From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 0E74EA04A4 for ; Wed, 2 Mar 2022 18:24:29 +0100 (CET) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 7A75F4277B; Wed, 2 Mar 2022 18:24:25 +0100 (CET) Received: from mga06.intel.com (mga06.intel.com [134.134.136.31]) by mails.dpdk.org (Postfix) with ESMTP id 002D84275B; Wed, 2 Mar 2022 18:24:22 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1646241863; x=1677777863; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=k065+2O+3oN0bZwLP1KzaeYRA3FLtfZgUoswBzpOpI4=; b=Oone0fVIDlU7cfxike6JGisqgWEc2MiAK3mmEgwuT8t2yvtiWXbJJ+p3 2xle5OT7jobRMxK4RUMUU1GDk9wXGAfHQepzJ6S4v+Hv+np6HcMbHbK8a MTQelC89cCTX1o0CIilKFiuFgFTbTNNMCy1WsO536LHpaDJLvGjm9PqCh gewEXvAvzQKIyt3WPOC5uYh+0r8SMIM3jxldoyEwDOMry0yRGF6QbKWot LjqfU5WxEVO9juCm7FAbB0O9yVGYcLdxLHDAMTDwsXYZXjRx1vnLKzGuv FonE9PheylcC307VwzzQU6fI2LDQSZ37LaTHXR4V2guGKcddVydmgkd4M w==; X-IronPort-AV: E=McAfee;i="6200,9189,10274"; a="314177971" X-IronPort-AV: E=Sophos;i="5.90,149,1643702400"; d="scan'208";a="314177971" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 02 Mar 2022 09:24:19 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.90,149,1643702400"; d="scan'208";a="551348163" Received: from silpixa00399126.ir.intel.com ([10.237.223.34]) by orsmga008.jf.intel.com with ESMTP; 02 Mar 2022 09:24:18 -0800 From: Bruce Richardson To: dev@dpdk.org Cc: stable@dpdk.org, Bruce Richardson Subject: [PATCH 8/9] doc/linux_gsg: consolidate all VFIO content Date: Wed, 2 Mar 2022 17:22:16 +0000 Message-Id: <20220302172217.472279-9-bruce.richardson@intel.com> X-Mailer: git-send-email 2.32.0 In-Reply-To: <20220302172217.472279-1-bruce.richardson@intel.com> References: <20220302172217.472279-1-bruce.richardson@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-BeenThere: stable@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: patches for DPDK stable branches List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: stable-bounces@dpdk.org Rather than having separate sections for VFIO and VFIO no-iommu mode, as well as a separate section further down the document on troubleshooting VFIO, we can consolidate all these as subsections into a primary VFIO section. This section starts with the basics of VFIO use, then covers no-iommu mode, before moving on to the more advanced topics such as creating VFs and ending with the troubleshooting subsection. Signed-off-by: Bruce Richardson --- doc/guides/linux_gsg/linux_drivers.rst | 116 ++++++++++++------------- 1 file changed, 58 insertions(+), 58 deletions(-) diff --git a/doc/guides/linux_gsg/linux_drivers.rst b/doc/guides/linux_gsg/linux_drivers.rst index b2be442d27..ef91999dd9 100644 --- a/doc/guides/linux_gsg/linux_drivers.rst +++ b/doc/guides/linux_gsg/linux_drivers.rst @@ -135,6 +135,38 @@ For proper operation of VFIO when running DPDK applications as a non-privileged For more information, please refer to :ref:`Running_Without_Root_Privileges`. +.. _vfio_noiommu: + +VFIO no-IOMMU mode +~~~~~~~~~~~~~~~~~~ + +If there is no IOMMU available on the system, VFIO can still be used, +but it has to be loaded with an additional module parameter: + +.. code-block:: console + + modprobe vfio enable_unsafe_noiommu_mode=1 + +Alternatively, one can also enable this option in an already loaded kernel module: + +.. code-block:: console + + echo 1 > /sys/module/vfio/parameters/enable_unsafe_noiommu_mode + +After that, VFIO can be used with hardware devices as usual. + +.. note:: + + It may be required to unload all VFIO related-modules before probing + the module again with ``enable_unsafe_noiommu_mode=1`` parameter. + +.. warning:: + + Since no-IOMMU mode forgoes IOMMU protection, it