Remove these unnecessary vring descriptor length updating, vhost should not change them. virtio in front end should assign value to desc.len for both rx and tx. Test report: http://dpdk.org/ml/archives/dev/2015-June/018610.html Signed-off-by: Changchun Ouyang <changchun.ouyang@intel.com> Acked-by: Huawei Xie <huawei.xie@intel.com>