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/kvm_irqfd.h>
27 #include <linux/workqueue.h>
28 #include <linux/syscalls.h>
29 #include <linux/wait.h>
30 #include <linux/poll.h>
31 #include <linux/file.h>
32 #include <linux/list.h>
33 #include <linux/eventfd.h>
34 #include <linux/kernel.h>
35 #include <linux/srcu.h>
36 #include <linux/slab.h>
37 #include <linux/seqlock.h>
38 #include <linux/irqbypass.h>
39 #include <trace/events/kvm.h>
41 #include <kvm/iodev.h>
43 #ifdef CONFIG_HAVE_KVM_IRQFD
45 static struct workqueue_struct *irqfd_cleanup_wq;
48 irqfd_inject(struct work_struct *work)
50 struct kvm_kernel_irqfd *irqfd =
51 container_of(work, struct kvm_kernel_irqfd, inject);
52 struct kvm *kvm = irqfd->kvm;
54 if (!irqfd->resampler) {
55 kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 1,
57 kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 0,
60 kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID,
61 irqfd->gsi, 1, false);
65 * Since resampler irqfds share an IRQ source ID, we de-assert once
66 * then notify all of the resampler irqfds using this GSI. We can't
67 * do multiple de-asserts or we risk racing with incoming re-asserts.
70 irqfd_resampler_ack(struct kvm_irq_ack_notifier *kian)
72 struct kvm_kernel_irqfd_resampler *resampler;
74 struct kvm_kernel_irqfd *irqfd;
77 resampler = container_of(kian,
78 struct kvm_kernel_irqfd_resampler, notifier);
81 kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID,
82 resampler->notifier.gsi, 0, false);
84 idx = srcu_read_lock(&kvm->irq_srcu);
86 list_for_each_entry_rcu(irqfd, &resampler->list, resampler_link)
87 eventfd_signal(irqfd->resamplefd, 1);
89 srcu_read_unlock(&kvm->irq_srcu, idx);
93 irqfd_resampler_shutdown(struct kvm_kernel_irqfd *irqfd)
95 struct kvm_kernel_irqfd_resampler *resampler = irqfd->resampler;
96 struct kvm *kvm = resampler->kvm;
98 mutex_lock(&kvm->irqfds.resampler_lock);
100 list_del_rcu(&irqfd->resampler_link);
101 synchronize_srcu(&kvm->irq_srcu);
103 if (list_empty(&resampler->list)) {
104 list_del(&resampler->link);
105 kvm_unregister_irq_ack_notifier(kvm, &resampler->notifier);
106 kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID,
107 resampler->notifier.gsi, 0, false);
111 mutex_unlock(&kvm->irqfds.resampler_lock);
115 * Race-free decouple logic (ordering is critical)
118 irqfd_shutdown(struct work_struct *work)
120 struct kvm_kernel_irqfd *irqfd =
121 container_of(work, struct kvm_kernel_irqfd, shutdown);
122 struct kvm *kvm = irqfd->kvm;
125 /* Make sure irqfd has been initalized in assign path. */
126 synchronize_srcu(&kvm->irq_srcu);
129 * Synchronize with the wait-queue and unhook ourselves to prevent
132 eventfd_ctx_remove_wait_queue(irqfd->eventfd, &irqfd->wait, &cnt);
135 * We know no new events will be scheduled at this point, so block
136 * until all previously outstanding events have completed
138 flush_work(&irqfd->inject);
140 if (irqfd->resampler) {
