diff mbox series

[v3] net/mlx5: use just sufficient barrier for ARM platforms

Message ID 20230309023247.1241515-1-honnappa.nagarahalli@arm.com (mailing list archive)
State Accepted, archived
Delegated to: Raslan Darawsheh
Headers
Series [v3] net/mlx5: use just sufficient barrier for ARM platforms |

Checks

Context Check Description
ci/checkpatch success coding style OK
ci/loongarch-compilation success Compilation OK
ci/loongarch-unit-testing success Unit Testing PASS
ci/Intel-compilation success Compilation OK
ci/intel-Testing success Testing PASS
ci/github-robot: build success github build: passed
ci/intel-Functional success Functional PASS
ci/iol-testing warning apply patch failure

Commit Message

Honnappa Nagarahalli March 9, 2023, 2:32 a.m. UTC 
  cqe->op_own indicates if the CQE is owned by the NIC. The rest of
the fields in CQE should be read only after op_own is read. On Arm
platforms using "dmb ishld" is sufficient to enforce this.

Fixes: 88c0733535d6 ("net/mlx5: extend Rx completion with error handling")
Cc: matan@mellanox.com
Cc: stable@dpdk.org

Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
---
 drivers/common/mlx5/mlx5_common.h | 6 +++++-
 1 file changed, 5 insertions(+), 1 deletion(-)

Comments

Slava Ovsiienko March 9, 2023, 3:44 p.m. UTC | #1 
> -----Original Message-----
> From: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> Sent: четверг, 9 марта 2023 г. 04:33
> To: Matan Azrad <matan@nvidia.com>; Shahaf Shuler <shahafs@nvidia.com>;
> Slava Ovsiienko <viacheslavo@nvidia.com>
> Cc: dev@dpdk.org; honnappa.nagarahalli@arm.com; ruifeng.wang@arm.com;
> nd@arm.com; Matan Azrad <matan@mellanox.com>; stable@dpdk.org
> Subject: [PATCH v3] net/mlx5: use just sufficient barrier for ARM platforms
> 
> cqe->op_own indicates if the CQE is owned by the NIC. The rest of
> the fields in CQE should be read only after op_own is read. On Arm platforms
> using "dmb ishld" is sufficient to enforce this.
> 
> Fixes: 88c0733535d6 ("net/mlx5: extend Rx completion with error handling")
> Cc: matan@mellanox.com
> Cc: stable@dpdk.org
> 
> Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>
Acked-by: Viacheslav Ovsiienko <viacheslavo@nvidia.com>
Raslan Darawsheh March 19, 2023, 1:32 p.m. UTC | #2 
Hi,

> -----Original Message-----
> From: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> Sent: Thursday, March 9, 2023 4:33 AM
> To: Matan Azrad <matan@nvidia.com>; Shahaf Shuler <shahafs@nvidia.com>;
> Slava Ovsiienko <viacheslavo@nvidia.com>
> Cc: dev@dpdk.org; honnappa.nagarahalli@arm.com; ruifeng.wang@arm.com;
> nd@arm.com; Matan Azrad <matan@mellanox.com>; stable@dpdk.org
> Subject: [PATCH v3] net/mlx5: use just sufficient barrier for ARM platforms
> 
> cqe->op_own indicates if the CQE is owned by the NIC. The rest of
> the fields in CQE should be read only after op_own is read. On Arm platforms
> using "dmb ishld" is sufficient to enforce this.
> 
> Fixes: 88c0733535d6 ("net/mlx5: extend Rx completion with error handling")
> Cc: matan@mellanox.com
> Cc: stable@dpdk.org
> 
> Signed-off-by: Honnappa Nagarahalli <honnappa.nagarahalli@arm.com>
> Reviewed-by: Ruifeng Wang <ruifeng.wang@arm.com>

Patch applied to next-net-mlx,

Kindest regards,
Raslan Darawsheh
diff mbox series

Patch

diff --git a/drivers/common/mlx5/mlx5_common.h b/drivers/common/mlx5/mlx5_common.h
index f8d07d6c6b..f4ddaf9f11 100644
--- a/drivers/common/mlx5/mlx5_common.h
+++ b/drivers/common/mlx5/mlx5_common.h
@@ -203,7 +203,11 @@  check_cqe(volatile struct mlx5_cqe *cqe, const uint16_t cqes_n,
 
 	if (unlikely((op_owner != (!!(idx))) || (op_code == MLX5_CQE_INVALID)))
 		return MLX5_CQE_STATUS_HW_OWN;
-	rte_io_rmb();
+	/* Prevent speculative reading of other fields in CQE until
+	 * CQE is valid.
+	 */
+	rte_atomic_thread_fence(__ATOMIC_ACQUIRE);
+
 	if (unlikely(op_code == MLX5_CQE_RESP_ERR ||
 		     op_code == MLX5_CQE_REQ_ERR))
 		return MLX5_CQE_STATUS_ERR;