From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mails.dpdk.org (mails.dpdk.org [217.70.189.124]) by inbox.dpdk.org (Postfix) with ESMTP id 93BC8A0557; Thu, 26 May 2022 05:26:28 +0200 (CEST) Received: from [217.70.189.124] (localhost [127.0.0.1]) by mails.dpdk.org (Postfix) with ESMTP id 8CCD742B7B; Thu, 26 May 2022 05:26:04 +0200 (CEST) Received: from mga05.intel.com (mga05.intel.com [192.55.52.43]) by mails.dpdk.org (Postfix) with ESMTP id 69CAD42684; Thu, 26 May 2022 05:26:01 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1653535561; x=1685071561; h=from:to:cc:subject:date:message-id:in-reply-to: references; bh=sZRv7qFqhKboZhwZcMMjXVIQLSLRa+OVqlzTkC2F0+c=; b=mERxkG8F3OIGco1JxoUvG77vIZl0pSWMjMQM+5KVdZoESY8wXt7V60yf i0z5Ld5suqtlWH+3QI0j6jt1cia8iBTPlb0oCAZrXcah9wj/XqnvKOnTt vJFfzUNOVPkkuCboaP84QBuLqjLmlEPxgbl5Q+Vkt33YnSQVg2qKF9bTt h3krjaNmI9f+i13lvTIqa96Ek6FcITAPeIcCS929UmqtzrC4ubkPAGVBg 0iAjDQMrYVQUdi+EiQPNvZY9XDClpnrFkPALHmSesZHxtEltqesNX/Vk8 4Eru9YrRK1M0GNjoJZ1HZIwgRPEnxL3B/VbNmPX8cJCT80yO78w7Dkrli w==; X-IronPort-AV: E=McAfee;i="6400,9594,10358"; a="360406244" X-IronPort-AV: E=Sophos;i="5.91,252,1647327600"; d="scan'208";a="360406244" Received: from orsmga005.jf.intel.com ([10.7.209.41]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 May 2022 20:26:00 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.91,252,1647327600"; d="scan'208";a="746084716" Received: from unknown (HELO zj-fpga-amt.sh.intel.com) ([10.238.175.102]) by orsmga005.jf.intel.com with ESMTP; 25 May 2022 20:25:58 -0700 From: Wei Huang To: dev@dpdk.org, thomas@monjalon.net, nipun.gupta@nxp.com, hemant.agrawal@nxp.com Cc: stable@dpdk.org, rosen.xu@intel.com, tianfei.zhang@intel.com, qi.z.zhang@intel.com, Wei Huang Subject: [PATCH v3 5/5] guides/rawdevs: add description of ofs in ifpga doc Date: Wed, 25 May 2022 23:32:54 -0400 Message-Id: <1653535974-1379-6-git-send-email-wei.huang@intel.com> X-Mailer: git-send-email 1.8.3.1 In-Reply-To: <1653535974-1379-1-git-send-email-wei.huang@intel.com> References: <1652862549-13131-1-git-send-email-wei.huang@intel.com> <1653535974-1379-1-git-send-email-wei.huang@intel.com> X-BeenThere: dev@dpdk.org X-Mailman-Version: 2.1.29 Precedence: list List-Id: DPDK patches and discussions List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Errors-To: dev-bounces@dpdk.org OFS (Open FPGA Stack) specification is introduced briefly. Signed-off-by: Wei Huang --- doc/guides/rawdevs/ifpga.rst | 114 ++++++++++++++++++++++++++++++++++++++++++- 1 file changed, 113 insertions(+), 1 deletion(-) diff --git a/doc/guides/rawdevs/ifpga.rst b/doc/guides/rawdevs/ifpga.rst index dbd0d6e..8809bfc 100644 --- a/doc/guides/rawdevs/ifpga.rst +++ b/doc/guides/rawdevs/ifpga.rst @@ -1,5 +1,5 @@ .. SPDX-License-Identifier: BSD-3-Clause - Copyright(c) 2018 Intel Corporation. + Copyright(c) 2018-2022 Intel Corporation. IFPGA Rawdev Driver ====================== @@ -100,3 +100,115 @@ The following device parameters are supported: If null, the AFU Bit Stream has been PR in FPGA, if not forces PR and identifies AFU Bit Stream file. + + +Open FPGA Stack +===================== + +Open FPGA Stack (OFS) is a collection of RTL and open source software providing +interfaces to access the instantiated RTL easily in an FPGA. OFS leverages the +DFL for the implementation of the FPGA RTL design. + +OFS designs allow for the arrangement of software interfaces across multiple +PCIe endpoints. Some of these interfaces may be PFs defined in the static region +that connect to interfaces in an IP that is loaded via Partial Reconfiguration (PR). +And some of these interfaces may be VFs defined in the PR region that can be +reconfigured by the end-user. Furthermore, these PFs/VFs may use DFLs such that +features may be discovered and accessed in user space (with the aid of a generic +kernel driver like vfio-pci). The diagram below depicts an example design with two +PFs and two VFs. In this example, it will export the management functions via PF0, +PF1 will bind with virtio-net driver presenting itself as a network interface to +the OS. The other functions, VF0 and VF1, leverage VFIO to export the MMIO space +to an application or assign to a VM.:: + + +-----------------+ +--------------+ +-------------+ +------------+ + | FPGA