2 * kvm eventfd support - use eventfd objects to signal various KVM events
4 * Copyright 2009 Novell. All Rights Reserved.
5 * Copyright 2010 Red Hat, Inc. and/or its affiliates.
8 * Gregory Haskins <ghaskins@novell.com>
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.
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.
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.
24 #include <linux/kvm_host.h>
25 #include <linux/kvm.h>
26 #include <linux/workqueue.h>
27 #include <linux/syscalls.h>
28 #include <linux/wait.h>
29 #include <linux/poll.h>
30 #include <linux/file.h>
31 #include <linux/list.h>
32 #include <linux/eventfd.h>
33 #include <linux/kernel.h>
34 #include <linux/srcu.h>
35 #include <linux/slab.h>
36 #include <linux/seqlock.h>
37 #include <trace/events/kvm.h>
42 #ifdef CONFIG_HAVE_KVM_IRQFD
44 * --------------------------------------------------------------------
45 * irqfd: Allows an fd to be used to inject an interrupt to the guest
47 * Credit goes to Avi Kivity for the original idea.
48 * --------------------------------------------------------------------
52 * Resampling irqfds are a special variety of irqfds used to emulate
53 * level triggered interrupts. The interrupt is asserted on eventfd
54 * trigger. On acknowledgement through the irq ack notifier, the
55 * interrupt is de-asserted and userspace is notified through the
56 * resamplefd. All resamplers on the same gsi are de-asserted
57 * together, so we don't need to track the state of each individual
58 * user. We can also therefore share the same irq source ID.
60 struct _irqfd_resampler {
63 * List of resampling struct _irqfd objects sharing this gsi.
64 * RCU list modified under kvm->irqfds.resampler_lock
66 struct list_head list;
67 struct kvm_irq_ack_notifier notifier;
69 * Entry in list of kvm->irqfd.resampler_list. Use for sharing
70 * resamplers among irqfds on the same gsi.
71 * Accessed and modified under kvm->irqfds.resampler_lock
73 struct list_head link;
77 /* Used for MSI fast-path */
80 /* Update side is protected by irqfds.lock */
81 struct kvm_kernel_irq_routing_entry irq_entry;
82 seqcount_t irq_entry_sc;
83 /* Used for level IRQ fast-path */
85 struct work_struct inject;
86 /* The resampler used by this irqfd (resampler-only) */
87 struct _irqfd_resampler *resampler;
88 /* Eventfd notified on resample (resampler-only) */
89 struct eventfd_ctx *resamplefd;
90 /* Entry in list of irqfds for a resampler (resampler-only) */
91 struct list_head resampler_link;
92 /* Used for setup/shutdown */
93 struct eventfd_ctx *eventfd;
94 struct list_head list;
96 struct work_struct shutdown;
99 static struct workqueue_struct *irqfd_cleanup_wq;
102 irqfd_inject(struct work_struct *work)
104 struct _irqfd *irqfd = container_of(work, struct _irqfd, inject);
105 struct kvm *kvm = irqfd->kvm;
107 if (!irqfd->resampler) {
108 kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 1,
110 kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 0,
113 kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID,
114 irqfd->gsi, 1, false);
118 * Since resampler irqfds share an IRQ source ID, we de-assert once
119 * then notify all of the resampler irqfds using this GSI. We can't
120 * do multiple de-asserts or we risk racing with incoming re-asserts.
