Commit message: KVM: Don't accept obviously wrong gsi values via KVM_IRQFD

We cannot add routes for gsi values >= KVM_MAX_IRQ_ROUTES -- see
kvm_set_irq_routing(). Hence, there is no sense in accepting them
via KVM_IRQFD. Prevent them from entering the system in the first
place.

Signed-off-by: Jan H. Schönherr <jschoenh@amazon.de>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
CVE: CVE-2017-1000252
CWE: CWE-20
Vulnerability description: The KVM subsystem in the Linux kernel through 4.13.3 allows guest OS users to cause a denial of service (assertion failure, and hypervisor hang or crash) via an out-of bounds guest_irq value, related to arch/x86/kvm/vmx.c and virt/kvm/eventfd.c.

Project: linux
File: eventfd.c

static enum kvm_bus ioeventfd_bus_from_flags(__u32 flags)
{
	if (flags & KVM_IOEVENTFD_FLAG_PIO)
		return KVM_PIO_BUS;
	if (flags & KVM_IOEVENTFD_FLAG_VIRTIO_CCW_NOTIFY)
		return KVM_VIRTIO_CCW_NOTIFY_BUS;
	return KVM_MMIO_BUS;
}

Project: linux
File: eventfd.c

ioeventfd_check_collision(struct kvm *kvm, struct _ioeventfd *p)
{
	struct _ioeventfd *_p;

	list_for_each_entry(_p, &kvm->ioeventfds, list)
		if (_p->bus_idx == p->bus_idx &&
		    _p->addr == p->addr &&
		    (!_p->length || !p->length ||
		     (_p->length == p->length &&
		      (_p->wildcard || p->wildcard ||
		       _p->datamatch == p->datamatch))))
			return true;

	return false;
}

Project: linux
File: eventfd.c

ioeventfd_destructor(struct kvm_io_device *this)
{
	struct _ioeventfd *p = to_ioeventfd(this);

	ioeventfd_release(p);
}

Project: linux
File: eventfd.c

ioeventfd_in_range(struct _ioeventfd *p, gpa_t addr, int len, const void *val)
{
	u64 _val;

	if (addr != p->addr)
		/* address must be precise for a hit */
		return false;

	if (!p->length)
		/* length = 0 means only look at the address, so always a hit */
		return true;

	if (len != p->length)
		/* address-range must be precise for a hit */
		return false;

	if (p->wildcard)
		/* all else equal, wildcard is always a hit */
		return true;

	/* otherwise, we have to actually compare the data */

	BUG_ON(!IS_ALIGNED((unsigned long)val, len));

	switch (len) {
	case 1:
		_val = *(u8 *)val;
		break;
	case 2:
		_val = *(u16 *)val;
		break;
	case 4:
		_val = *(u32 *)val;
		break;
	case 8:
		_val = *(u64 *)val;
		break;
	default:
		return false;
	}

	return _val == p->datamatch ? true : false;
}

Project: linux
File: eventfd.c

ioeventfd_release(struct _ioeventfd *p)
{
	eventfd_ctx_put(p->eventfd);
	list_del(&p->list);
	kfree(p);
}

Project: linux
File: eventfd.c

ioeventfd_write(struct kvm_vcpu *vcpu, struct kvm_io_device *this, gpa_t addr,
		int len, const void *val)
{
	struct _ioeventfd *p = to_ioeventfd(this);

	if (!ioeventfd_in_range(p, addr, len, val))
		return -EOPNOTSUPP;

	eventfd_signal(p->eventfd, 1);
	return 0;
}

Project: linux
File: eventfd.c

irqfd_deactivate(struct kvm_kernel_irqfd *irqfd)
{
	BUG_ON(!irqfd_is_active(irqfd));

	list_del_init(&irqfd->list);

	queue_work(irqfd_cleanup_wq, &irqfd->shutdown);
}

Project: linux
File: eventfd.c

irqfd_inject(struct work_struct *work)
{
	struct kvm_kernel_irqfd *irqfd =
		container_of(work, struct kvm_kernel_irqfd, inject);
	struct kvm *kvm = irqfd->kvm;

	if (!irqfd->resampler) {
		kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 1,
				false);
		kvm_set_irq(kvm, KVM_USERSPACE_IRQ_SOURCE_ID, irqfd->gsi, 0,
				false);
	} else
		kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID,
			    irqfd->gsi, 1, false);
}

