Re: [dpdk-dev] [PATCH v2 01/13] drivers: introduce mlx5 vDPA driver

[Maxime Coquelin <maxime.coquelin@redhat.com>]

On 1/29/20 11:08 AM, Matan Azrad wrote:
> Add a new driver to support vDPA operations by Mellanox devices.
> 
> The first Mellanox devices which support vDPA operations are
> ConnectX6DX and Bluefield1 HCA for their PF ports and VF ports.
> 
> This driver is depending on rdma-core like the mlx5 PMD, also it is
> going to use mlx5 DevX to create HW objects directly by the FW.
> Hence, the common/mlx5 library is linked to the mlx5_vdpa driver.

If possible, I would really appreciate to have the information on
the versions required for the above dependencies. Better if it is also
mentionned in the guide.

> This driver will not be compiled by default due to the above
> dependencies.
> 
> Register a new log type for this driver.
> 
> Signed-off-by: Matan Azrad <matan@mellanox.com>
> Acked-by: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
> ---
>  MAINTAINERS                                     |   7 +
>  config/common_base                              |   5 +
>  doc/guides/rel_notes/release_20_02.rst          |   5 +
>  doc/guides/vdpadevs/features/mlx5.ini           |  14 ++
>  doc/guides/vdpadevs/index.rst                   |   1 +
>  doc/guides/vdpadevs/mlx5.rst                    | 111 ++++++++++++
>  drivers/common/Makefile                         |   2 +-
>  drivers/common/mlx5/Makefile                    |  17 +-
>  drivers/meson.build                             |   8 +-
>  drivers/vdpa/Makefile                           |   2 +
>  drivers/vdpa/meson.build                        |   3 +-
>  drivers/vdpa/mlx5/Makefile                      |  36 ++++
>  drivers/vdpa/mlx5/meson.build                   |  29 +++
>  drivers/vdpa/mlx5/mlx5_vdpa.c                   | 227 ++++++++++++++++++++++++
>  drivers/vdpa/mlx5/mlx5_vdpa_utils.h             |  20 +++
>  drivers/vdpa/mlx5/rte_pmd_mlx5_vdpa_version.map |   3 +
>  mk/rte.app.mk                                   |  15 +-
>  17 files changed, 488 insertions(+), 17 deletions(-)
>  create mode 100644 doc/guides/vdpadevs/features/mlx5.ini
>  create mode 100644 doc/guides/vdpadevs/mlx5.rst
>  create mode 100644 drivers/vdpa/mlx5/Makefile
>  create mode 100644 drivers/vdpa/mlx5/meson.build
>  create mode 100644 drivers/vdpa/mlx5/mlx5_vdpa.c
>  create mode 100644 drivers/vdpa/mlx5/mlx5_vdpa_utils.h
>  create mode 100644 drivers/vdpa/mlx5/rte_pmd_mlx5_vdpa_version.map
> 
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 150d507..f697e9a 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -1103,6 +1103,13 @@ F: drivers/vdpa/ifc/
>  F: doc/guides/vdpadevs/ifc.rst
>  F: doc/guides/vdpadevs/features/ifcvf.ini
>  
> +Mellanox mlx5 vDPA
> +M: Matan Azrad <matan@mellanox.com>
