[dpdk-dev,v3,5/7] cryptodev: add document for virtio crypto PMD

diff --git a/doc/guides/cryptodevs/features/virtio.ini b/doc/guides/cryptodevs/features/virtio.ini
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+; Supported features of the 'virtio' crypto driver.
+;
+; Refer to default.ini for the full list of available PMD features.
+;
+[Features]
+Symmetric crypto       = Y
+Sym operation chaining = Y
+HW Accelerated         = N
+Mbuf scatter gather    = N
+
+;
+; Supported crypto algorithms of the 'virtio' crypto driver.
+;
+[Cipher]
+AES CBC (128)  = Y
+AES CBC (192)  = Y
+AES CBC (256)  = Y
+;
+; Supported authentication algorithms of the 'virtio' crypto driver.
+;
+[Auth]
+SHA1 HMAC      = Y
diff --git a/doc/guides/cryptodevs/virtio.rst b/doc/guides/cryptodevs/virtio.rst
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+..  SPDX-License-Identifier: BSD-3-Clause
+    Copyright(c) 2018 HUAWEI TECHNOLOGIES CO., LTD.
+
+Virtio Crypto Poll Mode Driver
+==============================
+
+The virtio crypto PMD provides poll mode driver support for the virtio crypto
+device.
+
+Features
+--------
+
+The virtio crypto PMD has support for:
+
+Cipher algorithms:
+
+* ``RTE_CRYPTO_CIPHER_AES_CBC``
+
+Hash algorithms:
+
+* ``RTE_CRYPTO_AUTH_SHA1_HMAC``
+
+Limitations
+-----------
+
+*  Only supports the session-oriented API implementation (session-less APIs are
+   not supported).
+*  Only supports modern mode since virtio crypto conforms to virtio-1.0.
+*  Only has two types of queues: data queue and control queue. These two queues
+   only support indirect buffers to communication with the virtio backend.
+*  Only supports AES_CBC cipher only algorithm and AES_CBC with HMAC_SHA1
+   chaining algorithm since the vhost crypto backend only these algorithms
+   are supported.
+*  Does not support Link State interrupt.
+*  Does not support runtime configuration.
+
+Virtio crypto PMD Rx/Tx Callbacks
+---------------------------------
+
+Rx callbacks:
+
+* ``virtio_crypto_pkt_rx_burst``
+
+Tx callbacks:
+
+* ``virtio_crypto_pkt_tx_burst``
+
+Installation
+------------
+
+Quick instructions are as follows:
+
+Firstly run DPDK vhost crypto sample as a server side and build QEMU with
+vhost crypto enabled.
+QEMU can then be started using the following parameters:
+
+.. code-block:: console
+
+    qemu-system-x86_64 \
+    [...] \
+        -chardev socket,id=charcrypto0,path=/path/to/your/socket \
+        -object cryptodev-vhost-user,id=cryptodev0,chardev=charcrypto0 \
+        -device virtio-crypto-pci,id=crypto0,cryptodev=cryptodev0
+    [...]
+
+Secondly bind the uio_generic driver for the virtio-crypto device.
+For example, 0000:00:04.0 is the domain, bus, device and function
+number of the virtio-crypto device:
+
+.. code-block:: console
+
+    modprobe uio_pci_generic
+    echo -n 0000:00:04.0 > /sys/bus/pci/drivers/virtio-pci/unbind
+    echo "1af4 1054" > /sys/bus/pci/drivers/uio_pci_generic/new_id
+
+Finally the front-end virtio crypto PMD driver can be installed:
+
+.. code-block:: console
+
+    cd to the top-level DPDK directory
+    sed -i 's,\(CONFIG_RTE_LIBRTE_PMD_VIRTIO_CRYPTO\)=n,\1=y,' config/common_base
+    make config T=x86_64-native-linuxapp-gcc
+    make install T=x86_64-native-linuxapp-gcc
+
+Tests
+-----
+
+The unit test cases can be tested as below:
+
+.. code-block:: console
+
+    reserve enough huge pages
+    cd to the top-level DPDK directory
+    export RTE_TARGET=x86_64-native-linuxapp-gcc
+    export RTE_SDK=`pwd`
+    cd to test/test
+    type the command "make" to compile
+    run the tests with "./test"
+    type the command "cryptodev_virtio_autotest" to test
+
+The performance can be tested as below:
+
+.. code-block:: console
+
+    reserve enough huge pages
+    cd to the top-level DPDK directory
+    export RTE_TARGET=x86_64-native-linuxapp-gcc
+    export RTE_SDK=`pwd`
+    cd to app/test-crypto-perf
+    type the command "make" to compile
+    run the tests with the following command:
+
+    ./dpdk-test-crypto-perf -l 0,1 -- --devtype crypto_virtio \
+        --ptest throughput --optype cipher-then-auth --cipher-algo aes-cbc \
+        --cipher-op encrypt --cipher-key-sz 16 --auth-algo sha1-hmac \
+        --auth-op generate --auth-key-sz 64 --digest-sz 12 \
+        --total-ops 100000000 --burst-sz 64 --buffer-sz 2048