alex Williamson7a844282012-09-21 11:58:03 -0600416 if (irqfd->resampler)
417 irqfd_resampler_shutdown(irqfd);
418
419 if (resamplefd && !IS_ERR(resamplefd))
420 eventfd_ctx_put(resamplefd);
421
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400422 if (eventfd && !IS_ERR(eventfd))
423 eventfd_ctx_put(eventfd);
424
Julia Lawall62230112009-07-28 17:53:24 +0200425 if (!IS_ERR(file))
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400426 fput(file);
427
428 kfree(irqfd);
429 return ret;
430}
Alexander Graf914daba2012-10-09 00:22:59 +0200431#endif
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400432
433void
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400434kvm_eventfd_init(struct kvm *kvm)
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400435{
Alexander Grafa725d562013-04-17 13:29:30 +0200436#ifdef CONFIG_HAVE_KVM_IRQ_ROUTING
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400437 spin_lock_init(&kvm->irqfds.lock);
438 INIT_LIST_HEAD(&kvm->irqfds.items);
Alex Williamson7a844282012-09-21 11:58:03 -0600439 INIT_LIST_HEAD(&kvm->irqfds.resampler_list);
440 mutex_init(&kvm->irqfds.resampler_lock);
Alexander Graf914daba2012-10-09 00:22:59 +0200441#endif
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400442 INIT_LIST_HEAD(&kvm->ioeventfds);
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400443}
444
Alexander Grafa725d562013-04-17 13:29:30 +0200445#ifdef CONFIG_HAVE_KVM_IRQ_ROUTING
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400446/*
447 * shutdown any irqfd's that match fd+gsi
448 */
449static int
Alex Williamsond4db2932012-06-29 09:56:08 -0600450kvm_irqfd_deassign(struct kvm *kvm, struct kvm_irqfd *args)
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400451{
452 struct _irqfd *irqfd, *tmp;
453 struct eventfd_ctx *eventfd;
454
Alex Williamsond4db2932012-06-29 09:56:08 -0600455 eventfd = eventfd_ctx_fdget(args->fd);
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400456 if (IS_ERR(eventfd))
457 return PTR_ERR(eventfd);
458
459 spin_lock_irq(&kvm->irqfds.lock);
460
461 list_for_each_entry_safe(irqfd, tmp, &kvm->irqfds.items, list) {
Alex Williamsond4db2932012-06-29 09:56:08 -0600462 if (irqfd->eventfd == eventfd && irqfd->gsi == args->gsi) {
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200463 /*
464 * This rcu_assign_pointer is needed for when
Michael S. Tsirkinc8ce0572011-03-06 13:03:26 +0200465 * another thread calls kvm_irq_routing_update before
466 * we flush workqueue below (we synchronize with
467 * kvm_irq_routing_update using irqfds.lock).
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200468 * It is paired with synchronize_rcu done by caller
469 * of that function.
470 */
471 rcu_assign_pointer(irqfd->irq_entry, NULL);
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400472 irqfd_deactivate(irqfd);
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200473 }
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400474 }
475
476 spin_unlock_irq(&kvm->irqfds.lock);
477 eventfd_ctx_put(eventfd);
478
479 /*
480 * Block until we know all outstanding shutdown jobs have completed
481 * so that we guarantee there will not be any more interrupts on this
482 * gsi once this deassign function returns.
483 */
484 flush_workqueue(irqfd_cleanup_wq);
485
486 return 0;
487}
488
489int
Alex Williamsond4db2932012-06-29 09:56:08 -0600490kvm_irqfd(struct kvm *kvm, struct kvm_irqfd *args)
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400491{
Alex Williamson7a844282012-09-21 11:58:03 -0600492 if (args->flags & ~(KVM_IRQFD_FLAG_DEASSIGN | KVM_IRQFD_FLAG_RESAMPLE))
Alex Williamson326cf032012-06-29 09:56:24 -0600493 return -EINVAL;
494
Alex Williamsond4db2932012-06-29 09:56:08 -0600495 if (args->flags & KVM_IRQFD_FLAG_DEASSIGN)
496 return kvm_irqfd_deassign(kvm, args);
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400497
Alex Williamsond4db2932012-06-29 09:56:08 -0600498 return kvm_irqfd_assign(kvm, args);
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400499}
500
501/*
502 * This function is called as the kvm VM fd is being released. Shutdown all
503 * irqfds that still remain open
504 */
505void
506kvm_irqfd_release(struct kvm *kvm)
507{
508 struct _irqfd *irqfd, *tmp;
509
510 spin_lock_irq(&kvm->irqfds.lock);
511
512 list_for_each_entry_safe(irqfd, tmp, &kvm->irqfds.items, list)
513 irqfd_deactivate(irqfd);
514
515 spin_unlock_irq(&kvm->irqfds.lock);
516
517 /*
518 * Block until we know all outstanding shutdown jobs have completed
519 * since we do not take a kvm* reference.
