virtio: introduce macro IRTIO_CONFIG_IRQ_IDX

To support configure interrupt for vhost-vdpa
Introduce VIRTIO_CONFIG_IRQ_IDX -1 as configure interrupt's queue index,
Then we can reuse the functions guest_notifier_mask and guest_notifier_pending.
Add the check of queue index in these drivers, if the driver does not support
configure interrupt, the function will just return

Signed-off-by: Cindy Lu <lulu@redhat.com>
Message-Id: <20211104164827.21911-2-lulu@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 8 insertions, 2 deletions

diff --git a/hw/net/virtio-net.c b/hw/net/virtio-net.c
index cf8ab0f..5e03c0d 100644
--- a/hw/net/virtio-net.c
+++ b/hw/net/virtio-net.c
@@ -3168,6 +3168,9 @@ static bool virtio_net_guest_notifier_pending(VirtIODevice *vdev, int idx)
     VirtIONet *n = VIRTIO_NET(vdev);
     NetClientState *nc = qemu_get_subqueue(n->nic, vq2q(idx));
     assert(n->vhost_started);
+    if (idx == VIRTIO_CONFIG_IRQ_IDX) {
+        return false;
+    }
     return vhost_net_virtqueue_pending(get_vhost_net(nc->peer), idx);
 }
 
@@ -3177,8 +3180,11 @@ static void virtio_net_guest_notifier_mask(VirtIODevice *vdev, int idx,
     VirtIONet *n = VIRTIO_NET(vdev);
     NetClientState *nc = qemu_get_subqueue(n->nic, vq2q(idx));
     assert(n->vhost_started);
-    vhost_net_virtqueue_mask(get_vhost_net(nc->peer),
-                             vdev, idx, mask);
+    if (idx == VIRTIO_CONFIG_IRQ_IDX) {
+        return;
+    }
+
+    vhost_net_virtqueue_mask(get_vhost_net(nc->peer), vdev, idx, mask);
 }
 
 static void virtio_net_set_config_size(VirtIONet *n, uint64_t host_features)