blob: 7d7e2aaffece234a81cef3f4181cc7ffe5bb14cb [file] [log] [blame]
Gregory Haskins721eecb2009-05-20 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 Haskins721eecb2009-05-20 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 Haskins721eecb2009-05-20 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 Haskins721eecb2009-05-20 10:30:49 -040037
38/*
39 * --------------------------------------------------------------------
40 * irqfd: Allows an fd to be used to inject an interrupt to the guest
41 *
42 * Credit goes to Avi Kivity for the original idea.
43 * --------------------------------------------------------------------
44 */
45
46struct _irqfd {
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +020047 /* Used for MSI fast-path */
48 struct kvm *kvm;
49 wait_queue_t wait;
50 /* Update side is protected by irqfds.lock */
51 struct kvm_kernel_irq_routing_entry __rcu *irq_entry;
52 /* Used for level IRQ fast-path */
53 int gsi;
54 struct work_struct inject;
55 /* Used for setup/shutdown */
56 struct eventfd_ctx *eventfd;
57 struct list_head list;
58 poll_table pt;
59 struct work_struct shutdown;
Gregory Haskins721eecb2009-05-20 10:30:49 -040060};
61
62static struct workqueue_struct *irqfd_cleanup_wq;
63
64static void
65irqfd_inject(struct work_struct *work)
66{
67 struct _irqfd *irqfd = container_of(work, struct _irqfd, inject);
68 struct kvm *kvm = irqfd->kvm;
69
Gregory Haskins721eecb2009-05-20 10:30:49 -040070 kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 1);
71 kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 0);
Gregory Haskins721eecb2009-05-20 10:30:49 -040072}
73
74/*
75 * Race-free decouple logic (ordering is critical)
76 */
77static void
78irqfd_shutdown(struct work_struct *work)
79{
80 struct _irqfd *irqfd = container_of(work, struct _irqfd, shutdown);
Michael S. Tsirkinb6a114d2010-01-13 19:12:30 +020081 u64 cnt;
Gregory Haskins721eecb2009-05-20 10:30:49 -040082
83 /*
84 * Synchronize with the wait-queue and unhook ourselves to prevent
85 * further events.
86 */
Michael S. Tsirkinb6a114d2010-01-13 19:12:30 +020087 eventfd_ctx_remove_wait_queue(irqfd->eventfd, &irqfd->wait, &cnt);
Gregory Haskins721eecb2009-05-20 10:30:49 -040088
89 /*
90 * We know no new events will be scheduled at this point, so block
91 * until all previously outstanding events have completed
92 */
Michael S. Tsirkin9e02fb92011-03-17 10:53:33 +020093 flush_work_sync(&irqfd->inject);
Gregory Haskins721eecb2009-05-20 10:30:49 -040094
95 /*
96 * It is now safe to release the object's resources
97 */
98 eventfd_ctx_put(irqfd->eventfd);
99 kfree(irqfd);
100}
101
102
103/* assumes kvm->irqfds.lock is held */
104static bool
105irqfd_is_active(struct _irqfd *irqfd)
106{
107 return list_empty(&irqfd->list) ? false : true;
108}
109
110/*
111 * Mark the irqfd as inactive and schedule it for removal
112 *
113 * assumes kvm->irqfds.lock is held
114 */
115static void
116irqfd_deactivate(struct _irqfd *irqfd)
117{
118 BUG_ON(!irqfd_is_active(irqfd));
119
120 list_del_init(&irqfd->list);
121
122 queue_work(irqfd_cleanup_wq, &irqfd->shutdown);
123}
124
125/*
126 * Called with wqh->lock held and interrupts disabled
127 */
128static int
129irqfd_wakeup(wait_queue_t *wait, unsigned mode, int sync, void *key)
130{
131 struct _irqfd *irqfd = container_of(wait, struct _irqfd, wait);
132 unsigned long flags = (unsigned long)key;
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200133 struct kvm_kernel_irq_routing_entry *irq;
134 struct kvm *kvm = irqfd->kvm;
Gregory Haskins721eecb2009-05-20 10:30:49 -0400135
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200136 if (flags & POLLIN) {
137 rcu_read_lock();
138 irq = rcu_dereference(irqfd->irq_entry);
Gregory Haskins721eecb2009-05-20 10:30:49 -0400139 /* An event has been signaled, inject an interrupt */
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200140 if (irq)
141 kvm_set_msi(irq, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1);
142 else
143 schedule_work(&irqfd->inject);
144 rcu_read_unlock();
145 }
Gregory Haskins721eecb2009-05-20 10:30:49 -0400146
147 if (flags & POLLHUP) {
148 /* The eventfd is closing, detach from KVM */
Gregory Haskins721eecb2009-05-20 10:30:49 -0400149 unsigned long flags;
150
151 spin_lock_irqsave(&kvm->irqfds.lock, flags);
152
153 /*
154 * We must check if someone deactivated the irqfd before
155 * we could acquire the irqfds.lock since the item is
156 * deactivated from the KVM side before it is unhooked from
157 * the wait-queue. If it is already deactivated, we can
158 * simply return knowing the other side will cleanup for us.