Management | | VirtIO | | User App | | Virtual | + | App | | App | | | | Machine | + +--------+--------+ +------+-------+ +------+------+ +-----+------+ + | | | | + +--------+--------+ +------+-------+ +------+------+ | + | DFL Driver | |VirtIO driver | | VFIO | | + +--------+--------+ +------+-------+ +------+------+ | + | | | | + | | | | + +--------+--------+ +------+-------+ +------+------+ +----+------+ + | PF0 | | PF1 | | PF0_VF0 | | PF0_VF1 | + +-----------------+ +--------------+ +-------------+ +-----------+ + +As accelerators are specialized hardware, they are typically limited in the +number installed in a given system. Many use cases require them to be shared +across multiple software contexts or threads of software execution, either +through partitioning of individual dedicated resources, or virtualization of +shared resources. OFS provides several models to share the AFU resources via +PR mechanism and hardware-based virtualization schemes. + +1. Legacy model. + With legacy model FPGA cards like Intel PAC N3000 or N5000, there is + a notion that the boundary between the AFU and the shell is also the unit of + PR for those FPGA platforms. This model is only able to handle a + single context, because it only has one PR engine, and one PR region which + has an associated Port device. +2. Multiple VFs per PR slot. + In this model, available AFU resources may allow instantiation of many VFs + which have a dedicated PCIe function with their own dedicated MMIO space, or + partition a region of MMIO space on a single PCIe function. Intel PAC N6000 + card has implemented this model. + In this model, the AFU/PR slot was not connected to port device. For DFL's view, + the Next_AFU pointer in FIU feature header of port device points to NULL in this + model, so in AFU driver perspective, there is no AFU MMIO region managed by + AFU driver. On the other hand, each VF can start with an AFU feature header without + being connected to a FIU Port feature header. + +In multiple VFs per PR slot model, the port device can still be accessed using +ioctls API which expose /dev/dfl-port.h device nodes, like port reset, get +port info, whose APIs were mentioned in AFU section in this documentation. But +it cannot access the AFU MMIO space via AFU ioctl APIs like DFL_FPGA_PORT_DMA_MAP +because there is no AFU MMIO space managed in the AFU driver. Users can access +the AFU resource by creating VF devices via PCIe SRIOV interface, and then access +the VF via VFIO driver or assign the VF to VM. + +In multiple VFs per PR slot model, the steps to enable VFs are compatible with +legacy mode which are mentioned in "FPGA virtualization - PCIe SRIOV" section +in this documentation. + +OFS provides the diversity for accessing the AFU resource to RTL developer. +An IP designer may choose to add more than one PF for interfacing with IP +on the FPGA and choose different model to access the AFU resource. + +There is one reference architecture design using the "Multiple VFs per PR slot" +model for OFS as illustrated below. In this reference design, it exports the +FPGA management functions via PF0. PF1 will bind with virtio-net driver +presenting itself as a network interface to the OS. PF2 will bind to the +vfio-pci driver allowing the user space software to discover and interface +with the specific workload like diagnostic test. To access the AFU resource, +it uses SR-IOV to partition workload interfaces across various VFs.:: + + +----------------------+ + | PF/VF mux/demux | + +--+--+-----+------+-+-+ + | | | | | + +------------------------+ | | | | + PF0 | +---------+ +-+ | | + +---+---+ | +---+----+ | | + | DFH | | | DFH | | | + +-------+ +-----+----+ +--------+ | | + | FME | | VirtIO | | Test | | | + +---+---+ +----------+ +--------+ | | + | PF1 PF2 | | + | | | + | +----------+ | + | | ++ + | | | + | | PF0_VF0 | PF0_VF1 + | +-----------------+-----------+------------+ + | | +-----+-----------+--------+ | + | | | | | | | + | | +------+ | +--+ -+ +--+---+ | | + | | | Port | | | DFH | | DFH | | | + +-----------+ +------+ | +-----+ +------+ | | + | | | DEV | | DEV | | | + | | +-----+ +------+ | | + | | PR Slot | | + | +--------------------------+ | + | Port Gasket | + +------------------------------------------+ -- 1.8.3.1