1 .. SPDX-License-Identifier: BSD-3-Clause
2 Copyright 2019 Mellanox Technologies, Ltd
4 .. include:: <isonum.txt>
9 The MLX5 vDPA (vhost data path acceleration) driver library
10 (**librte_vdpa_mlx5**) provides support for **Mellanox ConnectX-6**,
11 **Mellanox ConnectX-6 Dx** and **Mellanox BlueField** families of
12 10/25/40/50/100/200 Gb/s adapters as well as their virtual functions (VF) in
17 This driver is enabled automatically when using "meson" build system which
18 will detect dependencies.
24 For security reasons and robustness, this driver only deals with virtual
25 memory addresses. The way resources allocations are handled by the kernel,
26 combined with hardware specifications that allow to handle virtual memory
27 addresses directly, ensure that DPDK applications cannot access random
28 physical memory (or memory that does not belong to the current process).
30 The PMD can use libibverbs and libmlx5 to access the device firmware
31 or directly the hardware components.
32 There are different levels of objects and bypassing abilities
33 to get the best performances:
35 - Verbs is a complete high-level generic API
36 - Direct Verbs is a device-specific API
37 - DevX allows to access firmware objects
38 - Direct Rules manages flow steering at low-level hardware layer
40 Enabling librte_vdpa_mlx5 causes DPDK applications to be linked against
43 A Mellanox mlx5 PCI device can be probed by either net/mlx5 driver or vdpa/mlx5
44 driver but not in parallel. Hence, the user should decide the driver by the
45 ``class`` parameter in the device argument list.
46 By default, the mlx5 device will be probed by the net/mlx5 driver.
51 * Mellanox\ |reg| ConnectX\ |reg|-6 200G MCX654106A-HCAT (2x200G)
52 * Mellanox\ |reg| ConnectX\ |reg|-6 Dx EN 25G MCX621102AN-ADAT (2x25G)
53 * Mellanox\ |reg| ConnectX\ |reg|-6 Dx EN 100G MCX623106AN-CDAT (2x100G)
54 * Mellanox\ |reg| ConnectX\ |reg|-6 Dx EN 200G MCX623105AN-VDAT (1x200G)
55 * Mellanox\ |reg| BlueField SmartNIC 25G MBF1M332A-ASCAT (2x25G)
60 - Mellanox OFED version: **5.0**
61 see :doc:`../../nics/mlx5` guide for more Mellanox OFED details.
66 The meson option ``ibverbs_link`` is **shared** by default,
67 but can be configured to have the following values:
71 Build PMD with additional code to make it loadable without hard
72 dependencies on **libibverbs** nor **libmlx5**, which may not be installed
75 In this mode, their presence is still required for it to run properly,
76 however their absence won't prevent a DPDK application from starting (with
77 DPDK shared build disabled) and they won't show up as missing with ``ldd(1)``.
79 It works by moving these dependencies to a purpose-built rdma-core "glue"
80 plug-in which must be installed in a directory whose name is based
81 on ``RTE_EAL_PMD_PATH`` suffixed with ``-glue``.
83 This option has no performance impact.
87 Embed static flavor of the dependencies **libibverbs** and **libmlx5**
88 in the PMD shared library or the executable static binary.
92 Default armv8a configuration of meson build sets ``RTE_CACHE_LINE_SIZE``
93 to 128 then brings performance degradation.
95 Run-time configuration
96 ~~~~~~~~~~~~~~~~~~~~~~
98 - **ethtool** operations on related kernel interfaces also affect the PMD.
103 - ``class`` parameter [string]
105 Select the class of the driver that should probe the device.
106 `vdpa` for the mlx5 vDPA driver.
108 - ``event_mode`` parameter [int]
110 - 0, Completion queue scheduling will be managed by a timer thread which
111 automatically adjusts its delays to the coming traffic rate.
113 - 1, Completion queue scheduling will be managed by a timer thread with fixed
116 - 2, Completion queue scheduling will be managed by interrupts. Each CQ burst
117 arms the CQ in order to get an interrupt event in the next traffic burst.
121 - ``event_us`` parameter [int]
123 Per mode micro-seconds parameter - relevant only for event mode 0 and 1:
125 - 0, A nonzero value to set timer step in micro-seconds. The timer thread
126 dynamic delay change steps according to this value. Default value is 1us.
128 - 1, A nonzero value to set fixed timer delay in micro-seconds. Default value
131 - ``no_traffic_time`` parameter [int]
133 A nonzero value defines the traffic off time, in seconds, that moves the
134 driver to no-traffic mode. In this mode the timer events are stopped and
135 interrupts are configured to the device in order to notify traffic for the
136 driver. Default value is 2s.