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=-5.2 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS, USER_AGENT_SANE_1 autolearn=no 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 B01EDC433DF for ; Wed, 19 Aug 2020 07:14:37 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 921AB2054F for ; Wed, 19 Aug 2020 07:14:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726640AbgHSHOf (ORCPT ); Wed, 19 Aug 2020 03:14:35 -0400 Received: from mga05.intel.com ([192.55.52.43]:21269 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726570AbgHSHOf (ORCPT ); Wed, 19 Aug 2020 03:14:35 -0400 IronPort-SDR: zKM8CocMBkV5F4Gh4T6STG8QYBStDurDTZ80LoTnRb5i88YPbFCHUIBzFkuQGW2nT8QOdxgwHt 2OMbWFX0p64Q== X-IronPort-AV: E=McAfee;i="6000,8403,9717"; a="239893512" X-IronPort-AV: E=Sophos;i="5.76,330,1592895600"; d="scan'208";a="239893512" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga105.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 19 Aug 2020 00:14:35 -0700 IronPort-SDR: PAPOtQiS5AEH7w6GZmZ28FX+s6MpshHF1iZBNLdKvJlaDZP02BUDim8JqOPED1R5xUX76DUNVG +AppG9uv2lOA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.76,330,1592895600"; d="scan'208";a="326998478" Received: from joy-optiplex-7040.sh.intel.com (HELO joy-OptiPlex-7040) ([10.239.13.16]) by orsmga008.jf.intel.com with ESMTP; 19 Aug 2020 00:14:28 -0700 Date: Wed, 19 Aug 2020 14:59:51 +0800 From: Yan Zhao To: Jason Wang Cc: Parav Pandit , Cornelia Huck , Daniel =?iso-8859-1?Q?P=2E_Berrang=E9?= , "kvm@vger.kernel.org" , "libvir-list@redhat.com" , "qemu-devel@nongnu.org" , Kirti Wankhede , "eauger@redhat.com" , "xin-ran.wang@intel.com" , "corbet@lwn.net" , "openstack-discuss@lists.openstack.org" , "shaohe.feng@intel.com" , "kevin.tian@intel.com" , Parav Pandit , "jian-feng.ding@intel.com" , "dgilbert@redhat.com" , "zhenyuw@linux.intel.com" , "hejie.xu@intel.com" , "bao.yumeng@zte.com.cn" , Alex Williamson , "eskultet@redhat.com" , "sm ooney@redhat.com" , "intel-gvt-dev@lists.freedesktop.org" , Jiri Pirko , "dinechin@redhat.com" , "devel@ovirt.org" Subject: Re: [ovirt-devel] Re: device compatibility interface for live migration with assigned devices Message-ID: <20200819065951.GB21172@joy-OptiPlex-7040> Reply-To: Yan Zhao References: <20200814051601.GD15344@joy-OptiPlex-7040> <20200818085527.GB20215@redhat.com> <3a073222-dcfe-c02d-198b-29f6a507b2e1@redhat.com> <20200818091628.GC20215@redhat.com> <20200818113652.5d81a392.cohuck@redhat.com> <20200819033035.GA21172@joy-OptiPlex-7040> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/1.9.4 (2018-02-28) Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Wed, Aug 19, 2020 at 02:57:34PM +0800, Jason Wang wrote: > > On 2020/8/19 上午11:30, Yan Zhao wrote: > > hi All, > > could we decide that sysfs is the interface that every VFIO vendor driver > > needs to provide in order to support vfio live migration, otherwise the > > userspace management tool would not list the device into the compatible > > list? > > > > if that's true, let's move to the standardizing of the sysfs interface. > > (1) content > > common part: (must) > > - software_version: (in major.minor.bugfix scheme) > > > This can not work for devices whose features can be negotiated/advertised > independently. (E.g virtio devices) > sorry, I don't understand here, why virtio devices need to use vfio interface? I think this thread is discussing about vfio related devices. > > > - device_api: vfio-pci or vfio-ccw ... > > - type: mdev type for mdev device or > > a signature for physical device which is a counterpart for > > mdev type. > > > > device api specific part: (must) > > - pci id: pci id of mdev parent device or pci id of physical pci > > device (device_api is vfio-pci)API here. > > > So this assumes a PCI device which is probably not true. > for device_api of vfio-pci, why it's not true? for vfio-ccw, it's subchannel_type. > > > - subchannel_type (device_api is vfio-ccw) > > vendor driver specific part: (optional) > > - aggregator > > - chpid_type > > - remote_url > > > For "remote_url", just wonder if it's better to integrate or reuse the > existing NVME management interface instead of duplicating it here. Otherwise > it could be a burden for mgmt to learn. E.g vendor A may use "remote_url" > but vendor B may use a different attribute. > it's vendor driver specific. vendor specific attributes are inevitable, and that's why we are discussing here of a way to standardizing of it. our goal is that mgmt can use it without understanding the meaning of vendor specific attributes. > > > > > NOTE: vendors are free to add attributes in this part with a > > restriction that this attribute is able to be configured with the same > > name in sysfs too. e.g. > > > Sysfs works well for common attributes belongs to a class, but I'm not sure > it can work well for device/vendor specific attributes. Does this mean mgmt > need to iterate all the attributes in both src and dst? > no. just attributes under migration directory. > > > for aggregator, there must be a sysfs attribute in device node > > /sys/devices/pci0000:00/0000:00:02.0/882cc4da-dede-11e7-9180-078a62063ab1/intel_vgpu/aggregator, > > so that the userspace tool is able to configure the target device > > according to source device's aggregator attribute. > > > > > > (2) where and structure > > proposal 1: > > |- [path to device] > > |--- migration > > | |--- self > > | | |-software_version > > | | |-device_api > > | | |-type > > | | |-[pci_id or subchannel_type] > > | | |- > > | |--- compatible > > | | |-software_version > > | | |-device_api > > | | |-type > > | | |-[pci_id or subchannel_type] > > | | |- > > multiple compatible is allowed. > > attributes should be ASCII text files, preferably with only one value > > per file. > > > > > > proposal 2: use bin_attribute. > > |- [path to device] > > |--- migration > > | |--- self > > | |--- compatible > > > > so we can continue use multiline format. e.g. > > cat compatible > > software_version=0.1.0 > > device_api=vfio_pci > > type=i915-GVTg_V5_{val1:int:1,2,4,8} > > pci_id=80865963 > > aggregator={val1}/2 > > > So basically two questions: > > - how hard to standardize sysfs API for dealing with compatibility check (to > make it work for most types of devices) sorry, I just know we are in the process of standardizing of it :) > - how hard for the mgmt to learn with a vendor specific attributes (vs > existing management API) what is existing management API? Thanks