Hi Team,
In our application we use 2 interfaces one to communicate towards gNB and another to communicate with higher layers in a UE simulator NR stack. Now we use a PCI whose driver is i40e and is bind to dpdk vfio-pci driver and this works perfectly towards higher layer, but the other interface PCI whose is ixgbe driver is bind to vfio-pci dpdk driver and has some issues. 
The issues are:1. Application crashes when "rte_eth_dev_mac_addr_add" function is called when return with -1.  "on a 82599 VF, adding again the same MAC addr is not an idempotent operation..." this is a comment, but the function ixgbevf_add_mac_addr  return -1 when memcmp(hw->mac.perm_addr, mac_addr) == 0) is true. But above I commented the "return -1" and just returned from it, so crash is not seen.2. After above 1, application is started successfully but then I do not see any messages coming on this interface. This is the problem? 
Could you guide me what is the issue? I see only issue with ixgbvf but not for i40evf.
I am using dpdk-stable-19.11.5 version.

Kindly help me here.
Regards,Mohan