123 irqfd_resampler_ack(struct kvm_irq_ack_notifier *kian)
125 struct _irqfd_resampler *resampler;
127 struct _irqfd *irqfd;
130 resampler = container_of(kian, struct _irqfd_resampler, notifier);
131 kvm = resampler->kvm;
133 kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID,
134 resampler->notifier.gsi, 0, false);
136 idx = srcu_read_lock(&kvm->irq_srcu);
138 list_for_each_entry_rcu(irqfd, &resampler->list, resampler_link)
139 eventfd_signal(irqfd->resamplefd, 1);
141 srcu_read_unlock(&kvm->irq_srcu, idx);
145 irqfd_resampler_shutdown(struct _irqfd *irqfd)
147 struct _irqfd_resampler *resampler = irqfd->resampler;
148 struct kvm *kvm = resampler->kvm;
150 mutex_lock(&kvm->irqfds.resampler_lock);
152 list_del_rcu(&irqfd->resampler_link);
153 synchronize_srcu(&kvm->irq_srcu);
155 if (list_empty(&resampler->list)) {
156 list_del(&resampler->link);
157 kvm_unregister_irq_ack_notifier(kvm, &resampler->notifier);
158 kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID,
159 resampler->notifier.gsi, 0, false);
163 mutex_unlock(&kvm->irqfds.resampler_lock);
167 * Race-free decouple logic (ordering is critical)
170 irqfd_shutdown(struct work_struct *work)
172 struct _irqfd *irqfd = container_of(work, struct _irqfd, shutdown);
176 * Synchronize with the wait-queue and unhook ourselves to prevent
179 eventfd_ctx_remove_wait_queue(irqfd->eventfd, &irqfd->wait, &cnt);
182 * We know no new events will be scheduled at this point, so block
183 * until all previously outstanding events have completed
185 flush_work(&irqfd->inject);
187 if (irqfd->resampler) {
188 irqfd_resampler_shutdown(irqfd);
189 eventfd_ctx_put(irqfd->resamplefd);
193 * It is now safe to release the object's resources
195 eventfd_ctx_put(irqfd->eventfd);
200 /* assumes kvm->irqfds.lock is held */
202 irqfd_is_active(struct _irqfd *irqfd)
204 return list_empty(&irqfd->list) ? false : true;
208 * Mark the irqfd as inactive and schedule it for removal
210 * assumes kvm->irqfds.lock is held
213 irqfd_deactivate(struct _irqfd *irqfd)
215 BUG_ON(!irqfd_is_active(irqfd));
217 list_del_init(&irqfd->list);
219 queue_work(irqfd_cleanup_wq, &irqfd->shutdown);
223 * Called with wqh->lock held and interrupts disabled
226 irqfd_wakeup(wait_queue_t *wait, unsigned mode, int sync, void *key)
228 struct _irqfd *irqfd = container_of(wait, struct _irqfd, wait);
229 unsigned long flags = (unsigned long)key;
230 struct kvm_kernel_irq_routing_entry irq;
231 struct kvm *kvm = irqfd->kvm;
235 if (flags & POLLIN) {
236 idx = srcu_read_lock(&kvm->irq_srcu);
238 seq = read_seqcount_begin(&irqfd->irq_entry_sc);
239 irq = irqfd->irq_entry;
240 } while (read_seqcount_retry(&irqfd->irq_entry_sc, seq));
241 /* An event has been signaled, inject an interrupt */
242 if (irq.type == KVM_IRQ_ROUTING_MSI)
243 kvm_set_msi(&irq, kvm, KVM_USERSPACE_IRQ_SOURCE_ID, 1,
246 schedule_work(&irqfd->inject);
247 srcu_read_unlock(&kvm->irq_srcu, idx);
250 if (flags & POLLHUP) {
251 /* The eventfd is closing, detach from KVM */
254 spin_lock_irqsave(&kvm->irqfds.lock, flags);
257 * We must check if someone deactivated the irqfd before
258 * we could acquire the irqfds.lock since the item is
259 * deactivated from the KVM side before it is unhooked from
260 * the wait-queue. If it is already deactivated, we can
261 * simply return knowing the other side will cleanup for us.
