jammy (3) mlx5dv_create_qp.3.gz

NAME

       mlx5dv_create_qp - creates a queue pair (QP)

SYNOPSIS

              #include <infiniband/mlx5dv.h>

              struct ibv_qp *mlx5dv_create_qp(struct ibv_context         *context,
                                              struct ibv_qp_init_attr_ex *qp_attr,
                                              struct mlx5dv_qp_init_attr *mlx5_qp_attr)

DESCRIPTION

       mlx5dv_create_qp() creates a queue pair (QP) with specific driver properties.

ARGUMENTS

       Please see ibv_create_qp_ex(3) man page for context and qp_attr.

   mlx5_qp_attr
              struct mlx5dv_qp_init_attr {
                  uint64_t comp_mask;
                  uint32_t create_flags;
                  struct mlx5dv_dc_init_attr  dc_init_attr;
                  uint64_t send_ops_flags;
              };

       comp_mask
              Bitmask      specifying      what      fields      in      the      structure      are      valid:
              MLX5DV_QP_INIT_ATTR_MASK_QP_CREATE_FLAGS:        valid        values        in        create_flags
              MLX5DV_QP_INIT_ATTR_MASK_DC: valid values in dc_init_attr MLX5DV_QP_INIT_ATTR_MASK_SEND_OPS_FLAGS:
              valid values in send_ops_flags

       create_flags
              A bitwise OR of the various values described below.

              MLX5DV_QP_CREATE_TUNNEL_OFFLOADS:  Enable  offloading  such  as  checksum  and  LRO  for  incoming
              tunneling traffic.

              MLX5DV_QP_CREATE_TIR_ALLOW_SELF_LOOPBACK_UC: Allow receiving loopback unicast traffic.

              MLX5DV_QP_CREATE_TIR_ALLOW_SELF_LOOPBACK_MC: Allow receiving loopback multicast traffic.

              MLX5DV_QP_CREATE_DISABLE_SCATTER_TO_CQE:  Disable  scatter  to  CQE  feature  which  is enabled by
              default.

              MLX5DV_QP_CREATE_ALLOW_SCATTER_TO_CQE: Allow scatter to CQE for requester even if the qp  was  not
              configured to signal all WRs.

              MLX5DV_QP_CREATE_PACKET_BASED_CREDIT_MODE:  Set  QP  to  work  in  end-to-end packet-based credit,
              instead of the default message-based credits (IB spec.  section 9.7.7.2).
              It is the applications responsibility to make sure that the peer QP is configured with same mode.

              MLX5DV_QP_CREATE_SIG_PIPELINING: If  the  flag  is  set,  the  QP  is  moved  to  SQD  state  upon
              encountering  a  signature  error,  and  IBV_EVENT_SQ_DRAINED is generated to inform about the new
              state.  The signature pipelining feature is a performance optimization, which reduces latency  for
              read  operations in the storage protocols.  The feature is optional.  Creating the QP fails if the
              kernel or device does not support the feature.  In this case, an application  should  fallback  to
              backward  compatibility mode and handle read operations without the pipelining.  See details about
              the signature pipelining in mlx5dv_qp_cancel_posted_send_wrs(3).

       dc_init_attr
              DC init attributes.

   dc_init_attr
              struct mlx5dv_dci_streams {
                  uint8_t log_num_concurent;
                  uint8_t log_num_errored;
              };

              struct mlx5dv_dc_init_attr {
                  enum mlx5dv_dc_type dc_type;
                  union {
                      uint64_t dct_access_key;
                      struct mlx5dv_dci_streams dci_streams;
                  };
              };

       dc_type
              MLX5DV_DCTYPE_DCT QP type: Target DC.  MLX5DV_DCTYPE_DCI QP type: Initiator DC.

       dct_access_key
              used to create a DCT QP.

       dci_streams
              dci_streams used to define DCI QP with multiple concurrent streams.  Valid when comp_mask includes
              MLX5DV_QP_INIT_ATTR_MASK_DCI_STREAMS.

              log_num_concurent  Defines  the  number of parallel different streams that could be handled by HW.
              All work request of a specific stream_id are handled in order.

              log_num_errored Defines the number of dci error stream channels before  moving  DCI  to  an  error
              state.

       send_ops_flags
              A bitwise OR of the various values described below.

              MLX5DV_QP_EX_WITH_MR_INTERLEAVED: Enables the mlx5dv_wr_mr_interleaved() work requset on this QP.

              MLX5DV_QP_EX_WITH_MR_LIST: Enables the mlx5dv_wr_mr_list() work requset on this QP.

              MLX5DV_QP_EX_WITH_MKEY_CONFIGURE:  Enables  the  mlx5dv_wr_mkey_configure()  work  request and the
              related setters on this QP.

NOTES

       mlx5dv_qp_ex_from_ibv_qp_ex() is used to get struct mlx5dv_qp_ex for accessing the  send  ops  interfaces
       when IBV_QP_INIT_ATTR_SEND_OPS_FLAGS is used.

       The  MLX5DV_QP_CREATE_DISABLE_SCATTER_TO_CQE  flag  should  be  set  in cases that IOVA doesn’t match the
       process’ VA and the message payload size is small enough to trigger the scatter to CQE feature.

       When device memory is used IBV_SEND_INLINE and scatter to CQE should not be used, as the  memcpy  is  not
       possible.

RETURN VALUE

       mlx5dv_create_qp()  returns a pointer to the created QP, on error NULL will be returned and errno will be
       set.

SEE ALSO

       ibv_query_device_ex(3), ibv_create_qp_ex(3),

AUTHOR

       Yonatan Cohen <yonatanc@mellanox.com>