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

[Matan Azrad <matan@mellanox.com>]

Hi Maxime

Thank you very much for the review.

Please see answers inline.

From: Maxime Coquelin
> 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.
> 

It is already 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.
> 

Sure, will fix it.

> > +	}
> > +	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.

Ok, will save consistency.

> 
> > +	}
> > +	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