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NAME | SYNOPSIS | DESCRIPTION | RETURN VALUE | NOTES | SEE ALSO | AUTHORS | COLOPHON |
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IBV_REG_MR(3) Libibverbs Programmer's Manual IBV_REG_MR(3)
ibv_reg_mr, ibv_reg_mr_iova, ibv_reg_dmabuf_mr, ibv_dereg_mr -
register or deregister a memory region (MR)
#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);
struct ibv_mr *ibv_reg_dmabuf_mr(struct ibv_pd *pd, uint64_t offset,
size_t length, uint64_t iova,
int fd, int access);
int ibv_dereg_mr(struct ibv_mr *mr);
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 supported)
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
If IBV_ACCESS_REMOTE_WRITE or IBV_ACCESS_REMOTE_ATOMIC is set,
then 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_reg_dmabuf_mr() registers a dma-buf based memory region (MR)
associated with the protection domain pd. The MR starts at
offset of the dma-buf and its size is length. The dma-buf is
identified by the file descriptor fd. The argument iova
specifies the virtual base address of the MR when accessed
through a lkey or rkey. It must have the same page offset as
offset. The argument access describes the desired memory
protection attributes; it is similar to the ibv_reg_mr case
except that only the following flags are supported:
IBV_ACCESS_LOCAL_WRITE, IBV_ACCESS_REMOTE_WRITE,
IBV_ACCESS_REMOTE_READ, IBV_ACCESS_REMOTE_ATOMIC,
IBV_ACCESS_RELAXED_ORDERING.
ibv_dereg_mr() deregisters the MR mr.
ibv_reg_mr() / ibv_reg_mr_iova() / ibv_reg_dmabuf_mr() 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).
ibv_dereg_mr() fails if any memory window is still bound to this
MR.
ibv_alloc_pd(3), ibv_post_send(3), ibv_post_recv(3),
ibv_post_srq_recv(3)
Dotan Barak <dotanba@gmail.com>
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 2022-12-17. (At
that time, the date of the most recent commit that was found in
the repository was 2022-12-09.) 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 improvements to the information in this COLOPHON
(which is not part of the original manual page), send a mail to
man-pages@man7.org
libibverbs 2006-10-31 IBV_REG_MR(3)
Pages that refer to this page: ibv_alloc_mw(3), ibv_alloc_pd(3), ibv_bind_mw(3), rdma_dereg_mr(3), rdma_post_recv(3), rdma_post_recvv(3), rdma_reg_msgs(3), rdma_reg_read(3), rdma_reg_write(3)
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