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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>
40
41#include <kvm/iodev.h>
42
43#ifdef CONFIG_HAVE_KVM_IRQFD
44
45static struct workqueue_struct *irqfd_cleanup_wq;
46
47static void
48irqfd_inject(struct work_struct *work)
49{
50 struct kvm_kernel_irqfd *irqfd =
51 container_of(work, struct kvm_kernel_irqfd, inject);
52 struct kvm *kvm = irqfd->kvm;
53
54 if (!irqfd->resampler) {
55 kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 1,
56 false);
57 kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 0,
58 false);
59 } else
60 kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID,
61 irqfd->gsi, 1, false);
62}
63
64
65
66
67
68
69static void
70irqfd_resampler_ack(struct kvm_irq_ack_notifier *kian)
71{
72 struct kvm_kernel_irqfd_resampler *resampler;
73 struct kvm *kvm;
74 struct kvm_kernel_irqfd *irqfd;
75 int idx;
76
77 resampler = container_of(kian,
78 struct kvm_kernel_irqfd_resampler, notifier);
79 kvm = resampler->kvm;
80
81 kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID,
82 resampler->notifier.gsi, 0, false);
83
84 idx = srcu_read_lock(&kvm->irq_srcu);
85
86 list_for_each_entry_rcu(irqfd, &resampler->list, resampler_link)
87 eventfd_signal(irqfd->resamplefd, 1);
88
89 srcu_read_unlock(&kvm->irq_srcu, idx);
90}
91
92static void
93irqfd_resampler_shutdown(struct kvm_kernel_irqfd *irqfd)
94{
95 struct kvm_kernel_irqfd_resampler *resampler = irqfd->resampler;
96 struct kvm *kvm = resampler->kvm;
97
98 mutex_lock(&kvm->irqfds.resampler_lock);
99
100 list_del_rcu(&irqfd->resampler_link);
101 synchronize_srcu(&kvm->irq_srcu);
102
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);
108 kfree(resampler);
109 }
110
111 mutex_unlock(&kvm->irqfds.resampler_lock);
112}
113
114
115
116
117static void
118irqfd_shutdown(struct work_struct *work)
119{
120 struct kvm_kernel_irqfd *irqfd =
121 container_of(work, struct kvm_kernel_irqfd, shutdown);
122 u64 cnt;
123
124
125
126
127
128 eventfd_ctx_remove_wait_queue(irqfd->eventfd, &irqfd->wait, &cnt);
129
130
131
132
133
134 flush_work(&irqfd->inject);
135
136 if (irqfd->resampler) {
137 irqfd_resampler_shutdown(irqfd);
138 eventfd_ctx_put(irqfd->resamplefd);
139 }
140
141
142
143
144#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
145 irq_bypass_unregister_consumer(&irqfd->consumer);
146#endif
147 eventfd_ctx_put(irqfd->eventfd);
148 kfree(irqfd);
149}
150
151
152
153static bool
154irqfd_is_active(struct kvm_kernel_irqfd *irqfd)
155{
156 return list_empty(&irqfd->list) ? false : true;
157}
158
159
160
161
162
163
164static void
165irqfd_deactivate(struct kvm_kernel_irqfd *irqfd)
166{
167 BUG_ON(!irqfd_is_active(irqfd));
168
169 list_del_init(&irqfd->list);
170
171 queue_work(irqfd_cleanup_wq, &irqfd->shutdown);
172}
173
174int __attribute__((weak)) kvm_arch_set_irq_inatomic(
175 struct kvm_kernel_irq_routing_entry *irq,
176 struct kvm *kvm, int irq_source_id,
177 int level,
178 bool line_status)
179{
180 return -EWOULDBLOCK;
181}
182
183
184
185
186static int
187irqfd_wakeup(wait_queue_entry_t *wait, unsigned mode, int sync, void *key)
188{
