+ /**
+ * ask user application if we allowed to perform those functions
+ * if we get cb_param.retval == RTE_PMD_IXGBE_MB_EVENT_PROCEED
+ * then business as usual,
+ * if 0, do nothing and send ACK to VF
+ * if cb_param.retval > 1, do nothing and send NAK to VF
+ */
+ _rte_eth_dev_callback_process(dev, RTE_ETH_EVENT_VF_MBOX, &cb_param);
+
+ retval = cb_param.retval;
+