From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-12.3 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,MENTIONS_GIT_HOSTING,NICE_REPLY_A,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 78ACCC2D0E4 for ; Fri, 27 Nov 2020 03:53:41 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E77552222C for ; Fri, 27 Nov 2020 03:53:40 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="RhitAHqF" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726874AbgK0DxY (ORCPT ); Thu, 26 Nov 2020 22:53:24 -0500 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:51622 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726908AbgK0DxX (ORCPT ); Thu, 26 Nov 2020 22:53:23 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1606449201; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=SzWUasFbh+ss1wzTbk2nMb/2xT+F5CZGRE9hJTNxirg=; b=RhitAHqFmXm6bbOEZqeoHmEX0QCigpS92aTaP+Ga7U+fUh3cKFQEEGZTS+KjrdYJzILs+A rTmdL3L19ULDEBt7vjGyCDfYpLh6mG2JUSwlkdumZ71L56iPc4jUAdV7QYHhoHlU1KnB8V i+dxCXb9Bf+bRDEw6mgI4BK7Z+riMck= Received: from mimecast-mx01.redhat.com (mimecast-mx01.redhat.com [209.132.183.4]) (Using TLS) by relay.mimecast.com with ESMTP id us-mta-95-5cU5D7mFP9apiwLKa8gFXA-1; Thu, 26 Nov 2020 22:53:17 -0500 X-MC-Unique: 5cU5D7mFP9apiwLKa8gFXA-1 Received: from smtp.corp.redhat.com (int-mx02.intmail.prod.int.phx2.redhat.com [10.5.11.12]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 166F01005D50; Fri, 27 Nov 2020 03:53:16 +0000 (UTC) Received: from [10.72.13.168] (ovpn-13-168.pek2.redhat.com [10.72.13.168]) by smtp.corp.redhat.com (Postfix) with ESMTP id 8D11D60BF1; Fri, 27 Nov 2020 03:53:10 +0000 (UTC) Subject: Re: [PATCH 0/7] Introduce vdpa management tool To: Parav Pandit , virtualization@lists.linux-foundation.org Cc: mst@redhat.com, elic@nvidia.com, netdev@vger.kernel.org, =?UTF-8?B?6LCi5rC45ZCJ?= References: <20201112064005.349268-1-parav@nvidia.com> From: Jason Wang Message-ID: <5b2235f6-513b-dbc9-3670-e4c9589b4d1f@redhat.com> Date: Fri, 27 Nov 2020 11:53:09 +0800 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.10.0 MIME-Version: 1.0 In-Reply-To: <20201112064005.349268-1-parav@nvidia.com> Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.79 on 10.5.11.12 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 2020/11/12 下午2:39, Parav Pandit wrote: > This patchset covers user requirements for managing existing vdpa devices, > using a tool and its internal design notes for kernel drivers. > > Background and user requirements: > ---------------------------------- > (1) Currently VDPA device is created by driver when driver is loaded. > However, user should have a choice when to create or not create a vdpa device > for the underlying parent device. > > For example, mlx5 PCI VF and subfunction device supports multiple classes of > device such netdev, vdpa, rdma. Howevever it is not required to always created > vdpa device for such device. > > (2) In another use case, a device may support creating one or multiple vdpa > device of same or different class such as net and block. > Creating vdpa devices at driver load time further limits this use case. > > (3) A user should be able to monitor and query vdpa queue level or device level > statistics for a given vdpa device. > > (4) A user should be able to query what class of vdpa devices are supported > by its parent device. > > (5) A user should be able to view supported features and negotiated features > of the vdpa device. > > (6) A user should be able to create a vdpa device in vendor agnostic manner > using single tool. > > Hence, it is required to have a tool through which user can create one or more > vdpa devices from a parent device which addresses above user requirements. > > Example devices: > ---------------- > +-----------+ +-----------+ +---------+ +--------+ +-----------+ > |vdpa dev 0 | |vdpa dev 1 | |rdma dev | |netdev | |vdpa dev 3 | > |type=net | |type=block | |mlx5_0 | |ens3f0 | |type=net | > +----+------+ +-----+-----+ +----+----+ +-----+--+ +----+------+ > | | | | | > | | | | | > +----+-----+ | +----+----+ | +----+----+ > | mlx5 +--------+ |mlx5 +-------+ |mlx5 | > |pci vf 2 | |pci vf 4 | |pci sf 8 | > |03:00:2 | |03:00.4 | |mlx5_sf.8| > +----+-----+ +----+----+ +----+----+ > | | | > | +----+-----+ | > +----------------------+mlx5 +----------------+ > |pci pf 0 | > |03:00.0 | > +----------+ > > vdpa