py verbs tests

[Bob Pearson <rpearsonhpe@gmail.com>]

I am currently trying to figure out why one of the pyverbs tests is failing.

I added a check implementing C9-205 (p 419) of the IBA spec. I requires that a responder receiving a packet longer
than the receive buffer or the PMTU shall be silently dropped. I.e. a class D error.

    C9-205: Before executing the request, the responder shall validate the
    Packet Length field of the LRH and the PadCnt of the BTH as described
    in 9.8.3.2.2: Responder - Length Validation.
    The following characteristics shall be validated:
    • The Length fields shall be checked to confirm that there is sufficient
    space available in the receive buffer specified by the receive WQE.
    • The packet payload length must be between zero and PMTU bytes
    inclusive in size.
    If a packet is detected with an invalid length, the request shall be an invalid
    request and it shall be silently dropped by the responder as specified in
    Section 9.9.3 Responder Side Behavior on page 435. The responder then
    waits for a new request packet.

tests/test_cq_events.py passes PATH_MTU = 1024 in the modify QPs verb for RC and XRC but not UD.
This should be a required parameter as part of the primary destination address but is not getting
set for UD. The test then proceeds to send a 1024 byte payload to the destination and for UD hangs
waiting for the completion.

I don't want to mess with these tests because I am a poor python coder. Is there some reason why it is
OK to not set the PMTU for UD QPs?

Bob