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 70B7BC04FFE for ; Mon, 29 Apr 2024 14:03:34 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1s1Raa-0002Bf-I7; Mon, 29 Apr 2024 10:02:40 -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 1s1RaZ-0002BX-6a for qemu-devel@nongnu.org; Mon, 29 Apr 2024 10:02:39 -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 1s1RaW-0005ZH-Vv for qemu-devel@nongnu.org; Mon, 29 Apr 2024 10:02:38 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1714399355; 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=WhHwTMeuLgn8YWXUwPdpVnY0QjCwRoSzG6U+J1nWd9Y=; b=ElWXRyilGxMyWO8uIiOT4ciJfybk0xJcDvhbANwDAp/23RDqFi1/A62U2cpmYtGSgYHAYH H8LGmCOZdQeg5vNSgsId5QBWi/YAJXVWUPJKG/yh+v9ugOh2ApgEwwFfFLms/A1IlgfRls 56Nd2BiRtW4y/vlmQit/lJqdPVlvi5Y= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-161-llG11ZM7NLCgveYwLFgBQA-1; Mon, 29 Apr 2024 10:02:32 -0400 X-MC-Unique: llG11ZM7NLCgveYwLFgBQA-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.rdu2.redhat.com [10.11.54.7]) (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 mimecast-mx02.redhat.com (Postfix) with ESMTPS id ADA7C8FDD28; Mon, 29 Apr 2024 14:02:17 +0000 (UTC) Received: from blackfin.pond.sub.org (unknown [10.39.192.247]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 5B2A31C060D1; Mon, 29 Apr 2024 14:02:17 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id 7AEDA21E66E5; Mon, 29 Apr 2024 16:02:16 +0200 (CEST) From: Markus Armbruster To: Philippe =?utf-8?Q?Mathieu-Daud=C3=A9?= Cc: Daniil Tatianin , "Michael S. Tsirkin" , Paolo Bonzini , Eric Blake , qemu-devel@nongnu.org, Peter Maydell Subject: Re: [PATCH] mc146818rtc: add a way to generate RTC interrupts via QMP In-Reply-To: <40bee8cc-6cad-4c5b-a319-49dcbb2b82f1@linaro.org> ("Philippe =?utf-8?Q?Mathieu-Daud=C3=A9=22's?= message of "Mon, 29 Apr 2024 15:39:57 +0200") References: <20240425133745.464091-1-d-tatianin@yandex-team.ru> <87v844y0ul.fsf@pond.sub.org> <11c78645-e87b-4a43-8191-a73540c364a9@linaro.org> <87plu8ieut.fsf@pond.sub.org> <40bee8cc-6cad-4c5b-a319-49dcbb2b82f1@linaro.org> Date: Mon, 29 Apr 2024 16:02:16 +0200 Message-ID: <87zftcfes7.fsf@pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.7 Received-SPF: pass client-ip=170.10.129.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -30 X-Spam_score: -3.1 X-Spam_bar: --- X-Spam_report: (-3.1 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.987, 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_H4=0.001, RCVD_IN_MSPIKE_WL=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 Philippe Mathieu-Daud=C3=A9 writes: > (+Peter who has more experience on such design). > > On 29/4/24 13:32, Markus Armbruster wrote: >> Philippe Mathieu-Daud=C3=A9 writes: [...] >>> IMO to avoid any future ambiguity (in heterogeneous machines), this >>> command must take a QOM device path (or a list of) and only notify >>> those. >>=20 >> Let's compare: >>=20 >> =E2=80=A2 With QOM path: >>=20 >> =C2=B7 You need to know the machine's RTC device(s). >>=20 >> Unfortunately, this is bothersome, as the QOM path is not stable. > > But we'll need more of that with dynamic machines... I view /machine/unattached a technical debt (see "hate" right below). It saved us the trouble of coming up with sensible names for onboard devices. And now the interest is about to be due. >> For Q35, it's generally "/machine/unattached/device[N]/rtc", but N >> varies with configuration (TCG N=3D2, KVM N=3D3 for me), and it mig= ht >> vary with machine type version. That's because the machine code >> creates ICH9-LPC without a proper name. We do that a lot. I hate >> it. >>=20 >> Likewise for i440FX with PIIX3 instead of ICH9-LPC. >>=20 >> For isapc, it's /machine/unattached/device[3]. I suspect the 3 >> isn't reliable there, either. >>=20 >> microvm doesn't seem to have an RTC by default. [...]