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[209.51.188.17]) by mx.google.com with ESMTPS id n5si4917361jac.133.2021.09.28.02.59.18 for (version=TLS1_2 cipher=ECDHE-ECDSA-CHACHA20-POLY1305 bits=256/256); Tue, 28 Sep 2021 02:59:19 -0700 (PDT) Received-SPF: pass (google.com: domain of qemu-arm-bounces+alex.bennee=linaro.org@nongnu.org designates 209.51.188.17 as permitted sender) client-ip=209.51.188.17; Authentication-Results: mx.google.com; dkim=fail header.i=@redhat.com header.s=mimecast20190719 header.b=hyrwYLZH; spf=pass (google.com: domain of qemu-arm-bounces+alex.bennee=linaro.org@nongnu.org designates 209.51.188.17 as permitted sender) smtp.mailfrom="qemu-arm-bounces+alex.bennee=linaro.org@nongnu.org"; dmarc=fail (p=NONE sp=NONE dis=NONE) header.from=redhat.com Received: from localhost ([::1]:43886 helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1mV9tO-0007cG-FW for alex.bennee@linaro.org; Tue, 28 Sep 2021 05:59:18 -0400 Received: from eggs.gnu.org ([2001:470:142:3::10]:51656) by lists.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mV9tB-0007VI-SZ for qemu-arm@nongnu.org; Tue, 28 Sep 2021 05:59:05 -0400 Received: from us-smtp-delivery-124.mimecast.com ([216.205.24.124]:42651) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1mV9t5-00012M-Kx for qemu-arm@nongnu.org; Tue, 28 Sep 2021 05:59:05 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1632823137; 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=lC8tMbHGBad40yXcPh55m2sDRPJRZtnf4g7lkWlWssM=; b=hyrwYLZHPEY+upEtqA3PooxIZMeA+MbL3OtWbkeov56qbGIjwbd3Xq7OyApgPtsngB/S70 +MdFr2xUUTS7frf5m8rxQ1m9QXP37jqJ9L1HVJwXCHcrtkUKmsztqSW2izr5Au8y1N4SMI MZU9zIYqzDGhPfZMb/5+B2DIYdSrpTY= 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-447-DQqEn7jzNrqENS5go_vpGQ-1; Tue, 28 Sep 2021 05:58:56 -0400 X-MC-Unique: DQqEn7jzNrqENS5go_vpGQ-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.phx2.redhat.com [10.5.11.23]) (using TLSv1.2 with cipher AECDH-AES256-SHA (256/256 bits)) (No client certificate requested) by mimecast-mx01.redhat.com (Postfix) with ESMTPS id A51CA362F8; Tue, 28 Sep 2021 09:58:54 +0000 (UTC) Received: from redhat.com (unknown [10.39.194.52]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 6F9BD1972D; Tue, 28 Sep 2021 09:58:41 +0000 (UTC) Date: Tue, 28 Sep 2021 10:58:38 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Yanan Wang Subject: Re: [PATCH v11 01/14] machine: Deprecate "parameter=0" SMP configurations Message-ID: References: <20210928035755.11684-1-wangyanan55@huawei.com> <20210928035755.11684-2-wangyanan55@huawei.com> MIME-Version: 1.0 In-Reply-To: <20210928035755.11684-2-wangyanan55@huawei.com> User-Agent: Mutt/2.0.7 (2021-05-04) X-Scanned-By: MIMEDefang 2.84 on 10.5.11.23 Authentication-Results: relay.mimecast.com; auth=pass smtp.auth=CUSA124A263 smtp.mailfrom=berrange@redhat.com X-Mimecast-Spam-Score: 0 X-Mimecast-Originator: redhat.com Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit Received-SPF: pass client-ip=216.205.24.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -8 X-Spam_score: -0.9 X-Spam_bar: / X-Spam_report: (-0.9 / 5.0 requ) DKIMWL_WL_HIGH=-0.001, 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_H2=-0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable autolearn_force=no X-Spam_action: no action X-BeenThere: qemu-arm@nongnu.org X-Mailman-Version: 2.1.23 Precedence: list List-Id: List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Reply-To: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= Cc: Peter Maydell , Andrew Jones , Cornelia Huck , Eduardo Habkost , Pierre Morel , "Michael S . Tsirkin" , Pankaj Gupta , qemu-devel@nongnu.org, qemu-s390x@nongnu.org, qemu-arm@nongnu.org, qemu-ppc@nongnu.org, wanghaibin.wang@huawei.com, Paolo Bonzini , David Gibson Errors-To: qemu-arm-bounces+alex.bennee=linaro.org@nongnu.org Sender: "Qemu-arm" X-TUID: 1xZFMNnJbIwD On Tue, Sep 28, 2021 at 11:57:42AM +0800, Yanan Wang wrote: > In the SMP configuration, we should either provide a topology > parameter with a reasonable value (greater than zero) or just > omit it and QEMU will compute the missing value. > > The users shouldn't provide a configuration with any parameter > of it specified as zero (e.g. -smp 8,sockets=0) which could > possibly cause unexpected results in the -smp parsing. So we > deprecate