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=-3.9 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS 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 66724C433E1 for ; Tue, 18 Aug 2020 09:39:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 31BB120825 for ; Tue, 18 Aug 2020 09:39:33 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Kl6ZHbwC" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726357AbgHRJjc (ORCPT ); Tue, 18 Aug 2020 05:39:32 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:43509 "EHLO us-smtp-1.mimecast.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1726145AbgHRJjb (ORCPT ); Tue, 18 Aug 2020 05:39:31 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1597743569; 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=EWyBYJmhu+RufU33YGRbdTkRS4E+NRocVAwpjFgsfPA=; b=Kl6ZHbwC7lO4OokhJLY1yOagjFfT9Kk4+alyvo3djTqWavpDkhg/B/B8D2U3oq64ixWqo0 iNwn/ea84pfBa/KifWYHDbOArCW+dhxdwDnpE1F+7qGBAMoPDy7YwQUbXpf9elm9H/zRx9 kp5jFrv+e0vP0OvTc9BWsWXkVt7EY4s= 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-446-8_MTxrkrPNSOf6jLgjwKDA-1; Tue, 18 Aug 2020 05:39:26 -0400 X-MC-Unique: 8_MTxrkrPNSOf6jLgjwKDA-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id C64571084C81; Tue, 18 Aug 2020 09:39:23 +0000 (UTC) Received: from gondolin (ovpn-112-221.ams2.redhat.com [10.36.112.221]) by smtp.corp.redhat.com (Postfix) with ESMTP id 06C215D9D2; Tue, 18 Aug 2020 09:38:57 +0000 (UTC) Date: Tue, 18 Aug 2020 11:38:55 +0200 From: Cornelia Huck To: "Daniel P. =?UTF-8?B?QmVycmFuZ8Op?=" Cc: Jason Wang , Yan Zhao , 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, 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, smooney@redhat.com, intel-gvt-dev@lists.freedesktop.org, Jiri Pirko , dinechin@redhat.com, devel@ovirt.org Subject: Re: device compatibility interface for live migration with assigned devices Message-ID: <20200818113855.647938c0.cohuck@redhat.com> In-Reply-To: <20200818092433.GD20215@redhat.com> References: <20200805075647.GB2177@nanopsycho> <20200805093338.GC30485@joy-OptiPlex-7040> <20200805105319.GF2177@nanopsycho> <20200810074631.GA29059@joy-OptiPlex-7040> <20200814051601.GD15344@joy-OptiPlex-7040> <20200818085527.GB20215@redhat.com> <20200818110617.05def37c.cohuck@redhat.com> <20200818092433.GD20215@redhat.com> Organization: Red Hat GmbH MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 Sender: kvm-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org On Tue, 18 Aug 2020 10:24:33 +0100 Daniel P. Berrang=C3=A9 wrote: > On Tue, Aug 18, 2020 at 11:06:17AM +0200, Cornelia Huck wrote: > > On Tue, 18 Aug 2020 09:55:27 +0100 > > Daniel P. Berrang=C3=A9 wrote: > > =20 > > > On Tue, Aug 18, 2020 at 11:24:30AM +0800, Jason Wang wrote: =20 > > > > Another point, as we discussed in another thread, it's really hard = to make > > > > sure the above API work for all types of devices and frameworks. So= having a > > > > vendor specific API looks much better. =20 > > >=20 > > > From the POV of userspace mgmt apps doing device compat checking / mi= gration, > > > we certainly do NOT want to use different vendor specific APIs. We wa= nt to > > > have an API that can be used / controlled in a standard manner across= vendors. =20 > >=20 > > As we certainly will need to have different things to check for > > different device types and vendor drivers, would it still be fine to > > have differing (say) attributes, as long as they are presented (and can > > be discovered) in a standardized way? =20 >=20 > Yes, the control API and algorithm to deal with the problem needs to > have standardization, but the data passed in/out of the APIs can vary. >=20 > Essentially the key is that vendors should be able to create devices > at the kernel, and those devices should "just work" with the existing > generic userspace migration / compat checking code, without needing > extra vendor specific logic to be added. >=20 > Note, I'm not saying that the userspace decisions would be perfectly > optimal based on generic code. They might be making a simplified > decision that while functionally safe, is not the ideal solution. > Adding vendor specific code might be able to optimize the userspace > decisions, but that should be considered just optimization, not a > core must have for any opertion. Yes, that sounds reasonable.