Adding upstream version 14.2.21.upstream/14.2.21upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 221 insertions, 0 deletions

diff --git a/src/spdk/dpdk/doc/guides/nics/fail_safe.rst b/src/spdk/dpdk/doc/guides/nics/fail_safe.rst
new file mode 100644
index 00000000..6c02d7ef
--- /dev/null
+++ b/src/spdk/dpdk/doc/guides/nics/fail_safe.rst
@@ -0,0 +1,221 @@
+..  SPDX-License-Identifier: BSD-3-Clause
+    Copyright 2017 6WIND S.A.
+
+Fail-safe poll mode driver library
+==================================
+
+The Fail-safe poll mode driver library (**librte_pmd_failsafe**) is a virtual
+device that allows using any device supporting hotplug (sudden device removal
+and plugging on its bus), without modifying other components relying on such
+device (application, other PMDs).
+
+Additionally to the Seamless Hotplug feature, the Fail-safe PMD offers the
+ability to redirect operations to secondary devices when the primary has been
+removed from the system.
+
+.. note::
+
+   The library is enabled by default. You can enable it or disable it manually
+   by setting the ``CONFIG_RTE_LIBRTE_PMD_FAILSAFE`` configuration option.
+
+Features
+--------
+
+The Fail-safe PMD only supports a limited set of features. If you plan to use a
+device underneath the Fail-safe PMD with a specific feature, this feature must
+be supported by the Fail-safe PMD to avoid throwing any error.
+
+A notable exception is the device removal feature. The fail-safe PMD being a
+virtual device, it cannot currently be removed in the sense of a specific bus
+hotplug, like for PCI for example. It will however enable this feature for its
+sub-device automatically, detecting those that are capable and register the
+relevant callback for such event.
+
+Check the feature matrix for the complete set of supported features.
+
+Compilation option
+------------------
+
+This option can be modified in the ``$RTE_TARGET/build/.config`` file.
+
+- ``CONFIG_RTE_LIBRTE_PMD_FAILSAFE`` (default **y**)
+
+  Toggle compiling librte_pmd_failsafe.
+
+Using the Fail-safe PMD from the EAL command line
+-------------------------------------------------
+
+The Fail-safe PMD can be used like most other DPDK virtual devices, by passing a
+``--vdev`` parameter to the EAL when starting the application. The device name
+must start with the *net_failsafe* prefix, followed by numbers or letters. This
+name must be unique for each device. Each fail-safe instance must have at least one
+sub-device, up to ``RTE_MAX_ETHPORTS-1``.
+
+A sub-device can be any legal DPDK device, including possibly another fail-safe
+instance.
+
+Fail-safe command line parameters
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+- **dev(<iface>)** parameter
+
+  This parameter allows the user to define a sub-device. The ``<iface>`` part of
+  this parameter must be a valid device definition. It could be the argument
+  provided to any ``-w`` device specification or the argument that would be
+  given to a ``--vdev`` parameter (including a fail-safe).
+  Enclosing the device definition within parenthesis here allows using
+  additional sub-device parameters if need be. They will be passed on to the
+  sub-device.
+
+.. note::
+
+   In case of whitelist sub-device probed by EAL, fail-safe PMD will take the device
+   as is, which means that EAL device options are taken in this case.
+   When trying to use a PCI device automatically probed in blacklist mode,
+   the syntax for the fail-safe must be with the full PCI id:
+   Domain:Bus:Device.Function. See the usage example section.
+
+- **exec(<shell command>)** parameter
+
+  This parameter allows the user to provide a command to the fail-safe PMD to
+  execute and define a sub-device.
+  It is done within a regular shell context.
+  The first line of its output is read by the fail-safe PMD and otherwise
+  interpreted as if passed by the regular **dev** parameter.
+  Any other line is discarded.
+  If the command fail or output an incorrect string, the sub-device is not
+  initialized.
+  All commas within the ``shell command`` are replaced by spaces before
+  executing the command. This helps using scripts to specify devices.
+
+- **fd(<file descriptor number>)** parameter
+
+  This parameter reads a device definition from an arbitrary file descriptor
+  number in ``<iface>`` format as described above.
+
+  The file descriptor is read in non-blocking mode and is never closed in
+  order to take only the last line into account (unlike ``exec()``) at every
+  probe attempt.
+
+- **mac** parameter [MAC address]
+
+  This parameter allows the user to set a default MAC address to the fail-safe
+  and all of its sub-devices.
+  If no default mac address is provided, the fail-safe PMD will read the MAC
+  address of the first of its sub-device to be successfully probed and use it as
+  its default MAC address, trying to set it to all of its other sub-devices.
