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>