189 struct kvm_kernel_irqfd *irqfd =
190 container_of(wait, struct kvm_kernel_irqfd, wait);
191 unsigned long flags = (unsigned long)key;
192 struct kvm_kernel_irq_routing_entry irq;
193 struct kvm *kvm = irqfd->kvm;
194 unsigned seq;
195 int idx;
196
197 if (flags & POLLIN) {
198 idx = srcu_read_lock(&kvm->irq_srcu);
199 do {
200 seq = read_seqcount_begin(&irqfd->irq_entry_sc);
201 irq = irqfd->irq_entry;
202 } while (read_seqcount_retry(&irqfd->irq_entry_sc, seq));
203
204 if (kvm_arch_set_irq_inatomic(&irq, kvm,
205 KVM_USERSPACE_IRQ_SOURCE_ID, 1,
206 false) == -EWOULDBLOCK)
207 schedule_work(&irqfd->inject);
208 srcu_read_unlock(&kvm->irq_srcu, idx);
209 }
210
211 if (flags & POLLHUP) {
212
213 unsigned long flags;
214
215 spin_lock_irqsave(&kvm->irqfds.lock, flags);
216
217
218
219
220
221
222
223
224
225
226 if (irqfd_is_active(irqfd))
227 irqfd_deactivate(irqfd);
228
229 spin_unlock_irqrestore(&kvm->irqfds.lock, flags);
230 }
231
232 return 0;
233}
234
235static void
236irqfd_ptable_queue_proc(struct file *file, wait_queue_head_t *wqh,
237 poll_table *pt)
238{
239 struct kvm_kernel_irqfd *irqfd =
240 container_of(pt, struct kvm_kernel_irqfd, pt);
241 add_wait_queue(wqh, &irqfd->wait);
242}
243
244
245static void irqfd_update(struct kvm *kvm, struct kvm_kernel_irqfd *irqfd)
246{
247 struct kvm_kernel_irq_routing_entry *e;
248 struct kvm_kernel_irq_routing_entry entries[KVM_NR_IRQCHIPS];
249 int n_entries;
250
251 n_entries = kvm_irq_map_gsi(kvm, entries, irqfd->gsi);
252
253 write_seqcount_begin(&irqfd->irq_entry_sc);
254
255 e = entries;
256 if (n_entries == 1)
257 irqfd->irq_entry = *e;
258 else
259 irqfd->irq_entry.type = 0;
260
261 write_seqcount_end(&irqfd->irq_entry_sc);
262}
263
264#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
265void __attribute__((weak)) kvm_arch_irq_bypass_stop(
266 struct irq_bypass_consumer *cons)
267{
268}
269
270void __attribute__((weak)) kvm_arch_irq_bypass_start(
271 struct irq_bypass_consumer *cons)
272{
273}
274
275int __attribute__((weak)) kvm_arch_update_irqfd_routing(
276 struct kvm *kvm, unsigned int host_irq,
277 uint32_t guest_irq, bool set)
278{
279 return 0;
280}
281#endif
282
283static int
284kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
285{
286 struct kvm_kernel_irqfd *irqfd, *tmp;
287 struct fd f;
288 struct eventfd_ctx *eventfd = NULL, *resamplefd = NULL;
289 int ret;
290 unsigned int events;
291 int idx;
292
293 if (!kvm_arch_intc_initialized(kvm))
294 return -EAGAIN;
295
296 irqfd = kzalloc(sizeof(*irqfd), GFP_KERNEL);
297 if (!irqfd)
298 return -ENOMEM;
299
300 irqfd->kvm = kvm;
301 irqfd->gsi = args->gsi;
302 INIT_LIST_HEAD(&irqfd->list);
303 INIT_WORK(&irqfd->inject, irqfd_inject);
304 INIT_WORK(&irqfd->shutdown, irqfd_shutdown);
305 seqcount_init(&irqfd->irq_entry_sc);
306
307 f = fdget(args->fd);
308 if (!f.file) {
309 ret = -EBADF;
310 goto out;
311 }
312
313 eventfd = eventfd_ctx_fileget(f.file);
314 if (IS_ERR(eventfd)) {
315 ret = PTR_ERR(eventfd);
316 goto fail;
317 }
318
319 irqfd->eventfd = eventfd;
320
321 if (args->flags & KVM_IRQFD_FLAG_RESAMPLE) {
