vhost: prevent zero-copy with incompatible client mode

In server mode, virtio-user inits under the assumption that vhost-user
supports a list of features. However, this could be problematic when
in_order feature is negotiated but not supported by vhost-user when
enables dequeue_zero_copy later.

Add handling when vhost-user enables dequeue_zero_copy as client.

Fixes: 64ab701c3d1e ("vhost: add vhost-user client mode")
Cc: stable@dpdk.org
Signed-off-by: Xuan Ding <xuan.ding@intel.com>
Tested-by: Yinan Wang <yinan.wang@intel.com>
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

diff --git a/lib/librte_vhost/socket.c b/lib/librte_vhost/socket.c
index 7c80121..bb8d0d7 100644 (file)
--- a/lib/librte_vhost/socket.c
+++ b/lib/librte_vhost/socket.c
@@ -926,6 +926,12 @@ rte_vhost_driver_register(const char *path, uint64_t flags)
                        ret = -1;
                        goto out_mutex;
                }
+               if (!vsocket->is_server) {
+                       VHOST_LOG_CONFIG(ERR,
+                       "error: zero copy is incompatible with vhost client mode\n");
+                       ret = -1;
+                       goto out_mutex;
+               }
                vsocket->supported_features &= ~(1ULL << VIRTIO_F_IN_ORDER);
                vsocket->features &= ~(1ULL << VIRTIO_F_IN_ORDER);