159 * We cannot race against the irqfd going away since the
160 * other side is required to acquire wqh->lock, which we hold
161 */
162 if (irqfd_is_active(irqfd))
163 irqfd_deactivate(irqfd);
164
165 spin_unlock_irqrestore(&kvm->irqfds.lock, flags);
166 }
167
168 return 0;
169}
170
171static void
172irqfd_ptable_queue_proc(struct file *file, wait_queue_head_t *wqh,
173 poll_table *pt)
174{
175 struct _irqfd *irqfd = container_of(pt, struct _irqfd, pt);
Gregory Haskins721eecb2009-05-20 10:30:49 -0400176 add_wait_queue(wqh, &irqfd->wait);
177}
178
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200179/* Must be called under irqfds.lock */
180static void irqfd_update(struct kvm *kvm, struct _irqfd *irqfd,
181 struct kvm_irq_routing_table *irq_rt)
182{
183 struct kvm_kernel_irq_routing_entry *e;
184 struct hlist_node *n;
185
186 if (irqfd->gsi >= irq_rt->nr_rt_entries) {
187 rcu_assign_pointer(irqfd->irq_entry, NULL);
188 return;
189 }
190
191 hlist_for_each_entry(e, n, &irq_rt->map[irqfd->gsi], link) {
192 /* Only fast-path MSI. */
193 if (e->type == KVM_IRQ_ROUTING_MSI)
194 rcu_assign_pointer(irqfd->irq_entry, e);
195 else
196 rcu_assign_pointer(irqfd->irq_entry, NULL);
197 }
198}
199
Gregory Haskins721eecb2009-05-20 10:30:49 -0400200static int
Alex Williamsond4db2932012-06-29 09:56:08 -0600201kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
Gregory Haskins721eecb2009-05-20 10:30:49 -0400202{
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200203 struct kvm_irq_routing_table *irq_rt;
Michael S. Tsirkinf1d1c302010-01-13 18:58:09 +0200204 struct _irqfd *irqfd, *tmp;
Gregory Haskins721eecb2009-05-20 10:30:49 -0400205 struct file *file = NULL;
206 struct eventfd_ctx *eventfd = NULL;
207 int ret;
208 unsigned int events;
209
210 irqfd = kzalloc(sizeof(*irqfd), GFP_KERNEL);
211 if (!irqfd)
212 return -ENOMEM;
213
214 irqfd->kvm = kvm;
Alex Williamsond4db2932012-06-29 09:56:08 -0600215 irqfd->gsi = args->gsi;
Gregory Haskins721eecb2009-05-20 10:30:49 -0400216 INIT_LIST_HEAD(&irqfd->list);
217 INIT_WORK(&irqfd->inject, irqfd_inject);
218 INIT_WORK(&irqfd->shutdown, irqfd_shutdown);
219
Alex Williamsond4db2932012-06-29 09:56:08 -0600220 file = eventfd_fget(args->fd);
Gregory Haskins721eecb2009-05-20 10:30:49 -0400221 if (IS_ERR(file)) {
222 ret = PTR_ERR(file);
223 goto fail;
224 }
225
226 eventfd = eventfd_ctx_fileget(file);
227 if (IS_ERR(eventfd)) {
228 ret = PTR_ERR(eventfd);
229 goto fail;
230 }
231
232 irqfd->eventfd = eventfd;
233
234 /*
235 * Install our own custom wake-up handling so we are notified via
236 * a callback whenever someone signals the underlying eventfd
237 */
238 init_waitqueue_func_entry(&irqfd->wait, irqfd_wakeup);
239 init_poll_funcptr(&irqfd->pt, irqfd_ptable_queue_proc);
240
Michael S. Tsirkinf1d1c302010-01-13 18:58:09 +0200241 spin_lock_irq(&kvm->irqfds.lock);
242
243 ret = 0;
