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+..  SPDX-License-Identifier: BSD-3-Clause
+    Copyright(c) 2018 Intel Corporation.
+
+IFCVF vDPA driver
+=================
+
+The IFCVF vDPA (vhost data path acceleration) driver provides support for the
+Intel FPGA 100G VF (IFCVF). IFCVF's datapath is virtio ring compatible, it
+works as a HW vhost backend which can send/receive packets to/from virtio
+directly by DMA. Besides, it supports dirty page logging and device state
+report/restore, this driver enables its vDPA functionality.
+
+
+Pre-Installation Configuration
+------------------------------
+
+Config File Options
+~~~~~~~~~~~~~~~~~~~
+
+The following option can be modified in the ``config`` file.
+
+- ``CONFIG_RTE_LIBRTE_IFC_PMD`` (default ``y`` for linux)
+
+  Toggle compilation of the ``librte_pmd_ifc`` driver.
+
+
+IFCVF vDPA Implementation
+-------------------------
+
+IFCVF's vendor ID and device ID are same as that of virtio net pci device,
+with its specific subsystem vendor ID and device ID. To let the device be
+probed by IFCVF driver, adding "vdpa=1" parameter helps to specify that this
+device is to be used in vDPA mode, rather than polling mode, virtio pmd will
+skip when it detects this message. If no this parameter specified, device
+will not be used as a vDPA device, and it will be driven by virtio pmd.
+
+Different VF devices serve different virtio frontends which are in different
+VMs, so each VF needs to have its own DMA address translation service. During
+the driver probe a new container is created for this device, with this
+container vDPA driver can program DMA remapping table with the VM's memory
+region information.
+
+The device argument "sw-live-migration=1" will configure the driver into SW
+assisted live migration mode. In this mode, the driver will set up a SW relay
+thread when LM happens, this thread will help device to log dirty pages. Thus
+this mode does not require HW to implement a dirty page logging function block,
+but will consume some percentage of CPU resource depending on the network
+throughput. If no this parameter specified, driver will rely on device's logging
+capability.
+
+Key IFCVF vDPA driver ops
+~~~~~~~~~~~~~~~~~~~~~~~~~
+
+- ifcvf_dev_config:
+  Enable VF data path with virtio information provided by vhost lib, including
+  IOMMU programming to enable VF DMA to VM's memory, VFIO interrupt setup to
+  route HW interrupt to virtio driver, create notify relay thread to translate
+  virtio driver's kick to a MMIO write onto HW, HW queues configuration.
+
+  This function gets called to set up HW data path backend when virtio driver
+  in VM gets ready.
+
+- ifcvf_dev_close:
+  Revoke all the setup in ifcvf_dev_config.
+
+  This function gets called when virtio driver stops device in VM.
+
+To create a vhost port with IFC VF
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+- Create a vhost socket and assign a VF's device ID to this socket via
+  vhost API. When QEMU vhost connection gets ready, the assigned VF will
+  get configured automatically.
+
+
+Features
+--------
+
+Features of the IFCVF driver are:
+
+- Compatibility with virtio 0.95 and 1.0.
+- SW assisted vDPA live migration.
+
+
+Prerequisites
+-------------
+
+- Platform with IOMMU feature. IFC VF needs address translation service to
+  Rx/Tx directly with virtio driver in VM.
+
+
+Limitations
+-----------
+
+Dependency on vfio-pci
+~~~~~~~~~~~~~~~~~~~~~~
+
+vDPA driver needs to setup VF MSIX interrupts, each queue's interrupt vector
+is mapped to a callfd associated with a virtio ring. Currently only vfio-pci
+allows multiple interrupts, so the IFCVF driver is dependent on vfio-pci.
+
+Live Migration with VIRTIO_NET_F_GUEST_ANNOUNCE
+~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~
+
+IFC VF doesn't support RARP packet generation, virtio frontend supporting
+VIRTIO_NET_F_GUEST_ANNOUNCE feature can help to do that.