tool: > ---------- > vdpa tool is a tool to create, delete vdpa devices from a parent device. It is a > tool that enables user to query statistics, features and may be more attributes > in future. > > vdpa tool command draft: > ------------------------ > (a) List parent devices which supports creating vdpa devices. > It also shows which class types supported by this parent device. > In below command example two parent devices support vdpa device creation. > First is PCI VF whose bdf is 03.00:2. > Second is PCI VF whose name is 03:00.4. > Third is PCI SF whose name is mlx5_core.sf.8 > > $ vdpa parentdev list > vdpasim > supported_classes > net > pci/0000:03.00:3 > supported_classes > net block > pci/0000:03.00:4 > supported_classes > net block > auxiliary/mlx5_core.sf.8 > supported_classes > net > > (b) Now add a vdpa device of networking class and show the device. > $ vdpa dev add parentdev pci/0000:03.00:2 type net name foo0 $ vdpa dev show foo0 > foo0: parentdev pci/0000:03.00:2 type network parentdev vdpasim vendor_id 0 max_vqs 2 max_vq_size 256 > > (c) Show features of a vdpa device > $ vdpa dev features show foo0 > supported > iommu platform > version 1 > > (d) Dump vdpa device statistics > $ vdpa dev stats show foo0 > kickdoorbells 10 > wqes 100 > > (e) Now delete a vdpa device previously created. > $ vdpa dev del foo0 > > vdpa tool support in this patchset: > ----------------------------------- > vdpa tool is created to create, delete and query vdpa devices. > examples: > Show vdpa parent device that supports creating, deleting vdpa devices. > > $ vdpa parentdev show > vdpasim: > supported_classes > net > > $ vdpa parentdev show -jp > { > "show": { > "vdpasim": { > "supported_classes": { > "net" > } > } > } > > Create a vdpa device of type networking named as "foo2" from the parent device vdpasim: > > $ vdpa dev add parentdev vdpasim type net name foo2 > > Show the newly created vdpa device by its name: > $ vdpa dev show foo2 > foo2: type network parentdev vdpasim vendor_id 0 max_vqs 2 max_vq_size 256 > > $ vdpa dev show foo2 -jp > { > "dev": { > "foo2": { > "type": "network", > "parentdev": "vdpasim", > "vendor_id": 0, > "max_vqs": 2, > "max_vq_size": 256 > } > } > } > > Delete the vdpa device after its use: > $ vdpa dev del foo2 > > vdpa tool support by kernel: > ---------------------------- > vdpa tool user interface will be supported by existing vdpa kernel framework, > i.e. drivers/vdpa/vdpa.c It services user command through a netlink interface. > > Each parent device registers supported callback operations with vdpa subsystem > through which vdpa device(s) can be managed. > > FAQs: > ----- > 1. Where does userspace vdpa tool reside which users can use? > Ans: vdpa tool can possibly reside in iproute2 [1] as it enables user to > create vdpa net devices. > > 2. Why not create and delete vdpa device using sysfs/configfs? > Ans: > (a) A device creation may involve passing one or more attributes. > Passing multiple attributes and returning error code and more verbose > information for invalid attributes cannot be handled by sysfs/configfs. > > (b) netlink framework is rich that enables user space and kernel driver to > provide nested attributes. > > (c) Exposing device specific file under sysfs without net namespace > awareness exposes details to multiple containers. Instead exposing > attributes via a netlink socket secures the communication channel with kernel. > > (d) netlink socket interface enables to run syscaller kernel tests. > > 3. Why not use ioctl() interface? > Ans: ioctl() interface replicates the necessary plumbing which already > exists through netlink socket. > > 4. What happens when one or more user created vdpa devices exist for a > parent PCI VF or SF and such parent device is removed? > Ans: All user created vdpa devices are removed that belong to a parent. > > [1] git://git.kernel.org/pub/scm/network/iproute2/iproute2-next.git > > Next steps: > ----------- > (a) Post this patchset and iproute2/vdpa inclusion, remaining two drivers > will be coverted to support vdpa tool instead of creating unmanaged default > device on driver load. > (b) More net specific parameters such as mac, mtu will be added. > (c) Features bits get and set interface will be added. Adding Yong Ji for sharing some thoughts from the view of userspace vDPA device. Thanks