244 list_for_each_entry(tmp, &kvm->irqfds.items, list) {
245 if (irqfd->eventfd != tmp->eventfd)
246 continue;
247 /* This fd is used for another irq already. */
248 ret = -EBUSY;
249 spin_unlock_irq(&kvm->irqfds.lock);
250 goto fail;
251 }
252
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200253 irq_rt = rcu_dereference_protected(kvm->irq_routing,
254 lockdep_is_held(&kvm->irqfds.lock));
255 irqfd_update(kvm, irqfd, irq_rt);
256
Gregory Haskins721eecb2009-05-20 10:30:49 -0400257 events = file->f_op->poll(file, &irqfd->pt);
258
Gregory Haskins721eecb2009-05-20 10:30:49 -0400259 list_add_tail(&irqfd->list, &kvm->irqfds.items);
Gregory Haskins721eecb2009-05-20 10:30:49 -0400260
261 /*
262 * Check if there was an event already pending on the eventfd
263 * before we registered, and trigger it as if we didn't miss it.
264 */
265 if (events & POLLIN)
266 schedule_work(&irqfd->inject);
267
Michael S. Tsirkin6bbfb262010-09-19 19:02:31 +0200268 spin_unlock_irq(&kvm->irqfds.lock);
269
Gregory Haskins721eecb2009-05-20 10:30:49 -0400270 /*
271 * do not drop the file until the irqfd is fully initialized, otherwise
272 * we might race against the POLLHUP
273 */
274 fput(file);
275
276 return 0;
277
278fail:
279 if (eventfd && !IS_ERR(eventfd))
280 eventfd_ctx_put(eventfd);
281
Julia Lawall62230112009-07-28 17:53:24 +0200282 if (!IS_ERR(file))
Gregory Haskins721eecb2009-05-20 10:30:49 -0400283 fput(file);
284
285 kfree(irqfd);
286 return ret;
287}
288
289void
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400290kvm_eventfd_init(struct kvm *kvm)
Gregory Haskins721eecb2009-05-20 10:30:49 -0400291{
292 spin_lock_init(&kvm->irqfds.lock);
293 INIT_LIST_HEAD(&kvm->irqfds.items);
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400294 INIT_LIST_HEAD(&kvm->ioeventfds);
Gregory Haskins721eecb2009-05-20 10:30:49 -0400295}
296
297/*
298 * shutdown any irqfd's that match fd+gsi
299 */
300static int
Alex Williamsond4db2932012-06-29 09:56:08 -0600301kvm_irqfd_deassign(struct kvm *kvm, struct kvm_irqfd *args)
Gregory Haskins721eecb2009-05-20 10:30:49 -0400302{
303 struct _irqfd *irqfd, *tmp;
304 struct eventfd_ctx *eventfd;
305
Alex Williamsond4db2932012-06-29 09:56:08 -0600306 eventfd = eventfd_ctx_fdget(args->fd);
Gregory Haskins721eecb2009-05-20 10:30:49 -0400307 if (IS_ERR(eventfd))
308 return PTR_ERR(eventfd);
309
310 spin_lock_irq(&kvm->irqfds.lock);
311
312 list_for_each_entry_safe(irqfd, tmp, &kvm->irqfds.items, list) {
Alex Williamsond4db2932012-06-29 09:56:08 -0600313 if (irqfd->eventfd == eventfd && irqfd->gsi == args->gsi) {
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200314 /*
315 * This rcu_assign_pointer is needed for when
Michael S. Tsirkinc8ce0572011-03-06 13:03:26 +0200316 * another thread calls kvm_irq_routing_update before
317 * we flush workqueue below (we synchronize with
318 * kvm_irq_routing_update using irqfds.lock).