Project: linux
File: eventfd.c

irqfd_is_active(struct kvm_kernel_irqfd *irqfd)
{
	return list_empty(&irqfd->list) ? false : true;
}

Project: linux
File: eventfd.c

irqfd_ptable_queue_proc(struct file *file, wait_queue_head_t *wqh,
			poll_table *pt)
{
	struct kvm_kernel_irqfd *irqfd =
		container_of(pt, struct kvm_kernel_irqfd, pt);
	add_wait_queue(wqh, &irqfd->wait);
}

Project: linux
File: eventfd.c

irqfd_resampler_ack(struct kvm_irq_ack_notifier *kian)
{
	struct kvm_kernel_irqfd_resampler *resampler;
	struct kvm *kvm;
	struct kvm_kernel_irqfd *irqfd;
	int idx;

	resampler = container_of(kian,
			struct kvm_kernel_irqfd_resampler, notifier);
	kvm = resampler->kvm;

	kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID,
		    resampler->notifier.gsi, 0, false);

	idx = srcu_read_lock(&kvm->irq_srcu);

	list_for_each_entry_rcu(irqfd, &resampler->list, resampler_link)
		eventfd_signal(irqfd->resamplefd, 1);

	srcu_read_unlock(&kvm->irq_srcu, idx);
}

Project: linux
File: eventfd.c

irqfd_resampler_shutdown(struct kvm_kernel_irqfd *irqfd)
{
	struct kvm_kernel_irqfd_resampler *resampler = irqfd->resampler;
	struct kvm *kvm = resampler->kvm;

	mutex_lock(&kvm->irqfds.resampler_lock);

	list_del_rcu(&irqfd->resampler_link);
	synchronize_srcu(&kvm->irq_srcu);

	if (list_empty(&resampler->list)) {
		list_del(&resampler->link);
		kvm_unregister_irq_ack_notifier(kvm, &resampler->notifier);
		kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID,
			    resampler->notifier.gsi, 0, false);
		kfree(resampler);
	}

	mutex_unlock(&kvm->irqfds.resampler_lock);
}

Project: linux
File: eventfd.c

irqfd_shutdown(struct work_struct *work)
{
	struct kvm_kernel_irqfd *irqfd =
		container_of(work, struct kvm_kernel_irqfd, shutdown);
	u64 cnt;

	/*
	 * Synchronize with the wait-queue and unhook ourselves to prevent
	 * further events.
	 */
	eventfd_ctx_remove_wait_queue(irqfd->eventfd, &irqfd->wait, &cnt);

	/*
	 * We know no new events will be scheduled at this point, so block
	 * until all previously outstanding events have completed
	 */
	flush_work(&irqfd->inject);

	if (irqfd->resampler) {
		irqfd_resampler_shutdown(irqfd);
		eventfd_ctx_put(irqfd->resamplefd);
	}

	/*
	 * It is now safe to release the object's resources
	 */
#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
	irq_bypass_unregister_consumer(&irqfd->consumer);
#endif
	eventfd_ctx_put(irqfd->eventfd);
	kfree(irqfd);
}

Project: linux
File: eventfd.c

irqfd_wakeup(wait_queue_entry_t *wait, unsigned mode, int sync, void *key)
{
	struct kvm_kernel_irqfd *irqfd =
		container_of(wait, struct kvm_kernel_irqfd, wait);
	unsigned long flags = (unsigned long)key;
	struct kvm_kernel_irq_routing_entry irq;
	struct kvm *kvm = irqfd->kvm;
	unsigned seq;
	int idx;

	if (flags & POLLIN) {
		idx = srcu_read_lock(&kvm->irq_srcu);
		do {
			seq = read_seqcount_begin(&irqfd->irq_entry_sc);
			irq = irqfd->irq_entry;
		} while (read_seqcount_retry(&irqfd->irq_entry_sc, seq));
		/* An event has been signaled, inject an interrupt */
		if (kvm_arch_set_irq_inatomic(&irq, kvm,
					      KVM_USERSPACE_IRQ_SOURCE_ID, 1,
					      false) == -EWOULDBLOCK)
			schedule_work(&irqfd->inject);
		srcu_read_unlock(&kvm->irq_srcu, idx);
	}

	if (flags & POLLHUP) {
		/* The eventfd is closing, detach from KVM */
		unsigned long flags;

		spin_lock_irqsave(&kvm->irqfds.lock, flags);

