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 E1EC4C4345F for ; Thu, 25 Apr 2024 13:36:44 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rzzGD-0002RT-Qo; Thu, 25 Apr 2024 09:35:37 -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 1rzzGA-0002R9-Nw for qemu-devel@nongnu.org; Thu, 25 Apr 2024 09:35:34 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.133.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1rzzG7-0007pd-Ia for qemu-devel@nongnu.org; Thu, 25 Apr 2024 09:35:33 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1714052130; 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=deYhDDeVQ2YbPljmWRtpElyNmPdvYJQuVNd1eTOxHJU=; b=SYKf3G6nA4/CAlx/5LfCTOKj2TEcss3TUW74fBQnLqI+nOlS7zWMGh5HoXznHM9T7bJJo1 IgT0UqvexqbW0JkZx0Rc4b0csFMfRGu0zvnWnP6g5LpKVmxAJLPF0fztY7BI67NOqqNRYA wn/+uMLTMJnW/BS1UvWDCR7GF0UFAyc= Received: from mimecast-mx02.redhat.com (mimecast-mx02.redhat.com [66.187.233.88]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-46-8NHACXKEOTyKlT9SL6AXpA-1; Thu, 25 Apr 2024 09:35:27 -0400 X-MC-Unique: 8NHACXKEOTyKlT9SL6AXpA-1 Received: from smtp.corp.redhat.com (int-mx08.intmail.prod.int.rdu2.redhat.com [10.11.54.8]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits) key-exchange X25519 server-signature RSA-PSS (2048 bits) server-digest SHA256) (No client certificate requested) by mimecast-mx02.redhat.com (Postfix) with ESMTPS id 9BB608947C0; Thu, 25 Apr 2024 13:35:26 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.102]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 03952C13FA4; Thu, 25 Apr 2024 13:35:24 +0000 (UTC) Date: Thu, 25 Apr 2024 14:35:23 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Collin Walling Cc: qemu-s390x@nongnu.org, qemu-devel@nongnu.org, thuth@redhat.com, david@redhat.com, wangyanan55@huawei.com, philmd@linaro.org, marcel.apfelbaum@gmail.com, eduardo@habkost.net, armbru@redhat.com Subject: Re: [PATCH v2 1/3] cpu-models: add "disable-deprecated-feats" option to cpu model expansion Message-ID: References: <20240423210655.66656-1-walling@linux.ibm.com> <20240423210655.66656-2-walling@linux.ibm.com> <9a5fee10-4260-4311-95b9-77791217993e@linux.ibm.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: User-Agent: Mutt/2.2.12 (2023-09-09) X-Scanned-By: MIMEDefang 3.4.1 on 10.11.54.8 Received-SPF: pass client-ip=170.10.133.124; envelope-from=berrange@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -27 X-Spam_score: -2.8 X-Spam_bar: -- X-Spam_report: (-2.8 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.669, 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_H4=0.001, RCVD_IN_MSPIKE_WL=0.001, SPF_HELO_NONE=0.001, SPF_PASS=-0.001 autolearn=unavailable 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?= Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Wed, Apr 24, 2024 at 03:12:42PM -0400, Collin Walling wrote: > On 4/24/24 13:51, Collin Walling wrote: > > On 4/24/24 04:20, Daniel P. Berrangé wrote: > >> On Tue, Apr 23, 2024 at 05:06:53PM -0400, Collin Walling wrote: > >>> This optional parameter for query-cpu-model-expansion enables CPU > >>> model features flagged as deprecated to appear in the resulting > >>> list of properties. > >>> > >>> This commit does not add support beyond adding a new argument > >>> to the query. All queries with this option present will result > >>> in an error claiming this option is not supported. > >>> > >>> Signed-off-by: Collin Walling > >>> --- > >>> qapi/machine-target.json | 7 ++++++- > >>> target/arm/arm-qmp-cmds.c | 7 +++++++ > >>> target/i386/cpu-sysemu.c | 7 +++++++ > >>> target/s390x/cpu_models_sysemu.c | 7 +++++++ > >>> 4 files changed, 27 insertions(+), 1 deletion(-) > >>> > >>> diff --git a/qapi/machine-target.json b/qapi/machine-target.json > >>> index 29e695aa06..b9da284d2d 100644 > >>> --- a/qapi/machine-target.json > >>> +++ b/qapi/machine-target.json > >>> @@ -285,6 +285,10 @@ > >>> # > >>> # @type: expansion type, specifying how to expand the CPU model > >>> # > >>> +# @disable-deprecated-feats: include CPU model features that are > >>> +# flagged as deprecated. If supported, these features will appear > >>> +# in the properties list paired with false. > >>> +# > >>> # Returns: a CpuModelExpansionInfo describing the expanded CPU model > >>> # > >>> # Errors: > >>> @@ -298,7 +302,8 @@ > >>> ## > >>> { 'command': 'query-cpu-model-expansion', > >>> 'data': { 'type': 'CpuModelExpansionType', > >>> - 'model': 'CpuModelInfo' }, > >>> + 'model': 'CpuModelInfo', > >>> + '*disable-deprecated-feats': 'bool' }, > >>> 'returns': 'CpuModelExpansionInfo', > >>> 'if': { 'any': [ 'TARGET_S390X', > >>> 'TARGET_I386', > >> > >> I think this is an odd design approach. Lets consider the > >> current output: > >> > >> (QEMU) query-cpu-model-expansion type=static model={"name":"z14"} > >> { > >> "return": { > >> "model": { > >> "name": "z14-base", > >> "props": { > >> "aefsi": true, > >> "aen": true, > >> ...snip... > >> "vxpd": true, > >> "zpci": true > >> } > >> } > >> } > >> } > >> > >> > >> If we want to inform a mgmt app of some features being deprecated, > >> why not just unconditionally include that info in the reply thus: > >> > >> > >> (QEMU) query-cpu-model-expansion type=static model={"name":"z14"} > >> { > >> "return": { > >> "model": { > >> "name": "z14-base", > >> "props": { > >> "aefsi": true, > >> "aen": true, > >> ...snip... > >> "vxpd": true, > >> "zpci": true > >> } > >> "deprecated-props": ["ppa15", "ri"] > >> } > >> } > >> } > >> > >> > >> > >> With regards, > >> Daniel > > > > That's a good idea. In this way, we're not mucking up any of the CPU > > model information and this makes it much more clear as to which features > > are actually deprecated... I like this more. > > > > I'll work on this. > > > > Follow-up question as I look more closely to the QMP response data > structures: should the "deprecated-props" list be added to the > CpuModelInfo struct, or to the CpuModelExpansionInfo struct? > > The former makes more sense to me, as the deprecated features are tied > to the actual CPU model... but unsure if other QMP commands would even > care about this info? I will begin with this approach, and if feedback > in the interim strongly sways in the other direction, then it should be > an easy change :) I hink CpuModelInfo makes more sense than CpuModelExpansionInfo. The CpuModelExpansionInfo struct feels pretty pointless to me in fact, since the only thing it contains is CpuModelInfo ! I think it should also be added to 'CpuDefinitionInfo', which is the return type of 'query-cpu-defintions'. This command already has a 'unavailable-features' array listing features which the host does not support. Conceptually having a 'deprecated-features' array alongside that is a nice fit. 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 :|