520 */
521 flush_workqueue(irqfd_cleanup_wq);
522
523}
524
525/*
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200526 * Change irq_routing and irqfd.
527 * Caller must invoke synchronize_rcu afterwards.
528 */
529void kvm_irq_routing_update(struct kvm *kvm,
530 struct kvm_irq_routing_table *irq_rt)
531{
532 struct _irqfd *irqfd;
533
534 spin_lock_irq(&kvm->irqfds.lock);
535
536 rcu_assign_pointer(kvm->irq_routing, irq_rt);
537
538 list_for_each_entry(irqfd, &kvm->irqfds.items, list)
539 irqfd_update(kvm, irqfd, irq_rt);
540
541 spin_unlock_irq(&kvm->irqfds.lock);
542}
543
544/*
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400545 * create a host-wide workqueue for issuing deferred shutdown requests
546 * aggregated from all vm* instances. We need our own isolated single-thread
547 * queue to prevent deadlock against flushing the normal work-queue.
548 */
Cornelia Hucka0f155e2013-02-28 12:33:18 +0100549int kvm_irqfd_init(void)
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400550{
551 irqfd_cleanup_wq = create_singlethread_workqueue("kvm-irqfd-cleanup");
552 if (!irqfd_cleanup_wq)
553 return -ENOMEM;
554
555 return 0;
556}
557
Cornelia Hucka0f155e2013-02-28 12:33:18 +0100558void kvm_irqfd_exit(void)
Gregory Haskins721eecbf2009-05-20 10:30:49 -0400559{
560 destroy_workqueue(irqfd_cleanup_wq);
561}
Alexander Graf914daba2012-10-09 00:22:59 +0200562#endif
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400563
564/*
565 * --------------------------------------------------------------------
566 * ioeventfd: translate a PIO/MMIO memory write to an eventfd signal.
567 *
568 * userspace can register a PIO/MMIO address with an eventfd for receiving
569 * notification when the memory has been touched.
570 * --------------------------------------------------------------------
571 */
572
573struct _ioeventfd {
574 struct list_head list;
575 u64 addr;
576 int length;
577 struct eventfd_ctx *eventfd;
578 u64 datamatch;
579 struct kvm_io_device dev;
Michael S. Tsirkin05e07f92013-04-04 13:27:21 +0300580 u8 bus_idx;
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400581 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)
Michael S. Tsirkin05e07f92013-04-04 13:27:21 +0300673 if (_p->bus_idx == p->bus_idx &&
674 _p->addr == p->addr && _p->length == p->length &&
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400675 (_p->wildcard || p->wildcard ||
676 _p->datamatch == p->datamatch))
677 return true;
678
679 return false;
680}
681
Cornelia Huck2b834512013-02-28 12:33:20 +0100682static enum kvm_bus ioeventfd_bus_from_flags(__u32 flags)
683{
684 if (flags & KVM_IOEVENTFD_FLAG_PIO)
685 return KVM_PIO_BUS;
686 if (flags & KVM_IOEVENTFD_FLAG_VIRTIO_CCW_NOTIFY)
687 return KVM_VIRTIO_CCW_NOTIFY_BUS;
688 return KVM_MMIO_BUS;
689}
690
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400691static int
692kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
693{
Cornelia Huck2b834512013-02-28 12:33:20 +0100694 enum kvm_bus bus_idx;
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400695 struct _ioeventfd *p;
696 struct eventfd_ctx *eventfd;
697 int ret;
698
Cornelia Huck2b834512013-02-28 12:33:20 +0100699 bus_idx = ioeventfd_bus_from_flags(args->flags);
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400700 /* must be natural-word sized */
701 switch (args->len) {
702 case 1:
703 case 2:
704 case 4:
705 case 8:
706 break;
707 default:
708 return -EINVAL;
709 }
710
711 /* check for range overflow */
712 if (args->addr + args->len < args->addr)
713 return -EINVAL;
714
715 /* check for extra flags that we don't understand */
716 if (args->flags & ~KVM_IOEVENTFD_VALID_FLAG_MASK)