		/*
		 * We must check if someone deactivated the irqfd before
		 * we could acquire the irqfds.lock since the item is
		 * deactivated from the KVM side before it is unhooked from
		 * the wait-queue.  If it is already deactivated, we can
		 * simply return knowing the other side will cleanup for us.
		 * We cannot race against the irqfd going away since the
		 * other side is required to acquire wqh->lock, which we hold
		 */
		if (irqfd_is_active(irqfd))
			irqfd_deactivate(irqfd);

		spin_unlock_irqrestore(&kvm->irqfds.lock, flags);
	}

	return 0;
}

Project: linux
File: eventfd.c

void __attribute__((weak)) kvm_arch_irq_bypass_start(
				struct irq_bypass_consumer *cons)
{
}

Project: linux
File: eventfd.c

void __attribute__((weak)) kvm_arch_irq_bypass_stop(
				struct irq_bypass_consumer *cons)
{
}

Project: linux
File: eventfd.c

int __attribute__((weak)) kvm_arch_set_irq_inatomic(
				struct kvm_kernel_irq_routing_entry *irq,
				struct kvm *kvm, int irq_source_id,
				int level,
				bool line_status)
{
	return -EWOULDBLOCK;
}

Project: linux
File: eventfd.c

kvm_assign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
{
	enum kvm_bus              bus_idx;
	int ret;

	bus_idx = ioeventfd_bus_from_flags(args->flags);
	/* must be natural-word sized, or 0 to ignore length */
	switch (args->len) {
	case 0:
	case 1:
	case 2:
	case 4:
	case 8:
		break;
	default:
		return -EINVAL;
	}

	/* check for range overflow */
	if (args->addr + args->len < args->addr)
		return -EINVAL;

	/* check for extra flags that we don't understand */
	if (args->flags & ~KVM_IOEVENTFD_VALID_FLAG_MASK)
		return -EINVAL;

	/* ioeventfd with no length can't be combined with DATAMATCH */
	if (!args->len && (args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH))
		return -EINVAL;

	ret = kvm_assign_ioeventfd_idx(kvm, bus_idx, args);
	if (ret)
		goto fail;

	/* When length is ignored, MMIO is also put on a separate bus, for
	 * faster lookups.
	 */
	if (!args->len && bus_idx == KVM_MMIO_BUS) {
		ret = kvm_assign_ioeventfd_idx(kvm, KVM_FAST_MMIO_BUS, args);
		if (ret < 0)
			goto fast_fail;
	}

	return 0;

fast_fail:
	kvm_deassign_ioeventfd_idx(kvm, bus_idx, args);
fail:
	return ret;
}

Project: linux
File: eventfd.c

static int kvm_assign_ioeventfd_idx(struct kvm *kvm,
				enum kvm_bus bus_idx,
				struct kvm_ioeventfd *args)
{

	struct eventfd_ctx *eventfd;
	struct _ioeventfd *p;
	int ret;

	eventfd = eventfd_ctx_fdget(args->fd);
	if (IS_ERR(eventfd))
		return PTR_ERR(eventfd);

	p = kzalloc(sizeof(*p), GFP_KERNEL);
	if (!p) {
		ret = -ENOMEM;
		goto fail;
	}

	INIT_LIST_HEAD(&p->list);
	p->addr    = args->addr;
	p->bus_idx = bus_idx;
	p->length  = args->len;
	p->eventfd = eventfd;

	/* The datamatch feature is optional, otherwise this is a wildcard */
	if (args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH)
		p->datamatch = args->datamatch;
	else
		p->wildcard = true;

	mutex_lock(&kvm->slots_lock);

