1 files changed, 223 insertions, 133 deletions

diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index f2ac53ab8243..0e8b5277be3b 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -1,3 +1,4 @@
+// SPDX-License-Identifier: GPL-2.0-only
 /*
  * kvm eventfd support - use eventfd objects to signal various KVM events
  *
@@ -6,19 +7,6 @@
  *
  * Author:
  *	Gregory Haskins <ghaskins@novell.com>
- *
- * This file is free software; you can redistribute it and/or modify
- * it under the terms of version 2 of the GNU General Public License
- * as published by the Free Software Foundation.
- *
- * This program is distributed in the hope that it will be useful,
- * but WITHOUT ANY WARRANTY; without even the implied warranty of
- * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.	 See the
- * GNU General Public License for more details.
- *
- * You should have received a copy of the GNU General Public License
- * along with this program; if not, write to the Free Software Foundation,
- * Inc., 51 Franklin St, Fifth Floor, Boston, MA 02110-1301, USA.
  */
 
 #include <linux/kvm_host.h>
@@ -40,10 +28,16 @@
 
 #include <kvm/iodev.h>
 
-#ifdef CONFIG_HAVE_KVM_IRQFD
+#ifdef CONFIG_HAVE_KVM_IRQCHIP
 
 static struct workqueue_struct *irqfd_cleanup_wq;
 
+bool __attribute__((weak))
+kvm_arch_irqfd_allowed(struct kvm *kvm, struct kvm_irqfd *args)
+{
+	return true;
+}
+
 static void
 irqfd_inject(struct work_struct *work)
 {
@@ -61,6 +55,15 @@ irqfd_inject(struct work_struct *work)
 			    irqfd->gsi, 1, false);
 }
 
+static void irqfd_resampler_notify(struct kvm_kernel_irqfd_resampler *resampler)
+{
+	struct kvm_kernel_irqfd *irqfd;
+
+	list_for_each_entry_srcu(irqfd, &resampler->list, resampler_link,
+				 srcu_read_lock_held(&resampler->kvm->irq_srcu))
+		eventfd_signal(irqfd->resamplefd);
+}
+
 /*
  * Since resampler irqfds share an IRQ source ID, we de-assert once
  * then notify all of the resampler irqfds using this GSI.  We can't
@@ -71,7 +74,6 @@ 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,
@@ -82,10 +84,7 @@ irqfd_resampler_ack(struct kvm_irq_ack_notifier *kian)
 		    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);
-
+	irqfd_resampler_notify(resampler);
 	srcu_read_unlock(&kvm->irq_srcu, idx);
 }
 
@@ -98,14 +97,19 @@ irqfd_resampler_shutdown(struct kvm_kernel_irqfd *irqfd)
 	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);
+		list_del_rcu(&resampler->link);
 		kvm_unregister_irq_ack_notifier(kvm, &resampler->notifier);
+		/*
+		 * synchronize_srcu_expedited(&kvm->irq_srcu) already called
+		 * in kvm_unregister_irq_ack_notifier().
+		 */
 		kvm_set_irq(kvm, KVM_IRQFD_RESAMPLE_IRQ_SOURCE_ID,
 			    resampler->notifier.gsi, 0, false);
 		kfree(resampler);
+	} else {
+		synchronize_srcu_expedited(&kvm->irq_srcu);
 	}
 
 	mutex_unlock(&kvm->irqfds.resampler_lock);
@@ -119,8 +123,12 @@ irqfd_shutdown(struct work_struct *work)
 {
 	struct kvm_kernel_irqfd *irqfd =
 		container_of(work, struct kvm_kernel_irqfd, shutdown);
+	struct kvm *kvm = irqfd->kvm;
 	u64 cnt;
 