262 * We cannot race against the irqfd going away since the
263 * other side is required to acquire wqh->lock, which we hold
265 if (irqfd_is_active(irqfd))
266 irqfd_deactivate(irqfd);
268 spin_unlock_irqrestore(&kvm->irqfds.lock, flags);
275 irqfd_ptable_queue_proc(struct file *file, wait_queue_head_t *wqh,
278 struct _irqfd *irqfd = container_of(pt, struct _irqfd, pt);
279 add_wait_queue(wqh, &irqfd->wait);
282 /* Must be called under irqfds.lock */
283 static void irqfd_update(struct kvm *kvm, struct _irqfd *irqfd)
285 struct kvm_kernel_irq_routing_entry *e;
286 struct kvm_kernel_irq_routing_entry entries[KVM_NR_IRQCHIPS];
289 n_entries = kvm_irq_map_gsi(kvm, entries, irqfd->gsi);
291 write_seqcount_begin(&irqfd->irq_entry_sc);
293 irqfd->irq_entry.type = 0;
296 for (i = 0; i < n_entries; ++i, ++e) {
297 /* Only fast-path MSI. */
298 if (e->type == KVM_IRQ_ROUTING_MSI)
299 irqfd->irq_entry = *e;
302 write_seqcount_end(&irqfd->irq_entry_sc);
306 kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
308 struct _irqfd *irqfd, *tmp;
309 struct file *file = NULL;
310 struct eventfd_ctx *eventfd = NULL, *resamplefd = NULL;
315 irqfd = kzalloc(sizeof(*irqfd), GFP_KERNEL);
320 irqfd->gsi = args->gsi;
321 INIT_LIST_HEAD(&irqfd->list);
322 INIT_WORK(&irqfd->inject, irqfd_inject);
323 INIT_WORK(&irqfd->shutdown, irqfd_shutdown);
324 seqcount_init(&irqfd->irq_entry_sc);
326 file = eventfd_fget(args->fd);
332 eventfd = eventfd_ctx_fileget(file);
333 if (IS_ERR(eventfd)) {
334 ret = PTR_ERR(eventfd);
338 irqfd->eventfd = eventfd;
340 if (args->flags & KVM_IRQFD_FLAG_RESAMPLE) {
341 struct _irqfd_resampler *resampler;
343 resamplefd = eventfd_ctx_fdget(args->resamplefd);
344 if (IS_ERR(resamplefd)) {
345 ret = PTR_ERR(resamplefd);
349 irqfd->resamplefd = resamplefd;
350 INIT_LIST_HEAD(&irqfd->resampler_link);
352 mutex_lock(&kvm->irqfds.resampler_lock);
354 list_for_each_entry(resampler,
355 &kvm->irqfds.resampler_list, link) {
356 if (resampler->notifier.gsi == irqfd->gsi) {
357 irqfd->resampler = resampler;
362 if (!irqfd->resampler) {
363 resampler = kzalloc(sizeof(*resampler), GFP_KERNEL);
366 mutex_unlock(&kvm->irqfds.resampler_lock);
370 resampler->kvm = kvm;
371 INIT_LIST_HEAD(&resampler->list);
372 resampler->notifier.gsi = irqfd->gsi;
373 resampler->notifier.irq_acked = irqfd_resampler_ack;
374 INIT_LIST_HEAD(&resampler->link);
376 list_add(&resampler->link, &kvm->irqfds.resampler_list);
377 kvm_register_irq_ack_notifier(kvm,
378 &resampler->notifier);
379 irqfd->resampler = resampler;
382 list_add_rcu(&irqfd->resampler_link, &irqfd->resampler->list);
383 synchronize_srcu(&kvm->irq_srcu);
385 mutex_unlock(&kvm->irqfds.resampler_lock);
389 * Install our own custom wake-up handling so we are notified via
390 * a callback whenever someone signals the underlying eventfd
392 init_waitqueue_func_entry(&irqfd->wait, irqfd_wakeup);
393 init_poll_funcptr(&irqfd->pt, irqfd_ptable_queue_proc);
395 spin_lock_irq(&kvm->irqfds.lock);
398 list_for_each_entry(tmp, &kvm->irqfds.items, list) {
399 if (irqfd->eventfd != tmp->eventfd)
401 /* This fd is used for another irq already. */
403 spin_unlock_irq(&kvm->irqfds.lock);
407 idx = srcu_read_lock(&kvm->irq_srcu);
408 irqfd_update(kvm, irqfd);
409 srcu_read_unlock(&kvm->irq_srcu, idx);
411 events = file->f_op->poll(file, &irqfd->pt);
413 list_add_tail(&irqfd->list, &kvm->irqfds.items);
416 * Check if there was an event already pending on the eventfd
417 * before we registered, and trigger it as if we didn't miss it.
