[vs]: set mtu only on the physical port (#601)

Signed-off-by: Guohan Lu <[email protected]>

Author: lguohan

vslib/src/SwitchStateBase.cpp

@@ -403,7 +403,9 @@ sai_status_t SwitchStateBase::setPort(
         {
             SWSS_LOG_INFO("setting new MTU: %d on %s", mtu, name.c_str());
 
-            if (vs_set_dev_mtu(name.c_str(), mtu) < 0)
+            std::string vname = vs_get_veth_name(name, portId);
+
+            if (vs_set_dev_mtu(vname.c_str(), mtu) < 0)
             {
                 SWSS_LOG_ERROR("failed to set MTU on portId %s",
                     sai_serialize_object_id(portId).c_str());

vslib/src/SwitchStateBaseHostif.cpp

@@ -656,7 +656,7 @@ sai_status_t SwitchStateBase::vs_create_hostif_tap_interface(
         SWSS_LOG_INFO("setting new MTU: %d on %s", mtu, vname.c_str());
     }
 
-    vs_set_dev_mtu(name.c_str(), mtu);
+    vs_set_dev_mtu(vname.c_str(), mtu);
 
     if (!hostif_create_tap_veth_forwarding(name, tapfd, obj_id))
     {