[PATCH] doc/qat: clarify build config options

[Fiona Trahe <fiona.trahe@intel.com>]

Clarified documentation structure between
compressedev, cryptodev and common build parts.
Clarified build configuration options.
Added Testing section.
Fixed typos and made some cosmetic improvements.

Signed-off-by: Fiona Trahe <fiona.trahe@intel.com>
---
 doc/guides/compressdevs/qat_comp.rst |   6 +-
 doc/guides/cryptodevs/qat.rst        | 194 ++++++++++++++++++++++++-----------
 2 files changed, 138 insertions(+), 62 deletions(-)

diff --git a/doc/guides/compressdevs/qat_comp.rst b/doc/guides/compressdevs/qat_comp.rst
index 8b1270b70..7bffbe6ff 100644
--- a/doc/guides/compressdevs/qat_comp.rst
+++ b/doc/guides/compressdevs/qat_comp.rst
@@ -36,12 +36,14 @@ Limitations
 -----------
 
 * Compressdev level 0, no compression, is not supported.
-
 * Dynamic Huffman encoding is not yet supported.
+* Queue pairs are not thread-safe (that is, within a single queue pair, RX and TX from different lcores is not supported).
+* No BSD support as BSD QAT kernel driver not available.
+
 
 Installation
 ------------
 
 The QAT compression PMD is built by default with a standard DPDK build.
 
-It depends on a QAT kernel driver, see :ref:`qat_kernel_installation`.
+It depends on a QAT kernel driver, see :ref:`building_qat`.
diff --git a/doc/guides/cryptodevs/qat.rst b/doc/guides/cryptodevs/qat.rst
index bdc58eb2c..7b5929681 100644
--- a/doc/guides/cryptodevs/qat.rst
+++ b/doc/guides/cryptodevs/qat.rst
@@ -2,9 +2,21 @@
     Copyright(c) 2015-2016 Intel Corporation.
 
 Intel(R) QuickAssist (QAT) Crypto Poll Mode Driver
-==================================================
+===================================================
 
-The QAT PMD provides poll mode crypto driver support for the following
+QAT documentation consists of three parts:
+
+* Details of the symmetric crypto service below.
+* Details of the `compression service <http://dpdk.org/doc/guides/compressdevs/qat_comp.html>`_
+  in the compressdev drivers section.
+* Details of building the common QAT infrastructure and the PMDs to support the
+  above services. See :ref:`building_qat` below.
+
+
+Symmetric Crypto Service on QAT
+--------------------------------------------------
+
+The QAT crypto PMD provides poll mode crypto driver support for the following
 hardware accelerator devices:
 
 * ``Intel QuickAssist Technology DH895xCC``
@@ -14,7 +26,7 @@ hardware accelerator devices:
 
 
 Features
---------
+~~~~~~~~
 
 The QAT PMD has support for:
 
@@ -57,7 +69,7 @@ Supported AEAD algorithms:
 
 
 Limitations
------------
+~~~~~~~~~~~~~
 
 * Only supports the session-oriented API implementation (session-less APIs are not supported).
 * SNOW 3G (UEA2), KASUMI (F8) and ZUC (EEA3) supported only if cipher length and offset fields are byte-multiple.
@@ -69,104 +81,148 @@ Limitations
 
 
 Extra notes on KASUMI F9
-------------------------
+~~~~~~~~~~~~~~~~~~~~~~~~
 
 When using KASUMI F9 authentication algorithm, the input buffer must be
-constructed according to the 3GPP KASUMI specifications (section 4.4, page 13):
-`<http://cryptome.org/3gpp/35201-900.pdf>`_.
-Input buffer has to have COUNT (4 bytes), FRESH (4 bytes), MESSAGE and DIRECTION (1 bit)
-concatenated. After the DIRECTION bit, a single '1' bit is appended, followed by
-between 0 and 7 '0' bits, so that the total length of the buffer is multiple of 8 bits.
-Note that the actual message can be any length, specified in bits.
+constructed according to the
+`3GPP KASUMI specification <http://cryptome.org/3gpp/35201-900.pdf>`_
+(section 4.4, page 13). The input buffer has to have COUNT (4 bytes),
+FRESH (4 bytes), MESSAGE and DIRECTION (1 bit) concatenated. After the DIRECTION
+bit, a single '1' bit is appended, followed by between 0 and 7 '0' bits, so that
+the total length of the buffer is multiple of 8 bits. Note that the actual
+message can be any length, specified in bits.
 
 Once this buffer is passed this way, when creating the crypto operation,
-length of data to authenticate (op.sym.auth.data.length) must be the length
+length of data to authenticate "op.sym.auth.data.length" must be the length
 of all the items described above, including the padding at the end.
-Also, offset of data to authenticate (op.sym.auth.data.offset)
+Also, offset of data to authenticate "op.sym.auth.data.offset"
 must be such that points at the start of the COUNT bytes.
 