420 schedule_work(&irqfd->inject);
422 spin_unlock_irq(&kvm->irqfds.lock);
425 * do not drop the file until the irqfd is fully initialized, otherwise
426 * we might race against the POLLHUP
433 if (irqfd->resampler)
434 irqfd_resampler_shutdown(irqfd);
436 if (resamplefd && !IS_ERR(resamplefd))
437 eventfd_ctx_put(resamplefd);
439 if (eventfd && !IS_ERR(eventfd))
440 eventfd_ctx_put(eventfd);
449 bool kvm_irq_has_notifier(struct kvm *kvm, unsigned irqchip, unsigned pin)
451 struct kvm_irq_ack_notifier *kian;
454 idx = srcu_read_lock(&kvm->irq_srcu);
455 gsi = kvm_irq_map_chip_pin(kvm, irqchip, pin);
457 hlist_for_each_entry_rcu(kian, &kvm->irq_ack_notifier_list,
459 if (kian->gsi == gsi) {
460 srcu_read_unlock(&kvm->irq_srcu, idx);
464 srcu_read_unlock(&kvm->irq_srcu, idx);
468 EXPORT_SYMBOL_GPL(kvm_irq_has_notifier);
470 void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin)
472 struct kvm_irq_ack_notifier *kian;
475 trace_kvm_ack_irq(irqchip, pin);
477 idx = srcu_read_lock(&kvm->irq_srcu);
478 gsi = kvm_irq_map_chip_pin(kvm, irqchip, pin);
480 hlist_for_each_entry_rcu(kian, &kvm->irq_ack_notifier_list,
482 if (kian->gsi == gsi)
483 kian->irq_acked(kian);
484 srcu_read_unlock(&kvm->irq_srcu, idx);
487 void kvm_register_irq_ack_notifier(struct kvm *kvm,
488 struct kvm_irq_ack_notifier *kian)
490 mutex_lock(&kvm->irq_lock);
491 hlist_add_head_rcu(&kian->link, &kvm->irq_ack_notifier_list);
492 mutex_unlock(&kvm->irq_lock);
493 #ifdef __KVM_HAVE_IOAPIC
494 kvm_vcpu_request_scan_ioapic(kvm);
498 void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
499 struct kvm_irq_ack_notifier *kian)
501 mutex_lock(&kvm->irq_lock);
502 hlist_del_init_rcu(&kian->link);
503 mutex_unlock(&kvm->irq_lock);
504 synchronize_srcu(&kvm->irq_srcu);
505 #ifdef __KVM_HAVE_IOAPIC
506 kvm_vcpu_request_scan_ioapic(kvm);
512 kvm_eventfd_init(struct kvm *kvm)
514 #ifdef CONFIG_HAVE_KVM_IRQFD
515 spin_lock_init(&kvm->irqfds.lock);
516 INIT_LIST_HEAD(&kvm->irqfds.items);
517 INIT_LIST_HEAD(&kvm->irqfds.resampler_list);
518 mutex_init(&kvm->irqfds.resampler_lock);
520 INIT_LIST_HEAD(&kvm->ioeventfds);
523 #ifdef CONFIG_HAVE_KVM_IRQFD
525 * shutdown any irqfd's that match fd+gsi
528 kvm_irqfd_deassign(struct kvm *kvm, struct kvm_irqfd *args)
530 struct _irqfd *irqfd, *tmp;
531 struct eventfd_ctx *eventfd;
533 eventfd = eventfd_ctx_fdget(args->fd);
535 return PTR_ERR(eventfd);
537 spin_lock_irq(&kvm->irqfds.lock);
539 list_for_each_entry_safe(irqfd, tmp, &kvm->irqfds.items, list) {
540 if (irqfd->eventfd == eventfd && irqfd->gsi == args->gsi) {
542 * This clearing of irq_entry.type is needed for when
543 * another thread calls kvm_irq_routing_update before
544 * we flush workqueue below (we synchronize with
545 * kvm_irq_routing_update using irqfds.lock).
