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
       occurred),  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
       signature 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
                     specification, 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
                            information 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_destroy_mkey(3)

AUTHORS

       Oren Duer oren@nvidia.com

       Sergey Gorenko sergeygo@nvidia.com

                                                                                            mlx5dv_mkey_check(3)