1 files changed, 15 insertions, 3 deletions

diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index 30f70fd511c4..a9d3fc6c681c 100644
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -72,12 +72,13 @@ static void
 irqfd_shutdown(struct work_struct *work)
 {
         struct _irqfd *irqfd = container_of(work, struct _irqfd, shutdown);
+        u64 cnt;
 
         /*
          * Synchronize with the wait-queue and unhook ourselves to prevent
          * further events.
          */
-        remove_wait_queue(irqfd->wqh, &irqfd->wait);
+        eventfd_ctx_remove_wait_queue(irqfd->eventfd, &irqfd->wait, &cnt);
 
         /*
          * We know no new events will be scheduled at this point, so block
@@ -166,7 +167,7 @@ irqfd_ptable_queue_proc(struct file *file, wait_queue_head_t *wqh,
 static int
 kvm_irqfd_assign(struct kvm *kvm, int fd, int gsi)
 {
-        struct _irqfd *irqfd;
+        struct _irqfd *irqfd, *tmp;
         struct file *file = NULL;
         struct eventfd_ctx *eventfd = NULL;
         int ret;
@@ -203,9 +204,20 @@ kvm_irqfd_assign(struct kvm *kvm, int fd, int gsi)
         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;
+        }
+
         events = file->f_op->poll(file, &irqfd->pt);
 
-        spin_lock_irq(&kvm->irqfds.lock);
         list_add_tail(&irqfd->list, &kvm->irqfds.items);
         spin_unlock_irq(&kvm->irqfds.lock);