141 irqfd_resampler_shutdown(irqfd);
142 eventfd_ctx_put(irqfd->resamplefd);
146 * It is now safe to release the object's resources
148 #ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
149 irq_bypass_unregister_consumer(&irqfd->consumer);
151 eventfd_ctx_put(irqfd->eventfd);
156 /* assumes kvm->irqfds.lock is held */
158 irqfd_is_active(struct kvm_kernel_irqfd *irqfd)
160 return list_empty(&irqfd->list) ? false : true;
164 * Mark the irqfd as inactive and schedule it for removal
166 * assumes kvm->irqfds.lock is held
169 irqfd_deactivate(struct kvm_kernel_irqfd *irqfd)
171 BUG_ON(!irqfd_is_active(irqfd));
173 list_del_init(&irqfd->list);
175 queue_work(irqfd_cleanup_wq, &irqfd->shutdown);
178 int __attribute__((weak)) kvm_arch_set_irq_inatomic(
179 struct kvm_kernel_irq_routing_entry *irq,
180 struct kvm *kvm, int irq_source_id,
188 * Called with wqh->lock held and interrupts disabled
191 irqfd_wakeup(wait_queue_t *wait, unsigned mode, int sync, void *key)
193 struct kvm_kernel_irqfd *irqfd =
194 container_of(wait, struct kvm_kernel_irqfd, wait);
195 unsigned long flags = (unsigned long)key;
196 struct kvm_kernel_irq_routing_entry irq;
197 struct kvm *kvm = irqfd->kvm;
201 if (flags & POLLIN) {
202 idx = srcu_read_lock(&kvm->irq_srcu);
204 seq = read_seqcount_begin(&irqfd->irq_entry_sc);
205 irq = irqfd->irq_entry;
206 } while (read_seqcount_retry(&irqfd->irq_entry_sc, seq));
207 /* An event has been signaled, inject an interrupt */
208 if (kvm_arch_set_irq_inatomic(&irq, kvm,
209 KVM_USERSPACE_IRQ_SOURCE_ID, 1,
210 false) == -EWOULDBLOCK)
211 schedule_work(&irqfd->inject);
212 srcu_read_unlock(&kvm->irq_srcu, idx);
215 if (flags & POLLHUP) {
216 /* The eventfd is closing, detach from KVM */
219 spin_lock_irqsave(&kvm->irqfds.lock, flags);
222 * We must check if someone deactivated the irqfd before
223 * we could acquire the irqfds.lock since the item is
224 * deactivated from the KVM side before it is unhooked from
225 * the wait-queue. If it is already deactivated, we can
226 * simply return knowing the other side will cleanup for us.
227 * We cannot race against the irqfd going away since the
228 * other side is required to acquire wqh->lock, which we hold
230 if (irqfd_is_active(irqfd))
231 irqfd_deactivate(irqfd);
233 spin_unlock_irqrestore(&kvm->irqfds.lock, flags);
240 irqfd_ptable_queue_proc(struct file *file, wait_queue_head_t *wqh,
243 struct kvm_kernel_irqfd *irqfd =
244 container_of(pt, struct kvm_kernel_irqfd, pt);
245 add_wait_queue(wqh, &irqfd->wait);
248 /* Must be called under irqfds.lock */
249 static void irqfd_update(struct kvm *kvm, struct kvm_kernel_irqfd *irqfd)
251 struct kvm_kernel_irq_routing_entry *e;
252 struct kvm_kernel_irq_routing_entry entries[KVM_NR_IRQCHIPS];
255 n_entries = kvm_irq_map_gsi(kvm, entries, irqfd->gsi);
257 write_seqcount_begin(&irqfd->irq_entry_sc);
261 irqfd->irq_entry = *e;
263 irqfd->irq_entry.type = 0;
