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=-5.5 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 D8D78C433E0 for ; Mon, 27 Jul 2020 07:36:32 +0000 (UTC) Received: from lists.gnu.org (lists.gnu.org [209.51.188.17]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id AC35F2072E for ; Mon, 27 Jul 2020 07:36:32 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org AC35F2072E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:58314 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jzxgW-0005ay-07 for qemu-devel@archiver.kernel.org; Mon, 27 Jul 2020 03:36:32 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:35432) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jzxfr-0005AA-3O for qemu-devel@nongnu.org; Mon, 27 Jul 2020 03:35:51 -0400 Received: from mga04.intel.com ([192.55.52.120]:50148) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1jzxfo-00050c-LF for qemu-devel@nongnu.org; Mon, 27 Jul 2020 03:35:50 -0400 IronPort-SDR: yHFcR5k7wsMg8gtPws5NLXmc1mtRVq9wubahL84CQU+Aqy7i27vJiMa7N/7QusPieUEOA9q28J EmAFo3mB/v3w== X-IronPort-AV: E=McAfee;i="6000,8403,9694"; a="148444269" X-IronPort-AV: E=Sophos;i="5.75,401,1589266800"; d="scan'208";a="148444269" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga001.jf.intel.com ([10.7.209.18]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Jul 2020 00:35:45 -0700 IronPort-SDR: 0ffjI+i+TsbheWV9B1ekyPjpDXDKX5V9QqFeMTIOUgqFnBjB7356oNacj5t1wADBNDmVTD6CU1 TSX+YyW3cBSQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.75,401,1589266800"; d="scan'208";a="364039470" Received: from joy-optiplex-7040.sh.intel.com (HELO joy-OptiPlex-7040) ([10.239.13.16]) by orsmga001.jf.intel.com with ESMTP; 27 Jul 2020 00:35:38 -0700 Date: Mon, 27 Jul 2020 15:24:40 +0800 From: Yan Zhao To: Alex Williamson Subject: Re: device compatibility interface for live migration with assigned devices Message-ID: <20200727072440.GA28676@joy-OptiPlex-7040> References: <20200713232957.GD5955@joy-OptiPlex-7040> <9bfa8700-91f5-ebb4-3977-6321f0487a63@redhat.com> <20200716083230.GA25316@joy-OptiPlex-7040> <20200717101258.65555978@x1.home> <20200721005113.GA10502@joy-OptiPlex-7040> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200721005113.GA10502@joy-OptiPlex-7040> User-Agent: Mutt/1.9.4 (2018-02-28) Received-SPF: pass client-ip=192.55.52.120; envelope-from=yan.y.zhao@intel.com; helo=mga04.intel.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/07/27 03:35:45 X-ACL-Warn: Detected OS = FreeBSD 9.x or newer [fuzzy] X-Spam_score_int: -41 X-Spam_score: -4.2 X-Spam_bar: ---- X-Spam_report: (-4.2 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_MED=-2.3, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=ham autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-devel@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Yan Zhao Cc: kvm@vger.kernel.org, libvir-list@redhat.com, Jason Wang , qemu-devel@nongnu.org, kwankhede@nvidia.com, eauger@redhat.com, xin-ran.wang@intel.com, corbet@lwn.net, openstack-discuss@lists.openstack.org, shaohe.feng@intel.com, kevin.tian@intel.com, eskultet@redhat.com, jian-feng.ding@intel.com, dgilbert@redhat.com, zhenyuw@linux.intel.com, hejie.xu@intel.com, bao.yumeng@zte.com.cn, smooney@redhat.com, intel-gvt-dev@lists.freedesktop.org, berrange@redhat.com, cohuck@redhat.com, dinechin@redhat.com, devel@ovirt.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" > > As you indicate, the vendor driver is responsible for checking version > > information embedded within the migration stream. Therefore a > > migration should fail early if the devices are incompatible. Is it > but as I know, currently in VFIO migration protocol, we have no way to > get vendor specific compatibility checking string in migration setup stage > (i.e. .save_setup stage) before the device is set to _SAVING state. > In this way, for devices who does not save device data in precopy stage, > the migration compatibility checking is as late as in stop-and-copy > stage, which is too late. > do you think we need to add the getting/checking of vendor specific > compatibility string early in save_setup stage? > hi Alex, after an offline discussion with Kevin, I realized that it may not be a problem if migration compatibility check in vendor driver occurs late in stop-and-copy phase for some devices, because if we report device compatibility attributes clearly in an interface, the chances for libvirt/openstack to make a wrong decision is little. so, do you think we are now arriving at an agreement that we'll give up the read-and-test scheme and start to defining one interface (perhaps in json format), from which libvirt/openstack is able to parse and find out compatibility list of a source mdev/physical device? Thanks Yan