this kind of configurations since 6.2 by adding the > explicit sanity check. > > Signed-off-by: Yanan Wang > Reviewed-by: Cornelia Huck > --- > docs/about/deprecated.rst | 15 +++++++++++++++ > hw/core/machine.c | 14 ++++++++++++++ > qapi/machine.json | 2 +- > qemu-options.hx | 12 +++++++----- > 4 files changed, 37 insertions(+), 6 deletions(-) > > diff --git a/docs/about/deprecated.rst b/docs/about/deprecated.rst > index 3c2be84d80..97415dbecd 100644 > --- a/docs/about/deprecated.rst > +++ b/docs/about/deprecated.rst > @@ -160,6 +160,21 @@ Use ``-display sdl`` instead. > > Use ``-display curses`` instead. > > +``-smp`` ("parameter=0" SMP configurations) (since 6.2) > +''''''''''''''''''''''''''''''''''''''''''''''''''''''' > + > +Specified CPU topology parameters must be greater than zero. > + > +In the SMP configuration, users should either provide a CPU topology > +parameter with a reasonable value (greater than zero) or just omit it > +and QEMU will compute the missing value. > + > +However, historically it was implicitly allowed for users to provide > +a parameter with zero value, which is meaningless and could also possibly > +cause unexpected results in the -smp parsing. So support for this kind of > +configurations (e.g. -smp 8,sockets=0) is deprecated since 6.2 and will > +be removed in the near future, users have to ensure that all the topology > +members described with -smp are greater than zero. > > Plugin argument passing through ``arg=`` (since 6.1) > '''''''''''''''''''''''''''''''''''''''''''''''''''''''''''' > diff --git a/hw/core/machine.c b/hw/core/machine.c > index 067f42b528..711e83db54 100644 > --- a/hw/core/machine.c > +++ b/hw/core/machine.c > @@ -835,6 +835,20 @@ static void machine_set_smp(Object *obj, Visitor *v, const char *name, > return; > } > > + /* > + * Specified CPU topology parameters must be greater than zero, > + * explicit configuration like "cpus=0" is not allowed. > + */ > + if ((config->has_cpus && config->cpus == 0) || > + (config->has_sockets && config->sockets == 0) || > + (config->has_dies && config->dies == 0) || > + (config->has_cores && config->cores == 0) || > + (config->has_threads && config->threads == 0) || > + (config->has_maxcpus && config->maxcpus == 0)) { > + warn_report("Invalid CPU topology deprecated: " > + "CPU topology parameters must be greater than zero"); > + } > + > mc->smp_parse(ms, config, errp); > if (*errp) { > goto out_free; > diff --git a/qapi/machine.json b/qapi/machine.json > index 32d47f4e35..227e75d8af 100644 > --- a/qapi/machine.json > +++ b/qapi/machine.json > @@ -1331,7 +1331,7 @@ > # > # @dies: number of dies per socket in the CPU topology > # > -# @cores: number of cores per thread in the CPU topology > +# @cores: number of cores per die in the CPU topology > # > # @threads: number of threads per core in the CPU topology > # This change is unrelated to the rest of this commit. It just looks like a simple bug fix and should just be spun out into its own patch. > diff --git a/qemu-options.hx b/qemu-options.hx > index 8f603cc7e6..91d859aa29 100644 > --- a/qemu-options.hx > +++ b/qemu-options.hx > @@ -227,11 +227,13 @@ SRST > of computing the CPU maximum count. > > Either the initial CPU count, or at least one of the topology parameters > - must be specified. Values for any omitted parameters will be computed > - from those which are given. Historically preference was given to the > - coarsest topology parameters when computing missing values (ie sockets > - preferred over cores, which were preferred over threads), however, this > - behaviour is considered liable to change. > + must be specified. The specified parameters must be greater than zero, > + explicit configuration like "cpus=0" is not allowed. Values for any > + omitted parameters will be computed from those which are given. > + Historically preference was given to the coarsest topology parameters > + when computing missing values (ie sockets preferred over cores, which > + were preferred over threads), however, this behaviour is considered > + liable to change. > ERST > > DEF("numa", HAS_ARG, QEMU_OPTION_numa, If you split the docs fix out into its own patch then you can add Reviewed-by: Daniel P. Berrangé to both this patch and the new patch. 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 :|