+	/* Make sure irqfd has been initialized in assign path. */
+	synchronize_srcu_expedited(&kvm->irq_srcu);
+
 	/*
 	 * Synchronize with the wait-queue and unhook ourselves to prevent
 	 * further events.
@@ -141,7 +149,7 @@ irqfd_shutdown(struct work_struct *work)
 	/*
 	 * It is now safe to release the object's resources
 	 */
-#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
+#if IS_ENABLED(CONFIG_HAVE_KVM_IRQ_BYPASS)
 	irq_bypass_unregister_consumer(&irqfd->consumer);
 #endif
 	eventfd_ctx_put(irqfd->eventfd);
@@ -188,13 +196,22 @@ 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;
+	__poll_t flags = key_to_poll(key);
 	struct kvm_kernel_irq_routing_entry irq;
 	struct kvm *kvm = irqfd->kvm;
 	unsigned seq;
 	int idx;
+	int ret = 0;
+
+	if (flags & EPOLLIN) {
+		/*
+		 * WARNING: Do NOT take irqfds.lock in any path except EPOLLHUP,
+		 * as KVM holds irqfds.lock when registering the irqfd with the
+		 * eventfd.
+		 */
+		u64 cnt;
+		eventfd_ctx_do_read(irqfd->eventfd, &cnt);
 
-	if (flags & POLLIN) {
 		idx = srcu_read_lock(&kvm->irq_srcu);
 		do {
 			seq = read_seqcount_begin(&irqfd->irq_entry_sc);
@@ -206,13 +223,19 @@ irqfd_wakeup(wait_queue_entry_t *wait, unsigned mode, int sync, void *key)
 					      false) == -EWOULDBLOCK)
 			schedule_work(&irqfd->inject);
 		srcu_read_unlock(&kvm->irq_srcu, idx);
+		ret = 1;
 	}
 
-	if (flags & POLLHUP) {
+	if (flags & EPOLLHUP) {
 		/* The eventfd is closing, detach from KVM */
-		unsigned long flags;
+		unsigned long iflags;
 
-		spin_lock_irqsave(&kvm->irqfds.lock, flags);
+		/*
+		 * Taking irqfds.lock is safe here, as KVM holds a reference to
+		 * the eventfd when registering the irqfd, i.e. this path can't
+		 * be reached while kvm_irqfd_add() is running.
+		 */
+		spin_lock_irqsave(&kvm->irqfds.lock, iflags);
 
 		/*
 		 * We must check if someone deactivated the irqfd before
@@ -226,28 +249,20 @@ irqfd_wakeup(wait_queue_entry_t *wait, unsigned mode, int sync, void *key)
 		if (irqfd_is_active(irqfd))
 			irqfd_deactivate(irqfd);
 
-		spin_unlock_irqrestore(&kvm->irqfds.lock, flags);
+		spin_unlock_irqrestore(&kvm->irqfds.lock, iflags);
 	}
 
-	return 0;
-}
-
-static void
-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);
+	return ret;
 }
 
-/* Must be called under irqfds.lock */
 static void irqfd_update(struct kvm *kvm, struct kvm_kernel_irqfd *irqfd)
 {
 	struct kvm_kernel_irq_routing_entry *e;
 	struct kvm_kernel_irq_routing_entry entries[KVM_NR_IRQCHIPS];
 	int n_entries;
 
+	lockdep_assert_held(&kvm->irqfds.lock);
+
 	n_entries = kvm_irq_map_gsi(kvm, entries, irqfd->gsi);
 
 	write_seqcount_begin(&irqfd->irq_entry_sc);
@@ -261,7 +276,64 @@ static void irqfd_update(struct kvm *kvm, struct kvm_kernel_irqfd *irqfd)
 	write_seqcount_end(&irqfd->irq_entry_sc);
 }
 