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200319 * It is paired with synchronize_rcu done by caller
320 * of that function.
321 */
322 rcu_assign_pointer(irqfd->irq_entry, NULL);
Gregory Haskins721eecb2009-05-20 10:30:49 -0400323 irqfd_deactivate(irqfd);
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200324 }
Gregory Haskins721eecb2009-05-20 10:30:49 -0400325 }
326
327 spin_unlock_irq(&kvm->irqfds.lock);
328 eventfd_ctx_put(eventfd);
329
330 /*
331 * Block until we know all outstanding shutdown jobs have completed
332 * so that we guarantee there will not be any more interrupts on this
333 * gsi once this deassign function returns.
334 */
335 flush_workqueue(irqfd_cleanup_wq);
336
337 return 0;
338}
339
340int
Alex Williamsond4db2932012-06-29 09:56:08 -0600341kvm_irqfd(struct kvm *kvm, struct kvm_irqfd *args)
Gregory Haskins721eecb2009-05-20 10:30:49 -0400342{
Alex Williamson326cf032012-06-29 09:56:24 -0600343 if (args->flags & ~KVM_IRQFD_FLAG_DEASSIGN)
344 return -EINVAL;
345
Alex Williamsond4db2932012-06-29 09:56:08 -0600346 if (args->flags & KVM_IRQFD_FLAG_DEASSIGN)
347 return kvm_irqfd_deassign(kvm, args);
Gregory Haskins721eecb2009-05-20 10:30:49 -0400348
Alex Williamsond4db2932012-06-29 09:56:08 -0600349 return kvm_irqfd_assign(kvm, args);
Gregory Haskins721eecb2009-05-20 10:30:49 -0400350}
351
352/*
353 * This function is called as the kvm VM fd is being released. Shutdown all
354 * irqfds that still remain open
355 */
356void
357kvm_irqfd_release(struct kvm *kvm)
358{
359 struct _irqfd *irqfd, *tmp;
360
361 spin_lock_irq(&kvm->irqfds.lock);
362
363 list_for_each_entry_safe(irqfd, tmp, &kvm->irqfds.items, list)
364 irqfd_deactivate(irqfd);
365
366 spin_unlock_irq(&kvm->irqfds.lock);
367
368 /*
369 * Block until we know all outstanding shutdown jobs have completed
370 * since we do not take a kvm* reference.
371 */
372 flush_workqueue(irqfd_cleanup_wq);
373
374}
375
376/*
Michael S. Tsirkinbd2b53b2010-11-18 19:09:08 +0200377 * Change irq_routing and irqfd.
378 * Caller must invoke synchronize_rcu afterwards.
379 */
380void kvm_irq_routing_update(struct kvm *kvm,
381 struct kvm_irq_routing_table *irq_rt)
382{
383 struct _irqfd *irqfd;
384
385 spin_lock_irq(&kvm->irqfds.lock);
386
387 rcu_assign_pointer(kvm->irq_routing, irq_rt);
388
389 list_for_each_entry(irqfd, &kvm->irqfds.items, list)
390 irqfd_update(kvm, irqfd, irq_rt);
391
392 spin_unlock_irq(&kvm->irqfds.lock);
393}
394
395/*
Gregory Haskins721eecb2009-05-20 10:30:49 -0400396 * create a host-wide workqueue for issuing deferred shutdown requests
397 * aggregated from all vm* instances. We need our own isolated single-thread
398 * queue to prevent deadlock against flushing the normal work-queue.
399 */
400static int __init irqfd_module_init(void)
401{
402 irqfd_cleanup_wq = create_singlethread_workqueue("kvm-irqfd-cleanup");
403 if (!irqfd_cleanup_wq)
404 return -ENOMEM;
405
406 return 0;
407}
408
409static void __exit irqfd_module_exit(void)
410{
411 destroy_workqueue(irqfd_cleanup_wq);
412}
413
414module_init(irqfd_module_init);
415module_exit(irqfd_module_exit);
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400416
417/*
418 * --------------------------------------------------------------------
419 * ioeventfd: translate a PIO/MMIO memory write to an eventfd signal.
