vhost-net: vhost-kernel: introduce vhost_net_virtqueue_reset()

Introduce vhost_virtqueue_reset(), which can reset the specific
virtqueue in the device. Then it will unmap vrings and the desc
of the virtqueue.

Here we do not reuse the vhost_net_stop_one() or vhost_dev_stop(),
because they work at queue pair level. We do not use
vhost_virtqueue_stop() because it may stop the device in the
backend.

This patch only considers the case of vhost-kernel, when
NetClientDriver is NET_CLIENT_DRIVER_TAP.

Furthermore, we do not need net->nc->info->poll() because
it enables userspace datapath and we want to stop all
datapaths for this reset virtqueue here.

Signed-off-by: Kangjie Xu <kangjie.xu@linux.alibaba.com>
Signed-off-by: Xuan Zhuo <xuanzhuo@linux.alibaba.com>
Acked-by: Jason Wang <jasowang@redhat.com>
Message-Id: <20221017092558.111082-10-xuanzhuo@linux.alibaba.com>
Reviewed-by: Michael S. Tsirkin <mst@redhat.com>
Signed-off-by: Michael S. Tsirkin <mst@redhat.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/net/vhost_net.h b/include/net/vhost_net.h
index 387e913e4e..85d85a4957 100644
--- a/include/net/vhost_net.h
+++ b/include/net/vhost_net.h
@@ -48,4 +48,6 @@ uint64_t vhost_net_get_acked_features(VHostNetState *net);
 
 int vhost_net_set_mtu(struct vhost_net *net, uint16_t mtu);
 
+void vhost_net_virtqueue_reset(VirtIODevice *vdev, NetClientState *nc,
+                               int vq_index);
 #endif