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=-13.7 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, URIBL_BLOCKED,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 98F23C63777 for ; Mon, 30 Nov 2020 03:38:18 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 213AC206F9 for ; Mon, 30 Nov 2020 03:38:17 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="gFFs6fQc" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726969AbgK3Dh5 (ORCPT ); Sun, 29 Nov 2020 22:37:57 -0500 Received: from us-smtp-delivery-124.mimecast.com ([63.128.21.124]:51775 "EHLO us-smtp-delivery-124.mimecast.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726304AbgK3Dh4 (ORCPT ); Sun, 29 Nov 2020 22:37:56 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1606707388; 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=9dvBFyijkXomn/DdnU/wULW6sGAnhqEg3/Ff8ZEhTts=; b=gFFs6fQcAp/r6IdkyvTk9HvhtMKtXbQoAc0qp/kRZv4+g/rbyKKusoThqF2iP9qMCyGDlV aMTOHDnlY+x8tFNCfjo/GS3Hxykpj/WNA2oW8HJbVhTeMgFiwaFEzQ++atKNIbp2XqFx5L Z2TgyIYnLSHqlWVbTMf7iym7BRQtsQU= 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-54-ixcwaHmpMDu-ztlWPLhU7Q-1; Sun, 29 Nov 2020 22:36:25 -0500 X-MC-Unique: ixcwaHmpMDu-ztlWPLhU7Q-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A39168030A1; Mon, 30 Nov 2020 03:36:24 +0000 (UTC) Received: from [10.72.13.173] (ovpn-13-173.pek2.redhat.com [10.72.13.173]) by smtp.corp.redhat.com (Postfix) with ESMTP id 725691A882; Mon, 30 Nov 2020 03:36:19 +0000 (UTC) Subject: Re: [External] Re: [PATCH 0/7] Introduce vdpa management tool To: Yongji Xie , Parav Pandit Cc: virtualization@lists.linux-foundation.org, "Michael S. Tsirkin" , elic@nvidia.com, netdev@vger.kernel.org References: <20201112064005.349268-1-parav@nvidia.com> <5b2235f6-513b-dbc9-3670-e4c9589b4d1f@redhat.com> From: Jason Wang Message-ID: <182708df-1082-0678-49b2-15d0199f20df@redhat.com> Date: Mon, 30 Nov 2020 11:36:18 +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: Content-Type: text/plain; charset=utf-8; format=flowed Content-Transfer-Encoding: 8bit Content-Language: en-US X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Precedence: bulk List-ID: X-Mailing-List: netdev@vger.kernel.org On 2020/11/27 下午1:52, Yongji Xie wrote: > On Fri, Nov 27, 2020 at 11:53 AM Jason Wang > wrote: > > > 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 for adding me, Jason! > > Now I'm working on a v2 patchset for VDUSE (vDPA Device in Userspace) > [1]. This tool is very useful for the vduse device. So I'm considering > integrating this into my v2 patchset. But there is one problem： > > In this tool, vdpa device config action and enable action are combined > into one netlink msg: VDPA_CMD_DEV_NEW. But in vduse case, it needs to > be splitted because a chardev should be created and opened by a > userspace process before we enable the vdpa device (call > vdpa_register_device()). > > So I'd like to know whether it's possible (or have some plans) to add > two new netlink msgs something like: VDPA_CMD_DEV_ENABLE and > VDPA_CMD_DEV_DISABLE to make the config path more flexible. > Actually, we've discussed such intermediate step in some early discussion. It looks to me VDUSE could be one of the users of this. Or I wonder whether we can switch to use anonymous inode(fd) for VDUSE then fetching it via an VDUSE_GET_DEVICE_FD ioctl? Thanks > Thanks, > Yongji > > [1] https://www.spinics.net/lists/linux-mm/msg231576.html