265 write_seqcount_end(&irqfd->irq_entry_sc);
268 #ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
269 void __attribute__((weak)) kvm_arch_irq_bypass_stop(
270 struct irq_bypass_consumer *cons)
274 void __attribute__((weak)) kvm_arch_irq_bypass_start(
275 struct irq_bypass_consumer *cons)
279 int __attribute__((weak)) kvm_arch_update_irqfd_routing(
280 struct kvm *kvm, unsigned int host_irq,
281 uint32_t guest_irq, bool set)
288 kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
290 struct kvm_kernel_irqfd *irqfd, *tmp;
292 struct eventfd_ctx *eventfd = NULL, *resamplefd = NULL;
297 if (!kvm_arch_intc_initialized(kvm))
300 irqfd = kzalloc(sizeof(*irqfd), GFP_KERNEL);
305 irqfd->gsi = args->gsi;
306 INIT_LIST_HEAD(&irqfd->list);
307 INIT_WORK(&irqfd->inject, irqfd_inject);
308 INIT_WORK(&irqfd->shutdown, irqfd_shutdown);
309 seqcount_init(&irqfd->irq_entry_sc);
317 eventfd = eventfd_ctx_fileget(f.file);
318 if (IS_ERR(eventfd)) {
319 ret = PTR_ERR(eventfd);
323 irqfd->eventfd = eventfd;
325 if (args->flags & KVM_IRQFD_FLAG_RESAMPLE) {
326 struct kvm_kernel_irqfd_resampler *resampler;
328 resamplefd = eventfd_ctx_fdget(args->resamplefd);
329 if (IS_ERR(resamplefd)) {
330 ret = PTR_ERR(resamplefd);
334 irqfd->resamplefd = resamplefd;
335 INIT_LIST_HEAD(&irqfd->resampler_link);
337 mutex_lock(&kvm->irqfds.resampler_lock);
339 list_for_each_entry(resampler,
340 &kvm->irqfds.resampler_list, link) {
341 if (resampler->notifier.gsi == irqfd->gsi) {
342 irqfd->resampler = resampler;
347 if (!irqfd->resampler) {
348 resampler = kzalloc(sizeof(*resampler), GFP_KERNEL);
351 mutex_unlock(&kvm->irqfds.resampler_lock);
355 resampler->kvm = kvm;
356 INIT_LIST_HEAD(&resampler->list);
357 resampler->notifier.gsi = irqfd->gsi;
358 resampler->notifier.irq_acked = irqfd_resampler_ack;
359 INIT_LIST_HEAD(&resampler->link);
361 list_add(&resampler->link, &kvm->irqfds.resampler_list);
362 kvm_register_irq_ack_notifier(kvm,
363 &resampler->notifier);
364 irqfd->resampler = resampler;
367 list_add_rcu(&irqfd->resampler_link, &irqfd->resampler->list);
368 synchronize_srcu(&kvm->irq_srcu);
370 mutex_unlock(&kvm->irqfds.resampler_lock);
374 * Install our own custom wake-up handling so we are notified via
375 * a callback whenever someone signals the underlying eventfd
377 init_waitqueue_func_entry(&irqfd->wait, irqfd_wakeup);
378 init_poll_funcptr(&irqfd->pt, irqfd_ptable_queue_proc);
380 spin_lock_irq(&kvm->irqfds.lock);
383 list_for_each_entry(tmp, &kvm->irqfds.items, list) {
384 if (irqfd->eventfd != tmp->eventfd)
386 /* This fd is used for another irq already. */
388 spin_unlock_irq(&kvm->irqfds.lock);
392 idx = srcu_read_lock(&kvm->irq_srcu);
393 irqfd_update(kvm, irqfd);
395 list_add_tail(&irqfd->list, &kvm->irqfds.items);
397 spin_unlock_irq(&kvm->irqfds.lock);
400 * Check if there was an event already pending on the eventfd
401 * before we registered, and trigger it as if we didn't miss it.