322 struct kvm_kernel_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,
336 &kvm->irqfds.resampler_list, link) {
337 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_srcu(&kvm->irq_srcu);
365
366 mutex_unlock(&kvm->irqfds.resampler_lock);
367 }
368
369
370
371
372
373 init_waitqueue_func_entry(&irqfd->wait, irqfd_wakeup);
374 init_poll_funcptr(&irqfd->pt, irqfd_ptable_queue_proc);
375
376 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
383 ret = -EBUSY;
384 spin_unlock_irq(&kvm->irqfds.lock);
385 goto fail;
386 }
387
388 idx = srcu_read_lock(&kvm->irq_srcu);
389 irqfd_update(kvm, irqfd);
390 srcu_read_unlock(&kvm->irq_srcu, idx);
391
392 list_add_tail(&irqfd->list, &kvm->irqfds.items);
393
394 spin_unlock_irq(&kvm->irqfds.lock);
395
396
397
398
399
400 events = f.file->f_op->poll(f.file, &irqfd->pt);
401
402 if (events & POLLIN)
403 schedule_work(&irqfd->inject);
404
405
406
407
408
409 fdput(f);
410#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
411 if (kvm_arch_has_irq_bypass()) {
412 irqfd->consumer.token = (void *)irqfd->eventfd;
413 irqfd->consumer.add_producer = kvm_arch_irq_bypass_add_producer;
414 irqfd->consumer.del_producer = kvm_arch_irq_bypass_del_producer;
415 irqfd->consumer.stop = kvm_arch_irq_bypass_stop;
416 irqfd->consumer.start = kvm_arch_irq_bypass_start;
417 ret = irq_bypass_register_consumer(&irqfd->consumer);
418 if (ret)
419 pr_info("irq bypass consumer (token %p) registration fails: %d\n",
420 irqfd->consumer.token, ret);
421 }
422#endif
423
424 return 0;
425
426fail:
427 if (irqfd->resampler)
428 irqfd_resampler_shutdown(irqfd);
429
430 if (resamplefd && !IS_ERR(resamplefd))
431 eventfd_ctx_put(resamplefd);
432
433 if (eventfd && !IS_ERR(eventfd))
434 eventfd_ctx_put(eventfd);
435
436 fdput(f);
437
438out:
439 kfree(irqfd);
440 return ret;
441}
442
443bool kvm_irq_has_notifier(struct kvm *kvm, unsigned irqchip, unsigned pin)
444{
445 struct kvm_irq_ack_notifier *kian;
446 int gsi, idx;
447
448 idx = srcu_read_lock(&kvm->irq_srcu);
449 gsi = kvm_irq_map_chip_pin(kvm, irqchip, pin);
450 if (gsi != -1)
451 hlist_for_each_entry_rcu(kian, &kvm->irq_ack_notifier_list,
452 link)
453 if (kian->gsi == gsi) {
454 srcu_read_unlock(&kvm->irq_srcu, idx);
455 return true;
456 }
457
458 srcu_read_unlock(&kvm->irq_srcu, idx);
459
460 return false;
461}
462EXPORT_SYMBOL_GPL(kvm_irq_has_notifier);
463
464void kvm_notify_acked_gsi(struct kvm *kvm, int gsi)
465{
466 struct kvm_irq_ack_notifier *kian;
467
468 hlist_for_each_entry_rcu(kian, &kvm->irq_ack_notifier_list,
469 link)
470 if (kian->gsi == gsi)
471 kian->irq_acked(kian);
472}
473
474void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin)
475{
476 int gsi, idx;
477
478 trace_kvm_ack_irq(irqchip, pin);
479
480 idx = srcu_read_lock(&kvm->irq_srcu);
481 gsi = kvm_irq_map_chip_pin(kvm, irqchip, pin);
482 if (gsi != -1)
483 kvm_notify_acked_gsi(kvm, gsi);
484 srcu_read_unlock(&kvm->irq_srcu, idx);
485}
486
487void kvm_register_irq_ack_notifier(struct kvm *kvm,
488 struct kvm_irq_ack_notifier *kian)
489{
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 kvm_arch_post_irq_ack_notifier_list_update(kvm);
494}
495