> +M: Viacheslav Ovsiienko <viacheslavo@mellanox.com>
> +F: drivers/vdpa/mlx5/
> +F: doc/guides/vdpadevs/mlx5.rst
> +F: doc/guides/vdpadevs/features/mlx5.ini
> +
>  
>  Eventdev Drivers
>  ----------------
> diff --git a/config/common_base b/config/common_base
> index c897dd0..6ea9c63 100644
> --- a/config/common_base
> +++ b/config/common_base
> @@ -366,6 +366,11 @@ CONFIG_RTE_LIBRTE_MLX4_DEBUG=n
>  CONFIG_RTE_LIBRTE_MLX5_PMD=n
>  CONFIG_RTE_LIBRTE_MLX5_DEBUG=n
>  
> +#
> +# Compile vdpa-oriented Mellanox ConnectX-6 & Bluefield (MLX5) PMD
> +#
> +CONFIG_RTE_LIBRTE_MLX5_VDPA_PMD=n
> +
>  # Linking method for mlx4/5 dependency on ibverbs and related libraries
>  # Default linking is dynamic by linker.
>  # Other options are: dynamic by dlopen at run-time, or statically embedded.
> diff --git a/doc/guides/rel_notes/release_20_02.rst b/doc/guides/rel_notes/release_20_02.rst
> index 50e2c14..690e7db 100644
> --- a/doc/guides/rel_notes/release_20_02.rst
> +++ b/doc/guides/rel_notes/release_20_02.rst
> @@ -113,6 +113,11 @@ New Features
>    * Added support for RSS using L3/L4 source/destination only.
>    * Added support for matching on GTP tunnel header item.
>  
> +* **Add new vDPA PMD based on Mellanox devices**
> +
> +  Added a new Mellanox vDPA  (``mlx5_vdpa``) PMD.
> +  See the :doc:`../vdpadevs/mlx5` guide for more details on this driver.
> +
>  * **Updated testpmd application.**
>  
>    Added support for ESP and L2TPv3 over IP rte_flow patterns to the testpmd
> diff --git a/doc/guides/vdpadevs/features/mlx5.ini b/doc/guides/vdpadevs/features/mlx5.ini
> new file mode 100644
> index 0000000..d635bdf
> --- /dev/null
> +++ b/doc/guides/vdpadevs/features/mlx5.ini
> @@ -0,0 +1,14 @@
> +;
> +; Supported features of the 'mlx5' VDPA driver.
> +;
> +; Refer to default.ini for the full list of available driver features.
> +;
> +[Features]
> +Other kdrv           = Y
> +ARMv8                = Y
> +Power8               = Y
> +x86-32               = Y
> +x86-64               = Y
> +Usage doc            = Y
> +Design doc           = Y
> +
> diff --git a/doc/guides/vdpadevs/index.rst b/doc/guides/vdpadevs/index.rst
> index 9657108..1a13efe 100644
> --- a/doc/guides/vdpadevs/index.rst
> +++ b/doc/guides/vdpadevs/index.rst
> @@ -13,3 +13,4 @@ which can be used from an application through vhost API.
>  
>      features_overview
>      ifc
> +    mlx5
> diff --git a/doc/guides/vdpadevs/mlx5.rst b/doc/guides/vdpadevs/mlx5.rst
> new file mode 100644
> index 0000000..1861e71
> --- /dev/null
> +++ b/doc/guides/vdpadevs/mlx5.rst
> @@ -0,0 +1,111 @@
> +..  SPDX-License-Identifier: BSD-3-Clause
> +    Copyright 2019 Mellanox Technologies, Ltd
> +
> +MLX5 vDPA driver
> +================
> +
> +The MLX5 vDPA (vhost data path acceleration) driver library
