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 5EE93C05027 for ; Tue, 14 Feb 2023 08:54:55 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1pRr54-00036O-PX; Tue, 14 Feb 2023 03:54:30 -0500 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 1pRr53-00036F-Nn for qemu-devel@nongnu.org; Tue, 14 Feb 2023 03:54:29 -0500 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1pRr51-0000p3-Ts for qemu-devel@nongnu.org; Tue, 14 Feb 2023 03:54:29 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1676364866; 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=fsjeipjiQ7yxq9BsCSYjsPDzA7VHoXsZUedJYItFDKQ=; b=NP3qvmQ9q2OAek6Dd3y+IAAiNpuORgwKg/7lje9qfunTF4H35dkLHKoQOFbpjMlSBRgISk cFWNFlu4lyfxSnx6Bfe1vQRTIMmnw0oGtEudJHZTBsGKL5f3DSSKBOES0qbGs6HPWWMr88 qe02gByWWm8ypMy0ZOBwzRrF0fVhEtc= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-528-uCio9HQVOvq8eEPu_JsLPw-1; Tue, 14 Feb 2023 03:54:24 -0500 X-MC-Unique: uCio9HQVOvq8eEPu_JsLPw-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.rdu2.redhat.com [10.11.54.3]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id C7A52971087; Tue, 14 Feb 2023 08:54:23 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.192.124]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 652BD1121318; Tue, 14 Feb 2023 08:54:23 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 3A8B421E6A1F; Tue, 14 Feb 2023 09:54:22 +0100 (CET) From: Markus Armbruster To: Daniel P. =?utf-8?Q?Berrang=C3=A9?= Cc: Vladimir Sementsov-Ogievskiy , qemu-devel@nongnu.org, eblake@redhat.com, eduardo@habkost.net, pbonzini@redhat.com, marcel.apfelbaum@gmail.com, mst@redhat.com, philmd@linaro.org, den-plotnikov@yandex-team.ru, antonkuchin@yandex-team.ru, "reviewer:Incompatible changes" Subject: Re: [PATCH v4 14/16] qapi: deprecate "device" field of DEVICE_* events References: <20230213140103.1518173-1-vsementsov@yandex-team.ru> <20230213140103.1518173-15-vsementsov@yandex-team.ru> Date: Tue, 14 Feb 2023 09:54:22 +0100 In-Reply-To: ("Daniel P. =?utf-8?Q?Berrang?= =?utf-8?Q?=C3=A9=22's?= message of "Mon, 13 Feb 2023 14:13:15 +0000") Message-ID: <87bklwoce9.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/28.2 (gnu/linux) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.1 on 10.11.54.3 Received-SPF: pass client-ip=170.10.133.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.001, 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_H2=-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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Daniel P. Berrang=C3=A9 writes: > On Mon, Feb 13, 2023 at 05:01:01PM +0300, Vladimir Sementsov-Ogievskiy wr= ote: >> The device field is redundant, because QOM path always include device >> ID when this ID exist. > > The flipside to that view is that applications configuring QEMU are > specifying the device ID for -device (CLI) / device_add (QMP) and > not the QOM path. IOW, the device ID is the more interesting field > than QOM path, so feels like the wrong one to be dropping. QOM path is a reliable way to identify a device. Device ID isn't: devices need not have one. Therefore, dropping the QOM path would be wrong. > Is there any real benefit to dropping this ?=20 The device ID is a trap for the unwary: relying on it is fine until you run into a scenario where you have to deal with devices lacking IDs. I suggested to deprecate it in review of "[PATCH v3 14/15] qapi: introduce DEVICE_ON event" (Message-ID: <873579x67l.fsf@pond.sub.org>). Quote: We commonly send both device ID and QOM path, mostly for historical reasons: the former precede the latter. There are exceptions, such as query-cpus-fast. Can't say offhand whether CPUs can be created with IDs. [...] I'd be in favour of deprecating and deleting redundant device IDs in QMP output.