mlx5dv_create_qp(3)

1mlx5dv_create_qp(3)        mlx5 Programmer’s Manual        mlx5dv_create_qp(3)
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NAME

6       mlx5dv_create_qp - creates a queue pair (QP)
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SYNOPSIS

9              #include <infiniband/mlx5dv.h>
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11              struct ibv_qp *mlx5dv_create_qp(struct ibv_context         *context,
12                                              struct ibv_qp_init_attr_ex *qp_attr,
13                                              struct mlx5dv_qp_init_attr *mlx5_qp_attr)
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DESCRIPTION

16       mlx5dv_create_qp() creates a queue pair (QP) with specific driver prop‐
17       erties.
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ARGUMENTS

20       Please see ibv_create_qp_ex(3) man page for context and qp_attr.
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22   mlx5_qp_attr
23              struct mlx5dv_qp_init_attr {
24                  uint64_t comp_mask;
25                  uint32_t create_flags;
26                  struct mlx5dv_dc_init_attr  dc_init_attr;
27                  uint64_t send_ops_flags;
28              };
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30       comp_mask
31              Bitmask specifying what  fields  in  the  structure  are  valid:
32              MLX5DV_QP_INIT_ATTR_MASK_QP_CREATE_FLAGS:  valid  values in cre‐
33              ate_flags   MLX5DV_QP_INIT_ATTR_MASK_DC:   valid    values    in
34              dc_init_attr MLX5DV_QP_INIT_ATTR_MASK_SEND_OPS_FLAGS: valid val‐
35              ues in send_ops_flags
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37       create_flags
38              A bitwise OR of the various values described below.
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40              MLX5DV_QP_CREATE_TUNNEL_OFFLOADS:  Enable  offloading  such   as
41              checksum and LRO for incoming tunneling traffic.
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43              MLX5DV_QP_CREATE_TIR_ALLOW_SELF_LOOPBACK_UC:   Allow   receiving
44              loopback unicast traffic.
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46              MLX5DV_QP_CREATE_TIR_ALLOW_SELF_LOOPBACK_MC:   Allow   receiving
47              loopback multicast traffic.
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49              MLX5DV_QP_CREATE_DISABLE_SCATTER_TO_CQE:  Disable scatter to CQE
50              feature which is enabled by default.
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52              MLX5DV_QP_CREATE_ALLOW_SCATTER_TO_CQE: Allow scatter to CQE  for
53              requester even if the qp was not configured to signal all WRs.
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55              MLX5DV_QP_CREATE_PACKET_BASED_CREDIT_MODE:  Set  QP  to  work in
56              end-to-end packet-based credit, instead of the default  message-
57              based credits (IB spec.  section 9.7.7.2).
58              It is the applications responsibility to make sure that the peer
59              QP is configured with same mode.
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61              MLX5DV_QP_CREATE_SIG_PIPELINING: If the flag is set, the  QP  is
62              moved  to  SQD  state  upon  encountering a signature error, and
63              IBV_EVENT_SQ_DRAINED is generated to inform about the new state.
64              The  signature pipelining feature is a performance optimization,
65              which reduces latency for read operations in the storage  proto‐
66              cols.   The  feature  is optional.  Creating the QP fails if the
67              kernel or device does not support the feature.  In this case, an
68              application  should  fallback to backward compatibility mode and
69              handle read operations  without  the  pipelining.   See  details
70              about   the   signature   pipelining  in  mlx5dv_qp_cancel_post‐
71              ed_send_wrs(3).
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73       dc_init_attr
74              DC init attributes.
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76   dc_init_attr
77              struct mlx5dv_dci_streams {
78                  uint8_t log_num_concurent;
79                  uint8_t log_num_errored;
80              };
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82              struct mlx5dv_dc_init_attr {
83                  enum mlx5dv_dc_type dc_type;
84                  union {
85                      uint64_t dct_access_key;
86                      struct mlx5dv_dci_streams dci_streams;
87                  };
88              };
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90       dc_type
91              MLX5DV_DCTYPE_DCT QP  type:  Target  DC.   MLX5DV_DCTYPE_DCI  QP
92              type: Initiator DC.
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94       dct_access_key
95              used to create a DCT QP.
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97       dci_streams
98              dci_streams  used  to  define  DCI  QP  with multiple concurrent
99              streams.   Valid  when  comp_mask  includes   MLX5DV_QP_INIT_AT‐
100              TR_MASK_DCI_STREAMS.
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102              log_num_concurent  Defines  the  number  of  parallel  different
103              streams that could be handled by HW.  All work request of a spe‐
104              cific stream_id are handled in order.
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106              log_num_errored  Defines the number of dci error stream channels
107              before moving DCI to an error state.
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109       send_ops_flags
110              A bitwise OR of the various values described below.
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112              MLX5DV_QP_EX_WITH_MR_INTERLEAVED: Enables  the  mlx5dv_wr_mr_in‐
113              terleaved() work requset on this QP.
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115              MLX5DV_QP_EX_WITH_MR_LIST:  Enables the mlx5dv_wr_mr_list() work
116              requset on this QP.
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118              MLX5DV_QP_EX_WITH_MKEY_CONFIGURE:          Enables           the
119              mlx5dv_wr_mkey_configure()  work request and the related setters
120              on this QP.
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NOTES

123       mlx5dv_qp_ex_from_ibv_qp_ex() is used to get  struct  mlx5dv_qp_ex  for
124       accessing  the send ops interfaces when IBV_QP_INIT_ATTR_SEND_OPS_FLAGS
125       is used.
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127       The MLX5DV_QP_CREATE_DISABLE_SCATTER_TO_CQE flag should be set in cases
128       that IOVA doesn’t match the process’ VA and the message payload size is
129       small enough to trigger the scatter to CQE feature.
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131       When device memory is used IBV_SEND_INLINE and scatter  to  CQE  should
132       not be used, as the memcpy is not possible.
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RETURN VALUE

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

142       Yonatan Cohen <yonatanc@mellanox.com>
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146mlx5                               2018-9-1                mlx5dv_create_qp(3)