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 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 smtp.lore.kernel.org (Postfix) with ESMTPS id C1BD3C3DA64 for ; Thu, 1 Aug 2024 15:59:24 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1sZYCL-0003sE-Ex; Thu, 01 Aug 2024 11:58:37 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sZYCI-0003fY-7u for qemu-devel@nongnu.org; Thu, 01 Aug 2024 11:58:34 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1sZYCF-0008Je-C9 for qemu-devel@nongnu.org; Thu, 01 Aug 2024 11:58:33 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1722527909; h=from:from:reply-to: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=47nvAc0T0Uug6qvmgG658rUZGi8EVVmvavXa3Ool2QE=; b=Rf2lF8Tt+q7Hlm2y8YAfBfuki6Awa00wpjJNxsxqm0/K3eyIJI/I2cVhPlh9wc6L3lW2jZ yY9W80Tlw0ZbPmxnEoQ3valbQl6O0h7H0BR8eU7akVTtMSdZmJLmDd5olXBmK0kuduT0XP An6G92HR5dwrqbwJ+JZKIr23by0kJiI= Received: from mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-681-Ram8xBgbO_C5V2g0Kd9ljg-1; Thu, 01 Aug 2024 11:58:24 -0400 X-MC-Unique: Ram8xBgbO_C5V2g0Kd9ljg-1 Received: from mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.15]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mx-prod-mc-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 475BF1955D62; Thu, 1 Aug 2024 15:58:22 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.109]) by mx-prod-int-02.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 8BE3D1955D42; Thu, 1 Aug 2024 15:58:16 +0000 (UTC) Date: Thu, 1 Aug 2024 16:58:12 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: "Michael S. Tsirkin" Cc: Peter Xu , Thomas Huth , Yuri Benditovich , eduardo@habkost.net, marcel.apfelbaum@gmail.com, philmd@linaro.org, wangyanan55@huawei.com, dmitry.fleytman@gmail.com, akihiko.odaki@daynix.com, jasowang@redhat.com, sriram.yagnaraman@est.tech, sw@weilnetz.de, qemu-devel@nongnu.org, yan@daynix.com, Fabiano Rosas , devel@lists.libvirt.org Subject: Re: [PATCH v2 4/4] virtio-net: Add support for USO features Message-ID: References: <20240730151746-mutt-send-email-mst@kernel.org> <20240730172148-mutt-send-email-mst@kernel.org> <20240731033803-mutt-send-email-mst@kernel.org> <20240801014222-mutt-send-email-mst@kernel.org> <20240801114900-mutt-send-email-mst@kernel.org> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20240801114900-mutt-send-email-mst@kernel.org> User-Agent: Mutt/2.2.12 (2023-09-09) X-Scanned-By: MIMEDefang 3.0 on 10.30.177.15 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -21 X-Spam_score: -2.2 X-Spam_bar: -- X-Spam_report: (-2.2 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.131, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_NONE=-0.0001, RCVD_IN_MSPIKE_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=0.001, RCVD_IN_VALIDITY_SAFE_BLOCKED=0.001, 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: 2.1.29 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Thu, Aug 01, 2024 at 11:50:40AM -0400, Michael S. Tsirkin wrote: > On Thu, Aug 01, 2024 at 04:45:17PM +0100, Daniel P. Berrangé wrote: > > So to ensure a QEMU is started with migration compatible features > > will still require teaching libvirt about every single feature > > that has a host kernel dependancy, so libvirt (or the app using > > libvirt) knows to turn this off. This is alot more work for both > > libvirt & the mgmt app, than having QEMU provide the generic > > "platforms" concept which is extensible without needing further > > work outside QEMU. > > I am just not sure it can all amount to selecting from a list. > For example, some resource can be limited on one host or another. > Thus we get a number. Or there could be a set of N flags, with 2^N > combinations. We don't have to support all possible combinations IMHO. If a user really does require precise control over every combination of some settings, then exposing those tunables in libvirt is inevitable. The platform concept only has to be able to express a "good enough" subset of combinations, such that it is unlikely users will need to have fine tuning for most of the tunables. We might end up exposing a handful of tunables in libvirt anyway, but as long as we get the common case satisifed, we'll eliminate most of the ongoing burden. With regards, Daniel -- |: https://berrange.com -o- https://www.flickr.com/photos/dberrange :| |: https://libvirt.org -o- https://fstop138.berrange.com :| |: https://entangle-photo.org -o- https://www.instagram.com/dberrange :|