virtio: move common irqfd handling out of virtio-pci

All transports can use the same event handler for the irqfd, though the
exact mechanics of the assignment will be specific.  Note that there
are three states: handled by the kernel, handled in userspace, disabled.

This also lets virtio use event_notifier_set_handler.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Avi Kivity <avi@redhat.com>

1 files changed, 24 insertions, 0 deletions

diff --git a/hw/virtio.c b/hw/virtio.c
index 197edf00f4..d146f86f13 100644
--- a/hw/virtio.c
+++ b/hw/virtio.c
@@ -984,6 +984,30 @@ VirtQueue *virtio_get_queue(VirtIODevice *vdev, int n)
     return vdev->vq + n;
 }
 
+static void virtio_queue_guest_notifier_read(EventNotifier *n)
+{
+    VirtQueue *vq = container_of(n, VirtQueue, guest_notifier);
+    if (event_notifier_test_and_clear(n)) {
+        virtio_irq(vq);
+    }
+}
+
+void virtio_queue_set_guest_notifier_fd_handler(VirtQueue *vq, bool assign,
+                                                bool with_irqfd)
+{
+    if (assign && !with_irqfd) {
+        event_notifier_set_handler(&vq->guest_notifier,
+                                   virtio_queue_guest_notifier_read);
+    } else {
+        event_notifier_set_handler(&vq->guest_notifier, NULL);
+    }
+    if (!assign) {
+        /* Test and clear notifier before closing it,
+         * in case poll callback didn't have time to run. */
+        virtio_queue_guest_notifier_read(&vq->guest_notifier);
+    }
+}
+
 EventNotifier *virtio_queue_get_guest_notifier(VirtQueue *vq)
 {
     return &vq->guest_notifier;