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=-0.9 required=3.0 tests=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 13BDDC33CB3 for ; Wed, 15 Jan 2020 12:27:14 +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 D78DC214AF for ; Wed, 15 Jan 2020 12:27:13 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=redhat.com header.i=@redhat.com header.b="Cf9r/D/K" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org D78DC214AF 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]:53034 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1irhlQ-000249-TK for qemu-devel@archiver.kernel.org; Wed, 15 Jan 2020 07:27:12 -0500 Received: from eggs.gnu.org ([2001:470:142:3::10]:47793) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1irhjm-0008EH-D5 for qemu-devel@nongnu.org; Wed, 15 Jan 2020 07:25:31 -0500 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1irhji-00033O-QE for qemu-devel@nongnu.org; Wed, 15 Jan 2020 07:25:30 -0500 Received: from us-smtp-1.mimecast.com ([207.211.31.81]:49410 helo=us-smtp-delivery-1.mimecast.com) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1irhji-000332-Mp for qemu-devel@nongnu.org; Wed, 15 Jan 2020 07:25:26 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1579091126; 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=LgVTufXyo/q47fR/teQLe9bmw5/5vM7mbmzGMIphM1c=; b=Cf9r/D/K32D0f/R6q0CwjKhGv2HGyrR/pmz0NHYpMjNLK11mffVZpRLFtjbXmoK7X8lDbr slKFfvrhgyUBF/KRM3t4XB9Hocvw9E+MdgQQUvyoo9Lvkj6xlH7RC4JcmJs/Rq6FNl/w3U sgDH42wS0d0ZdWO+/xteDGxPhnjO/Ho= 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-283-poN85bLbOBOPfR8WNXkEkQ-1; Wed, 15 Jan 2020 07:25:23 -0500 Received: from smtp.corp.redhat.com (int-mx06.intmail.prod.int.phx2.redhat.com [10.5.11.16]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id D1CB312BF5D; Wed, 15 Jan 2020 12:25:21 +0000 (UTC) Received: from blackfin.pond.sub.org (ovpn-116-131.ams2.redhat.com [10.36.116.131]) by smtp.corp.redhat.com (Postfix) with ESMTPS id DB41F5C219; Wed, 15 Jan 2020 12:25:16 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 6FF0F1138600; Wed, 15 Jan 2020 13:25:15 +0100 (CET) From: Markus Armbruster To: =?utf-8?Q?Marc-Andr=C3=A9?= Lureau Subject: Re: Making QEMU easier for management tools and applications References: <1EFEF446-AFEA-429F-B6BA-3206A7C41836@redhat.com> <20200108104306.GC5057@dhcp-200-226.str.redhat.com> <97F153BD-FB8A-46C7-90D0-9E894B9E0292@redhat.com> <20200108133842.GE5057@dhcp-200-226.str.redhat.com> <87d0bmchq0.fsf@dusky.pond.sub.org> <1B253197-5592-472A-AA26-E0614A13C91A@redhat.com> <87o8v52hz9.fsf@dusky.pond.sub.org> Date: Wed, 15 Jan 2020 13:25:15 +0100 In-Reply-To: (=?utf-8?Q?=22Marc-Andr=C3=A9?= Lureau"'s message of "Wed, 15 Jan 2020 13:35:21 +0400") Message-ID: <87muaozz2s.fsf@dusky.pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/26.3 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.16 X-MC-Unique: poN85bLbOBOPfR8WNXkEkQ-1 X-Mimecast-Spam-Score: 0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 207.211.31.81 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: , Cc: Kevin Wolf , Peter Maydell , "Daniel P. Berrange" , "Denis V. Lunev" , Stefan Hajnoczi , qemu-devel , Christophe de Dinechin , Paolo Bonzini , John Snow , Dominik Csapak Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Marc-Andr=C3=A9 Lureau writes: > Hi > > On Wed, Jan 15, 2020 at 1:21 PM Markus Armbruster wro= te: >> >> Christophe de Dinechin writes: >> >> >> To make this worthwhile, we'd have to replace dynamic QOM properties = by >> >> static ones when possible. Monumental task. >> > >> > I=E2=80=99m sure you are right, but it=E2=80=99s hard for me to evalua= te, given how >> > many ways there are to access an object. Naively, grepping for >> > set_prop and for new_with_prop does not give me that many hits. >> >> Look for object_property_add*(). Some 450 hits. > > fwiw, I have started tackling that. Laudable. > Easy first step is to move all QDev properties to class properties, > and this is done in : > https://patchew.org/QEMU/20200110153039.1379601-1-marcandre.lureau@redhat= .com/ Easy because qdev properties are declarative by design. Imperative came in when they got rebased onto QOM. > Moving from instance to class properties is straightforward many times > (when the property is unconditonally added in instance init for > example). There are a few complicated cases though. > > To me, the most problematic is reviewer-time and willingness to do > such low-benefits changes. Understand. >> Basing the QAPI language on JSON was a poor choice. Aggravated by immediately extending it in ways that defeat all common JSON tools. >> Not sure that's >> fixable at a reasonable cost. > > Translating it to another language should be relatively easy, but to what= ? The QAPI language is layered on top of JSON (see docs/devel/qapi-code-gen.txt section "Schema syntax"). Swapping out JSON for another language that is at least as expressive is an relatively simple change. Obvious candidates: s-expressions, TOML, YAML. The latter is far too complex for my taste. The expensive part is dealing with the conflicts during the transition, and having everybody relearn QAPI schema syntax.