403 events = f.file->f_op->poll(f.file, &irqfd->pt);
406 schedule_work(&irqfd->inject);
408 #ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
409 irqfd->consumer.token = (void *)irqfd->eventfd;
410 irqfd->consumer.add_producer = kvm_arch_irq_bypass_add_producer;
411 irqfd->consumer.del_producer = kvm_arch_irq_bypass_del_producer;
412 irqfd->consumer.stop = kvm_arch_irq_bypass_stop;
413 irqfd->consumer.start = kvm_arch_irq_bypass_start;
414 ret = irq_bypass_register_consumer(&irqfd->consumer);
416 pr_info("irq bypass consumer (token %p) registration fails: %d\n",
417 irqfd->consumer.token, ret);
420 srcu_read_unlock(&kvm->irq_srcu, idx);
423 * do not drop the file until the irqfd is fully initialized, otherwise
424 * we might race against the POLLHUP
430 if (irqfd->resampler)
431 irqfd_resampler_shutdown(irqfd);
433 if (resamplefd && !IS_ERR(resamplefd))
434 eventfd_ctx_put(resamplefd);
436 if (eventfd && !IS_ERR(eventfd))
437 eventfd_ctx_put(eventfd);
446 bool kvm_irq_has_notifier(struct kvm *kvm, unsigned irqchip, unsigned pin)
448 struct kvm_irq_ack_notifier *kian;
451 idx = srcu_read_lock(&kvm->irq_srcu);
452 gsi = kvm_irq_map_chip_pin(kvm, irqchip, pin);
454 hlist_for_each_entry_rcu(kian, &kvm->irq_ack_notifier_list,
456 if (kian->gsi == gsi) {
457 srcu_read_unlock(&kvm->irq_srcu, idx);
461 srcu_read_unlock(&kvm->irq_srcu, idx);
465 EXPORT_SYMBOL_GPL(kvm_irq_has_notifier);
467 void kvm_notify_acked_gsi(struct kvm *kvm, int gsi)
469 struct kvm_irq_ack_notifier *kian;
471 hlist_for_each_entry_rcu(kian, &kvm->irq_ack_notifier_list,
473 if (kian->gsi == gsi)
474 kian->irq_acked(kian);
477 void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin)
481 trace_kvm_ack_irq(irqchip, pin);
483 idx = srcu_read_lock(&kvm->irq_srcu);
484 gsi = kvm_irq_map_chip_pin(kvm, irqchip, pin);
486 kvm_notify_acked_gsi(kvm, gsi);
487 srcu_read_unlock(&kvm->irq_srcu, idx);
490 void kvm_register_irq_ack_notifier(struct kvm *kvm,
491 struct kvm_irq_ack_notifier *kian)
493 mutex_lock(&kvm->irq_lock);
494 hlist_add_head_rcu(&kian->link, &kvm->irq_ack_notifier_list);
495 mutex_unlock(&kvm->irq_lock);
496 kvm_vcpu_request_scan_ioapic(kvm);
499 void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
500 struct kvm_irq_ack_notifier *kian)
502 mutex_lock(&kvm->irq_lock);
503 hlist_del_init_rcu(&kian->link);
504 mutex_unlock(&kvm->irq_lock);
505 synchronize_srcu(&kvm->irq_srcu);
506 kvm_vcpu_request_scan_ioapic(kvm);
511 kvm_eventfd_init(struct kvm *kvm)
513 #ifdef CONFIG_HAVE_KVM_IRQFD
514 spin_lock_init(&kvm->irqfds.lock);
515 INIT_LIST_HEAD(&kvm->irqfds.items);
516 INIT_LIST_HEAD(&kvm->irqfds.resampler_list);
517 mutex_init(&kvm->irqfds.resampler_lock);
519 INIT_LIST_HEAD(&kvm->ioeventfds);
522 #ifdef CONFIG_HAVE_KVM_IRQFD
524 * shutdown any irqfd's that match fd+gsi
527 kvm_irqfd_deassign(struct kvm *kvm, struct kvm_irqfd *args)
529 struct kvm_kernel_irqfd *irqfd, *tmp;
530 struct eventfd_ctx *eventfd;
532 eventfd = eventfd_ctx_fdget(args->fd);
534 return PTR_ERR(eventfd);
536 spin_lock_irq(&kvm->irqfds.lock);
538 list_for_each_entry_safe(irqfd, tmp, &kvm->irqfds.items, list) {
539 if (irqfd->eventfd == eventfd && irqfd->gsi == args->gsi) {
541 * This clearing of irq_entry.type is needed for when
542 * another thread calls kvm_irq_routing_update before
543 * we flush workqueue below (we synchronize with
544 * kvm_irq_routing_update using irqfds.lock).
546 write_seqcount_begin(&irqfd->irq_entry_sc);
547 irqfd->irq_entry.type = 0;
548 write_seqcount_end(&irqfd->irq_entry_sc);
549 irqfd_deactivate(irqfd);
553 spin_unlock_irq(&kvm->irqfds.lock);
554 eventfd_ctx_put(eventfd);
557 * Block until we know all outstanding shutdown jobs have completed
558 * so that we guarantee there will not be any more interrupts on this
559 * gsi once this deassign function returns.
