XL710 VF driver can reply to ARP request but cannot reply to ICMP's

We try to write a XL710 VF driver simply,and test it by using  ping command form PF to VF.

Now the VF driver can receive the ARP request and can reply it successfully, and the VF can also receive the ICMP request,and the reply data seems to put into the transmit buffer.

But in the PF, we cannot catch any reply data.

The ARP request can be reply that is to say the VF driver works normally, does it correctly? At least, it shows that the receive part and transmit part are correct.

Things that I want to know is what registers are relative to this issues, or any ideas about this issues?

Thanks & regards!

Animy.