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 C360CC83F12 for ; Mon, 28 Aug 2023 14:47:50 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1qadW0-0001Ki-6k; Mon, 28 Aug 2023 10:46:52 -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 1qadVy-0001Jt-7y for qemu-devel@nongnu.org; Mon, 28 Aug 2023 10:46:50 -0400 Received: from us-smtp-delivery-124.mimecast.com ([170.10.129.124]) by eggs.gnu.org with esmtps (TLS1.2:ECDHE_RSA_AES_256_GCM_SHA384:256) (Exim 4.90_1) (envelope-from ) id 1qadVt-0007OZ-ST for qemu-devel@nongnu.org; Mon, 28 Aug 2023 10:46:50 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1693234005; 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=la0wXIW9eKdFxskg3EnYaYaGDCPF1pneIYfeY+4dcZ0=; b=aeuLIYAxYIlA65Iqa7YVwAKWAN/rwpju+Brn15tbGy33ESdoVL9sRsTsiYzs5VToFJzWcB 74/8t37nEyvGZDc0oM9RSEeoC700Wt9AQa+1Aiw7xd/6WROrv1I4PecKkll8ORIn/ppwM7 1DnMkj0NxaMHVQ8LBwbty7ScQv5fP7M= Received: from mail-ed1-f69.google.com (mail-ed1-f69.google.com [209.85.208.69]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-303-Cl4hJAZ6ODWxgBL6KcnumQ-1; Mon, 28 Aug 2023 10:46:42 -0400 X-MC-Unique: Cl4hJAZ6ODWxgBL6KcnumQ-1 Received: by mail-ed1-f69.google.com with SMTP id 4fb4d7f45d1cf-518676b6d09so2678486a12.1 for ; Mon, 28 Aug 2023 07:46:42 -0700 (PDT) X-Google-DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=1e100.net; s=20221208; t=1693234001; x=1693838801; h=content-transfer-encoding:mime-version:references:in-reply-to :message-id:subject:cc:to:from:date:x-gm-message-state:from:to:cc :subject:date:message-id:reply-to; bh=la0wXIW9eKdFxskg3EnYaYaGDCPF1pneIYfeY+4dcZ0=; b=QTPxdb5o+NwHd/GdCvv69qjZZD7sOwv7rMeByLNg7n73pVCv0zan92Ms2Rx0XUUb7y 3YcQA3WAMlphYka3haMpaHnABIMUA+hajKsuvI+5Mbbg+7a07x+Q4g0LE33DsSoNfSsk n27JQVLa4dkiPHMktcrwCIxiAK3KG/21LC801/CTsidAdyS5ek4yaof1ihYuOJRHLcwp tsRdwjAB8fJH9udFzgrwDOryY968BO6qmQ0ylHvc/9/3FnjKN69MF2ef0jQLwJ09flsn 9gCpC0k3vgIZygEegIEJfCek588/JQZX0nCBJuuj/0MtPONgo1gnukqcvwekaP7ntt8W iX4Q== X-Gm-Message-State: AOJu0YzqCUp1fCKqYssSjSd8DtHSy8bApqTdQxbWgY8yvMKgMTlH9Xvc afBCrJNo5/sYTEN4LqmPy3IUHmN6jv/jAQt9RmVmefFU9ituLOJnBqms/wJAhAhwWsHIEkztpsO 7CX3Wqa0m3t7i3Js= X-Received: by 2002:aa7:d397:0:b0:522:cb97:f196 with SMTP id x23-20020aa7d397000000b00522cb97f196mr21255459edq.36.1693234001080; Mon, 28 Aug 2023 07:46:41 -0700 (PDT) X-Google-Smtp-Source: AGHT+IGgk9PxOGdwnRyQ4yOWU5l6+eh//VImg7lkpR9gypn7FRAAG5Z90IIOYGc8nmnnwppyoq3HJg== X-Received: by 2002:aa7:d397:0:b0:522:cb97:f196 with SMTP id x23-20020aa7d397000000b00522cb97f196mr21255427edq.36.1693234000707; Mon, 28 Aug 2023 07:46:40 -0700 (PDT) Received: from imammedo.users.ipa.redhat.com (nat-pool-brq-t.redhat.com. [213.175.37.10]) by smtp.gmail.com with ESMTPSA id v10-20020aa7d80a000000b005233deb30aesm4479916edq.10.2023.08.28.07.46.38 (version=TLS1_3 cipher=TLS_AES_256_GCM_SHA384 bits=256/256); Mon, 28 Aug 2023 07:46:39 -0700 (PDT) Date: Mon, 28 Aug 2023 16:46:37 +0200 From: Igor Mammedov To: Gavin Shan Cc: Richard Henderson , qemu-arm@nongnu.org, qemu-devel@nongnu.org, qemu-riscv@nongnu.org, peter.maydell@linaro.org, b.galvani@gmail.com, strahinja.p.jankovic@gmail.com, sundeep.lkml@gmail.com, kfting@nuvoton.com, wuhaotsh@google.com, nieklinnenbank@gmail.com, rad@semihalf.com, quic_llindhol@quicinc.com, marcin.juszkiewicz@linaro.org, eduardo@habkost.net, marcel.apfelbaum@gmail.com, philmd@linaro.org, wangyanan55@huawei.com, laurent@vivier.eu, vijai@behindbytes.com, palmer@dabbelt.com, alistair.francis@wdc.com, bin.meng@windriver.com, liweiwei@iscas.ac.cn, dbarboza@ventanamicro.com, zhiwei_liu@linux.alibaba.com, cohuck@redhat.com, pbonzini@redhat.com, shan.gavin@gmail.com, qemu-ppc@nongnu.org