rxe: IB_WR_REG_MR does not capture MR's iova field

chucklever · jgunthorpe · commit b024dd0eba6e · 2018-11-29T17:10:06.000-07:00
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.

rxe_map_mr_sg captures the MR's iova but later when rxe processes the
REG_MR WR, it ignores the MR's iova field. If a ULP alters the MR's iova
after step 2 but before step 3, rxe never captures that change.

When the remote sends an RDMA Read targeting that MR, rxe looks up the
R_key, but the altered iova does not match the iova stored in the MR,
causing the RDMA Read request to fail.

Reported-by: Anna Schumaker &lt;schumaker.anna@gmail.com&gt;
Signed-off-by: Chuck Lever &lt;chuck.lever@oracle.com&gt;
Reviewed-by: Sagi Grimberg &lt;sagi@grimberg.me&gt;
Signed-off-by: Jason Gunthorpe &lt;jgg@mellanox.com&gt;
diff --git a/drivers/infiniband/sw/rxe/rxe_req.c b/drivers/infiniband/sw/rxe/rxe_req.c
@@ -643,6 +643,7 @@ int rxe_requester(void *arg)
 			rmr->access = wqe->wr.wr.reg.access;
 			rmr->lkey = wqe->wr.wr.reg.key;
 			rmr->rkey = wqe->wr.wr.reg.key;
+			rmr->iova = wqe->wr.wr.reg.mr->iova;
 			wqe->state = wqe_state_done;
 			wqe->status = IB_WC_SUCCESS;
 		} else {
