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, URIBL_BLOCKED,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 CA446C433DF for ; Fri, 14 Aug 2020 05:34:27 +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 9C26A20791 for ; Fri, 14 Aug 2020 05:34:27 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 9C26A20791 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]:41272 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1k6SME-00024f-SR for qemu-devel@archiver.kernel.org; Fri, 14 Aug 2020 01:34:26 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:47866) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1k6SLh-0001eZ-0w for qemu-devel@nongnu.org; Fri, 14 Aug 2020 01:33:53 -0400 Received: from mga03.intel.com ([134.134.136.65]:34462) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1k6SLd-0002fi-W3 for qemu-devel@nongnu.org; Fri, 14 Aug 2020 01:33:52 -0400 IronPort-SDR: CrRiXL5pNT7p+CEdQYeo6CqP2cUBFaIdXMzovgI0ik24CF9kblzHFuB1/jzRJoWcdK7kSIALTA oTjjOYrwEuvg== X-IronPort-AV: E=McAfee;i="6000,8403,9712"; a="154323690" X-IronPort-AV: E=Sophos;i="5.76,311,1592895600"; d="scan'208";a="154323690" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 13 Aug 2020 22:33:42 -0700 IronPort-SDR: 17ObhB5L4p5rZsodtaj4w23ZImAhmDiWJogmKa2wPSRra7i4k7Xor01hjtt9SY9BA0hx1EzUd4 hSz/jzm8mpvw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.76,311,1592895600"; d="scan'208";a="325623341" Received: from joy-optiplex-7040.sh.intel.com (HELO joy-OptiPlex-7040) ([10.239.13.16]) by orsmga008.jf.intel.com with ESMTP; 13 Aug 2020 22:33:36 -0700 Date: Fri, 14 Aug 2020 13:16:01 +0800 From: Yan Zhao To: Jason Wang Subject: Re: device compatibility interface for live migration with assigned devices Message-ID: <20200814051601.GD15344@joy-OptiPlex-7040> References: <20200804183503.39f56516.cohuck@redhat.com> <20200805021654.GB30485@joy-OptiPlex-7040> <2624b12f-3788-7e2b-2cb7-93534960bcb7@redhat.com> <20200805075647.GB2177@nanopsycho> <20200805093338.GC30485@joy-OptiPlex-7040> <20200805105319.GF2177@nanopsycho> <20200810074631.GA29059@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) Received-SPF: pass client-ip=134.134.136.65; envelope-from=yan.y.zhao@intel.com; helo=mga03.intel.com X-detected-operating-system: by eggs.gnu.org: First seen = 2020/08/14 01:33:42 X-ACL-Warn: Detected OS = FreeBSD 9.x or newer [fuzzy] X-Spam_score_int: -68 X-Spam_score: -6.9 X-Spam_bar: ------ X-Spam_report: (-6.9 / 5.0 requ) BAYES_00=-1.9, RCVD_IN_DNSWL_HI=-5, SPF_HELO_NONE=0.001, SPF_PASS=-0.001, URIBL_BLOCKED=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, qemu-devel@nongnu.org, kwankhede@nvidia.com, eauger@redhat.com, xin-ran.wang@intel.com, corbet@lwn.net, eskultet@redhat.com, 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 , smooney@redhat.com, intel-gvt-dev@lists.freedesktop.org, berrange@redhat.com, Cornelia Huck , Jiri Pirko , dinechin@redhat.com, devel@ovirt.org Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, Aug 13, 2020 at 12:24:50PM +0800, Jason Wang wrote: > > On 2020/8/10 下午3:46, Yan Zhao wrote: > > > driver is it handled by? > > It looks that the devlink is for network device specific, and in > > devlink.h, it says > > include/uapi/linux/devlink.h - Network physical device Netlink > > interface, > > > Actually not, I think there used to have some discussion last year and the > conclusion is to remove this comment. > > It supports IB and probably vDPA in the future. > hmm... sorry, I didn't find the referred discussion. only below discussion regarding to why to add devlink. https://www.mail-archive.com/netdev@vger.kernel.org/msg95801.html >This doesn't seem to be too much related to networking? Why can't something >like this be in sysfs? It is related to networking quite bit. There has been couple of iteration of this, including sysfs and configfs implementations. There has been a consensus reached that this should be done by netlink. I believe netlink is really the best for this purpose. Sysfs is not a good idea https://www.mail-archive.com/netdev@vger.kernel.org/msg96102.html >there is already a way to change eth/ib via >echo 'eth' > /sys/bus/pci/drivers/mlx4_core/0000:02:00.0/mlx4_port1 > >sounds like this is another way to achieve the same? It is. However the current way is driver-specific, not correct. For mlx5, we need the same, it cannot be done in this way. Do devlink is the correct way to go. https://lwn.net/Articles/674867/ There a is need for some userspace API that would allow to expose things that are not directly related to any device class like net_device of ib_device, but rather chip-wide/switch-ASIC-wide stuff. Use cases: 1) get/set of port type (Ethernet/InfiniBand) 2) monitoring of hardware messages to and from chip 3) setting up port splitters - split port into multiple ones and squash again, enables usage of splitter cable 4) setting up shared buffers - shared among multiple ports within one chip we actually can also retrieve the same information through sysfs, .e.g |- [path to device] |--- migration | |--- self | | |---device_api | | |---mdev_type | | |---software_version | | |---device_id | | |---aggregator | |--- compatible | | |---device_api | | |---mdev_type | | |---software_version | | |---device_id | | |---aggregator > > > I feel like it's not very appropriate for a GPU driver to use > > this interface. Is that right? > > > I think not though most of the users are switch or ethernet devices. It > doesn't prevent you from inventing new abstractions. so need to patch devlink core and the userspace devlink tool? e.g. devlink migration > Note that devlink is based on netlink, netlink has been widely used by > various subsystems other than networking. the advantage of netlink I see is that it can monitor device status and notify upper layer that migration database needs to get updated. But not sure whether openstack would like to use this capability. As Sean said, it's heavy for openstack. it's heavy for vendor driver as well :) And devlink monitor now listens the notification and dumps the state changes. If we want to use it, need to let it forward the notification and dumped info to openstack, right? Thanks Yan