Subject: Re: [PATCH v2 3/8] machine: Print supported CPU models instead of typenames Message-ID: <20230828164637.52c2b5b0@imammedo.users.ipa.redhat.com> In-Reply-To: <5f26299e-f1e0-a2ab-db83-87011fe524d5@redhat.com> References: <20230726003205.1599788-1-gshan@redhat.com> <20230726003205.1599788-4-gshan@redhat.com> <24e54bac-9149-20da-e4cf-5829a6dcb174@linaro.org> <0454c1ad-314c-3df6-d6e9-1a05cb4c4050@redhat.com> <20230727110010.648b61a6@imammedo.users.ipa.redhat.com> <5f26299e-f1e0-a2ab-db83-87011fe524d5@redhat.com> X-Mailer: Claws Mail 4.1.1 (GTK 3.24.38; x86_64-redhat-linux-gnu) MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: quoted-printable Received-SPF: pass client-ip=170.10.129.124; envelope-from=imammedo@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -20 X-Spam_score: -2.1 X-Spam_bar: -- X-Spam_report: (-2.1 / 5.0 requ) BAYES_00=-1.9, 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_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: , Errors-To: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org Sender: qemu-devel-bounces+qemu-devel=archiver.kernel.org@nongnu.org On Mon, 31 Jul 2023 15:07:30 +1000 Gavin Shan wrote: > On 7/27/23 19:00, Igor Mammedov wrote: > > On Thu, 27 Jul 2023 15:16:18 +1000 > > Gavin Shan wrote: > > =20 > >> On 7/27/23 09:08, Richard Henderson wrote: =20 > >>> On 7/25/23 17:32, Gavin Shan wrote: =20 > >>>> -static const char *q800_machine_valid_cpu_types[] =3D { > >>>> +static const char * const q800_machine_valid_cpu_types[] =3D { > >>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 M68K_CPU_TYPE_NAME("m68040"), > >>>> =C2=A0=C2=A0=C2=A0=C2=A0=C2=A0 NULL > >>>> =C2=A0 }; > >>>> +static const char * const q800_machine_valid_cpu_models[] =3D { > >>>> +=C2=A0=C2=A0=C2=A0 "m68040", > >>>> +=C2=A0=C2=A0=C2=A0 NULL > >>>> +}; =20 > >>> > >>> I really don't like this replication. > >>> =20 > >> > >> Right, it's going to be lots of replications, but gives much flexibili= ty. > >> There are 21 targets and we don't have fixed pattern for the mapping b= etween > >> CPU model name and CPU typename. I'm summarizing the used patterns lik= e below. > >> > >> 1 All CPU model names are mappinged to fixed CPU typename; =20 > >=20 > > plainly spelled it would be: cpu_model name ignored and > > a cpu type is returned anyways. > >=20 > > I'd make this hard error right away, as "junk in =3D> error out" > > it's clearly user error. I think we don't even have to follow > > deprecation process for that. > > =20 >=20 > Right, It's not expected behavior to map ambiguous CPU model names to > the fixed CPU typename. to be nice we can deprecate those and then later remove. (while deprecating make those targets accept typenames) >=20 > >> 2 CPU model name is same to CPU typename; > >> 3 CPU model name is alias to CPU typename; > >> 4 CPU model name is prefix of CPU typename; =20 > >=20 > > and some more: > > 5. cpu model names aren't names at all sometimes, and some other > > CPU property is used. (ppc) > > This one I'd prefer to get rid of and ppc handling more consistent > > with other targets, which would need PPC folks to persuaded to