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=-2.1 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 417F0C352A3 for ; Mon, 10 Feb 2020 11:09:20 +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 0D5802080C for ; Mon, 10 Feb 2020 11:09:20 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=fail reason="signature verification failed" (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="IQ7LgQ07" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 0D5802080C Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Received: from localhost ([::1]:60186 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j16wJ-0007OH-7P for qemu-devel@archiver.kernel.org; Mon, 10 Feb 2020 06:09:19 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:58667) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1j16vf-0006pw-Dg for qemu-devel@nongnu.org; Mon, 10 Feb 2020 06:08:40 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1j16ve-0004nd-6v for qemu-devel@nongnu.org; Mon, 10 Feb 2020 06:08:39 -0500 Received: from us-smtp-delivery-1.mimecast.com ([207.211.31.120]:45944 helo=us-smtp-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1j16ve-0004nN-3B for qemu-devel@nongnu.org; Mon, 10 Feb 2020 06:08:38 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1581332917; 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=xIb2kGGeRaHTC95b0eLfQB7HWNahXRCA/gEMap+k1Jk=; b=IQ7LgQ074SgMIv3QJxa8QLHvpUCPzYaQnkxghxEZCqCk5hcJR0jacQWtAHOE3Vg9kCGhG0 xxyXL4ftdd8jnpUDc5ZmrDQ/j3akFSPHSDQXGx6uJYzCtOW6fWKacgKvDy79kUXJGBn0lI xHmfvHTZKVkrCIVnl/1zqWuEONz0zaY= 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-63-jSwBx0IaP46F6gg866wynA-1; Mon, 10 Feb 2020 06:08:26 -0500 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id ED91818CA240; Mon, 10 Feb 2020 11:08:23 +0000 (UTC) Received: from redhat.com (ovpn-112-55.ams2.redhat.com [10.36.112.55]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 57EAB26FD6; Mon, 10 Feb 2020 11:08:15 +0000 (UTC) Date: Mon, 10 Feb 2020 11:08:12 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Peter Maydell Subject: Re: Summary of Re: Making QEMU easier for management tools and applications Message-ID: <20200210110812.GB3269@redhat.com> References: <875zgm2vqv.fsf@dusky.pond.sub.org> MIME-Version: 1.0 In-Reply-To: User-Agent: Mutt/1.13.3 (2020-01-12) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 X-MC-Unique: jSwBx0IaP46F6gg866wynA-1 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Content-Disposition: inline X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.120 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: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: Kevin Wolf , "Denis V. Lunev" , Stefan Hajnoczi , Markus Armbruster , qemu-devel , Paolo Bonzini , =?utf-8?Q?Marc-Andr=C3=A9?= Lureau , John Snow , Dominik Csapak Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Mon, Feb 10, 2020 at 11:01:48AM +0000, Peter Maydell wrote: > On Mon, 10 Feb 2020 at 10:57, Stefan Hajnoczi wrote: > > I'm in favor of simplifying QEMU at the expense of an incompatible CLI > > change in QEMU 6.0. >=20 > If we want to do wholesale incompatible changes to the CLI > I think we definitely need some kind of tool where a user > can say "here's my old command line, what's the new style > equivalent?". Otherwise we're going to have a deluge of > user issues where their old working setups broke and > QEMU didn't give them any useful hints about why. There is a risk that if we promise to have a fully automated conversion that it will be alot of work, and could force us to introduce hacks into the new impl just to satisfy conversion. IMHO we shouldn't be afraid of declaring that some parts of the old syntax can NOT be directly transformed into new syntax, simply for the sake of making a new impl more practical to move forward with. An alternative approach to mitigate the disruption is to *not* make any incompatible changes to qemu-system-XXXX. Instead introduce new binaries with the new syntax and any other architectural changes we wish to make. The old binaries can be deprecated but remain around for an extended period of time, to give people and apps time to migrate. We can provide rough guidance and perhaps partially automated conversion to help people move, but not aim for a 100% automated conversion.=20 Regards, Daniel --=20 |: 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= :|