561 flush_workqueue(irqfd_cleanup_wq);
567 kvm_irqfd(struct kvm *kvm, struct kvm_irqfd *args)
569 if (args->flags & ~(KVM_IRQFD_FLAG_DEASSIGN | KVM_IRQFD_FLAG_RESAMPLE))
572 if (args->flags & KVM_IRQFD_FLAG_DEASSIGN)
573 return kvm_irqfd_deassign(kvm, args);
575 return kvm_irqfd_assign(kvm, args);
579 * This function is called as the kvm VM fd is being released. Shutdown all
580 * irqfds that still remain open
583 kvm_irqfd_release(struct kvm *kvm)
585 struct kvm_kernel_irqfd *irqfd, *tmp;
587 spin_lock_irq(&kvm->irqfds.lock);
589 list_for_each_entry_safe(irqfd, tmp, &kvm->irqfds.items, list)
590 irqfd_deactivate(irqfd);
592 spin_unlock_irq(&kvm->irqfds.lock);
595 * Block until we know all outstanding shutdown jobs have completed
596 * since we do not take a kvm* reference.
598 flush_workqueue(irqfd_cleanup_wq);
603 * Take note of a change in irq routing.
604 * Caller must invoke synchronize_srcu(&kvm->irq_srcu) afterwards.
606 void kvm_irq_routing_update(struct kvm *kvm)
608 struct kvm_kernel_irqfd *irqfd;
610 spin_lock_irq(&kvm->irqfds.lock);
612 list_for_each_entry(irqfd, &kvm->irqfds.items, list) {
613 irqfd_update(kvm, irqfd);
615 #ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
616 if (irqfd->producer) {
617 int ret = kvm_arch_update_irqfd_routing(
618 irqfd->kvm, irqfd->producer->irq,
625 spin_unlock_irq(&kvm->irqfds.lock);
629 * create a host-wide workqueue for issuing deferred shutdown requests
630 * aggregated from all vm* instances. We need our own isolated single-thread
631 * queue to prevent deadlock against flushing the normal work-queue.
633 int kvm_irqfd_init(void)
635 irqfd_cleanup_wq = create_singlethread_workqueue("kvm-irqfd-cleanup");
636 if (!irqfd_cleanup_wq)
642 void kvm_irqfd_exit(void)
644 destroy_workqueue(irqfd_cleanup_wq);
649 * --------------------------------------------------------------------
650 * ioeventfd: translate a PIO/MMIO memory write to an eventfd signal.
652 * userspace can register a PIO/MMIO address with an eventfd for receiving
653 * notification when the memory has been touched.
654 * --------------------------------------------------------------------
658 struct list_head list;
661 struct eventfd_ctx *eventfd;
663 struct kvm_io_device dev;
668 static inline struct _ioeventfd *
669 to_ioeventfd(struct kvm_io_device *dev)
671 return container_of(dev, struct _ioeventfd, dev);
675 ioeventfd_release(struct _ioeventfd *p)
677 eventfd_ctx_put(p->eventfd);
683 ioeventfd_in_range(struct _ioeventfd *p, gpa_t addr, int len, const void *val)
688 /* address must be precise for a hit */
692 /* length = 0 means only look at the address, so always a hit */
695 if (len != p->length)
696 /* address-range must be precise for a hit */
700 /* all else equal, wildcard is always a hit */
703 /* otherwise, we have to actually compare the data */
705 BUG_ON(!IS_ALIGNED((unsigned long)val, len));
724 return _val == p->datamatch ? true : false;
727 /* MMIO/PIO writes trigger an event if the addr/val match */
729 ioeventfd_write(struct kvm_vcpu *vcpu, struct kvm_io_device *this, gpa_t addr,
730 int len, const void *val)
732 struct _ioeventfd *p = to_ioeventfd(this);
734 if (!ioeventfd_in_range(p, addr, len, val))