	/* Verify that there isn't a match already */
	if (ioeventfd_check_collision(kvm, p)) {
		ret = -EEXIST;
		goto unlock_fail;
	}

	kvm_iodevice_init(&p->dev, &ioeventfd_ops);

	ret = kvm_io_bus_register_dev(kvm, bus_idx, p->addr, p->length,
				      &p->dev);
	if (ret < 0)
		goto unlock_fail;

	kvm_get_bus(kvm, bus_idx)->ioeventfd_count++;
	list_add_tail(&p->list, &kvm->ioeventfds);

	mutex_unlock(&kvm->slots_lock);

	return 0;

unlock_fail:
	mutex_unlock(&kvm->slots_lock);

fail:
	kfree(p);
	eventfd_ctx_put(eventfd);

	return ret;
}

Project: linux
File: eventfd.c

static int kvm_deassign_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
{
	enum kvm_bus bus_idx = ioeventfd_bus_from_flags(args->flags);
	int ret = kvm_deassign_ioeventfd_idx(kvm, bus_idx, args);

	if (!args->len && bus_idx == KVM_MMIO_BUS)
		kvm_deassign_ioeventfd_idx(kvm, KVM_FAST_MMIO_BUS, args);

	return ret;
}

Project: linux
File: eventfd.c

kvm_deassign_ioeventfd_idx(struct kvm *kvm, enum kvm_bus bus_idx,
			   struct kvm_ioeventfd *args)
{
	struct _ioeventfd        *p, *tmp;
	struct eventfd_ctx       *eventfd;
	struct kvm_io_bus	 *bus;
	int                       ret = -ENOENT;

	eventfd = eventfd_ctx_fdget(args->fd);
	if (IS_ERR(eventfd))
		return PTR_ERR(eventfd);

	mutex_lock(&kvm->slots_lock);

	list_for_each_entry_safe(p, tmp, &kvm->ioeventfds, list) {
		bool wildcard = !(args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH);

		if (p->bus_idx != bus_idx ||
		    p->eventfd != eventfd  ||
		    p->addr != args->addr  ||
		    p->length != args->len ||
		    p->wildcard != wildcard)
			continue;

		if (!p->wildcard && p->datamatch != args->datamatch)
			continue;

		kvm_io_bus_unregister_dev(kvm, bus_idx, &p->dev);
		bus = kvm_get_bus(kvm, bus_idx);
		if (bus)
			bus->ioeventfd_count--;
		ioeventfd_release(p);
		ret = 0;
		break;
	}

	mutex_unlock(&kvm->slots_lock);

	eventfd_ctx_put(eventfd);

	return ret;
}

Project: linux
File: eventfd.c

kvm_eventfd_init(struct kvm *kvm)
{
#ifdef CONFIG_HAVE_KVM_IRQFD
	spin_lock_init(&kvm->irqfds.lock);
	INIT_LIST_HEAD(&kvm->irqfds.items);
	INIT_LIST_HEAD(&kvm->irqfds.resampler_list);
	mutex_init(&kvm->irqfds.resampler_lock);
#endif
	INIT_LIST_HEAD(&kvm->ioeventfds);
}

Project: linux
File: eventfd.c

kvm_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
{
	if (args->flags & KVM_IOEVENTFD_FLAG_DEASSIGN)
		return kvm_deassign_ioeventfd(kvm, args);

	return kvm_assign_ioeventfd(kvm, args);
}

Project: linux
File: eventfd.c

bool kvm_irq_has_notifier(struct kvm *kvm, unsigned irqchip, unsigned pin)
{
	struct kvm_irq_ack_notifier *kian;
	int gsi, idx;

	idx = srcu_read_lock(&kvm->irq_srcu);
	gsi = kvm_irq_map_chip_pin(kvm, irqchip, pin);
	if (gsi != -1)
		hlist_for_each_entry_rcu(kian, &kvm->irq_ack_notifier_list,
					 link)
			if (kian->gsi == gsi) {
				srcu_read_unlock(&kvm->irq_srcu, idx);
				return true;
			}

	srcu_read_unlock(&kvm->irq_srcu, idx);

	return false;
}

Project: linux
File: eventfd.c

kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
{
	struct kvm_kernel_irqfd *irqfd, *tmp;
	struct fd f;
	struct eventfd_ctx *eventfd = NULL, *resamplefd = NULL;
	int ret;
	unsigned int events;
	int idx;

	if (!kvm_arch_intc_initialized(kvm))
		return -EAGAIN;

	irqfd = kzalloc(sizeof(*irqfd), GFP_KERNEL);
	if (!irqfd)
		return -ENOMEM;

	irqfd->kvm = kvm;
	irqfd->gsi = args->gsi;
	INIT_LIST_HEAD(&irqfd->list);
	INIT_WORK(&irqfd->inject, irqfd_inject);
	INIT_WORK(&irqfd->shutdown, irqfd_shutdown);
	seqcount_init(&irqfd->irq_entry_sc);

