vhost: add vhost_net_set_backend()

Not all vhost-user backends support ops->vhost_net_set_backend(). It is
a nicer to provide an assert/error than to crash trying to
call. Furthermore, it improves a bit the code by hiding vhost_ops
details.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

diff --git a/hw/net/vhost_net.c b/hw/net/vhost_net.c
index dd41a8eda850199e7587ed34be15987c888f263c..dc61dc1c5f5004911fb22300ea0962b6a34b930f 100644 (file)
--- a/hw/net/vhost_net.c
+++ b/hw/net/vhost_net.c
@@ -242,8 +242,7 @@ static int vhost_net_start_one(struct vhost_net *net,
         qemu_set_fd_handler(net->backend, NULL, NULL, NULL);
         file.fd = net->backend;
         for (file.index = 0; file.index < net->dev.nvqs; ++file.index) {
-            const VhostOps *vhost_ops = net->dev.vhost_ops;
-            r = vhost_ops->vhost_net_set_backend(&net->dev, &file);
+            r = vhost_net_set_backend(&net->dev, &file);
             if (r < 0) {
                 r = -errno;
                 goto fail;
@@ -255,8 +254,7 @@ fail:
     file.fd = -1;
     if (net->nc->info->type == NET_CLIENT_DRIVER_TAP) {
         while (file.index-- > 0) {
-            const VhostOps *vhost_ops = net->dev.vhost_ops;
-            int r = vhost_ops->vhost_net_set_backend(&net->dev, &file);
+            int r = vhost_net_set_backend(&net->dev, &file);
             assert(r >= 0);
         }
     }
@@ -277,8 +275,7 @@ static void vhost_net_stop_one(struct vhost_net *net,
 
     if (net->nc->info->type == NET_CLIENT_DRIVER_TAP) {
         for (file.index = 0; file.index < net->dev.nvqs; ++file.index) {
-            const VhostOps *vhost_ops = net->dev.vhost_ops;
-            int r = vhost_ops->vhost_net_set_backend(&net->dev, &file);
+            int r = vhost_net_set_backend(&net->dev, &file);
             assert(r >= 0);
         }
     }

diff --git a/hw/virtio/vhost.c b/hw/virtio/vhost.c
index 2d0d1d1ba994d2d996d8125037845c8140cc222a..b0e8ecce605c0e6eb4d2f9d8b7dd1e16d38dcd76 100644 (file)
--- a/hw/virtio/vhost.c
+++ b/hw/virtio/vhost.c
@@ -1369,3 +1369,13 @@ void vhost_dev_stop(struct vhost_dev *hdev, VirtIODevice *vdev)
     vhost_log_put(hdev, true);
     hdev->started = false;
 }
+
+int vhost_net_set_backend(struct vhost_dev *hdev,
+                          struct vhost_vring_file *file)
+{
+    if (hdev->vhost_ops->vhost_net_set_backend) {
+        return hdev->vhost_ops->vhost_net_set_backend(hdev, file);
+    }
+
+    return -1;
+}

diff --git a/include/hw/virtio/vhost.h b/include/hw/virtio/vhost.h
index 2106ed8c0de7e5724e99dc278f3be3b43a4f2a5b..e433089ea97fb2a1175998c305d948445248a0b4 100644 (file)
--- a/include/hw/virtio/vhost.h
+++ b/include/hw/virtio/vhost.h
@@ -86,4 +86,8 @@ uint64_t vhost_get_features(struct vhost_dev *hdev, const int *feature_bits,
 void vhost_ack_features(struct vhost_dev *hdev, const int *feature_bits,
                         uint64_t features);
 bool vhost_has_free_slot(void);
+
+int vhost_net_set_backend(struct vhost_dev *hdev,
+                          struct vhost_vring_file *file);
+
 #endif