> +(**librte_pmd_mlx5_vdpa**) provides support for **Mellanox ConnectX-6**,
> +**Mellanox ConnectX-6DX** 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(R) ConnectX(R)-6 200G MCX654106A-HCAT (4x200G)
> +* Mellanox(R) ConnectX(R)-6DX EN 100G MCX623106AN-CDAT (2*100G)
> +* Mellanox(R) ConnectX(R)-6DX EN 200G MCX623105AN-VDAT (1*200G)
> +* Mellanox(R) BlueField SmartNIC 25G MBF1M332A-ASCAT (2*25G)
> +
> +Prerequisites
> +-------------
> +
> +- Mellanox OFED version: **4.7**
> +  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.
> +
> diff --git a/drivers/common/Makefile b/drivers/common/Makefile
> index 4775d4b..96bd7ac 100644
> --- a/drivers/common/Makefile
> +++ b/drivers/common/Makefile
> @@ -35,7 +35,7 @@ ifneq (,$(findstring y,$(IAVF-y)))
>  DIRS-y += iavf
>  endif
>  
> -ifeq ($(CONFIG_RTE_LIBRTE_MLX5_PMD),y)
> +ifeq ($(findstring y,$(CONFIG_RTE_LIBRTE_MLX5_PMD)$(CONFIG_RTE_LIBRTE_MLX5_VDPA_PMD)),y)
>  DIRS-y += mlx5
>  endif
>  
> diff --git a/drivers/common/mlx5/Makefile b/drivers/common/mlx5/Makefile
> index 9d4d81f..c4b7999 100644
> --- a/drivers/common/mlx5/Makefile
> +++ b/drivers/common/mlx5/Makefile
> @@ -10,15 +10,16 @@ LIB_GLUE_BASE = librte_pmd_mlx5_glue.so
>  LIB_GLUE_VERSION = 20.02.0
>  
>  # Sources.
> +ifeq ($(findstring y,$(CONFIG_RTE_LIBRTE_MLX5_PMD)$(CONFIG_RTE_LIBRTE_MLX5_VDPA_PMD)),y)
>  ifneq ($(CONFIG_RTE_IBVERBS_LINK_DLOPEN),y)
> -SRCS-$(CONFIG_RTE_LIBRTE_MLX5_PMD) += mlx5_glue.c
> +SRCS-y += mlx5_glue.c
>  endif
> -SRCS-$(CONFIG_RTE_LIBRTE_MLX5_PMD) += mlx5_devx_cmds.c
> -SRCS-$(CONFIG_RTE_LIBRTE_MLX5_PMD) += mlx5_common.c
> -SRCS-$(CONFIG_RTE_LIBRTE_MLX5_PMD) += mlx5_nl.c
> -
> +SRCS-y += mlx5_devx_cmds.c
> +SRCS-y += mlx5_common.c
> +SRCS-y += mlx5_nl.c
>  ifeq ($(CONFIG_RTE_IBVERBS_LINK_DLOPEN),y)
> -INSTALL-$(CONFIG_RTE_LIBRTE_MLX5_PMD)-lib += $(LIB_GLUE)
> +INSTALL-y-lib += $(LIB_GLUE)
> +endif
>  endif
>  
>  # Basic CFLAGS.
> @@ -317,7 +318,9 @@ mlx5_autoconf.h: mlx5_autoconf.h.new
>  		cmp '$<' '$@' $(AUTOCONF_OUTPUT) || \
>  		mv '$<' '$@'
>  
> -$(SRCS-$(CONFIG_RTE_LIBRTE_MLX5_PMD):.c=.o): mlx5_autoconf.h
> +ifeq ($(findstring y,$(CONFIG_RTE_LIBRTE_MLX5_PMD)$(CONFIG_RTE_LIBRTE_MLX5_VDPA_PMD)),y)
> +$(SRCS-y:.c=.o): mlx5_autoconf.h
> +endif
>  
>  # Generate dependency plug-in for rdma-core when the PMD must not be linked
>  # directly, so that applications do not inherit this dependency.
> diff --git a/drivers/meson.build b/drivers/meson.build
> index 29708cc..bd154fa 100644
> --- a/drivers/meson.build
> +++ b/drivers/meson.build
> @@ -42,6 +42,7 @@ foreach class:dpdk_driver_classes
>  		build = true # set to false to disable, e.g. missing deps
>  		reason = '<unknown reason>' # set if build == false to explain
>  		name = drv
> +		fmt_name = ''
>  		allow_experimental_apis = false