496void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
497 struct kvm_irq_ack_notifier *kian)
498{
499 mutex_lock(&kvm->irq_lock);
500 hlist_del_init_rcu(&kian->link);
501 mutex_unlock(&kvm->irq_lock);
502 synchronize_srcu(&kvm->irq_srcu);
503 kvm_arch_post_irq_ack_notifier_list_update(kvm);
504}
505#endif
506
507void
508kvm_eventfd_init(struct kvm *kvm)
509{
510#ifdef CONFIG_HAVE_KVM_IRQFD
511 spin_lock_init(&kvm->irqfds.lock);
512 INIT_LIST_HEAD(&kvm->irqfds.items);
513 INIT_LIST_HEAD(&kvm->irqfds.resampler_list);
514 mutex_init(&kvm->irqfds.resampler_lock);
515#endif
516 INIT_LIST_HEAD(&kvm->ioeventfds);
517}
518
519#ifdef CONFIG_HAVE_KVM_IRQFD
520
521
522
523static int
524kvm_irqfd_deassign(struct kvm *kvm, struct kvm_irqfd *args)
525{
526 struct kvm_kernel_irqfd *irqfd, *tmp;
527 struct eventfd_ctx *eventfd;
528
529 eventfd = eventfd_ctx_fdget(args->fd);
530 if (IS_ERR(eventfd))
531 return PTR_ERR(eventfd);
532
533 spin_lock_irq(&kvm->irqfds.lock);
534
535 list_for_each_entry_safe(irqfd, tmp, &kvm->irqfds.items, list) {
536 if (irqfd->eventfd == eventfd && irqfd->gsi == args->gsi) {
537
538
539
540
541
542
543 write_seqcount_begin(&irqfd->irq_entry_sc);
544 irqfd->irq_entry.type = 0;
545 write_seqcount_end(&irqfd->irq_entry_sc);
546 irqfd_deactivate(irqfd);
547 }
548 }
549
550 spin_unlock_irq(&kvm->irqfds.lock);
551 eventfd_ctx_put(eventfd);
552
553
554
555
556
557
558 flush_workqueue(irqfd_cleanup_wq);
559
560 return 0;
561}
562
563int
564kvm_irqfd(struct kvm *kvm, struct kvm_irqfd *args)
565{
566 if (args->flags & ~(KVM_IRQFD_FLAG_DEASSIGN | KVM_IRQFD_FLAG_RESAMPLE))
567 return -EINVAL;
568
569 if (args->flags & KVM_IRQFD_FLAG_DEASSIGN)
570 return kvm_irqfd_deassign(kvm, args);
571
572 return kvm_irqfd_assign(kvm, args);
573}
574
575
576
577
578
579void
580kvm_irqfd_release(struct kvm *kvm)
581{
582 struct kvm_kernel_irqfd *irqfd, *tmp;
583
584 spin_lock_irq(&kvm->irqfds.lock);
585
586 list_for_each_entry_safe(irqfd, tmp, &kvm->irqfds.items, list)
587 irqfd_deactivate(irqfd);
588
589 spin_unlock_irq(&kvm->irqfds.lock);
590
591
592
593
594
595 flush_workqueue(irqfd_cleanup_wq);
596
597}
598
599
600
601
602
603void kvm_irq_routing_update(struct kvm *kvm)
604{
605 struct kvm_kernel_irqfd *irqfd;
606
607 spin_lock_irq(&kvm->irqfds.lock);
608
609 list_for_each_entry(irqfd, &kvm->irqfds.items, list) {
610 irqfd_update(kvm, irqfd);
611
612#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
613 if (irqfd->producer) {
614 int ret = kvm_arch_update_irqfd_routing(
615 irqfd->kvm, irqfd->producer->irq,
616 irqfd->gsi, 1);
617 WARN_ON(ret);
618 }
619#endif
620 }
621
622 spin_unlock_irq(&kvm->irqfds.lock);
623}
624
625
626
627
628
629
630int kvm_irqfd_init(void)
631{
632 irqfd_cleanup_wq = alloc_workqueue("kvm-irqfd-cleanup", 0, 0);
633 if (!irqfd_cleanup_wq)
634 return -ENOMEM;
635
636 return 0;
637}
638
639void kvm_irqfd_exit(void)
640{
641 destroy_workqueue(irqfd_cleanup_wq);
642}
643#endif
644
645
646
647
648
649
650
651
652
653
654struct _ioeventfd {
655 struct list_head list;
656 u64 addr;
657 int length;
658 struct eventfd_ctx *eventfd;
659 u64 datamatch;