	f = fdget(args->fd);
	if (!f.file) {
		ret = -EBADF;
		goto out;
	}

	eventfd = eventfd_ctx_fileget(f.file);
	if (IS_ERR(eventfd)) {
		ret = PTR_ERR(eventfd);
		goto fail;
	}

	irqfd->eventfd = eventfd;

	if (args->flags & KVM_IRQFD_FLAG_RESAMPLE) {
		struct kvm_kernel_irqfd_resampler *resampler;

		resamplefd = eventfd_ctx_fdget(args->resamplefd);
		if (IS_ERR(resamplefd)) {
			ret = PTR_ERR(resamplefd);
			goto fail;
		}

		irqfd->resamplefd = resamplefd;
		INIT_LIST_HEAD(&irqfd->resampler_link);

		mutex_lock(&kvm->irqfds.resampler_lock);

		list_for_each_entry(resampler,
				    &kvm->irqfds.resampler_list, link) {
			if (resampler->notifier.gsi == irqfd->gsi) {
				irqfd->resampler = resampler;
				break;
			}
		}

		if (!irqfd->resampler) {
			resampler = kzalloc(sizeof(*resampler), GFP_KERNEL);
			if (!resampler) {
				ret = -ENOMEM;
				mutex_unlock(&kvm->irqfds.resampler_lock);
				goto fail;
			}

			resampler->kvm = kvm;
			INIT_LIST_HEAD(&resampler->list);
			resampler->notifier.gsi = irqfd->gsi;
			resampler->notifier.irq_acked = irqfd_resampler_ack;
			INIT_LIST_HEAD(&resampler->link);

			list_add(&resampler->link, &kvm->irqfds.resampler_list);
			kvm_register_irq_ack_notifier(kvm,
						      &resampler->notifier);
			irqfd->resampler = resampler;
		}

		list_add_rcu(&irqfd->resampler_link, &irqfd->resampler->list);
		synchronize_srcu(&kvm->irq_srcu);

		mutex_unlock(&kvm->irqfds.resampler_lock);
	}

	/*
	 * Install our own custom wake-up handling so we are notified via
	 * a callback whenever someone signals the underlying eventfd
	 */
	init_waitqueue_func_entry(&irqfd->wait, irqfd_wakeup);
	init_poll_funcptr(&irqfd->pt, irqfd_ptable_queue_proc);

	spin_lock_irq(&kvm->irqfds.lock);

	ret = 0;
	list_for_each_entry(tmp, &kvm->irqfds.items, list) {
		if (irqfd->eventfd != tmp->eventfd)
			continue;
		/* This fd is used for another irq already. */
		ret = -EBUSY;
		spin_unlock_irq(&kvm->irqfds.lock);
		goto fail;
	}

	idx = srcu_read_lock(&kvm->irq_srcu);
	irqfd_update(kvm, irqfd);
	srcu_read_unlock(&kvm->irq_srcu, idx);

	list_add_tail(&irqfd->list, &kvm->irqfds.items);

	spin_unlock_irq(&kvm->irqfds.lock);

	/*
	 * Check if there was an event already pending on the eventfd
	 * before we registered, and trigger it as if we didn't miss it.
	 */
	events = f.file->f_op->poll(f.file, &irqfd->pt);

	if (events & POLLIN)
		schedule_work(&irqfd->inject);

	/*
	 * do not drop the file until the irqfd is fully initialized, otherwise
	 * we might race against the POLLHUP
	 */
	fdput(f);
#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
	if (kvm_arch_has_irq_bypass()) {
		irqfd->consumer.token = (void *)irqfd->eventfd;
		irqfd->consumer.add_producer = kvm_arch_irq_bypass_add_producer;
		irqfd->consumer.del_producer = kvm_arch_irq_bypass_del_producer;
		irqfd->consumer.stop = kvm_arch_irq_bypass_stop;
		irqfd->consumer.start = kvm_arch_irq_bypass_start;
		ret = irq_bypass_register_consumer(&irqfd->consumer);
		if (ret)
			pr_info("irq bypass consumer (token %p) registration fails: %d\n",
				irqfd->consumer.token, ret);
	}
#endif

	return 0;

