Hi folks,
We have a problem with hfi1 that has cropped up after:
0a93fbcb16e6 ("xprtrdma: Plant XID in on-the-wire RDMA offset (FRWR))"
What this does is overwrite the upper 32 bits of what is the memory
address (on OPA) so that this gets sent across the wire as the iova.
Upon arriving on the other side the receiver doesn't like this and
tosses it. I'm looking into a fix.
Now, a related commit I found for RXE has an interesting comment in the
commit message:
b024dd0eba6e ("rxe: IB_WR_REG_MR does not capture MR's iova field)"
> FRWR memory registration is done with a series of calls and WRs.
> 1. ULP invokes ib_dma_map_sg()
> 2. ULP invokes ib_map_mr_sg()
> 3. ULP posts an IB_WR_REG_MR on the Send queue
>
> Step 2 generates an iova. It is permissible for ULPs to change this
> iova (with certain restrictions) between steps 2 and 3.
I'm curious what these "certain restrictions" are. Can someone point me
to a discussion/thread or section of the IBTA spec that explains this?
-Denny