717 return -EINVAL;
718
719 eventfd = eventfd_ctx_fdget(args->fd);
720 if (IS_ERR(eventfd))
721 return PTR_ERR(eventfd);
722
723 p = kzalloc(sizeof(*p), GFP_KERNEL);
724 if (!p) {
725 ret = -ENOMEM;
726 goto fail;
727 }
728
729 INIT_LIST_HEAD(&p->list);
730 p->addr = args->addr;
Michael S. Tsirkin05e07f92013-04-04 13:27:21 +0300731 p->bus_idx = bus_idx;
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400732 p->length = args->len;
733 p->eventfd = eventfd;
734
735 /* The datamatch feature is optional, otherwise this is a wildcard */
736 if (args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH)
737 p->datamatch = args->datamatch;
738 else
739 p->wildcard = true;
740
Marcelo Tosatti79fac952009-12-23 14:35:26 -0200741 mutex_lock(&kvm->slots_lock);
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400742
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300743 /* Verify that there isn't a match already */
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400744 if (ioeventfd_check_collision(kvm, p)) {
745 ret = -EEXIST;
746 goto unlock_fail;
747 }
748
749 kvm_iodevice_init(&p->dev, &ioeventfd_ops);
750
Sasha Levin743eeb02011-07-27 16:00:48 +0300751 ret = kvm_io_bus_register_dev(kvm, bus_idx, p->addr, p->length,
752 &p->dev);
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400753 if (ret < 0)
754 goto unlock_fail;
755
756 list_add_tail(&p->list, &kvm->ioeventfds);
757
Marcelo Tosatti79fac952009-12-23 14:35:26 -0200758 mutex_unlock(&kvm->slots_lock);
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400759
760 return 0;
761
762unlock_fail:
Marcelo Tosatti79fac952009-12-23 14:35:26 -0200763 mutex_unlock(&kvm->slots_lock);
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400764
765fail:
766 kfree(p);
767 eventfd_ctx_put(eventfd);
768
769 return ret;
770}
771
772static int
773kvm_deassign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
774{
Cornelia Huck2b834512013-02-28 12:33:20 +0100775 enum kvm_bus bus_idx;
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400776 struct _ioeventfd *p, *tmp;
777 struct eventfd_ctx *eventfd;
778 int ret = -ENOENT;
779
Cornelia Huck2b834512013-02-28 12:33:20 +0100780 bus_idx = ioeventfd_bus_from_flags(args->flags);
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400781 eventfd = eventfd_ctx_fdget(args->fd);
782 if (IS_ERR(eventfd))
783 return PTR_ERR(eventfd);
784
Marcelo Tosatti79fac952009-12-23 14:35:26 -0200785 mutex_lock(&kvm->slots_lock);
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400786
787 list_for_each_entry_safe(p, tmp, &kvm->ioeventfds, list) {
788 bool wildcard = !(args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH);
789
Michael S. Tsirkin05e07f92013-04-04 13:27:21 +0300790 if (p->bus_idx != bus_idx ||
791 p->eventfd != eventfd ||
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400792 p->addr != args->addr ||
793 p->length != args->len ||
794 p->wildcard != wildcard)
795 continue;
796
797 if (!p->wildcard && p->datamatch != args->datamatch)
798 continue;
799
Marcelo Tosattie93f8a02009-12-23 14:35:24 -0200800 kvm_io_bus_unregister_dev(kvm, bus_idx, &p->dev);
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400801 ioeventfd_release(p);
802 ret = 0;
803 break;
804 }
805
Marcelo Tosatti79fac952009-12-23 14:35:26 -0200806 mutex_unlock(&kvm->slots_lock);
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400807
808 eventfd_ctx_put(eventfd);
809
810 return ret;
811}
812
813int
814kvm_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
815{
816 if (args->flags & KVM_IOEVENTFD_FLAG_DEASSIGN)
817 return kvm_deassign_ioeventfd(kvm, args);
818
819 return kvm_assign_ioeventfd(kvm, args);
820}