660 struct kvm_io_device dev;
661 u8 bus_idx;
662 bool wildcard;
663};
664
665static inline struct _ioeventfd *
666to_ioeventfd(struct kvm_io_device *dev)
667{
668 return container_of(dev, struct _ioeventfd, dev);
669}
670
671static void
672ioeventfd_release(struct _ioeventfd *p)
673{
674 eventfd_ctx_put(p->eventfd);
675 list_del(&p->list);
676 kfree(p);
677}
678
679static bool
680ioeventfd_in_range(struct _ioeventfd *p, gpa_t addr, int len, const void *val)
681{
682 u64 _val;
683
684 if (addr != p->addr)
685
686 return false;
687
688 if (!p->length)
689
690 return true;
691
692 if (len != p->length)
693
694 return false;
695
696 if (p->wildcard)
697
698 return true;
699
700
701
702 BUG_ON(!IS_ALIGNED((unsigned long)val, len));
703
704 switch (len) {
705 case 1:
706 _val = *(u8 *)val;
707 break;
708 case 2:
709 _val = *(u16 *)val;
710 break;
711 case 4:
712 _val = *(u32 *)val;
713 break;
714 case 8:
715 _val = *(u64 *)val;
716 break;
717 default:
718 return false;
719 }
720
721 return _val == p->datamatch ? true : false;
722}
723
724
725static int
726ioeventfd_write(struct kvm_vcpu *vcpu, struct kvm_io_device *this, gpa_t addr,
727 int len, const void *val)
728{
729 struct _ioeventfd *p = to_ioeventfd(this);
730
731 if (!ioeventfd_in_range(p, addr, len, val))
732 return -EOPNOTSUPP;
733
734 eventfd_signal(p->eventfd, 1);
735 return 0;
736}
737
738
739
740
741
742static void
743ioeventfd_destructor(struct kvm_io_device *this)
744{
745 struct _ioeventfd *p = to_ioeventfd(this);
746
747 ioeventfd_release(p);
748}
749
750static const struct kvm_io_device_ops ioeventfd_ops = {
751 .write = ioeventfd_write,
752 .destructor = ioeventfd_destructor,
753};
754
755
756static bool
757ioeventfd_check_collision(struct kvm *kvm, struct _ioeventfd *p)
758{
759 struct _ioeventfd *_p;
760
761 list_for_each_entry(_p, &kvm->ioeventfds, list)
762 if (_p->bus_idx == p->bus_idx &&
763 _p->addr == p->addr &&
764 (!_p->length || !p->length ||
765 (_p->length == p->length &&
766 (_p->wildcard || p->wildcard ||
767 _p->datamatch == p->datamatch))))
768 return true;
769
770 return false;
771}
772
773static enum kvm_bus ioeventfd_bus_from_flags(__u32 flags)
774{
775 if (flags & KVM_IOEVENTFD_FLAG_PIO)
776 return KVM_PIO_BUS;
777 if (flags & KVM_IOEVENTFD_FLAG_VIRTIO_CCW_NOTIFY)
778 return KVM_VIRTIO_CCW_NOTIFY_BUS;
779 return KVM_MMIO_BUS;
780}
781
782static int kvm_assign_ioeventfd_idx(struct kvm *kvm,
783 enum kvm_bus bus_idx,
784 struct kvm_ioeventfd *args)
785{
786
787 struct eventfd_ctx *eventfd;
788 struct _ioeventfd *p;
789 int ret;
790
791 eventfd = eventfd_ctx_fdget(args->fd);
792 if (IS_ERR(eventfd))
793 return PTR_ERR(eventfd);
794
795 p = kzalloc(sizeof(*p), GFP_KERNEL);
796 if (!p) {
797 ret = -ENOMEM;
798 goto fail;
799 }
800
801 INIT_LIST_HEAD(&p->list);
802 p->addr = args->addr;
803 p->bus_idx = bus_idx;
804 p->length = args->len;
805 p->eventfd = eventfd;
806
807
808 if (args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH)
809 p->datamatch = args->datamatch;
810 else
811 p->wildcard = true;
812
813 mutex_lock(&kvm->slots_lock);
814
815
816 if (ioeventfd_check_collision(kvm, p)) {
