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 7F8BEFA3744 for ; Mon, 31 Oct 2022 13:51:16 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1opVBZ-0002T8-JM; Mon, 31 Oct 2022 09:50:41 -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 1opVBW-0002R2-Ts for qemu-devel@nongnu.org; Mon, 31 Oct 2022 09:50:39 -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 1opVBU-0008P5-Pl for qemu-devel@nongnu.org; Mon, 31 Oct 2022 09:50:38 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1667224235; 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=UjSDTtlqXaAJEl+LPIikK84n3xPN46awoYe7rcX5Uh4=; b=SzKbm8zUyvsWS45XyeFTn2HSgpKcnqPL107jvXKoUHJfcQhEzlawdiJvNZQtx7C/Pm+aip EN8ZQlbl4X4Qbz4xTU4y8TE+e7vsZdn8fY+6piE/KF7+15pZK7UGSiUmxY+H4sHCGqvgk7 78JuE2Kp9w6JkM6qp1uZtjqbU0nMLQc= Received: from mimecast-mx02.redhat.com (mx3-rdu2.redhat.com [66.187.233.73]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.2, cipher=TLS_ECDHE_RSA_WITH_AES_256_GCM_SHA384) id us-mta-65-Q1Z6qiFzPb6eghuX-JyWtg-1; Mon, 31 Oct 2022 09:50:32 -0400 X-MC-Unique: Q1Z6qiFzPb6eghuX-JyWtg-1 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.rdu2.redhat.com [10.11.54.4]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 1355128004B0; Mon, 31 Oct 2022 13:50:32 +0000 (UTC) Received: from redhat.com (unknown [10.33.36.145]) by smtp.corp.redhat.com (Postfix) with ESMTPS id E77F72027061; Mon, 31 Oct 2022 13:50:27 +0000 (UTC) Date: Mon, 31 Oct 2022 13:50:24 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: qemu-devel@nongnu.org Cc: Laurent Vivier , Richard Henderson , Ani Sinha , Igor Mammedov , "Michael S. Tsirkin" , Thomas Huth , Paolo Bonzini , Eduardo Habkost , Marcel Apfelbaum , "Richard W.M. Jones" Subject: Re: [PATCH 0/4] hw: make TCO watchdog actually work by default for Q35 Message-ID: References: <20221031131934.425448-1-berrange@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <20221031131934.425448-1-berrange@redhat.com> User-Agent: Mutt/2.2.7 (2022-08-07) X-Scanned-By: MIMEDefang 3.1 on 10.11.54.4 Received-SPF: pass client-ip=170.10.129.124; envelope-from=berrange@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=-1.048, 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: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Sender: "Qemu-devel" Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org+qemu-devel=archiver.kernel.org@nongnu.org On Mon, Oct 31, 2022 at 01:19:30PM +0000, Daniel P. Berrangé wrote: > The TCO watchdog is unconditionally integrated into the Q35 machine > type by default, but at the same time is unconditionally disabled > from firing by a host config option that overrides guest OS attempts > to enable it. People have to know to set a magic -global to make > it non-broken Incidentally I found that originally the TCO watchdog was not unconditionally enabled. Its exposure to the guest could be turned on/off using -global ICH9-LPC.enable_tco=bool This was implemented for machine type compat, but it also gave apps a way to disable the watchdog functionality. Unfortunately that ability was discarded in this series: https://lore.kernel.org/all/1453564933-29638-1-git-send-email-ehabkost@redhat.com/ but the 'enable_tco' property still exists in QOM, but silently ignored. Seems we should either fix the impl of 'enable_tco', or remove the QOM property entirely, so we don't pretend it can be toggled anymore. With regards, Daniel -- |: 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 :|