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=-0.6 required=3.0 tests=DKIM_INVALID,DKIM_SIGNED, 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 2CE4CC5ACBF for ; Fri, 13 Mar 2020 09:37:25 +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 F03FF2073E for ; Fri, 13 Mar 2020 09:37:24 +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="hsxp0wlQ" DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org F03FF2073E 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]:56100 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jCgku-0000db-6K for qemu-devel@archiver.kernel.org; Fri, 13 Mar 2020 05:37:24 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:47780) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1jCgj7-00062a-4i for qemu-devel@nongnu.org; Fri, 13 Mar 2020 05:35:34 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1jCgj5-0000Il-BI for qemu-devel@nongnu.org; Fri, 13 Mar 2020 05:35:32 -0400 Received: from us-smtp-delivery-1.mimecast.com ([205.139.110.120]:39762 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 1jCgj5-0000Fh-5M for qemu-devel@nongnu.org; Fri, 13 Mar 2020 05:35:31 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1584092129; 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=6QONFVL31dn4a5WaWws7Lyy3oKhCx4xrGr+nCVIN6wM=; b=hsxp0wlQ8SnxvLL06uppr3D5UY9LWf1LhK3EiQdVYzgdPHUBDNnQwTpeTBiW9X7EPKX1Pc guNDSsBYvDhwNk31qfXL6nWAeqoiXqmqTcexw17/ElceDZ/DY3pZKe1vNU/j4T3JVQiXlF 8wQj7suVLD1wNBhldjNL1XWhNYKWcic= 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-180-YBbNXAnaPUCxss5KuNGulA-1; Fri, 13 Mar 2020 05:35:27 -0400 X-MC-Unique: YBbNXAnaPUCxss5KuNGulA-1 Received: from smtp.corp.redhat.com (int-mx03.intmail.prod.int.phx2.redhat.com [10.5.11.13]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 2F660189CD02; Fri, 13 Mar 2020 09:35:26 +0000 (UTC) Received: from localhost (ovpn-200-60.brq.redhat.com [10.40.200.60]) by smtp.corp.redhat.com (Postfix) with ESMTP id 46C84909FD; Fri, 13 Mar 2020 09:35:20 +0000 (UTC) Date: Fri, 13 Mar 2020 10:35:18 +0100 From: Igor Mammedov To: Liran Alon Subject: Re: [PATCH] acpi: Add Windows ACPI Emulated Device Table (WAET) Message-ID: <20200313103518.072e1edc@redhat.com> In-Reply-To: <1cd97deb-be90-5698-a99a-14bd4918a82d@oracle.com> References: <20200311170826.79419-1-liran.alon@oracle.com> <20200311162509-mutt-send-email-mst@kernel.org> <92564357-25c1-0a0f-537b-6902f45a88d0@oracle.com> <20200312012859-mutt-send-email-mst@kernel.org> <8cab6eba-22bc-a62e-d4a8-e2138b815a01@oracle.com> <20200312080602-mutt-send-email-mst@kernel.org> <20200312173527.3a218dc0@redhat.com> <1cd97deb-be90-5698-a99a-14bd4918a82d@oracle.com> MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.79 on 10.5.11.13 X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] X-Received-From: 205.139.110.120 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: , Cc: ehabkost@redhat.com, "Michael S. Tsirkin" , qemu-devel@nongnu.org, Elad Gabay , pbonzini@redhat.com, rth@twiddle.net Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On Thu, 12 Mar 2020 20:48:48 +0200 Liran Alon wrote: > On 12/03/2020 18:35, Igor Mammedov wrote: > > On Thu, 12 Mar 2020 14:55:50 +0200 > > Liran Alon wrote: > > > >> On 12/03/2020 14:19, Michael S. Tsirkin wrote: > >>> On Thu, Mar 12, 2020 at 01:30:01PM +0200, Liran Alon wrote: > >>>> On 12/03/2020 8:12, Michael S. Tsirkin wrote: > >>>>> On Thu, Mar 12, 2020 at 01:20:02AM +0200, Liran Alon wrote: > >>>>>> But this is just a good practice in general and in the past it was said by > >>>>>> maintainers that this is one of the main reasons that ACPI and SMBIOS > >>>>>> generation have moved from SeaBIOS to QEMU. > >>>>> I think a flag to disable this might make sense though. For example, > >>>>> some guests might behave differently and get broken. > >>>> Right. That's why I think it's a good practice to have this flag and tie it > >>>> to machine-type. > >>> Tying things to the machine type is not what I had in mind. > >>> A separate flag would also be helpful so users can tweak this > >>> for new machine types, too. > >> I think it's unnecessary, given how common WAET ACPI table is exposed by > >> default by other hypervisors. > >> > >> But if you insist, I can add such flag on a separate commit in v2... > >> Where do you want to have such flag? It cannot be a property of some > >> qdev object. > >> So you want to add a new QEMU_OPTION_no_weat in vl.c? > > If it doesn't break any windows guests we probably don't need an option. > > Can you test if old guests are booting fine with new table, to confirm > > that it's fine? (starting with XPsp3) > > Old guests boot fine with the new WAET table. > We are running with this table in production for many years with many > Windows XP guests (and much more esoteric guests) > > Just to verify, I've just now run it with a WinXP SP3 VM and it works > just fine. > So should I remove the flag completely or remain with the current > functionality I have that makes sure WAET is only exposed on new > machine-types? In this case I'd drop flag. > > -Liran > > >>>> Guest-visible changes shouldn't be exposed to old machine-types. > >>> Well almost any change in qemu is guest visible to some level. > >>> Even optimizations are guest visible. > >>> We made changes in ACPI without versioning in the past but I'm not > >>> opposed to versioning here. However in that case pls do add a bit > >>> of documentation about why this is done here. > >> I remember that maintainers have explicitly specified that ACPI/SMBIOS > >> should not be changed between machine-types. > >> This have been one of the reasons to move ACPI/SMBIOS generation from > >> SeaBIOS to QEMU control. > >> > >> What can of documentation you want me to add and where? > >> The only thing I can say is that I tie it to machine-type because I do > >> not think a given machine-type should suddenly change BIOS exposed info > >> to guest. > >> But that's kinda generic. I haven't found similar documentation in other > >> ACPI-disable flags to copy from (E.g. do_not_add_smb_acpi). > >> > >>> What I am asking about is whether we need a flag to disable > >>> this as part of the stable interface. > >> I personally think not. But if you think otherwise, can you provide > >> guidance of where you suggest to add this flag? > >> As the only place I see fit is adding a new QEMU_OPTION_no_weat. >