420 *
421 * userspace can register a PIO/MMIO address with an eventfd for receiving
422 * notification when the memory has been touched.
423 * --------------------------------------------------------------------
424 */
425
426struct _ioeventfd {
427 struct list_head list;
428 u64 addr;
429 int length;
430 struct eventfd_ctx *eventfd;
431 u64 datamatch;
432 struct kvm_io_device dev;
433 bool wildcard;
434};
435
436static inline struct _ioeventfd *
437to_ioeventfd(struct kvm_io_device *dev)
438{
439 return container_of(dev, struct _ioeventfd, dev);
440}
441
442static void
443ioeventfd_release(struct _ioeventfd *p)
444{
445 eventfd_ctx_put(p->eventfd);
446 list_del(&p->list);
447 kfree(p);
448}
449
450static bool
451ioeventfd_in_range(struct _ioeventfd *p, gpa_t addr, int len, const void *val)
452{
453 u64 _val;
454
455 if (!(addr == p->addr && len == p->length))
456 /* address-range must be precise for a hit */
457 return false;
458
459 if (p->wildcard)
460 /* all else equal, wildcard is always a hit */
461 return true;
462
463 /* otherwise, we have to actually compare the data */
464
465 BUG_ON(!IS_ALIGNED((unsigned long)val, len));
466
467 switch (len) {
468 case 1:
469 _val = *(u8 *)val;
470 break;
471 case 2:
472 _val = *(u16 *)val;
473 break;
474 case 4:
475 _val = *(u32 *)val;
476 break;
477 case 8:
478 _val = *(u64 *)val;
479 break;
480 default:
481 return false;
482 }
483
484 return _val == p->datamatch ? true : false;
485}
486
487/* MMIO/PIO writes trigger an event if the addr/val match */
488static int
489ioeventfd_write(struct kvm_io_device *this, gpa_t addr, int len,
490 const void *val)
491{
492 struct _ioeventfd *p = to_ioeventfd(this);
493
494 if (!ioeventfd_in_range(p, addr, len, val))
495 return -EOPNOTSUPP;
496
497 eventfd_signal(p->eventfd, 1);
498 return 0;
499}
500
501/*
502 * This function is called as KVM is completely shutting down. We do not
503 * need to worry about locking just nuke anything we have as quickly as possible
504 */
505static void
506ioeventfd_destructor(struct kvm_io_device *this)
507{
508 struct _ioeventfd *p = to_ioeventfd(this);
509
510 ioeventfd_release(p);
511}
512
513static const struct kvm_io_device_ops ioeventfd_ops = {
514 .write = ioeventfd_write,
515 .destructor = ioeventfd_destructor,
516};
517
518/* assumes kvm->slots_lock held */
519static bool
520ioeventfd_check_collision(struct kvm *kvm, struct _ioeventfd *p)
521{
522 struct _ioeventfd *_p;
523
524 list_for_each_entry(_p, &kvm->ioeventfds, list)
525 if (_p->addr == p->addr && _p->length == p->length &&
526 (_p->wildcard || p->wildcard ||
527 _p->datamatch == p->datamatch))
528 return true;
529
530 return false;
531}
532
533static int
534kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
535{
536 int pio = args->flags & KVM_IOEVENTFD_FLAG_PIO;
Marcelo Tosattie93f8a02009-12-23 14:35:24 -0200537 enum kvm_bus bus_idx = pio ? KVM_PIO_BUS : KVM_MMIO_BUS;
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400538 struct _ioeventfd *p;
539 struct eventfd_ctx *eventfd;
540 int ret;
541
542 /* must be natural-word sized */
543 switch (args->len) {
544 case 1:
545 case 2:
546 case 4:
547 case 8:
548 break;
549 default:
550 return -EINVAL;
551 }
552
553 /* check for range overflow */
554 if (args->addr + args->len < args->addr)
555 return -EINVAL;
556
557 /* check for extra flags that we don't understand */
