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=-2.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 CF37AECE58E for ; Thu, 17 Oct 2019 16:56:17 +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 A589520820 for ; Thu, 17 Oct 2019 16:56:17 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org A589520820 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]:53412 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iL94S-0005RT-CI for qemu-devel@archiver.kernel.org; Thu, 17 Oct 2019 12:56:16 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:37273) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1iL8Ts-0007OX-Hg for qemu-devel@nongnu.org; Thu, 17 Oct 2019 12:18:29 -0400 Received: from Debian-exim by eggs.gnu.org with spam-scanned (Exim 4.71) (envelope-from ) id 1iL8Tr-0003Or-JT for qemu-devel@nongnu.org; Thu, 17 Oct 2019 12:18:28 -0400 Received: from mx1.redhat.com ([209.132.183.28]:56826) by eggs.gnu.org with esmtps (TLS1.0:DHE_RSA_AES_256_CBC_SHA1:32) (Exim 4.71) (envelope-from ) id 1iL8Tr-0003OX-EA for qemu-devel@nongnu.org; Thu, 17 Oct 2019 12:18:27 -0400 Received: from smtp.corp.redhat.com (int-mx04.intmail.prod.int.phx2.redhat.com [10.5.11.14]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 6CCF718CB915; Thu, 17 Oct 2019 16:18:26 +0000 (UTC) Received: from [10.36.117.42] (ovpn-117-42.ams2.redhat.com [10.36.117.42]) by smtp.corp.redhat.com (Postfix) with ESMTP id 641445D9CA; Thu, 17 Oct 2019 16:18:23 +0000 (UTC) Subject: Re: Default CPU models on s390x and ppc64 To: Peter Maydell References: <20191017151606.GA1880840@orkuz.int.mamuti.net> <82ea23ea-be23-c374-3f10-65d8f6e79432@redhat.com> From: David Hildenbrand Organization: Red Hat GmbH Message-ID: <1feb4b48-a380-8c9e-561d-d62e8e45b3e8@redhat.com> Date: Thu, 17 Oct 2019 18:18:22 +0200 User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:68.0) Gecko/20100101 Thunderbird/68.1.1 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.14 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.6.2 (mx1.redhat.com [10.5.110.63]); Thu, 17 Oct 2019 16:18:26 +0000 (UTC) X-detected-operating-system: by eggs.gnu.org: GNU/Linux 2.2.x-3.x [generic] [fuzzy] X-Received-From: 209.132.183.28 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: David Gibson , Jiri Denemark , David Hildenbrand , QEMU Developers Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" On 17.10.19 18:13, Peter Maydell wrote: > On Thu, 17 Oct 2019 at 17:09, David Hildenbrand wrote: >> The default model under KVM is "host", under TCG it's "qemu". We should >> not use "qemu" under KVM, although it might work on some setups ... > > Possibly a tangent, but on Arm the approach we used to deal > with "'-cpu host' only works for kvm" was to define a "-cpu max" > meaning "best thing you can give me", which is an alias for > -cpu host with KVM and an alias for a CPU with all the extra > features we have emulation support under TCG. Then users can > use '-cpu max' and have something that generally will DTRT > regardless of accelerator. > We do have "-cpu max" on s390x as well. (under TCG, it enables some additional features over "qemu", under KVM it is basically "host). -- Thanks, David / dhildenb