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authorDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:45:59 +0000
committerDaniel Baumann <daniel.baumann@progress-linux.org>2024-04-07 18:45:59 +0000
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Adding upstream version 16.2.11+ds.upstream/16.2.11+dsupstream
Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>
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+.. SPDX-License-Identifier: BSD-3-Clause
+ Copyright 2019 Mellanox Technologies, Ltd
+
+.. include:: <isonum.txt>
+
+MLX5 vDPA driver
+================
+
+The MLX5 vDPA (vhost data path acceleration) driver library
+(**librte_pmd_mlx5_vdpa**) provides support for **Mellanox ConnectX-6**,
+**Mellanox ConnectX-6 Dx** and **Mellanox BlueField** families of
+10/25/40/50/100/200 Gb/s adapters as well as their virtual functions (VF) in
+SR-IOV context.
+
+.. note::
+
+ Due to external dependencies, this driver is disabled in default
+ configuration of the "make" build. It can be enabled with
+ ``CONFIG_RTE_LIBRTE_MLX5_VDPA_PMD=y`` or by using "meson" build system which
+ will detect dependencies.
+
+
+Design
+------
+
+For security reasons and robustness, this driver only deals with virtual
+memory addresses. The way resources allocations are handled by the kernel,
+combined with hardware specifications that allow to handle virtual memory
+addresses directly, ensure that DPDK applications cannot access random
+physical memory (or memory that does not belong to the current process).
+
+The PMD can use libibverbs and libmlx5 to access the device firmware
+or directly the hardware components.
+There are different levels of objects and bypassing abilities
+to get the best performances:
+
+- Verbs is a complete high-level generic API
+- Direct Verbs is a device-specific API
+- DevX allows to access firmware objects
+- Direct Rules manages flow steering at low-level hardware layer
+
+Enabling librte_pmd_mlx5_vdpa causes DPDK applications to be linked against
+libibverbs.
+
+A Mellanox mlx5 PCI device can be probed by either net/mlx5 driver or vdpa/mlx5
+driver but not in parallel. Hence, the user should decide the driver by the
+``class`` parameter in the device argument list.
+By default, the mlx5 device will be probed by the net/mlx5 driver.
+
+Supported NICs
+--------------
+
+* Mellanox\ |reg| ConnectX\ |reg|-6 200G MCX654106A-HCAT (2x200G)
+* Mellanox\ |reg| ConnectX\ |reg|-6 Dx EN 100G MCX623106AN-CDAT (2x100G)
+* Mellanox\ |reg| ConnectX\ |reg|-6 Dx EN 200G MCX623105AN-VDAT (1x200G)
+* Mellanox\ |reg| BlueField SmartNIC 25G MBF1M332A-ASCAT (2x25G)
+
+Prerequisites
+-------------
+
+- Mellanox OFED version: **5.0**
+ see :doc:`../../nics/mlx5` guide for more Mellanox OFED details.
+
+Compilation options
+~~~~~~~~~~~~~~~~~~~
+
+These options can be modified in the ``.config`` file.
+
+- ``CONFIG_RTE_LIBRTE_MLX5_VDPA_PMD`` (default **n**)
+
+ Toggle compilation of librte_pmd_mlx5 itself.
+
+- ``CONFIG_RTE_IBVERBS_LINK_DLOPEN`` (default **n**)
+
+ Build PMD with additional code to make it loadable without hard
+ dependencies on **libibverbs** nor **libmlx5**, which may not be installed
+ on the target system.
+
+ In this mode, their presence is still required for it to run properly,
+ however their absence won't prevent a DPDK application from starting (with
+ ``CONFIG_RTE_BUILD_SHARED_LIB`` disabled) and they won't show up as
+ missing with ``ldd(1)``.
+
+ It works by moving these dependencies to a purpose-built rdma-core "glue"
+ plug-in which must either be installed in a directory whose name is based
+ on ``CONFIG_RTE_EAL_PMD_PATH`` suffixed with ``-glue`` if set, or in a
+ standard location for the dynamic linker (e.g. ``/lib``) if left to the
+ default empty string (``""``).
+
+ This option has no performance impact.
+
+- ``CONFIG_RTE_IBVERBS_LINK_STATIC`` (default **n**)
+
+ Embed static flavor of the dependencies **libibverbs** and **libmlx5**
+ in the PMD shared library or the executable static binary.
+
+.. note::
+
+ For BlueField, target should be set to ``arm64-bluefield-linux-gcc``. This
+ will enable ``CONFIG_RTE_LIBRTE_MLX5_VDPA_PMD`` and set
+ ``RTE_CACHE_LINE_SIZE`` to 64. Default armv8a configuration of make build and
+ meson build set it to 128 then brings performance degradation.
+
+Run-time configuration
+~~~~~~~~~~~~~~~~~~~~~~
+
+- **ethtool** operations on related kernel interfaces also affect the PMD.
+
+- ``class`` parameter [string]
+
+ Select the class of the driver that should probe the device.
+ `vdpa` for the mlx5 vDPA driver.
+