drop > > PVR lookup. > > =20 >=20 > I put this into class 3, meaning the PVRs are regarded as aliases to CPU > typenames. with PPC using 'true' aliases, -cpu input is lost after it's translated int= o typename. (same for alpha) it also adds an extra fun with 'max' cpu model but that boils down to above= statement. (same for * sh4 * cris(in user mode only, but you are making sysemu extension, so it does= n't count) ) For this class of aliases reverse translation won't yield the same result as used -cpu. The only option you have is to store -cpu cpu_model somewhere (use qemu_opts??, and then fetch it later to print in error messa= ge) x86 has 'aliases' as well, but in reality it creates distinct cpu types for each 'alias', so it's possible to do reverse translation. > >> > >> Target Categories suffix-of-CPU-typename > >> ------------------------------------------------------- > >> alpha -234 -alpha-cpu > >> arm ---4 -arm-cpu > >> avr -2-- > >> cris --34 -cris-cpu > >> hexagon ---4 -hexagon-cpu > >> hppa 1--- > >> i386 ---4 -i386-cpu > >> loongarch -2-4 -loongarch-cpu > >> m68k ---4 -m68k-cpu > >> microblaze 1--- > >> mips ---4 -mips64-cpu -mips-cpu > >> nios2 1--- > >> openrisc ---4 -or1k-cpu > >> ppc --34 -powerpc64-cpu -powerpc-cpu > >> riscv ---4 -riscv-cpu > >> rx -2-4 -rx-cpu > >> s390x ---4 -s390x-cpu > >> sh4 --34 -superh-cpu > >> sparc -2-- it's case 4 > >> tricore ---4 -tricore-cpu > >> xtensa ---4 -xtensa-cpu > >> > >> There are several options as below. Please let me know which one or so= mething > >> else is the best. > >> > >> (a) Keep what we have and use mc->valid_{cpu_types, cpu_models}[] to t= rack > >> the valid CPU typenames and CPU model names. > >> > >> (b) Introduce CPUClass::model_name_by_typename(). Every target has the= ir own > >> implementation to convert CPU typename to CPU model name. The CPU mode= l name > >> is parsed from mc->valid_cpu_types[i]. > >> > >> char *CPUClass::model_by_typename(const char *typename); > >> > >> (c) As we discussed before, use mc->valid_cpu_type_suffix and mc->vali= d_cpu_models > >> because the CPU type check is currently needed by target arm/m68k/risc= v where we > >> do have fixed pattern to convert CPU model names to CPU typenames. The= CPU typename > >> is comprised of CPU model name and suffix. However, it won't be workin= g when the CPU > >> type check is required by other target where we have patterns other th= an this. =20 > >=20 > > none of above is really good, that's why I was objecting to introducing > > reverse type->name mapping. That ends up with increased amount junk, > > and it's not because your patches are bad, but because you are trying > > to deal with cpu model names (which is a historically evolved mess). > > The best from engineering POV would be replacing CPU models with > > type names. > >=20 > > Even though it's a bit radical, I very much prefer replacing > > cpu_model names with '-cpu type'usage directly. Making it > > consistent with -device/other interfaces and coincidentally that > > obsoletes need in reverse name mapping. > >=20 > > It's painful for end users who will need to change configs/scripts, > > but it's one time job. Additionally from QEMU pov, codebase > > will be less messy =3D> more maintainable which benefits not only > > developers but end-users in the end. > > =20 >=20 > I have to clarify the type->model mapping has been