547 write_seqcount_begin(&irqfd->irq_entry_sc);
548 irqfd->irq_entry.type = 0;
549 write_seqcount_end(&irqfd->irq_entry_sc);
550 irqfd_deactivate(irqfd);
554 spin_unlock_irq(&kvm->irqfds.lock);
555 eventfd_ctx_put(eventfd);
558 * Block until we know all outstanding shutdown jobs have completed
559 * so that we guarantee there will not be any more interrupts on this
560 * gsi once this deassign function returns.
562 flush_workqueue(irqfd_cleanup_wq);
568 kvm_irqfd(struct kvm *kvm, struct kvm_irqfd *args)
570 if (args->flags & ~(KVM_IRQFD_FLAG_DEASSIGN | KVM_IRQFD_FLAG_RESAMPLE))
573 if (args->flags & KVM_IRQFD_FLAG_DEASSIGN)
574 return kvm_irqfd_deassign(kvm, args);
576 return kvm_irqfd_assign(kvm, args);
580 * This function is called as the kvm VM fd is being released. Shutdown all
581 * irqfds that still remain open
584 kvm_irqfd_release(struct kvm *kvm)
586 struct _irqfd *irqfd, *tmp;
588 spin_lock_irq(&kvm->irqfds.lock);
590 list_for_each_entry_safe(irqfd, tmp, &kvm->irqfds.items, list)
591 irqfd_deactivate(irqfd);
593 spin_unlock_irq(&kvm->irqfds.lock);
596 * Block until we know all outstanding shutdown jobs have completed
597 * since we do not take a kvm* reference.
599 flush_workqueue(irqfd_cleanup_wq);
604 * Take note of a change in irq routing.
605 * Caller must invoke synchronize_srcu(&kvm->irq_srcu) afterwards.
607 void kvm_irq_routing_update(struct kvm *kvm)
609 struct _irqfd *irqfd;
611 spin_lock_irq(&kvm->irqfds.lock);
613 list_for_each_entry(irqfd, &kvm->irqfds.items, list)
614 irqfd_update(kvm, irqfd);
616 spin_unlock_irq(&kvm->irqfds.lock);
620 * create a host-wide workqueue for issuing deferred shutdown requests
621 * aggregated from all vm* instances. We need our own isolated single-thread
622 * queue to prevent deadlock against flushing the normal work-queue.
624 int kvm_irqfd_init(void)
626 irqfd_cleanup_wq = create_singlethread_workqueue("kvm-irqfd-cleanup");
627 if (!irqfd_cleanup_wq)
633 void kvm_irqfd_exit(void)
635 destroy_workqueue(irqfd_cleanup_wq);
640 * --------------------------------------------------------------------
641 * ioeventfd: translate a PIO/MMIO memory write to an eventfd signal.
643 * userspace can register a PIO/MMIO address with an eventfd for receiving
644 * notification when the memory has been touched.
