[PATCH v17 06/10] virtio: add support for configure interrupt

[Cindy Lu <lulu@redhat.com>]

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>
---
 hw/virtio/virtio.c         | 29 +++++++++++++++++++++++++++++
 include/hw/virtio/virtio.h |  4 ++++
 2 files changed, 33 insertions(+)

diff --git a/hw/virtio/virtio.c b/hw/virtio/virtio.c
index 808446b4c9..7b53800ac1 100644
--- a/hw/virtio/virtio.c
+++ b/hw/virtio/virtio.c
@@ -3975,7 +3975,14 @@ 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)
 {
@@ -3992,6 +3999,23 @@ 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;
@@ -4072,6 +4096,11 @@ 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;
diff --git a/include/hw/virtio/virtio.h b/include/hw/virtio/virtio.h
index a9953cf8b0..62f2161844 100644
--- a/include/hw/virtio/virtio.h
+++ b/include/hw/virtio/virtio.h
@@ -131,6 +131,7 @@ struct VirtIODevice
     AddressSpace *dma_as;
     QLIST_HEAD(, VirtQueue) *vector_queues;
     QTAILQ_ENTRY(VirtIODevice) next;
+    EventNotifier config_notifier;
 };
 
 struct VirtioDeviceClass {
@@ -345,6 +346,9 @@ void virtio_queue_aio_attach_host_notifier_no_poll(VirtQueue *vq, AioContext *ct
 void virtio_queue_aio_detach_host_notifier(VirtQueue *vq, AioContext *ctx);
 VirtQueue *virtio_vector_first_queue(VirtIODevice *vdev, uint16_t vector);
 VirtQueue *virtio_vector_next_queue(VirtQueue *vq);
+EventNotifier *virtio_config_get_guest_notifier(VirtIODevice *vdev);
+void virtio_config_set_guest_notifier_fd_handler(VirtIODevice *vdev,
+                                                 bool assign, bool with_irqfd);
 
 static inline void virtio_add_feature(uint64_t *features, unsigned int fbit)
 {
-- 
2.34.3