fail:
	if (irqfd->resampler)
		irqfd_resampler_shutdown(irqfd);

	if (resamplefd && !IS_ERR(resamplefd))
		eventfd_ctx_put(resamplefd);

	if (eventfd && !IS_ERR(eventfd))
		eventfd_ctx_put(eventfd);

	fdput(f);

out:
	kfree(irqfd);
	return ret;
}

Project: linux
File: eventfd.c

kvm_irqfd_deassign(struct kvm *kvm, struct kvm_irqfd *args)
{
	struct kvm_kernel_irqfd *irqfd, *tmp;
	struct eventfd_ctx *eventfd;

	eventfd = eventfd_ctx_fdget(args->fd);
	if (IS_ERR(eventfd))
		return PTR_ERR(eventfd);

	spin_lock_irq(&kvm->irqfds.lock);

	list_for_each_entry_safe(irqfd, tmp, &kvm->irqfds.items, list) {
		if (irqfd->eventfd == eventfd && irqfd->gsi == args->gsi) {
			/*
			 * This clearing of irq_entry.type is needed for when
			 * another thread calls kvm_irq_routing_update before
			 * we flush workqueue below (we synchronize with
			 * kvm_irq_routing_update using irqfds.lock).
			 */
			write_seqcount_begin(&irqfd->irq_entry_sc);
			irqfd->irq_entry.type = 0;
			write_seqcount_end(&irqfd->irq_entry_sc);
			irqfd_deactivate(irqfd);
		}
	}

	spin_unlock_irq(&kvm->irqfds.lock);
	eventfd_ctx_put(eventfd);

	/*
	 * Block until we know all outstanding shutdown jobs have completed
	 * so that we guarantee there will not be any more interrupts on this
	 * gsi once this deassign function returns.
	 */
	flush_workqueue(irqfd_cleanup_wq);

	return 0;
}

Project: linux
File: eventfd.c

void kvm_irqfd_exit(void)
{
	destroy_workqueue(irqfd_cleanup_wq);
}

Project: linux
File: eventfd.c

int kvm_irqfd_init(void)
{
	irqfd_cleanup_wq = alloc_workqueue("kvm-irqfd-cleanup", 0, 0);
	if (!irqfd_cleanup_wq)
		return -ENOMEM;

	return 0;
}

Project: linux
File: eventfd.c

kvm_irqfd_release(struct kvm *kvm)
{
	struct kvm_kernel_irqfd *irqfd, *tmp;

	spin_lock_irq(&kvm->irqfds.lock);

	list_for_each_entry_safe(irqfd, tmp, &kvm->irqfds.items, list)
		irqfd_deactivate(irqfd);

	spin_unlock_irq(&kvm->irqfds.lock);

	/*
	 * Block until we know all outstanding shutdown jobs have completed
	 * since we do not take a kvm* reference.
	 */
	flush_workqueue(irqfd_cleanup_wq);

}

Project: linux
File: eventfd.c

void kvm_notify_acked_gsi(struct kvm *kvm, int gsi)
{
	struct kvm_irq_ack_notifier *kian;

	hlist_for_each_entry_rcu(kian, &kvm->irq_ack_notifier_list,
				 link)
		if (kian->gsi == gsi)
			kian->irq_acked(kian);
}

Project: linux
File: eventfd.c

void kvm_notify_acked_irq(struct kvm *kvm, unsigned irqchip, unsigned pin)
{
	int gsi, idx;

	trace_kvm_ack_irq(irqchip, pin);

	idx = srcu_read_lock(&kvm->irq_srcu);
	gsi = kvm_irq_map_chip_pin(kvm, irqchip, pin);
	if (gsi != -1)
		kvm_notify_acked_gsi(kvm, gsi);
	srcu_read_unlock(&kvm->irq_srcu, idx);
}

Project: linux
File: eventfd.c

void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
				    struct kvm_irq_ack_notifier *kian)
{
	mutex_lock(&kvm->irq_lock);
	hlist_del_init_rcu(&kian->link);
	mutex_unlock(&kvm->irq_lock);
	synchronize_srcu(&kvm->irq_srcu);
	kvm_arch_post_irq_ack_notifier_list_update(kvm);
}

Project: linux
File: eventfd.c

to_ioeventfd(struct kvm_io_device *dev)
{
	return container_of(dev, struct _ioeventfd, dev);
}