ibv_reg_mr_iova(3) — Linux manual page


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

NAME         top

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

SYNOPSIS         top

       #include <infiniband/verbs.h>

       struct ibv_mr *ibv_reg_mr(struct ibv_pd *pd, void *addr,
                                 size_t length, int access);

       struct ibv_mr *ibv_reg_mr_iova(struct ibv_pd *pd, void *addr,
                                      size_t length, uint64_t hca_va,
                                      int access);

       int ibv_dereg_mr(struct ibv_mr *mr);

DESCRIPTION         top

       ibv_reg_mr() registers a memory region (MR) associated with the
       protection domain pd.  The MR's starting address is addr and its size
       is length.  The argument access describes the desired memory
       protection attributes; it is either 0 or the bitwise OR of one or
       more of the following flags:

       IBV_ACCESS_LOCAL_WRITE  Enable Local Write Access

       IBV_ACCESS_REMOTE_WRITE  Enable Remote Write Access

       IBV_ACCESS_REMOTE_READ Enable Remote Read Access

       IBV_ACCESS_REMOTE_ATOMIC Enable Remote Atomic Operation Access (if

       IBV_ACCESS_MW_BIND Enable Memory Window Binding

       IBV_ACCESS_ZERO_BASED Use byte offset from beginning of MR to access
       this MR, instead of a pointer address

       IBV_ACCESS_ON_DEMAND Create an on-demand paging MR

       IBV_ACCESS_HUGETLB Huge pages are guaranteed to be used for this MR,
       applicable with IBV_ACCESS_ON_DEMAND in explicit mode only

       IBV_ACCESS_RELAXED_ORDERING Allow system to reorder accesses to the
       MR to improve performance

       IBV_ACCESS_LOCAL_WRITE must be set too.

       Local read access is always enabled for the MR.

       To create an implicit ODP MR, IBV_ACCESS_ON_DEMAND should be set,
       addr should be 0 and length should be SIZE_MAX.

       If IBV_ACCESS_HUGETLB is set, then application awares that for this
       MR all pages are huge and must promise it will never do anything to
       break huge pages.

       ibv_reg_mr_iova() ibv_reg_mr_iova is the same as the normal reg_mr,
       except that the user is allowed to specify the virtual base address
       of the MR when accessed through a lkey or rkey. The offset in the
       memory region is computed as 'addr + (iova - hca_va)'. Specifying 0
       for hca_va has the same effect as IBV_ACCESS_ZERO_BASED.

       ibv_dereg_mr() deregisters the MR mr.

RETURN VALUE         top

       ibv_reg_mr() / ibv_reg_mr_iova() returns a pointer to the registered
       MR, or NULL if the request fails.  The local key (L_Key) field lkey
       is used as the lkey field of struct ibv_sge when posting buffers with
       ibv_post_* verbs, and the the remote key (R_Key) field rkey is used
       by remote processes to perform Atomic and RDMA operations.  The
       remote process places this rkey as the rkey field of struct
       ibv_send_wr passed to the ibv_post_send function.

       ibv_dereg_mr() returns 0 on success, or the value of errno on failure
       (which indicates the failure reason).

NOTES         top

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

SEE ALSO         top

       ibv_alloc_pd(3), ibv_post_send(3), ibv_post_recv(3),

AUTHORS         top

       Dotan Barak <dotanba@gmail.com>

COLOPHON         top

       This page is part of the rdma-core (RDMA Core Userspace Libraries and
       Daemons) project.  Information about the project can be found at 
       ⟨https://github.com/linux-rdma/rdma-core⟩.  If you have a bug report
       for this manual page, send it to linux-rdma@vger.kernel.org.  This
       page was obtained from the project's upstream Git repository
       ⟨https://github.com/linux-rdma/rdma-core.git⟩ on 2020-09-18.  (At
       that time, the date of the most recent commit that was found in the
       repository was 2020-09-16.)  If you discover any rendering problems
       in this HTML version of the page, or you believe there is a better or
       more up-to-date source for the page, or you have corrections or
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       of the original manual page), send a mail to man-pages@man7.org

libibverbs                       2006-10-31                    IBV_REG_MR(3)