NAME

       mlx5dv_mkey_check - Check a MKEY for errors

SYNOPSIS

              #include <infiniband/mlx5dv.h>

              int mlx5dv_mkey_check(struct mlx5dv_mkey *mkey,
                            struct mlx5dv_mkey_err *err_info);

DESCRIPTION

       Checks mkey for errors and provides the result in err_info on success.

       This  should  be  called after using a MKEY configured with signature validation in a transfer operation.
       While the transfer operation itself may be completed successfully (i.e. no transport related  errors  oc‐
       curred),  there  still  may be errors related to the integrity of the data.  The first of these errors is
       reported to the MKEY and kept there until application software queries it by calling this API.

       The type of error indicates which part of the signature was bad (guard, reftag or apptag).  Also provided
       is the actual calculated value based on the transferred data, and the expected value based on the  signa‐
       ture fields.  Last part provided is the offset in the transfer that caused the error.

ARGUMENTS

       mkey   The MKEY to check for errors.

       err_info
              The result of the MKEY check, information about the errors detected, if any.

                     struct mlx5dv_mkey_err {
                         enum mlx5dv_mkey_err_type err_type;
                         union {
                             struct mlx5dv_sig_err sig;
                         } err;
                     };

              err_type
                     What  kind of error happened.  If several errors exist in one block verified by the device,
                     only the first of them is reported, according to the order specified in  T10DIF  specifica‐
                     tion,    which   is:   MLX5DV_MKEY_SIG_BLOCK_BAD_GUARD,   MLX5DV_MKEY_SIG_BLOCK_BAD_APPTAG,
                     MLX5DV_MKEY_SIG_BLOCK_BAD_REFTAG.

                     MLX5DV_MKEY_NO_ERR
                            No error is detected for the MKEY.

                     MLX5DV_MKEY_SIG_BLOCK_BAD_GUARD
                            A   signature   error   was   detected    in    CRC/CHECKSUM    for    T10-DIF    or
                            CRC32/CRC32C/CRC64_XP10  (depends on the configured signature type).  Additional in‐
                            formation about the error is provided in struct mlx5dv_sig_err of err.

                     MLX5DV_MKEY_SIG_BLOCK_BAD_REFTAG
                            A signature error was detected in the reference tag.  This kind of  signature  error
                            is relevant for T10-DIF only.  Additional information about the error is provided in
                            struct mlx5dv_sig_err of err.

                     MLX5DV_MKEY_SIG_BLOCK_BAD_APPTAG
                            A signature error was detected in the application tag.  This kind of signature error
                            is relevant for T10-DIF only.  Additional information about the error is provided in
                            struct mlx5dv_sig_err of err.

              err    Information about the detected error if err_type is not MLX5DV_MKEY_NO_ERR.  Otherwise, its
                     value is not defined.

   Signature error
              struct mlx5dv_sig_err {
                  uint64_t actual_value;
                  uint64_t expected_value;
                  uint64_t offset;
              };

       actual_value
              The actual value that was calculated from the transferred data.

       expected_value
              The expected value based on what appears in the signature respected field.

       offset The  offset  within the transfer where the error happened.  In block signature, this is guaranteed
              to be a block boundary offset.

RETURN VALUE

       0 on success or the value of errno on failure (which indicates the failure reason).

NOTES

       A DEVX context should be opened by using mlx5dv_open_device(3).

       Checking the MKEY for errors should be done after the application knows the data transfer that was  using
       the  MKEY  has finished.  Application should wait for the respected completion (if this was a local MKEY)
       or wait for a received message from a peer (if this was a remote MKEY).

SEE ALSO

       mlx5dv_wr_mkey_configure(3),    mlx5dv_wr_set_mkey_sig_block(3),    mlx5dv_create_mkey(3),     mlx5dv_de‐
       stroy_mkey(3)

AUTHORS

       Oren Duer <oren@nvidia.com>

       Sergey Gorenko <sergeygo@nvidia.com>

                                                                                            mlx5dv_mkey_check(3)