-#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
+struct kvm_irqfd_pt {
+	struct kvm_kernel_irqfd *irqfd;
+	struct kvm *kvm;
+	poll_table pt;
+	int ret;
+};
+
+static void kvm_irqfd_register(struct file *file, wait_queue_head_t *wqh,
+			       poll_table *pt)
+{
+	struct kvm_irqfd_pt *p = container_of(pt, struct kvm_irqfd_pt, pt);
+	struct kvm_kernel_irqfd *irqfd = p->irqfd;
+	struct kvm *kvm = p->kvm;
+
+	/*
+	 * Note, irqfds.lock protects the irqfd's irq_entry, i.e. its routing,
+	 * and irqfds.items.  It does NOT protect registering with the eventfd.
+	 */
+	spin_lock_irq(&kvm->irqfds.lock);
+
+	/*
+	 * Initialize the routing information prior to adding the irqfd to the
+	 * eventfd's waitqueue, as irqfd_wakeup() can be invoked as soon as the
+	 * irqfd is registered.
+	 */
+	irqfd_update(kvm, irqfd);
+
+	/*
+	 * Add the irqfd as a priority waiter on the eventfd, with a custom
+	 * wake-up handler, so that KVM *and only KVM* is notified whenever the
+	 * underlying eventfd is signaled.
+	 */
+	init_waitqueue_func_entry(&irqfd->wait, irqfd_wakeup);
+
+	/*
+	 * Temporarily lie to lockdep about holding irqfds.lock to avoid a
+	 * false positive regarding potential deadlock with irqfd_wakeup()
+	 * (see irqfd_wakeup() for details).
+	 *
+	 * Adding to the wait queue will fail if there is already a priority
+	 * waiter, i.e. if the eventfd is associated with another irqfd (in any
+	 * VM).  Note, kvm_irqfd_deassign() waits for all in-flight shutdown
+	 * jobs to complete, i.e. ensures the irqfd has been removed from the
+	 * eventfd's waitqueue before returning to userspace.
+	 */
+	spin_release(&kvm->irqfds.lock.dep_map, _RET_IP_);
+	p->ret = add_wait_queue_priority_exclusive(wqh, &irqfd->wait);
+	spin_acquire(&kvm->irqfds.lock.dep_map, 0, 0, _RET_IP_);
+	if (p->ret)
+		goto out;
+
+	list_add_tail(&irqfd->list, &kvm->irqfds.items);
+
+out:
+	spin_unlock_irq(&kvm->irqfds.lock);
+}
+
+#if IS_ENABLED(CONFIG_HAVE_KVM_IRQ_BYPASS)
 void __attribute__((weak)) kvm_arch_irq_bypass_stop(
 				struct irq_bypass_consumer *cons)
 {
@@ -272,28 +344,31 @@ void __attribute__((weak)) kvm_arch_irq_bypass_start(
 {
 }
 
-int  __attribute__((weak)) kvm_arch_update_irqfd_routing(
-				struct kvm *kvm, unsigned int host_irq,
-				uint32_t guest_irq, bool set)
+void __weak kvm_arch_update_irqfd_routing(struct kvm_kernel_irqfd *irqfd,
+					  struct kvm_kernel_irq_routing_entry *old,
+					  struct kvm_kernel_irq_routing_entry *new)
 {
-	return 0;
+
 }
 #endif
 
 static int
 kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
 {
-	struct kvm_kernel_irqfd *irqfd, *tmp;
-	struct fd f;
+	struct kvm_kernel_irqfd *irqfd;
 	struct eventfd_ctx *eventfd = NULL, *resamplefd = NULL;
+	struct kvm_irqfd_pt irqfd_pt;
 	int ret;
-	unsigned int events;
+	__poll_t events;
 	int idx;
 
 	if (!kvm_arch_intc_initialized(kvm))
 		return -EAGAIN;
 
-	irqfd = kzalloc(sizeof(*irqfd), GFP_KERNEL);
+	if (!kvm_arch_irqfd_allowed(kvm, args))
+		return -EINVAL;
+
+	irqfd = kzalloc(sizeof(*irqfd), GFP_KERNEL_ACCOUNT);
 	if (!irqfd)
 		return -ENOMEM;
 
@@ -302,18 +377,18 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
 	INIT_LIST_HEAD(&irqfd->list);
 	INIT_WORK(&irqfd->inject, irqfd_inject);
 	INIT_WORK(&irqfd->shutdown, irqfd_shutdown);
-	seqcount_init(&irqfd->irq_entry_sc);
+	seqcount_spinlock_init(&irqfd->irq_entry_sc, &kvm->irqfds.lock);
 