737 eventfd_signal(p->eventfd, 1);
742 * This function is called as KVM is completely shutting down. We do not
743 * need to worry about locking just nuke anything we have as quickly as possible
746 ioeventfd_destructor(struct kvm_io_device *this)
748 struct _ioeventfd *p = to_ioeventfd(this);
750 ioeventfd_release(p);
753 static const struct kvm_io_device_ops ioeventfd_ops = {
754 .write = ioeventfd_write,
755 .destructor = ioeventfd_destructor,
758 /* assumes kvm->slots_lock held */
760 ioeventfd_check_collision(struct kvm *kvm, struct _ioeventfd *p)
762 struct _ioeventfd *_p;
764 list_for_each_entry(_p, &kvm->ioeventfds, list)
765 if (_p->bus_idx == p->bus_idx &&
766 _p->addr == p->addr &&
767 (!_p->length || !p->length ||
768 (_p->length == p->length &&
769 (_p->wildcard || p->wildcard ||
770 _p->datamatch == p->datamatch))))
776 static enum kvm_bus ioeventfd_bus_from_flags(__u32 flags)
778 if (flags & KVM_IOEVENTFD_FLAG_PIO)
780 if (flags & KVM_IOEVENTFD_FLAG_VIRTIO_CCW_NOTIFY)
781 return KVM_VIRTIO_CCW_NOTIFY_BUS;
785 static int kvm_assign_ioeventfd_idx(struct kvm *kvm,
786 enum kvm_bus bus_idx,
787 struct kvm_ioeventfd *args)
790 struct eventfd_ctx *eventfd;
791 struct _ioeventfd *p;
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 kvm->buses[bus_idx]->ioeventfd_count++;
832 list_add_tail(&p->list, &kvm->ioeventfds);
834 mutex_unlock(&kvm->slots_lock);
839 mutex_unlock(&kvm->slots_lock);
843 eventfd_ctx_put(eventfd);
849 kvm_deassign_ioeventfd_idx(struct kvm *kvm, enum kvm_bus bus_idx,
850 struct kvm_ioeventfd *args)
852 struct _ioeventfd *p, *tmp;
853 struct eventfd_ctx *eventfd;
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 if (kvm->buses[bus_idx])
877 kvm->buses[bus_idx]->ioeventfd_count--;
878 ioeventfd_release(p);
883 mutex_unlock(&kvm->slots_lock);
885 eventfd_ctx_put(eventfd);
890 static int kvm_deassign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
892 enum kvm_bus bus_idx = ioeventfd_bus_from_flags(args->flags);
893 int ret = kvm_deassign_ioeventfd_idx(kvm, bus_idx, args);
895 if (!args->len && bus_idx == KVM_MMIO_BUS)
896 kvm_deassign_ioeventfd_idx(kvm, KVM_FAST_MMIO_BUS, args);
902 kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
904 enum kvm_bus bus_idx;
907 bus_idx = ioeventfd_bus_from_flags(args->flags);
908 /* must be natural-word sized, or 0 to ignore length */
920 /* check for range overflow */
921 if (args->addr + args->len < args->addr)
924 /* check for extra flags that we don't understand */
925 if (args->flags & ~KVM_IOEVENTFD_VALID_FLAG_MASK)
928 /* ioeventfd with no length can't be combined with DATAMATCH */
929 if (!args->len && (args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH))
932 ret = kvm_assign_ioeventfd_idx(kvm, bus_idx, args);
936 /* When length is ignored, MMIO is also put on a separate bus, for
939 if (!args->len && bus_idx == KVM_MMIO_BUS) {
940 ret = kvm_assign_ioeventfd_idx(kvm, KVM_FAST_MMIO_BUS, args);
948 kvm_deassign_ioeventfd_idx(kvm, bus_idx, args);
954 kvm_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
956 if (args->flags & KVM_IOEVENTFD_FLAG_DEASSIGN)
957 return kvm_deassign_ioeventfd(kvm, args);
959 return kvm_assign_ioeventfd(kvm, args);