existing since the > model->type mapping was introduced with the help of CPU_RESOLVING_TYPE. > I mean the logic has been existing since the existence of CPU_RESOLVING_T= YPE, > even the code wasn't there. >=20 > I'm not sure about the idea to switch to '-cpu ' since > it was rejected by Peter Maydell before. Hope Peter can double confirm > for this. For me, the shorter name is beneficial. For example, users > needn't to have '-cpu host-arm-cpu' for '-cpu host'. >=20 >=20 > > [rant: > > It's the same story repeating over and over, when it comes to > > changing QEMU CLI, which hits resistance wall. But with QEMU > > deprecation process we've changed CLI behavior before, > > despite of that world didn't cease to exist and users > > have adapted to new QEMU and arguably QEMU became a tiny > > bit more maintainable since we don't have to deal some > > legacy behavior. > > ] > > =20 >=20 > I need more context about 'deprecation process' here. My understanding > is both CPU typename and model name will be accepted for a fixed period > of time. However, a warning message will be given to indicate that the > model name will be obsoleted soon. Eventually, we switch to CPU typename > completely. Please correct me if there are anything wrong. yep, that's the gist of deprecation in this case.=20 =20 > > Another idea back in the days was (as a compromise), > > 1. keep using keep valid_cpu_types > > 2. instead of introducing yet another way to do reverse mapping, > > clean/generalize/make it work everywhere list_cpus (which > > already does that mapping) and then use that to do your thing. > > It will have drawbacks you've listed above, but hopefully > > that will clean up and reuse existing list_cpus. > > (only this time, I'd build it around query-cpu-model-expansion, > > which output is used by generic list_cpus) > > [and here I'm asking to rewrite directly unrelated QEMU part yet a= gain] > > =20 >=20 > I'm afraid that list_cpus() is hard to be reused. All available CPU model= names > are listed by list_cpus(). mc->valid_cpu_types[] are just part of them an= d variable > on basis of boards. Generally speaking, we need a function to do reverse = things > as to CPUClass::class_by_name(). So I would suggest to introduce CPUClass= ::model_from_type(), > as below. Could you please suggest if it sounds reasonable to you? >=20 > - CPUClass::class_by_name() is modified to > char *CPUClass::model_to_type(const char *model) >=20 > - char *CPUClass::type_to_model(const char *type) >=20 > - CPUClass::type_to_model() is used in cpu_list() for every target when C= PU > model name, fetched from CPU type name, is printed in xxx_cpu_list_ent= ry() >=20 > - CPUClass::type_to_model() is reused in hw/core/machine.c to get the CPU > model name from CPU type names in mc->valid_cpu_types[]. instead of per target hooks (which are atm mostly open-coded in several pla= ces) how about adding generic handler for cases 2,4: cpu_type_to_model(typename) cpu_suffix =3D re'-*-cpu' if (class_exists(typename - cpu_suffix)) return typename - cpu_suffix else if (class_exists(typename)) return typename explode that should work for translating valid_cpus typenames to cpumodel names and once that in place cleanup all open-coded translations with it tree-wide you can find those easily by: git grep _CPU_TYPE_SUFFIX git grep query_cpu_definitions >=20 > Thanks, > Gavin >=20