Thank you for posting your question on the Mellanox Community.
Based on the information provided, we see that you correctly configure RoCEv2 on the adapter. Based on the 'ibstat' output, there is no physical link to the switch.
Please check the cable used, make sure it is a validated and supported cable based on the latest Release Notes of the ConnectX-3 Pro firmware in use.
Also check, if the port on the switch is disabled. If needed move the link to another switch port. Also on the adapter, please perform a back-to-back between the two adapters to see if the link comes up.
If after this the issue is not resolved, please open a Mellanox Support case by sending an email to firstname.lastname@example.org.
Thanks and regards,
~Mellanox Technical Support