Template Version: @(#)sac_nextcase %I% %G% SMI
This information is Copyright 2008 Sun Microsystems
1. Introduction
1.1. Project/Component Working Name:
IBTF IO Memory
1.2. Name of Document Author/Supplier:
Author: Lida Horn
1.3 Date of This Document:
10 October, 2008
4. Technical Description
A. Background
The DDI distinguishes between different "types" of memory. Memory from
ddi_dma_mem_alloc(9F) is usable for DMA and takes into account various
factors such alignment and other device attributes. Memory from
kmem_(z)alloc is not guaranteed to be usable for DMA, though most of
the time it does work for that purpose, because of the capability of
modern platforms. Nevertheless, there is value in maintaining these
DDI distinctions, especially when considering certain platform issues
such as memory DR.
In the context of InfiniBand, registered memory is the target of DMA
operations. This case introduces new InfiniBand related interfaces
analogous to the ddi_dma_mem_alloc family of functions to IBTF
(InfiniBand Transport Framework, PSARC/2002/132 and follow-on
cases). This addition will help the InfiniBand stack maintain the
proper DDI memory distinctions important for certain types of
platforms.
B. Proposal
The proposal is to make additions to the IBTF Channel and Transport
interfaces. The functionality added to the Transport Interface (TI) is
used by the ULPs to allocate memory suitable for DMA and IB memory
registration. In turn, the framework uses new entry points in the
Channel Interface (CI) to request memory allocation from the
underlying HCA driver. These interfaces are basically a wrapper for
DDI functions which on the one hand abstract away HCA device specific
details at the ULP level, but at the same time allow for the HCA
driver to adjust the memory attributes (alignment, etc.) as necessary
for efficiency.
These additions include an IBTF ABI change, so this case also marks an
internal flag day, incrementing our interface version numbers for both
the TI and CI as noted below.
All interface additions and changes in this proposal have a
micro/patch binding.
Transport Interface (ON Consolidation Private):
ibt_alloc_io_mem() - Allocates DMA memory (at the transport level)
ibt_free_io_mem() - Deallocates DMA memory
IBTI_V3 - TI version change
Channel Interface (ON Consolidation Private):
ibc_alloc_io_mem() - Allocates DMA memory (at the HCA driver level)
ibc_free_io_mem() - Deallocates DMA memory
IBCI_V3 - CI version change
C. Summary of Changes by man page
See materials directory for copies of man pages. Modified man pages
have change bars in the left margin.
ibci.9 - modfied (new CI entry points added)
ibc_alloc_io_mem.9e - new (alloc & free CI entry points)
ibt_alloc_io_mem.9f - new (alloc & free TI functions)
ibt_clnt_modinfo_t.9s - modified (IBTI_V3 version)
ibc_hca_info_t.9s - modified (IBCI_V3 version)
ibc_operations_t.9s - modified (new CI entry points added)
6. Resources and Schedule
6.4. Steering Committee requested information
6.4.1. Consolidation C-team Name:
ON
6.5. ARC review type: FastTrack
6.6. ARC Exposure: open