558 if (args->flags & ~KVM_IOEVENTFD_VALID_FLAG_MASK)
559 return -EINVAL;
560
561 eventfd = eventfd_ctx_fdget(args->fd);
562 if (IS_ERR(eventfd))
563 return PTR_ERR(eventfd);
564
565 p = kzalloc(sizeof(*p), GFP_KERNEL);
566 if (!p) {
567 ret = -ENOMEM;
568 goto fail;
569 }
570
571 INIT_LIST_HEAD(&p->list);
572 p->addr = args->addr;
573 p->length = args->len;
574 p->eventfd = eventfd;
575
576 /* The datamatch feature is optional, otherwise this is a wildcard */
577 if (args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH)
578 p->datamatch = args->datamatch;
579 else
580 p->wildcard = true;
581
Marcelo Tosatti79fac952009-12-23 14:35:26 -0200582 mutex_lock(&kvm->slots_lock);
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400583
Lucas De Marchi25985ed2011-03-30 22:57:33 -0300584 /* Verify that there isn't a match already */
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400585 if (ioeventfd_check_collision(kvm, p)) {
586 ret = -EEXIST;
587 goto unlock_fail;
588 }
589
590 kvm_iodevice_init(&p->dev, &ioeventfd_ops);
591
Sasha Levin743eeb02011-07-27 16:00:48 +0300592 ret = kvm_io_bus_register_dev(kvm, bus_idx, p->addr, p->length,
593 &p->dev);
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400594 if (ret < 0)
595 goto unlock_fail;
596
597 list_add_tail(&p->list, &kvm->ioeventfds);
598
Marcelo Tosatti79fac952009-12-23 14:35:26 -0200599 mutex_unlock(&kvm->slots_lock);
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400600
601 return 0;
602
603unlock_fail:
Marcelo Tosatti79fac952009-12-23 14:35:26 -0200604 mutex_unlock(&kvm->slots_lock);
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400605
606fail:
607 kfree(p);
608 eventfd_ctx_put(eventfd);
609
610 return ret;
611}
612
613static int
614kvm_deassign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
615{
616 int pio = args->flags & KVM_IOEVENTFD_FLAG_PIO;
Marcelo Tosattie93f8a02009-12-23 14:35:24 -0200617 enum kvm_bus bus_idx = pio ? KVM_PIO_BUS : KVM_MMIO_BUS;
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400618 struct _ioeventfd *p, *tmp;
619 struct eventfd_ctx *eventfd;
620 int ret = -ENOENT;
621
622 eventfd = eventfd_ctx_fdget(args->fd);
623 if (IS_ERR(eventfd))
624 return PTR_ERR(eventfd);
625
Marcelo Tosatti79fac952009-12-23 14:35:26 -0200626 mutex_lock(&kvm->slots_lock);
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400627
628 list_for_each_entry_safe(p, tmp, &kvm->ioeventfds, list) {
629 bool wildcard = !(args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH);
630
631 if (p->eventfd != eventfd ||
632 p->addr != args->addr ||
633 p->length != args->len ||
634 p->wildcard != wildcard)
635 continue;
636
637 if (!p->wildcard && p->datamatch != args->datamatch)
638 continue;
639
Marcelo Tosattie93f8a02009-12-23 14:35:24 -0200640 kvm_io_bus_unregister_dev(kvm, bus_idx, &p->dev);
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400641 ioeventfd_release(p);
642 ret = 0;
643 break;
644 }
645
Marcelo Tosatti79fac952009-12-23 14:35:26 -0200646 mutex_unlock(&kvm->slots_lock);
Gregory Haskinsd34e6b12009-07-07 17:08:49 -0400647
648 eventfd_ctx_put(eventfd);
649
650 return ret;
651}
652
653int
654kvm_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
655{
656 if (args->flags & KVM_IOEVENTFD_FLAG_DEASSIGN)
657 return kvm_deassign_ioeventfd(kvm, args);
658
659 return kvm_assign_ioeventfd(kvm, args);
660}