[Qemu-devel] [PATCH 4/8] add and use virtqueue_from_guest_notifier

[Paolo Bonzini <pbonzini@redhat.com>]

This changes the opaque pointer passed to the handler, from being
the virtqueue to being the eventnotifier.  It is useful as soon as
the eventnotifier will be able to set its own (type-safe) handler.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
        I don't have a vhost-enabled machine yet.  So only compile-tested
        for now, but pretty trivial.

 hw/virtio-pci.c |    6 +++---
 hw/virtio.c     |    5 +++++
 hw/virtio.h     |    1 +
 3 files changed, 9 insertions(+), 3 deletions(-)

diff --git a/hw/virtio-pci.c b/hw/virtio-pci.c
index 7ddf612..988c75c 100644
--- a/hw/virtio-pci.c
+++ b/hw/virtio-pci.c
@@ -421,8 +421,8 @@ static unsigned virtio_pci_get_features(void *opaque)
 
 static void virtio_pci_guest_notifier_read(void *opaque)
 {
-    VirtQueue *vq = opaque;
-    EventNotifier *n = virtio_queue_get_guest_notifier(vq);
+    EventNotifier *n = opaque;
+    VirtQueue *vq = virtqueue_from_guest_notifier(n);
     if (event_notifier_test_and_clear(n)) {
         virtio_irq(vq);
     }
@@ -440,7 +440,7 @@ static int virtio_pci_set_guest_notifier(void *opaque, int n, bool assign)
             return r;
         }
         qemu_set_fd_handler(event_notifier_get_fd(notifier),
-                            virtio_pci_guest_notifier_read, NULL, vq);
+                            virtio_pci_guest_notifier_read, NULL, notifier);
     } else {
         qemu_set_fd_handler(event_notifier_get_fd(notifier),
                             NULL, NULL, NULL);
diff --git a/hw/virtio.c b/hw/virtio.c
index 4475bb3..bfce44b 100644
--- a/hw/virtio.c
+++ b/hw/virtio.c
@@ -805,6 +805,11 @@ VirtQueue *virtio_get_queue(VirtIODevice *vdev, int n)
     return vdev->vq + n;
 }
 
+VirtQueue *virtqueue_from_guest_notifier(EventNotifier *e)
+{
+    return container_of(e, VirtQueue, guest_notifier);
+}
+
 EventNotifier *virtio_queue_get_guest_notifier(VirtQueue *vq)
 {
     return &vq->guest_notifier;
diff --git a/hw/virtio.h b/hw/virtio.h
index e4306cd..d6a5b00 100644
--- a/hw/virtio.h
+++ b/hw/virtio.h
@@ -210,6 +210,7 @@ target_phys_addr_t virtio_queue_get_ring_size(VirtIODevice *vdev, int n);
 uint16_t virtio_queue_get_last_avail_idx(VirtIODevice *vdev, int n);
 void virtio_queue_set_last_avail_idx(VirtIODevice *vdev, int n, uint16_t idx);
 VirtQueue *virtio_get_queue(VirtIODevice *vdev, int n);
+VirtQueue *virtqueue_from_guest_notifier(EventNotifier *vq);
 EventNotifier *virtio_queue_get_guest_notifier(VirtQueue *vq);
 EventNotifier *virtio_queue_get_host_notifier(VirtQueue *vq);
 void virtio_irq(VirtQueue *vq);
-- 
1.6.6.1