+  If no sub-device was successfully probed at initialization, then a random MAC
+  address is generated, that will be subsequently applied to all sub-device once
+  they are probed.
+
+- **hotplug_poll** parameter [UINT64] (default **2000**)
+
+  This parameter allows the user to configure the amount of time in milliseconds
+  between two slave upkeep round.
+
+Usage example
+~~~~~~~~~~~~~
+
+This section shows some example of using **testpmd** with a fail-safe PMD.
+
+#. To build a PMD and configure DPDK, refer to the document
+   :ref:`compiling and testing a PMD for a NIC <pmd_build_and_test>`.
+
+#. Start testpmd. The slave device should be blacklisted from normal EAL
+   operations to avoid probing it twice when in PCI blacklist mode.
+
+   .. code-block:: console
+
+      $RTE_TARGET/build/app/testpmd -c 0xff -n 4 \
+         --vdev 'net_failsafe0,mac=de:ad:be:ef:01:02,dev(84:00.0),dev(net_ring0)' \
+         -b 84:00.0 -b 00:04.0 -- -i
+
+   If the slave device being used is not blacklisted, it will be probed by the
+   EAL first. When the fail-safe then tries to initialize it the probe operation
+   fails.
+
+   Note that PCI blacklist mode is the default PCI operating mode.
+
+#. Alternatively, it can be used alongside any other device in whitelist mode.
+
+   .. code-block:: console
+
+      $RTE_TARGET/build/app/testpmd -c 0xff -n 4 \
+         --vdev 'net_failsafe0,mac=de:ad:be:ef:01:02,dev(84:00.0),dev(net_ring0)' \
+         -w 81:00.0 -- -i
+
+#. Start testpmd using a flexible device definition
+
+   .. code-block:: console
+
+      $RTE_TARGET/build/app/testpmd -c 0xff -n 4 --no-pci \
+         --vdev='net_failsafe0,exec(echo 84:00.0)' -- -i
+
+#. Start testpmd, automatically probing the device 84:00.0 and using it with
+   the fail-safe.
+ 
+   .. code-block:: console
+ 
+      $RTE_TARGET/build/app/testpmd -c 0xff -n 4 \
+         --vdev 'net_failsafe0,dev(0000:84:00.0),dev(net_ring0)' -- -i
+
+
+Using the Fail-safe PMD from an application
+-------------------------------------------
+
+This driver strives to be as seamless as possible to existing applications, in
+order to propose the hotplug functionality in the easiest way possible.
+
+Care must be taken, however, to respect the **ether** API concerning device
+access, and in particular, using the ``RTE_ETH_FOREACH_DEV`` macro to iterate
+over ethernet devices, instead of directly accessing them or by writing one's
+own device iterator.
+
+Plug-in feature
+---------------
+
+A sub-device can be defined without existing on the system when the fail-safe
+PMD is initialized. Upon probing this device, the fail-safe PMD will detect its
+absence and postpone its use. It will then register for a periodic check on any
+missing sub-device.
+
+During this time, the fail-safe PMD can be used normally, configured and told to
+emit and receive packets. It will store any applied configuration, and try to
+apply it upon the probing of its missing sub-device. After this configuration
+pass, the new sub-device will be synchronized with other sub-devices, i.e. be
+started if the fail-safe PMD has been started by the user before.
+
+Plug-out feature
+----------------
+
+A sub-device supporting the device removal event can be removed from its bus at
+any time. The fail-safe PMD will register a callback for such event and react
+accordingly. It will try to safely stop, close and uninit the sub-device having
+emitted this event, allowing it to free its eventual resources.
+
+Fail-safe glossary
+------------------
+
+Fallback device : Secondary device
+    The fail-safe will fail-over onto this device when the preferred device is
+    absent.
+
+Preferred device : Primary device
+    The first declared sub-device in the fail-safe parameters.
+    When this device is plugged, it is always used as emitting device.
+    It is the main sub-device and is used as target for configuration
+    operations if there is any ambiguity.
+
+Upkeep round
+    Periodical process when slaves are serviced. Each devices having a state
+    different to that of the fail-safe device itself, is synchronized with it.
+    Additionally, each slave having the remove flag set are cleaned-up.
+
+Slave
+    In the context of the fail-safe PMD, synonymous to sub-device.
+
+Sub-device
+    A device being utilized by the fail-safe PMD.
+    This is another PMD running underneath the fail-safe PMD.
+    Any sub-device can disappear at any time. The fail-safe will ensure
+    that the device removal happens gracefully.