>  		sources = []
>  		objs = []
> @@ -98,8 +99,11 @@ foreach class:dpdk_driver_classes
>  		else
>  			class_drivers += name
>  
> -			dpdk_conf.set(config_flag_fmt.format(name.to_upper()),1)
> -			lib_name = driver_name_fmt.format(name)
> +			if fmt_name == ''
> +				fmt_name = name
> +			endif
> +			dpdk_conf.set(config_flag_fmt.format(fmt_name.to_upper()),1)
> +			lib_name = driver_name_fmt.format(fmt_name)
>  
>  			if allow_experimental_apis
>  				cflags += '-DALLOW_EXPERIMENTAL_API'
> diff --git a/drivers/vdpa/Makefile b/drivers/vdpa/Makefile
> index b5a7a11..6e88359 100644
> --- a/drivers/vdpa/Makefile
> +++ b/drivers/vdpa/Makefile
> @@ -7,4 +7,6 @@ ifeq ($(CONFIG_RTE_EAL_VFIO),y)
>  DIRS-$(CONFIG_RTE_LIBRTE_IFC_PMD) += ifc
>  endif
>  
> +DIRS-$(CONFIG_RTE_LIBRTE_MLX5_VDPA_PMD) += mlx5
> +
>  include $(RTE_SDK)/mk/rte.subdir.mk
> diff --git a/drivers/vdpa/meson.build b/drivers/vdpa/meson.build
> index 2f047b5..e3ed54a 100644
> --- a/drivers/vdpa/meson.build
> +++ b/drivers/vdpa/meson.build
> @@ -1,7 +1,8 @@
>  # SPDX-License-Identifier: BSD-3-Clause
>  # Copyright 2019 Mellanox Technologies, Ltd
>  
> -drivers = ['ifc']
> +drivers = ['ifc',
> +	   'mlx5',]
>  std_deps = ['bus_pci', 'kvargs']
>  std_deps += ['vhost']
>  config_flag_fmt = 'RTE_LIBRTE_@0@_PMD'
> diff --git a/drivers/vdpa/mlx5/Makefile b/drivers/vdpa/mlx5/Makefile
> new file mode 100644
> index 0000000..c1c8cc0
> --- /dev/null
> +++ b/drivers/vdpa/mlx5/Makefile
> @@ -0,0 +1,36 @@
> +#   SPDX-License-Identifier: BSD-3-Clause
> +#   Copyright 2019 Mellanox Technologies, Ltd
> +
> +include $(RTE_SDK)/mk/rte.vars.mk
> +
> +# Library name.
> +LIB = librte_pmd_mlx5_vdpa.a
> +
> +# Sources.
> +SRCS-$(CONFIG_RTE_LIBRTE_MLX5_VDPA_PMD) += mlx5_vdpa.c
> +
> +# Basic CFLAGS.
> +CFLAGS += -O3
> +CFLAGS += -std=c11 -Wall -Wextra
> +CFLAGS += -g
> +CFLAGS += -I$(RTE_SDK)/drivers/common/mlx5
> +CFLAGS += -I$(RTE_SDK)/drivers/net/mlx5_vdpa
> +CFLAGS += -I$(BUILDDIR)/drivers/common/mlx5
> +CFLAGS += -D_BSD_SOURCE
> +CFLAGS += -D_DEFAULT_SOURCE
> +CFLAGS += -D_XOPEN_SOURCE=600
> +CFLAGS += $(WERROR_FLAGS)
> +CFLAGS += -Wno-strict-prototypes
> +LDLIBS += -lrte_common_mlx5
> +LDLIBS += -lrte_eal -lrte_vhost -lrte_kvargs -lrte_bus_pci
> +
> +# A few warnings cannot be avoided in external headers.
> +CFLAGS += -Wno-error=cast-qual
> +
> +EXPORT_MAP := rte_pmd_mlx5_vdpa_version.map
> +# memseg walk is not part of stable API
> +CFLAGS += -DALLOW_EXPERIMENTAL_API
> +
> +CFLAGS += -DNDEBUG -UPEDANTIC
> +
> +include $(RTE_SDK)/mk/rte.lib.mk
> diff --git a/drivers/vdpa/mlx5/meson.build b/drivers/vdpa/mlx5/meson.build
> new file mode 100644
> index 0000000..4bca6ea
> --- /dev/null
> +++ b/drivers/vdpa/mlx5/meson.build
> @@ -0,0 +1,29 @@
> +# SPDX-License-Identifier: BSD-3-Clause
