virtio: add support for configure interrupt

Add the functions to support the configure interrupt in virtio
The function virtio_config_guest_notifier_read will notify the
guest if there is an configure interrupt.
The function virtio_config_set_guest_notifier_fd_handler is
to set the fd hander for the notifier

Signed-off-by: Cindy Lu <lulu@redhat.com>
Message-Id: <20211104164827.21911-7-lulu@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 29 insertions, 0 deletions

diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index e11a8a0dba..36edb1dad5 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -3493,7 +3493,14 @@ static void virtio_queue_guest_notifier_read(EventNotifier *n)
         virtio_irq(vq);
     }
 }
+static void virtio_config_guest_notifier_read(EventNotifier *n)
+{
+    VirtIODevice *vdev = container_of(n, VirtIODevice, config_notifier);
 
+    if (event_notifier_test_and_clear(n)) {
+        virtio_notify_config(vdev);
+    }
+}
 void virtio_queue_set_guest_notifier_fd_handler(VirtQueue *vq, bool assign,
                                                 bool with_irqfd)
 {
@@ -3510,6 +3517,23 @@ void virtio_queue_set_guest_notifier_fd_handler(VirtQueue *vq, bool assign,
     }
 }
 
+void virtio_config_set_guest_notifier_fd_handler(VirtIODevice *vdev,
+                                                 bool assign, bool with_irqfd)
+{
+    EventNotifier *n;
+    n = &vdev->config_notifier;
+    if (assign && !with_irqfd) {
+        event_notifier_set_handler(n, virtio_config_guest_notifier_read);
+    } else {
+        event_notifier_set_handler(n, NULL);
+    }
+    if (!assign) {
+        /* Test and clear notifier before closing it,*/
+        /* in case poll callback didn't have time to run. */
+        virtio_config_guest_notifier_read(n);
+    }
+}
+
 EventNotifier *virtio_queue_get_guest_notifier(VirtQueue *vq)
 {
     return &vq->guest_notifier;
@@ -3583,6 +3607,11 @@ EventNotifier *virtio_queue_get_host_notifier(VirtQueue *vq)
     return &vq->host_notifier;
 }
 
+EventNotifier *virtio_config_get_guest_notifier(VirtIODevice *vdev)
+{
+    return &vdev->config_notifier;
+}
+
 void virtio_queue_set_host_notifier_enabled(VirtQueue *vq, bool enabled)
 {
     vq->host_notifier_enabled = enabled;