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From: Bruce Richardson <bruce.richardson@intel.com>
To: dev@dpdk.org
Cc: stable@dpdk.org, Bruce Richardson <bruce.richardson@intel.com>
Subject: [PATCH 8/9] doc/linux_gsg: consolidate all VFIO content
Date: Wed,  2 Mar 2022 17:22:16 +0000	[thread overview]
Message-ID: <20220302172217.472279-9-bruce.richardson@intel.com> (raw)
In-Reply-To: <20220302172217.472279-1-bruce.richardson@intel.com>

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 <bruce.richardson@intel.com>
---
 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
-<https://www.dpdk.org/wp-content/uploads/sites/35/2016/10/Day02-Session04-RonyEfraim-Userspace2016.pdf>`__.
-
 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
+<https://www.dpdk.org/wp-content/uploads/sites/35/2016/10/Day02-Session04-RonyEfraim-Userspace2016.pdf>`__.
+
 .. _uio:
 
 UIO
-- 
2.32.0


  parent reply	other threads:[~2022-03-02 17:24 UTC|newest]

Thread overview: 19+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2022-03-02 17:22 [PATCH 0/9] Improve linux drivers GSG section Bruce Richardson
2022-03-02 17:22 ` [PATCH 1/9] doc/linux_gsg: replace special characters for (R) symbol Bruce Richardson
2022-03-02 17:22 ` [PATCH 2/9] doc/linux_gsg: fix missing note on UIO module Bruce Richardson
2022-03-02 17:22 ` [PATCH 3/9] doc/linux_gsg: make UIO safety warning more visible Bruce Richardson
2022-03-02 17:22 ` [PATCH 4/9] doc/linux_gsg: move section on binding drivers up the page Bruce Richardson
2022-03-02 17:22 ` [PATCH 5/9] doc/linux_gsg: emphasise VFIO over UIO-based modules Bruce Richardson
2022-03-02 17:22 ` [PATCH 6/9] doc/linux_gsg: split VFIO section into subsections Bruce Richardson
2022-03-02 17:22 ` [PATCH 7/9] doc/linux_gsg: move UIO section to the end Bruce Richardson
2022-03-02 17:22 ` Bruce Richardson [this message]
2022-03-02 17:22 ` [PATCH 9/9] doc/linux_gsg: change informational warnings to notes Bruce Richardson
     [not found] ` <20220316134551.1099599-1-bruce.richardson@intel.com>
2022-03-16 13:45   ` [PATCH v2 1/9] doc: replace special characters for (R) symbol in Linux GSG Bruce Richardson
2022-03-16 13:45   ` [PATCH v2 2/9] doc: fix missing note on UIO module " Bruce Richardson
2022-03-16 13:45   ` [PATCH v2 3/9] doc: make UIO safety warning more visible " Bruce Richardson
2022-03-16 13:45   ` [PATCH v2 4/9] doc: move section on binding drivers up the page in GSG Bruce Richardson
2022-03-16 13:45   ` [PATCH v2 5/9] doc: emphasise VFIO over UIO-based modules " Bruce Richardson
2022-03-16 13:45   ` [PATCH v2 6/9] doc: split GSG VFIO section into subsections Bruce Richardson
2022-03-16 13:45   ` [PATCH v2 7/9] doc: move GSG section on UIO to the end of drivers page Bruce Richardson
2022-03-16 13:45   ` [PATCH v2 8/9] doc: consolidate all VFIO content on GSG driver page Bruce Richardson
2022-03-16 13:45   ` [PATCH v2 9/9] doc: change informational warnings to notes in Linux GSG Bruce Richardson

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