-	f = fdget(args->fd);
-	if (!f.file) {
+	CLASS(fd, f)(args->fd);
+	if (fd_empty(f)) {
 		ret = -EBADF;
 		goto out;
 	}
 
-	eventfd = eventfd_ctx_fileget(f.file);
+	eventfd = eventfd_ctx_fileget(fd_file(f));
 	if (IS_ERR(eventfd)) {
 		ret = PTR_ERR(eventfd);
-		goto fail;
+		goto out;
 	}
 
 	irqfd->eventfd = eventfd;
@@ -341,7 +416,8 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
 		}
 
 		if (!irqfd->resampler) {
-			resampler = kzalloc(sizeof(*resampler), GFP_KERNEL);
+			resampler = kzalloc(sizeof(*resampler),
+					    GFP_KERNEL_ACCOUNT);
 			if (!resampler) {
 				ret = -ENOMEM;
 				mutex_unlock(&kvm->irqfds.resampler_lock);
@@ -354,75 +430,67 @@ kvm_irqfd_assign(struct kvm *kvm, struct kvm_irqfd *args)
 			resampler->notifier.irq_acked = irqfd_resampler_ack;
 			INIT_LIST_HEAD(&resampler->link);
 
-			list_add(&resampler->link, &kvm->irqfds.resampler_list);
+			list_add_rcu(&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);
+		synchronize_srcu_expedited(&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
+	 * Set the irqfd routing and add it to KVM's list before registering
+	 * the irqfd with the eventfd, so that the routing information is valid
+	 * and stays valid, e.g. if there are GSI routing changes, prior to
+	 * making the irqfd visible, i.e. before it might be signaled.
+	 *
+	 * Note, holding SRCU ensures a stable read of routing information, and
+	 * also prevents irqfd_shutdown() from freeing the irqfd before it's
+	 * fully initialized.
 	 */
-	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.
+	 * Register the irqfd with the eventfd by polling on the eventfd, and
+	 * simultaneously and the irqfd to KVM's list.  If there was en event
+	 * pending on the eventfd prior to registering, manually trigger IRQ
+	 * injection.
 	 */
-	events = f.file->f_op->poll(f.file, &irqfd->pt);
+	irqfd_pt.irqfd = irqfd;
+	irqfd_pt.kvm = kvm;
+	init_poll_funcptr(&irqfd_pt.pt, kvm_irqfd_register);
+
+	events = vfs_poll(fd_file(f), &irqfd_pt.pt);
+
+	ret = irqfd_pt.ret;
+	if (ret)
+		goto fail_poll;
 
-	if (events & POLLIN)
+	if (events & EPOLLIN)
 		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 IS_ENABLED(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);
+		ret = irq_bypass_register_consumer(&irqfd->consumer, irqfd->eventfd);
 		if (ret)
-			pr_info("irq bypass consumer (token %p) registration fails: %d\n",
-				irqfd->consumer.token, ret);
+			pr_info("irq bypass consumer (eventfd %p) registration fails: %d\n",
+				irqfd->eventfd, ret);
 	}
 #endif
 
+	srcu_read_unlock(&kvm->irq_srcu, idx);
 	return 0;
 
+fail_poll:
+	srcu_read_unlock(&kvm->irq_srcu, idx);
 fail:
 	if (irqfd->resampler)
 		irqfd_resampler_shutdown(irqfd);
@@ -433,8 +501,6 @@ fail:
 	if (eventfd && !IS_ERR(eventfd))
 		eventfd_ctx_put(eventfd);
 
