Linux RDMA and InfiniBand development
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From: Bob Pearson <rpearsonhpe@gmail.com>
To: Jason Gunthorpe <jgg@nvidia.com>
Cc: "linux-rdma@vger.kernel.org" <linux-rdma@vger.kernel.org>
Subject: another change breaks rxe
Date: Fri, 30 Oct 2020 00:41:12 -0500	[thread overview]
Message-ID: <32fa9c9f-5816-7474-b821-ccccd4cb5af0@gmail.com> (raw)

Jason,

commit 628c02bf38aa42c09c3dde61284ba348290e6650
Author: Jason Gunthorpe <jgg@ziepe.ca>
Date:   Sat Oct 3 20:20:10 2020 -0300

    RDMA: Remove uverbs cmds from drivers that don't use them
    
    Allowing userspace to invoke these commands is probably going to crash
    these drivers as they are not tested and not expecting to use them on a
    user object.
    
    For example pvrdma touches cq->ring_state which is not initialized for
    user QPs.
    
    These commands are effected:
    
    - IB_USER_VERBS_CMD_REQ_NOTIFY_CQ is ibv_cmd_req_notify_cq() in
      rdma-core, only hfi1, ipath and rxe calls it.
    
    - IB_USER_VERBS_CMD_POLL_CQ is ibv_cmd_poll_cq() in rdma-core, only
      ipath and hfi1 calls it.
    
    - IB_USER_VERBS_CMD_POST_SEND/RECV is ibv_cmd_post_send/recv() in
      rdma-core, only ipath and hfi1 call them.

breaks rxe because it does use IB_USER_VERBS_CMD_POST_SEND. rxe posts wqes to a work queue in shared memory and then calls ibv_post_send with zero wqes as a doorbell to the kernel which uses this as a hint to go read the shared memory.

Bob

             reply	other threads:[~2020-10-30  5:51 UTC|newest]

Thread overview: 4+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-10-30  5:41 Bob Pearson [this message]
2020-10-30 11:47 ` another change breaks rxe Jason Gunthorpe
2020-10-30 12:50   ` Bernard Metzler
2020-10-30 16:28     ` Jason Gunthorpe

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