is inherently unsafe. + That said, it does make it possible for the user + to keep the degree of device access and programming that VFIO has, + in situations where IOMMU is not available. + VFIO Memory Mapping Limits ~~~~~~~~~~~~~~~~~~~~~~~~~~~ @@ -218,65 +250,8 @@ The token will be used for all PF and VF ports within the application. Linux versions earlier than version 5.7 do not support the creation of virtual functions within the VFIO framework. -.. _vfio_noiommu: - -VFIO no-IOMMU mode ------------------- - -If there is no IOMMU available on the system, VFIO can still be used, -but it has to be loaded with an additional module parameter: - -.. code-block:: console - - modprobe vfio enable_unsafe_noiommu_mode=1 - -Alternatively, one can also enable this option in an already loaded kernel module: - -.. code-block:: console - - echo 1 > /sys/module/vfio/parameters/enable_unsafe_noiommu_mode - -After that, VFIO can be used with hardware devices as usual. - -.. note:: - - It may be required to unload all VFIO related-modules before probing - the module again with ``enable_unsafe_noiommu_mode=1`` parameter. - -.. warning:: - - Since no-IOMMU mode forgoes IOMMU protection, it is inherently unsafe. - That said, it does make it possible for the user - to keep the degree of device access and programming that VFIO has, - in situations where IOMMU is not available. - -.. _bifurcated_driver: - -Bifurcated Driver ------------------ - -PMDs which use the bifurcated driver co-exists with the device kernel driver. -On such model the NIC is controlled by the kernel, while the data -path is performed by the PMD directly on top of the device. - -Such model has the following benefits: - - - It is secure and robust, as the memory management and isolation - is done by the kernel. - - It enables the user to use legacy linux tools such as ``ethtool`` or - ``ifconfig`` while running DPDK application on the same network ports. - - It enables the DPDK application to filter only part of the traffic, - while the rest will be directed and handled by the kernel driver. - The flow bifurcation is performed by the NIC hardware. - As an example, using :ref:`flow_isolated_mode` allows to choose - strictly what is received in DPDK. - -More about the bifurcated driver can be found in -`Mellanox Bifurcated DPDK PMD -`__. - Troubleshooting VFIO --------------------- +~~~~~~~~~~~~~~~~~~~~ In certain situations, using ``dpdk-devbind.py`` script to bind a device to VFIO driver may fail. @@ -321,6 +296,31 @@ If ``CONFIG_VFIO_NOIOMMU`` is not enabled in the kernel configuration, VFIO driver will not support the no-IOMMU mode, and other alternatives (such as UIO drivers) will have to be used. +.. _bifurcated_driver: + +Bifurcated Driver +----------------- + +PMDs which use the bifurcated driver co-exists with the device kernel driver. +On such model the NIC is controlled by the kernel, while the data +path is performed by the PMD directly on top of the device. + +Such model has the following benefits: + + - It is secure and robust, as the memory management and isolation + is done by the kernel. + - It enables the user to use legacy linux tools such as ``ethtool`` or + ``ifconfig`` while running DPDK application on the same network ports. + - It enables the DPDK application to filter only part of the traffic, + while the rest will be directed and handled by the kernel driver. + The flow bifurcation is performed by the NIC hardware. + As an example, using :ref:`flow_isolated_mode` allows to choose + strictly what is received in DPDK. + +More about the bifurcated driver can be found in +`Mellanox Bifurcated DPDK PMD +`__. + .. _uio: UIO -- 2.32.0