817 ret = -EEXIST;
818 goto unlock_fail;
819 }
820
821 kvm_iodevice_init(&p->dev, &ioeventfd_ops);
822
823 ret = kvm_io_bus_register_dev(kvm, bus_idx, p->addr, p->length,
824 &p->dev);
825 if (ret < 0)
826 goto unlock_fail;
827
828 kvm_get_bus(kvm, bus_idx)->ioeventfd_count++;
829 list_add_tail(&p->list, &kvm->ioeventfds);
830
831 mutex_unlock(&kvm->slots_lock);
832
833 return 0;
834
835unlock_fail:
836 mutex_unlock(&kvm->slots_lock);
837
838fail:
839 kfree(p);
840 eventfd_ctx_put(eventfd);
841
842 return ret;
843}
844
845static int
846kvm_deassign_ioeventfd_idx(struct kvm *kvm, enum kvm_bus bus_idx,
847 struct kvm_ioeventfd *args)
848{
849 struct _ioeventfd *p, *tmp;
850 struct eventfd_ctx *eventfd;
851 struct kvm_io_bus *bus;
852 int ret = -ENOENT;
853
854 eventfd = eventfd_ctx_fdget(args->fd);
855 if (IS_ERR(eventfd))
856 return PTR_ERR(eventfd);
857
858 mutex_lock(&kvm->slots_lock);
859
860 list_for_each_entry_safe(p, tmp, &kvm->ioeventfds, list) {
861 bool wildcard = !(args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH);
862
863 if (p->bus_idx != bus_idx ||
864 p->eventfd != eventfd ||
865 p->addr != args->addr ||
866 p->length != args->len ||
867 p->wildcard != wildcard)
868 continue;
869
870 if (!p->wildcard && p->datamatch != args->datamatch)
871 continue;
872
873 kvm_io_bus_unregister_dev(kvm, bus_idx, &p->dev);
874 bus = kvm_get_bus(kvm, bus_idx);
875 if (bus)
876 bus->ioeventfd_count--;
877 ioeventfd_release(p);
878 ret = 0;
879 break;
880 }
881
882 mutex_unlock(&kvm->slots_lock);
883
884 eventfd_ctx_put(eventfd);
885
886 return ret;
887}
888
889static int kvm_deassign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
890{
891 enum kvm_bus bus_idx = ioeventfd_bus_from_flags(args->flags);
892 int ret = kvm_deassign_ioeventfd_idx(kvm, bus_idx, args);
893
894 if (!args->len && bus_idx == KVM_MMIO_BUS)
895 kvm_deassign_ioeventfd_idx(kvm, KVM_FAST_MMIO_BUS, args);
896
897 return ret;
898}
899
900static int
901kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
902{
903 enum kvm_bus bus_idx;
904 int ret;
905
906 bus_idx = ioeventfd_bus_from_flags(args->flags);
907
908 switch (args->len) {
909 case 0:
910 case 1:
911 case 2:
912 case 4:
913 case 8:
914 break;
915 default:
916 return -EINVAL;
917 }
918
919
920 if (args->addr + args->len < args->addr)
921 return -EINVAL;
922
923
924 if (args->flags & ~KVM_IOEVENTFD_VALID_FLAG_MASK)
925 return -EINVAL;
926
927
928 if (!args->len && (args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH))
929 return -EINVAL;
930
931 ret = kvm_assign_ioeventfd_idx(kvm, bus_idx, args);
932 if (ret)
933 goto fail;
934
935
936
937
938 if (!args->len && bus_idx == KVM_MMIO_BUS) {
939 ret = kvm_assign_ioeventfd_idx(kvm, KVM_FAST_MMIO_BUS, args);
940 if (ret < 0)
941 goto fast_fail;
942 }
943
944 return 0;
945
946fast_fail:
947 kvm_deassign_ioeventfd_idx(kvm, bus_idx, args);
948fail:
949 return ret;
950}
951
952int
953kvm_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
954{
955 if (args->flags & KVM_IOEVENTFD_FLAG_DEASSIGN)
956 return kvm_deassign_ioeventfd(kvm, args);
957
958 return kvm_assign_ioeventfd(kvm, args);
959}
960