 
-Building the DPDK QAT cryptodev PMD
------------------------------------
 
+.. _building_qat:
+
+Building PMDs on QAT
+----------------------------------
+
+A QAT device can host multiple acceleration services:
+
+* symmetric cryptography
+* data compression
 
-To enable QAT crypto in DPDK, follow the instructions for modifying the compile-time
-configuration file as described `here <http://dpdk.org/doc/guides/linux_gsg/build_dpdk.html>`_.
+These services are provided to DPDK applications via PMDs which register to
+implement the corresponding cryptodev and compressdev APIs. The PMDs use
+common QAT driver code which manages the QAT PCI device. They also depend on a
+QAT kernel driver being installed on the platform, see :ref:`qat_kernel` below.
 
 
-Quick instructions are as follows:
+Configuring and Building the DPDK QAT PMDs
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+
+Further information on configuring, building and installing DPDK is described
+`here <http://dpdk.org/doc/guides/linux_gsg/build_dpdk.html>`_.
+
+
+Quick instructions for QAT cryptodev PMD are as follows:
 
 .. code-block:: console
 
 	cd to the top-level DPDK directory
 	make config T=x86_64-native-linuxapp-gcc
-	sed -i 's,\(CONFIG_RTE_LIBRTE_PMD_QAT\)=n,\1=y,' build/.config
 	sed -i 's,\(CONFIG_RTE_LIBRTE_PMD_QAT_SYM\)=n,\1=y,' build/.config
 	make
 
+Quick instructions for QAT compressdev PMD are as follows:
 
-.. _qat_kernel_installation:
+.. code-block:: console
 
-Dependency on the QAT kernel driver
------------------------------------
+	cd to the top-level DPDK directory
+	make config T=x86_64-native-linuxapp-gcc
+	make
 
-To use the QAT PMD an SRIOV-enabled QAT kernel driver is required. The VF
-devices created and initialised by this driver will be used by the QAT PMD.
+Build Configuration
+~~~~~~~~~~~~~~~~~~~~
 
-Instructions for installation are below, but first an explanation of the
-relationships between the PF/VF devices and the PMDs visible to
-DPDK applications.
+These are the build configuration options affecting QAT, and their default values:
 
+.. code-block:: console
 
-Acceleration services - cryptography and compression - are provided to DPDK
-applications via PMDs which register to implement the corresponding
-cryptodev and compressdev APIs.
+	CONFIG_RTE_LIBRTE_PMD_QAT=y
+	CONFIG_RTE_LIBRTE_PMD_QAT_SYM=n
+	CONFIG_RTE_PMD_QAT_MAX_PCI_DEVICES=48
+	CONFIG_RTE_PMD_QAT_COMP_SGL_MAX_SEGMENTS=16
 
-Each QuickAssist VF device can expose one cryptodev PMD and/or one compressdev PMD.
-These QAT PMDs share the same underlying device and pci-mgmt code, but are
-enumerated independently on their respective APIs and appear as independent
-devices to applications.
+CONFIG_RTE_LIBRTE_PMD_QAT must be enabled for any QAT PMD to be built.
 
-.. Note::
+The QAT cryptodev PMD has an external dependency on libcrypto, so is not
+built by default. CONFIG_RTE_LIBRTE_PMD_QAT_SYM should be enabled to build it.
 
-   Each VF can only be used by one DPDK process. It is not possible to share
-   the same VF across multiple processes, even if these processes are using
-   different acceleration services.
+The QAT compressdev PMD has no external dependencies, so needs no configuration
+options and is built by default.
 
-   Conversely one DPDK process can use one or more QAT VFs and can expose both
-   cryptodev and compressdev instances on each of those VFs.
+The number of VFs per PF varies - see table below. If multiple QAT packages are
+installed on a platform then CONFIG_RTE_PMD_QAT_MAX_PCI_DEVICES should be
+adjusted to the number of VFs which the QAT common code will need to handle.
+Note, there is a separate config item for max cryptodevs CONFIG_RTE_CRYPTO_MAX_DEVS,
+if necessary this should be adjusted to handle the total of QAT and other devices
+which the process will use.
 
+QAT allocates internal structures to handle SGLs. For the compression service
+CONFIG_RTE_PMD_QAT_COMP_SGL_MAX_SEGMENTS can be changed if more segments are needed.
+An extra (max_inflight_ops x 16) bytes per queue_pair will be used for every increment.
 
 
 Device and driver naming
-------------------------
+~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 * The qat cryptodev driver name is "crypto_qat".
-  The rte_cryptodev_devices_get() returns the devices exposed by this driver.
+  The "rte_cryptodev_devices_get()" returns the devices exposed by this driver.
 
 * Each qat crypto device has a unique name, in format
-  <pci bdf>_<service>, e.g. "0000:41:01.0_qat_sym".
-  This name can be passed to rte_cryptodev_get_dev_id() to get the device_id.
+  "<pci bdf>_<service>", e.g. "0000:41:01.0_qat_sym".
+  This name can be passed to "rte_cryptodev_get_dev_id()" to get the device_id.
 
