-------- Forwarded Message --------
Subject: Re: Bug in pyverbs for test_qp_ex_rc_bind_mw
Date: Tue, 17 May 2022 22:41:08 -0500
From: Bob Pearson <rpearsonhpe@xxxxxxxxx>
To: Jason Gunthorpe <jgg@xxxxxxxxxx>, Zhu Yanjun <zyjzyj2000@xxxxxxxxx>, Edward Srouji <edwards@xxxxxxxxxx>, Leon Romanovsky <leon@xxxxxxxxxx>
On 5/17/22 21:57, Bob Pearson wrote:
> test_qp_ex_rc_bind_mw has an error in that the new_rkey is computed from the old mr rkey and not the old mw rkey.
> The following lines
>
> mw = MW(server.pd, mw_type=e.IBV_MW_TYPE_2)
> ...
> new_rkey = inc_rkey(server.mr.rkey)
> server.qp.wr_bind_mw(mw, new_rkey, bind_info)
>
> will compute a new rkey with the same index as mr and a key portion that is one larger than mr modulo 256.
> This is passed to wr_bind_mw which expects a parameter with a new key portion of the mw (not the mr).
> The memory windows implementation in rxe generates a random initial rkey for mw and for bind_mw it
> checks that the new 8 bit key is different than the old key. Since the mr and mw are random wrt each other
> we expect that the new key will match the old key approx 1 out of 256 test runs which will cause an error
> which is just what I see.
>
> The correct code should be
>
> new_key = inc_rkey(<old mw.rkey>)
>
> which will guarantee that it is always different than the previous key. The problem is I can't figure out
> how to compute the rkey from the mw or I would submit a patch.
>
> Bob
>
If in test_qpex.py I type
print("mw = ", mw)
print("mr = ", self.server.mr)
I get
mw = MW:
Rkey : 12345678
Handle : 4
MW Type : IBV_MW_TYPE_2
mr = MR
lkey : 432134
rkey : 432134
length : 1024
buf : 9403912345678
handle : 2
The difference is the colon ':' after MW and caps.
I can refer to mr.rkey as self.server.mr.rkey no problem
but mw.Rkey doesn't work. Neither does mw.rkey or anything else I have thought of.
I hate python. Just hate it.
Bob
