kvm/eventfd: Drain events from eventfd in irqfd_wakeup()

Don't allow the events to accumulate in the eventfd counter, drain them
as they are handled.

Signed-off-by: David Woodhouse <dwmw@amazon.co.uk>

diff --git a/virt/kvm/eventfd.c b/virt/kvm/eventfd.c
index d6408bb497dc196469e96a1e7d2e07a264d35dc5..87fe943553508285016481e9bcd7c37e08788d8d 100644 (file)
--- a/virt/kvm/eventfd.c
+++ b/virt/kvm/eventfd.c
@@ -193,6 +193,9 @@ irqfd_wakeup(wait_queue_entry_t *wait, unsigned mode, int sync, void *key)
        int idx;
 
        if (flags & EPOLLIN) {
+               u64 cnt;
+               eventfd_ctx_do_read(irqfd->eventfd, &cnt);
+
                idx = srcu_read_lock(&kvm->irq_srcu);
                do {
                        seq = read_seqcount_begin(&irqfd->irq_entry_sc);