From b63264c8342e6a1b6971c79550d2af2024b6a4de Mon Sep 17 00:00:00 2001 From: Luca Boccassi Date: Tue, 14 Aug 2018 18:52:30 +0100 Subject: New upstream version 18.08 Change-Id: I32fdf5e5016556d9c0a6d88ddaf1fc468961790a Signed-off-by: Luca Boccassi --- doc/guides/nics/ifc.rst | 96 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 96 insertions(+) create mode 100644 doc/guides/nics/ifc.rst (limited to 'doc/guides/nics/ifc.rst') diff --git a/doc/guides/nics/ifc.rst b/doc/guides/nics/ifc.rst new file mode 100644 index 00000000..48f9adf1 --- /dev/null +++ b/doc/guides/nics/ifc.rst @@ -0,0 +1,96 @@ +.. 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_IFCVF_VDPA_PMD`` (default ``y`` for linux) + + Toggle compilation of the ``librte_ifcvf_vdpa`` 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. + +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. + +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. + + +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. -- cgit 1.2.3-korg