-	fdput(f);
-
 out:
 	kfree(irqfd);
 	return ret;
@@ -448,8 +514,8 @@ bool kvm_irq_has_notifier(struct kvm *kvm, unsigned irqchip, unsigned pin)
 	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)
+		hlist_for_each_entry_srcu(kian, &kvm->irq_ack_notifier_list,
+					  link, srcu_read_lock_held(&kvm->irq_srcu))
 			if (kian->gsi == gsi) {
 				srcu_read_unlock(&kvm->irq_srcu, idx);
 				return true;
@@ -459,14 +525,14 @@ bool kvm_irq_has_notifier(struct kvm *kvm, unsigned irqchip, unsigned pin)
 
 	return false;
 }
-EXPORT_SYMBOL_GPL(kvm_irq_has_notifier);
+EXPORT_SYMBOL_FOR_KVM_INTERNAL(kvm_irq_has_notifier);
 
 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)
+	hlist_for_each_entry_srcu(kian, &kvm->irq_ack_notifier_list,
+				  link, srcu_read_lock_held(&kvm->irq_srcu))
 		if (kian->gsi == gsi)
 			kian->irq_acked(kian);
 }
@@ -499,24 +565,10 @@ void kvm_unregister_irq_ack_notifier(struct kvm *kvm,
 	mutex_lock(&kvm->irq_lock);
 	hlist_del_init_rcu(&kian->link);
 	mutex_unlock(&kvm->irq_lock);
-	synchronize_srcu(&kvm->irq_srcu);
+	synchronize_srcu_expedited(&kvm->irq_srcu);
 	kvm_arch_post_irq_ack_notifier_list_update(kvm);
 }
-#endif
-
-void
-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);
-}
 
-#ifdef CONFIG_HAVE_KVM_IRQFD
 /*
  * shutdown any irqfd's that match fd+gsi
  */
@@ -598,7 +650,7 @@ kvm_irqfd_release(struct kvm *kvm)
 
 /*
  * Take note of a change in irq routing.
- * Caller must invoke synchronize_srcu(&kvm->irq_srcu) afterwards.
+ * Caller must invoke synchronize_srcu_expedited(&kvm->irq_srcu) afterwards.
  */
 void kvm_irq_routing_update(struct kvm *kvm)
 {
@@ -607,21 +659,47 @@ void kvm_irq_routing_update(struct kvm *kvm)
 	spin_lock_irq(&kvm->irqfds.lock);
 
 	list_for_each_entry(irqfd, &kvm->irqfds.items, list) {
+#if IS_ENABLED(CONFIG_HAVE_KVM_IRQ_BYPASS)
+		/* Under irqfds.lock, so can read irq_entry safely */
+		struct kvm_kernel_irq_routing_entry old = irqfd->irq_entry;
+#endif
+
 		irqfd_update(kvm, irqfd);
 
-#ifdef CONFIG_HAVE_KVM_IRQ_BYPASS
-		if (irqfd->producer) {
-			int ret = kvm_arch_update_irqfd_routing(
-					irqfd->kvm, irqfd->producer->irq,
-					irqfd->gsi, 1);
-			WARN_ON(ret);
-		}
+#if IS_ENABLED(CONFIG_HAVE_KVM_IRQ_BYPASS)
+		if (irqfd->producer)
+			kvm_arch_update_irqfd_routing(irqfd, &old, &irqfd->irq_entry);
 #endif
 	}
 
 	spin_unlock_irq(&kvm->irqfds.lock);
 }
 
+bool kvm_notify_irqfd_resampler(struct kvm *kvm,
+				unsigned int irqchip,
+				unsigned int pin)
+{
+	struct kvm_kernel_irqfd_resampler *resampler;
+	int gsi, idx;
+
+	idx = srcu_read_lock(&kvm->irq_srcu);
+	gsi = kvm_irq_map_chip_pin(kvm, irqchip, pin);
+	if (gsi != -1) {
+		list_for_each_entry_srcu(resampler,
+					 &kvm->irqfds.resampler_list, link,
+					 srcu_read_lock_held(&kvm->irq_srcu)) {
+			if (resampler->notifier.gsi == gsi) {
+				irqfd_resampler_notify(resampler);
+				srcu_read_unlock(&kvm->irq_srcu, idx);
+				return true;
+			}
+		}
+	}
+	srcu_read_unlock(&kvm->irq_srcu, idx);
+
+	return false;
+}
+
 /*
  * create a host-wide workqueue for issuing deferred shutdown requests
  * aggregated from all vm* instances. We need our own isolated
@@ -629,7 +707,7 @@ void kvm_irq_routing_update(struct kvm *kvm)
  */
 int kvm_irqfd_init(void)
 {
-	irqfd_cleanup_wq = alloc_workqueue("kvm-irqfd-cleanup", 0, 0);
+	irqfd_cleanup_wq = alloc_workqueue("kvm-irqfd-cleanup", WQ_PERCPU, 0);
 	if (!irqfd_cleanup_wq)
 		return -ENOMEM;
 