645 * --------------------------------------------------------------------
649 struct list_head list;
652 struct eventfd_ctx *eventfd;
654 struct kvm_io_device dev;
659 static inline struct _ioeventfd *
660 to_ioeventfd(struct kvm_io_device *dev)
662 return container_of(dev, struct _ioeventfd, dev);
666 ioeventfd_release(struct _ioeventfd *p)
668 eventfd_ctx_put(p->eventfd);
674 ioeventfd_in_range(struct _ioeventfd *p, gpa_t addr, int len, const void *val)
678 if (!(addr == p->addr && len == p->length))
679 /* address-range must be precise for a hit */
683 /* all else equal, wildcard is always a hit */
686 /* otherwise, we have to actually compare the data */
688 BUG_ON(!IS_ALIGNED((unsigned long)val, len));
707 return _val == p->datamatch ? true : false;
710 /* MMIO/PIO writes trigger an event if the addr/val match */
712 ioeventfd_write(struct kvm_io_device *this, gpa_t addr, int len,
715 struct _ioeventfd *p = to_ioeventfd(this);
717 if (!ioeventfd_in_range(p, addr, len, val))
720 eventfd_signal(p->eventfd, 1);
725 * This function is called as KVM is completely shutting down. We do not
726 * need to worry about locking just nuke anything we have as quickly as possible
729 ioeventfd_destructor(struct kvm_io_device *this)
731 struct _ioeventfd *p = to_ioeventfd(this);
733 ioeventfd_release(p);
736 static const struct kvm_io_device_ops ioeventfd_ops = {
737 .write = ioeventfd_write,
738 .destructor = ioeventfd_destructor,
741 /* assumes kvm->slots_lock held */
743 ioeventfd_check_collision(struct kvm *kvm, struct _ioeventfd *p)
745 struct _ioeventfd *_p;
747 list_for_each_entry(_p, &kvm->ioeventfds, list)
748 if (_p->bus_idx == p->bus_idx &&
749 _p->addr == p->addr && _p->length == p->length &&
750 (_p->wildcard || p->wildcard ||
751 _p->datamatch == p->datamatch))
757 static enum kvm_bus ioeventfd_bus_from_flags(__u32 flags)
759 if (flags & KVM_IOEVENTFD_FLAG_PIO)
761 if (flags & KVM_IOEVENTFD_FLAG_VIRTIO_CCW_NOTIFY)
762 return KVM_VIRTIO_CCW_NOTIFY_BUS;
767 kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
769 enum kvm_bus bus_idx;
770 struct _ioeventfd *p;
771 struct eventfd_ctx *eventfd;
774 bus_idx = ioeventfd_bus_from_flags(args->flags);
775 /* must be natural-word sized */
786 /* check for range overflow */
787 if (args->addr + args->len < args->addr)
790 /* check for extra flags that we don't understand */
791 if (args->flags & ~KVM_IOEVENTFD_VALID_FLAG_MASK)
794 eventfd = eventfd_ctx_fdget(args->fd);
796 return PTR_ERR(eventfd);
798 p = kzalloc(sizeof(*p), GFP_KERNEL);
804 INIT_LIST_HEAD(&p->list);
805 p->addr = args->addr;
806 p->bus_idx = bus_idx;
807 p->length = args->len;
808 p->eventfd = eventfd;
810 /* The datamatch feature is optional, otherwise this is a wildcard */
811 if (args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH)
812 p->datamatch = args->datamatch;
816 mutex_lock(&kvm->slots_lock);
818 /* Verify that there isn't a match already */
819 if (ioeventfd_check_collision(kvm, p)) {
824 kvm_iodevice_init(&p->dev, &ioeventfd_ops);
826 ret = kvm_io_bus_register_dev(kvm, bus_idx, p->addr, p->length,
831 list_add_tail(&p->list, &kvm->ioeventfds);
833 mutex_unlock(&kvm->slots_lock);
838 mutex_unlock(&kvm->slots_lock);
842 eventfd_ctx_put(eventfd);
848 kvm_deassign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
850 enum kvm_bus bus_idx;
851 struct _ioeventfd *p, *tmp;
852 struct eventfd_ctx *eventfd;
855 bus_idx = ioeventfd_bus_from_flags(args->flags);
856 eventfd = eventfd_ctx_fdget(args->fd);
858 return PTR_ERR(eventfd);
860 mutex_lock(&kvm->slots_lock);
862 list_for_each_entry_safe(p, tmp, &kvm->ioeventfds, list) {
863 bool wildcard = !(args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH);
865 if (p->bus_idx != bus_idx ||
866 p->eventfd != eventfd ||
867 p->addr != args->addr ||
868 p->length != args->len ||
869 p->wildcard != wildcard)
872 if (!p->wildcard && p->datamatch != args->datamatch)
875 kvm_io_bus_unregister_dev(kvm, bus_idx, &p->dev);
876 ioeventfd_release(p);
881 mutex_unlock(&kvm->slots_lock);
883 eventfd_ctx_put(eventfd);
889 kvm_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
891 if (args->flags & KVM_IOEVENTFD_FLAG_DEASSIGN)
892 return kvm_deassign_ioeventfd(kvm, args);
894 return kvm_assign_ioeventfd(kvm, args);