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=-13.6 required=3.0 tests=BAYES_00,DKIM_INVALID, DKIM_SIGNED,HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,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 75B03C4338F for ; Fri, 23 Jul 2021 08:03:51 +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 BC4B460E8E for ; Fri, 23 Jul 2021 08:03:50 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.4.1 mail.kernel.org BC4B460E8E Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=redhat.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=nongnu.org Received: from localhost ([::1]:34046 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1m6q9t-00083c-Qo for qemu-devel@archiver.kernel.org; Fri, 23 Jul 2021 04:03:49 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:60286) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m6q8z-0007O7-V9 for qemu-devel@nongnu.org; Fri, 23 Jul 2021 04:02:53 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:41457) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1m6q8x-0003mv-8Q for qemu-devel@nongnu.org; Fri, 23 Jul 2021 04:02:53 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1627027370; 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=C41s+cxFDve2fB+LwOAyOoaqnVhovgqA3hp/MUIbBI4=; b=OfGs3y2dLU8yL0TJZXe2/M2n1MNSR6hFbL+asr8WYX8UZwa+TcygpMC79MzqeMA701MMN9 LomydqbO1ahNs4l/JIxlGqOUCncUtwtH7zxXwDECIC2zg+V0MAtXpf+eN5gPiOMcM5WG9Q s6CMO4wLPn87Nz3wpyc1H09qgQweQYQ= 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-133-oFiZyUWuOjuMpo70SHAwMQ-1; Fri, 23 Jul 2021 04:02:48 -0400 X-MC-Unique: oFiZyUWuOjuMpo70SHAwMQ-1 Received: from smtp.corp.redhat.com (int-mx07.intmail.prod.int.phx2.redhat.com [10.5.11.22]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id 0D1531074661; Fri, 23 Jul 2021 08:02:46 +0000 (UTC) Received: from blackfin.pond.sub.org (ovpn-114-187.ams2.redhat.com [10.36.114.187]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 31C03100164C; Fri, 23 Jul 2021 08:02:45 +0000 (UTC) Received: by blackfin.pond.sub.org (Postfix, from userid 1000) id AE51611326B9; Fri, 23 Jul 2021 10:02:43 +0200 (CEST) From: Markus Armbruster To: Daniel P. =?utf-8?Q?Berrang=C3=A9?= Subject: Re: [PATCH for-6.1 v2] machine: Disallow specifying topology parameters as zero References: <20210722154326.1464-1-wangyanan55@huawei.com> <20210722154326.1464-2-wangyanan55@huawei.com> Date: Fri, 23 Jul 2021 10:02:43 +0200 In-Reply-To: ("Daniel P. =?utf-8?Q?Berrang?= =?utf-8?Q?=C3=A9=22's?= message of "Thu, 22 Jul 2021 17:01:18 +0100") Message-ID: <87o8atcva4.fsf@dusky.pond.sub.org> User-Agent: Gnus/5.13 (Gnus v5.13) Emacs/27.2 (gnu/linux) MIME-Version: 1.0 X-Scanned-By: MIMEDefang 2.84 on 10.5.11.22 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=armbru@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=216.205.24.124; envelope-from=armbru@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -42 X-Spam_score: -4.3 X-Spam_bar: ---- X-Spam_report: (-4.3 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-1.472, DKIM_SIGNED=0.1, DKIM_VALID=-0.1, DKIM_VALID_AU=-0.1, DKIM_VALID_EF=-0.1, RCVD_IN_DNSWL_LOW=-0.7, 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: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Cc: Peter Maydell , Andrew Jones , Eduardo Habkost , Pierre Morel , Pankaj Gupta , Cornelia Huck , qemu-devel@nongnu.org, Yanan Wang , wanghaibin.wang@huawei.com, yuzenghui@huawei.com, Paolo Bonzini Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: "Qemu-devel" Daniel P. Berrang=C3=A9 writes: > On Thu, Jul 22, 2021 at 11:43:26PM +0800, Yanan Wang wrote: >> In the SMP configuration, we should either specify a topology >> parameter with a reasonable value (equal to or greater than 1) >> or just leave it omitted and QEMU will calculate its value. >> Configurations which explicitly specify the topology parameters >> as zero like "sockets=3D0" are meaningless, so disallow them. >>=20 >> However, the commit 1e63fe685804d >> (machine: pass QAPI struct to mc->smp_parse) has documented that >> '0' has the same semantics as omitting a parameter in the qapi >> comment for SMPConfiguration. So this patch fixes the doc and >> also adds the corresponding sanity check in the smp parsers. >>=20 >> Suggested-by: Andrew Jones >> Signed-off-by: Yanan Wang >> --- >> hw/core/machine.c | 14 ++++++++++++++ >> qapi/machine.json | 6 +++--- >> qemu-options.hx | 12 +++++++----- >> 3 files changed, 24 insertions(+), 8 deletions(-) >>=20 >> diff --git a/hw/core/machine.c b/hw/core/machine.c >> index 775add0795..db129d937b 100644 >> --- a/hw/core/machine.c >> +++ b/hw/core/machine.c >> @@ -829,6 +829,20 @@ static void machine_set_smp(Object *obj, Visitor *v= , const char *name, >> return; >> } >> =20 >> + /* >> + * The topology parameters must be specified equal to or great than= one >> + * or just omitted, explicit configuration like "cpus=3D0" is not a= llowed. >> + */ >> + if ((config->has_cpus && config->cpus =3D=3D 0) || >> + (config->has_sockets && config->sockets =3D=3D 0) || >> + (config->has_dies && config->dies =3D=3D 0) || >> + (config->has_cores && config->cores =3D=3D 0) || >> + (config->has_threads && config->threads =3D=3D 0) || >> + (config->has_maxcpus && config->maxcpus =3D=3D 0)) { >> + error_setg(errp, "parameters must be equal to or greater than o= ne if provided"); > > I'd suggest a slight tweak since when seen it lacks context: > > $ ./qemu-system-x86_64 -smp 4,cores=3D0,sockets=3D2 > qemu-system-x86_64: parameters must be equal to or greater than one if pr= ovided > > > error_setg(errp, "CPU topology parameters must be equal to or greater= than one if provided"); Let's scratch "if provided". I'd replace "must be equal to or greater than one" by "must be positive", or maybe "must be greater than zero". >> diff --git a/qemu-options.hx b/qemu-options.hx >> index 99ed5ec5f1..b0168f8c48 100644 >> --- a/qemu-options.hx >> +++ b/qemu-options.hx >> @@ -223,11 +223,13 @@ SRST >> of computing the CPU maximum count. >> =20 >> Either the initial CPU count, or at least one of the topology param= eters >> - must be specified. Values for any omitted parameters will be comput= ed >> - from those which are given. Historically preference was given to th= e >> - coarsest topology parameters when computing missing values (ie sock= ets >> - preferred over cores, which were preferred over threads), however, = this >> - behaviour is considered liable to change. >> + must be specified. The specified parameters must be equal to or gre= at > > s/great/greater/ > >> + than one, explicit configuration like "cpus=3D0" is not allowed. Va= lues "positive" again. >> + for any omitted parameters will be computed from those which are gi= ven. >> + Historically preference was given to the coarsest topology paramete= rs >> + when computing missing values (ie sockets preferred over cores, whi= ch >> + were preferred over threads), however, this behaviour is considered >> + liable to change. >> ERST > > > If you make the text changes, then feel free to add this when posting v2: > > Reviewed-by: Daniel P. Berrang=C3=A9 > Tested-by: Daniel P. Berrang=C3=A9 > =20 > > > Regards, > Daniel