@@ -718,7 +796,7 @@ ioeventfd_in_range(struct _ioeventfd *p, gpa_t addr, int len, const void *val)
 		return false;
 	}
 
-	return _val == p->datamatch ? true : false;
+	return _val == p->datamatch;
 }
 
 /* MMIO/PIO writes trigger an event if the addr/val match */
@@ -731,7 +809,7 @@ ioeventfd_write(struct kvm_vcpu *vcpu, struct kvm_io_device *this, gpa_t addr,
 	if (!ioeventfd_in_range(p, addr, len, val))
 		return -EOPNOTSUPP;
 
-	eventfd_signal(p->eventfd, 1);
+	eventfd_signal(p->eventfd);
 	return 0;
 }
 
@@ -792,7 +870,7 @@ static int kvm_assign_ioeventfd_idx(struct kvm *kvm,
 	if (IS_ERR(eventfd))
 		return PTR_ERR(eventfd);
 
-	p = kzalloc(sizeof(*p), GFP_KERNEL);
+	p = kzalloc(sizeof(*p), GFP_KERNEL_ACCOUNT);
 	if (!p) {
 		ret = -ENOMEM;
 		goto fail;
@@ -834,9 +912,9 @@ static int kvm_assign_ioeventfd_idx(struct kvm *kvm,
 
 unlock_fail:
 	mutex_unlock(&kvm->slots_lock);
+	kfree(p);
 
 fail:
-	kfree(p);
 	eventfd_ctx_put(eventfd);
 
 	return ret;
@@ -846,20 +924,21 @@ static int
 kvm_deassign_ioeventfd_idx(struct kvm *kvm, enum kvm_bus bus_idx,
 			   struct kvm_ioeventfd *args)
 {
-	struct _ioeventfd        *p, *tmp;
+	struct _ioeventfd        *p;
 	struct eventfd_ctx       *eventfd;
 	struct kvm_io_bus	 *bus;
 	int                       ret = -ENOENT;
+	bool                      wildcard;
 
 	eventfd = eventfd_ctx_fdget(args->fd);
 	if (IS_ERR(eventfd))
 		return PTR_ERR(eventfd);
 
-	mutex_lock(&kvm->slots_lock);
+	wildcard = !(args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH);
 
-	list_for_each_entry_safe(p, tmp, &kvm->ioeventfds, list) {
-		bool wildcard = !(args->flags & KVM_IOEVENTFD_FLAG_DATAMATCH);
+	mutex_lock(&kvm->slots_lock);
 
+	list_for_each_entry(p, &kvm->ioeventfds, list) {
 		if (p->bus_idx != bus_idx ||
 		    p->eventfd != eventfd  ||
 		    p->addr != args->addr  ||
@@ -874,7 +953,6 @@ kvm_deassign_ioeventfd_idx(struct kvm *kvm, enum kvm_bus bus_idx,
 		bus = kvm_get_bus(kvm, bus_idx);
 		if (bus)
 			bus->ioeventfd_count--;
-		ioeventfd_release(p);
 		ret = 0;
 		break;
 	}
@@ -957,3 +1035,15 @@ kvm_ioeventfd(struct kvm *kvm, struct kvm_ioeventfd *args)
 
 	return kvm_assign_ioeventfd(kvm, args);
 }
+
+void
+kvm_eventfd_init(struct kvm *kvm)
+{
+#ifdef CONFIG_HAVE_KVM_IRQCHIP
+	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);
+}