 .. Note::
 
-	The qat crypto driver name is passed to the dpdk-test-crypto-perf tool in the -devtype parameter.
+	The qat crypto driver name is passed to the dpdk-test-crypto-perf tool in the "-devtype" parameter.
 
 	The qat crypto device name is in the format of the slave parameter passed to the crypto scheduler.
 
-* The qat compressdev driver name is "comp_qat".
-  The rte_compressdev_devices_get() returns the devices exposed by this driver.
 
-* Each qat compression device has a unique name, in format
-  <pci bdf>_<service>, e.g. "0000:41:01.0_qat_comp".
-  This name can be passed to rte_compressdev_get_dev_id() to get the device_id.
+.. _qat_kernel:
+
+Dependency on the QAT kernel driver
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+To use QAT an SRIOV-enabled QAT kernel driver is required. The VF
+devices created and initialised by this driver will be used by the QAT PMDs.
+
+Instructions for installation are below, but first an explanation of the
+relationships between the PF/VF devices and the PMDs visible to
+DPDK applications.
+
+Each QuickAssist PF device exposes a number of VF devices. Each VF device can
+enable one cryptodev PMD and/or one compressdev PMD.
+These QAT PMDs share the same underlying device and pci-mgmt code, but are
+enumerated independently on their respective APIs and appear as independent
+devices to applications.
+
+.. Note::
+
+   Each VF can only be used by one DPDK process. It is not possible to share
+   the same VF across multiple processes, even if these processes are using
+   different acceleration services.
+
+   Conversely one DPDK process can use one or more QAT VFs and can expose both
+   cryptodev and compressdev instances on each of those VFs.
 
 
 Available kernel drivers
-------------------------
+~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Kernel drivers for each device are listed in the following table. Scroll right
-to check that the driver and device supports the servic you require.
+to check that the driver and device supports the service you require.
 
 
 .. _table_qat_pmds_drivers:
@@ -203,7 +259,7 @@ If you are running on a kernel which includes a driver for your device, see
 
 
 Installation using kernel.org driver
-------------------------------------
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 The examples below are based on the C62x device, if you have a different device
 use the corresponding values in the above table.
@@ -274,7 +330,7 @@ To complete the installation follow the instructions in
 
 
 Installation using 01.org QAT driver
-------------------------------------
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Download the latest QuickAssist Technology Driver from `01.org
 <https://01.org/packet-processing/intel%C2%AE-quickassist-technology-drivers-and-patches>`_.
@@ -368,12 +424,12 @@ To complete the installation - follow instructions in `Binding the available VFs
 
 
 Binding the available VFs to the DPDK UIO driver
-------------------------------------------------
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
 
 Unbind the VFs from the stock driver so they can be bound to the uio driver.
 
 For an Intel(R) QuickAssist Technology DH895xCC device
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 The unbind command below assumes ``BDFs`` of ``03:01.00-03:04.07``, if your
 VFs are different adjust the unbind command below::
@@ -386,7 +442,7 @@ VFs are different adjust the unbind command below::
     done
 
 For an Intel(R) QuickAssist Technology C62x device
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 The unbind command below assumes ``BDFs`` of ``1a:01.00-1a:02.07``,
 ``3d:01.00-3d:02.07`` and ``3f:01.00-3f:02.07``, if your VFs are different
@@ -406,7 +462,7 @@ adjust the unbind command below::
     done
 
 For Intel(R) QuickAssist Technology C3xxx or D15xx device
-~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 The unbind command below assumes ``BDFs`` of ``01:01.00-01:02.07``, if your
 VFs are different adjust the unbind command below::
@@ -419,7 +475,7 @@ VFs are different adjust the unbind command below::
     done
 
 Bind to the DPDK uio driver
-~~~~~~~~~~~~~~~~~~~~~~~~~~~
+^^^^^^^^^^^^^^^^^^^^^^^^^^^^
 
 Install the DPDK igb_uio driver, bind the VF PCI Device id to it and use lspci
 to confirm the VF devices are now in use by igb_uio kernel driver,
@@ -438,9 +494,27 @@ Another way to bind the VFs to the DPDK UIO driver is by using the
     cd to the top-level DPDK directory
     ./usertools/dpdk-devbind.py -b igb_uio 0000:03:01.1
 
+Testing
+~~~~~~~
+
+QAT crypto PMD can be tested by running the test application::
+
+    make test-build -j
+    cd ./build/build/test/test
+    ./test -l1 -n1 -w <your qat bdf>
+    RTE>>cryptodev_qat_autotest
+
+QAT compression PMD can be tested by running the test application::
+
+    sed -i 's,\(CONFIG_RTE_COMPRESSDEV_TEST\)=n,\1=y,' build/.config
+    make test-build -j
+    cd ./build/build/test/test
+    ./test -l1 -n1 -w <your qat bdf>
+    RTE>>compressdev_autotest
+
 
 Debugging
-----------------------------------------
+~~~~~~~~~
 
 There are 2 sets of trace available via the dynamic logging feature:
 
-- 
2.13.6