vhost_net: introduce set_config & get_config

This patch introduces set_config & get_config  method which allows
vhost_net set/get the config to backend

Signed-off-by: Cindy Lu <lulu@redhat.com>
Message-Id: <20200701145538.22333-13-lulu@redhat.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>
Acked-by: Jason Wang <jasowang@redhat.com>

hw/net/vhost_net-stub.c

@@ -52,6 +52,17 @@ uint64_t vhost_net_get_features(struct vhost_net *net, uint64_t features)
     return features;
 }
 
+int vhost_net_get_config(struct vhost_net *net,  uint8_t *config,
+                         uint32_t config_len)
+{
+    return 0;
+}
+int vhost_net_set_config(struct vhost_net *net, const uint8_t *data,
+                         uint32_t offset, uint32_t size, uint32_t flags)
+{
+    return 0;
+}
+
 void vhost_net_ack_features(struct vhost_net *net, uint64_t features)
 {
 }

hw/net/vhost_net.c

@@ -110,6 +110,16 @@ uint64_t vhost_net_get_features(struct vhost_net *net, uint64_t features)
     return vhost_get_features(&net->dev, vhost_net_get_feature_bits(net),
             features);
 }
+int vhost_net_get_config(struct vhost_net *net,  uint8_t *config,
+                         uint32_t config_len)
+{
+    return vhost_dev_get_config(&net->dev, config, config_len);
+}
+int vhost_net_set_config(struct vhost_net *net, const uint8_t *data,
+                         uint32_t offset, uint32_t size, uint32_t flags)
+{
+    return vhost_dev_set_config(&net->dev, data, offset, size, flags);
+}
 
 void vhost_net_ack_features(struct vhost_net *net, uint64_t features)
 {

include/net/vhost_net.h

@@ -28,6 +28,11 @@ void vhost_net_cleanup(VHostNetState *net);
 uint64_t vhost_net_get_features(VHostNetState *net, uint64_t features);
 void vhost_net_ack_features(VHostNetState *net, uint64_t features);
 
+int vhost_net_get_config(struct vhost_net *net,  uint8_t *config,
+                         uint32_t config_len);
+
+int vhost_net_set_config(struct vhost_net *net, const uint8_t *data,
+                         uint32_t offset, uint32_t size, uint32_t flags);
 bool vhost_net_virtqueue_pending(VHostNetState *net, int n);
 void vhost_net_virtqueue_mask(VHostNetState *net, VirtIODevice *dev,
                               int idx, bool mask);