1IBV_REG_MR(3)           Libibverbs Programmer's Manual           IBV_REG_MR(3)
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NAME

6       ibv_reg_mr,  ibv_reg_mr_iova,  ibv_dereg_mr  - register or deregister a
7       memory region (MR)
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SYNOPSIS

10       #include <infiniband/verbs.h>
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12       struct ibv_mr *ibv_reg_mr(struct ibv_pd *pd, void *addr,
13                                 size_t length, int access);
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15       struct ibv_mr *ibv_reg_mr_iova(struct ibv_pd *pd, void *addr,
16                                      size_t length, uint64_t hca_va,
17                                      int access);
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19       int ibv_dereg_mr(struct ibv_mr *mr);
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DESCRIPTION

22       ibv_reg_mr() registers a memory region (MR) associated with the protec‐
23       tion  domain  pd.   The  MR's  starting address is addr and its size is
24       length.  The argument access describes the  desired  memory  protection
25       attributes; it is either 0 or the bitwise OR of one or more of the fol‐
26       lowing flags:
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28       IBV_ACCESS_LOCAL_WRITE  Enable Local Write Access
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30       IBV_ACCESS_REMOTE_WRITE  Enable Remote Write Access
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32       IBV_ACCESS_REMOTE_READ Enable Remote Read Access
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34       IBV_ACCESS_REMOTE_ATOMIC Enable Remote Atomic Operation Access (if sup‐
35       ported)
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37       IBV_ACCESS_MW_BIND Enable Memory Window Binding
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39       IBV_ACCESS_ZERO_BASED  Use  byte  offset from beginning of MR to access
40       this MR, instead of a pointer address
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42       IBV_ACCESS_ON_DEMAND Create an on-demand paging MR
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44       IBV_ACCESS_HUGETLB Huge pages are guaranteed to be used  for  this  MR,
45       applicable with IBV_ACCESS_ON_DEMAND in explicit mode only
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47       IBV_ACCESS_RELAXED_ORDERING  Allow system to reorder accesses to the MR
48       to improve performance
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50       If IBV_ACCESS_REMOTE_WRITE or  IBV_ACCESS_REMOTE_ATOMIC  is  set,  then
51       IBV_ACCESS_LOCAL_WRITE must be set too.
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53       Local read access is always enabled for the MR.
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55       To  create an implicit ODP MR, IBV_ACCESS_ON_DEMAND should be set, addr
56       should be 0 and length should be SIZE_MAX.
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58       If IBV_ACCESS_HUGETLB is set, then application awares that for this  MR
59       all  pages are huge and must promise it will never do anything to break
60       huge pages.
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62       ibv_reg_mr_iova() ibv_reg_mr_iova is the same  as  the  normal  reg_mr,
63       except  that the user is allowed to specify the virtual base address of
64       the MR when accessed through a lkey or rkey. The offset in  the  memory
65       region is computed as 'addr + (iova - hca_va)'. Specifying 0 for hca_va
66       has the same effect as IBV_ACCESS_ZERO_BASED.
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68       ibv_dereg_mr() deregisters the MR mr.
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RETURN VALUE

71       ibv_reg_mr() / ibv_reg_mr_iova() returns a pointer  to  the  registered
72       MR,  or NULL if the request fails.  The local key (L_Key) field lkey is
73       used as the lkey field of struct  ibv_sge  when  posting  buffers  with
74       ibv_post_*  verbs, and the the remote key (R_Key) field rkey is used by
75       remote processes to perform Atomic and  RDMA  operations.   The  remote
76       process places this rkey as the rkey field of struct ibv_send_wr passed
77       to the ibv_post_send function.
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79       ibv_dereg_mr() returns 0 on success, or the value of errno  on  failure
80       (which indicates the failure reason).
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NOTES

83       ibv_dereg_mr() fails if any memory window is still bound to this MR.
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SEE ALSO

86       ibv_alloc_pd(3),           ibv_post_send(3),          ibv_post_recv(3),
87       ibv_post_srq_recv(3)
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AUTHORS

90       Dotan Barak <dotanba@gmail.com>
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94libibverbs                        2006-10-31                     IBV_REG_MR(3)
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