> +# Copyright 2019 Mellanox Technologies, Ltd
> +
> +if not is_linux
> +	build = false
> +	reason = 'only supported on Linux'
> +	subdir_done()
> +endif
> +
> +fmt_name = 'mlx5_vdpa'
> +allow_experimental_apis = true
> +deps += ['hash', 'common_mlx5', 'vhost', 'bus_pci', 'eal']
> +sources = files(
> +	'mlx5_vdpa.c',
> +)
> +cflags_options = [
> +	'-std=c11',
> +	'-Wno-strict-prototypes',
> +	'-D_BSD_SOURCE',
> +	'-D_DEFAULT_SOURCE',
> +	'-D_XOPEN_SOURCE=600'
> +]
> +foreach option:cflags_options
> +	if cc.has_argument(option)
> +		cflags += option
> +	endif
> +endforeach
> +
> +cflags += [ '-DNDEBUG', '-UPEDANTIC' ]
> diff --git a/drivers/vdpa/mlx5/mlx5_vdpa.c b/drivers/vdpa/mlx5/mlx5_vdpa.c
> new file mode 100644
> index 0000000..6286d7a
> --- /dev/null
> +++ b/drivers/vdpa/mlx5/mlx5_vdpa.c
> @@ -0,0 +1,227 @@
> +/* SPDX-License-Identifier: BSD-3-Clause
> + * Copyright 2019 Mellanox Technologies, Ltd
> + */
> +#include <rte_malloc.h>
> +#include <rte_log.h>
> +#include <rte_errno.h>
> +#include <rte_bus_pci.h>
> +#include <rte_vdpa.h>
> +
> +#include <mlx5_glue.h>
> +#include <mlx5_common.h>
> +
> +#include "mlx5_vdpa_utils.h"
> +
> +
> +struct mlx5_vdpa_priv {
> +	TAILQ_ENTRY(mlx5_vdpa_priv) next;
> +	int id; /* vDPA device id. */
> +	struct ibv_context *ctx; /* Device context. */
> +	struct rte_vdpa_dev_addr dev_addr;
> +};
> +
> +TAILQ_HEAD(mlx5_vdpa_privs, mlx5_vdpa_priv) priv_list =
> +					      TAILQ_HEAD_INITIALIZER(priv_list);
> +static pthread_mutex_t priv_list_lock = PTHREAD_MUTEX_INITIALIZER;
> +int mlx5_vdpa_logtype;
> +
> +static struct rte_vdpa_dev_ops mlx5_vdpa_ops = {
> +	.get_queue_num = NULL,
> +	.get_features = NULL,
> +	.get_protocol_features = NULL,
> +	.dev_conf = NULL,
> +	.dev_close = NULL,
> +	.set_vring_state = NULL,
> +	.set_features = NULL,
> +	.migration_done = NULL,
> +	.get_vfio_group_fd = NULL,
> +	.get_vfio_device_fd = NULL,
> +	.get_notify_area = NULL,
> +};
> +
> +/**
> + * DPDK callback to register a PCI device.
> + *
> + * This function spawns vdpa device out of a given PCI device.
> + *
> + * @param[in] pci_drv
> + *   PCI driver structure (mlx5_vpda_driver).
> + * @param[in] pci_dev
> + *   PCI device information.
> + *
> + * @return
> + *   0 on success, a negative errno value otherwise and rte_errno is set.
> + */
> +static int
> +mlx5_vdpa_pci_probe(struct rte_pci_driver *pci_drv __rte_unused,
> +		    struct rte_pci_device *pci_dev __rte_unused)
> +{
> +	struct ibv_device **ibv_list;
> +	struct ibv_device *ibv_match = NULL;
> +	struct mlx5_vdpa_priv *priv = NULL;
> +	struct ibv_context *ctx = NULL;
> +	int ret;
> +
> +	if (mlx5_class_get(pci_dev->device.devargs) != MLX5_CLASS_VDPA) {
> +		DRV_LOG(DEBUG, "Skip probing - should be probed by other mlx5"
> +			" driver.");
> +		return 1;

