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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,URIBL_BLOCKED autolearn=ham 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 6D245C43381 for ; Wed, 20 Feb 2019 09:22:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 3D3E921902 for ; Wed, 20 Feb 2019 09:22:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726772AbfBTJW4 (ORCPT ); Wed, 20 Feb 2019 04:22:56 -0500 Received: from mx1.redhat.com ([209.132.183.28]:48834 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1725989AbfBTJW4 (ORCPT ); Wed, 20 Feb 2019 04:22:56 -0500 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.phx2.redhat.com [10.5.11.15]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mx1.redhat.com (Postfix) with ESMTPS id 4B2CAC3A6D; Wed, 20 Feb 2019 09:22:56 +0000 (UTC) Received: from gondolin (dhcp-192-187.str.redhat.com [10.33.192.187]) by smtp.corp.redhat.com (Postfix) with ESMTP id 1E33F5D6B6; Wed, 20 Feb 2019 09:22:54 +0000 (UTC) Date: Wed, 20 Feb 2019 10:22:52 +0100 From: Cornelia Huck To: Guenter Roeck Cc: Martin Schwidefsky , Heiko Carstens , linux-s390@vger.kernel.org, linux-kernel@vger.kernel.org Subject: Re: [PATCH] s390/setup: fix early warning messages Message-ID: <20190220102252.43dd10a4.cohuck@redhat.com> In-Reply-To: References: <20190218154640.GA27699@roeck-us.net> <20190218180146.79930fe6@mschwideX1> <20190218182106.61b10ee4@mschwideX1> <20190218191655.103c81ca.cohuck@redhat.com> <05e78442-07e1-9783-965f-b3d64a2c5e99@roeck-us.net> <20190218233021.368bb475.cohuck@redhat.com> Organization: Red Hat GmbH MIME-Version: 1.0 Content-Type: text/plain; charset=US-ASCII Content-Transfer-Encoding: 7bit X-Scanned-By: MIMEDefang 2.79 on 10.5.11.15 X-Greylist: Sender IP whitelisted, not delayed by milter-greylist-4.5.16 (mx1.redhat.com [10.5.110.30]); Wed, 20 Feb 2019 09:22:56 +0000 (UTC) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Tue, 19 Feb 2019 10:47:38 -0800 Guenter Roeck wrote: > Hi Cornelia, > > On 2/18/19 2:30 PM, Cornelia Huck wrote: > > >> What is your qemu command line ? > > > > Ignoring any additional devices: > > > > s390x-softmmu/qemu-system-s390x -M s390-ccw-virtio,accel=tcg -cpu max -m 1024 -nographic -device virtio-scsi-ccw,id=scsi0,devno=fe.0.0001 -drive file=/home/cohuck/vm-images/vm1.qcow2,format=qcow2,if=none,id=drive-scsi0-0-0-0 -device scsi-hd,bus=scsi0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0-0-0-0,id=scsi0-0-0-0,bootindex=1 -sandbox on -kernel ~/git/linux/arch/s390/boot/bzImage -append "root=/dev/sda3" > > > > Is "accel=tcg" and "-cpu max" expected to make any difference ? CPU consumption > on my system seems to be identical to the default (no -M or -cpu on command line). > This is with qemu 3.1. If you're not running on a s390x, QEMU will pick tcg even if not specified (as it needs to emulate anyway), so that should not make any difference. The 'max' cpu model was is not yet available with 3.1 (merged in the current development cycle); it will not make much difference in practice (a few more cpu features are currently provided with it over the default 'qemu' cpu model). As I'm testing various combinations (tcg vs. kvm on an s390x host, different cpu models) when I'm queuing patches, my command line is not necessarily exactly the same every time (this was just the one I happened to be testing the kernel patch with). If you simply want to be able to boot a test kernel on a non-s390x host, relying on the default accelerator (tcg) and the default cpu model (qemu) being picked should be completely fine.