Maybe the function doc should be implemented for return 1 case:

* @return
*   0 on success, a negative errno value otherwise and rte_errno is set.

> +	}
> +	errno = 0;
> +	ibv_list = mlx5_glue->get_device_list(&ret);
> +	if (!ibv_list) {
> +		rte_errno = errno;
> +		DRV_LOG(ERR, "Failed to get device list, is ib_uverbs loaded?");
> +		return -ENOSYS;

Shouldn't return -rte_errno to be consistent with the rest of the
function?

For the sake of consistency, you could also goto error instead.

> +	}
> +	while (ret-- > 0) {
> +		struct rte_pci_addr pci_addr;
> +
> +		DRV_LOG(DEBUG, "Checking device \"%s\"..", ibv_list[ret]->name);
> +		if (mlx5_dev_to_pci_addr(ibv_list[ret]->ibdev_path, &pci_addr))
> +			continue;
> +		if (pci_dev->addr.domain != pci_addr.domain ||
> +		    pci_dev->addr.bus != pci_addr.bus ||
> +		    pci_dev->addr.devid != pci_addr.devid ||
> +		    pci_dev->addr.function != pci_addr.function)
> +			continue;
> +		DRV_LOG(INFO, "PCI information matches for device \"%s\".",
> +			ibv_list[ret]->name);
> +		ibv_match = ibv_list[ret];
> +		break;
> +	}
> +	mlx5_glue->free_device_list(ibv_list);
> +	if (!ibv_match) {
> +		DRV_LOG(ERR, "No matching IB device for PCI slot "
> +			"%" SCNx32 ":%" SCNx8 ":%" SCNx8 ".%" SCNx8 ".",
> +			pci_dev->addr.domain, pci_dev->addr.bus,
> +			pci_dev->addr.devid, pci_dev->addr.function);
> +		rte_errno = ENOENT;
> +		return -rte_errno;
> +	}
> +	ctx = mlx5_glue->dv_open_device(ibv_match);
> +	if (!ctx) {
> +		DRV_LOG(ERR, "Failed to open IB device \"%s\".",
> +			ibv_match->name);
> +		rte_errno = ENODEV;
> +		return -rte_errno;
> +	}
> +	priv = rte_zmalloc("mlx5 vDPA device private", sizeof(*priv),
> +			   RTE_CACHE_LINE_SIZE);
> +	if (!priv) {
> +		DRV_LOG(ERR, "Failed to allocate private memory.");
> +		rte_errno = ENOMEM;
> +		goto error;
> +	}
> +	priv->ctx = ctx;
> +	priv->dev_addr.pci_addr = pci_dev->addr;
> +	priv->dev_addr.type = PCI_ADDR;
> +	priv->id = rte_vdpa_register_device(&priv->dev_addr, &mlx5_vdpa_ops);
> +	if (priv->id < 0) {
> +		DRV_LOG(ERR, "Failed to register vDPA device.");
> +		rte_errno = rte_errno ? rte_errno : EINVAL;
> +		goto error;
> +	}
> +	pthread_mutex_lock(&priv_list_lock);
> +	TAILQ_INSERT_TAIL(&priv_list, priv, next);
> +	pthread_mutex_unlock(&priv_list_lock);
> +	return 0;
> +
> +error:
> +	if (priv)
> +		rte_free(priv);
> +	if (ctx)
> +		mlx5_glue->close_device(ctx);
> +	return -rte_errno;
> +}
> +

These are minor comments.
If directly fixed in v3, feel free to add my:
Reviewed-by: Maxime Coquelin <maxime.coquelin@redhat.com>

Thanks,
Maxime