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 EAEF1D6B6A7 for ; Thu, 31 Oct 2024 12:26:03 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1t6UEj-0005o8-Al; Thu, 31 Oct 2024 08:25:13 -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 1t6UEc-0005kQ-Ib for qemu-devel@nongnu.org; Thu, 31 Oct 2024 08:25:06 -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 1t6UEb-0006Rz-6N for qemu-devel@nongnu.org; Thu, 31 Oct 2024 08:25:06 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1730377497; 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=KPd7oDcX9eG7TVtE1AQlSacTh7/i7Z+qfMhr0px/qxo=; b=TiPecWKq0o3/ypSC0VlwdbZP0Oh/nTb5xMTCE836UT0CuMwjT0thixAoCpQUVSsXEPt2Wc Ogq4skR7lS11q4BgRDd2VDau93ohjZyZJHFNiH4olRI5dMdXvVHxaj9FNJGuVyPk5VkAO9 3KSTcqYCkvm614rMohvWERpNyanxRAc= Received: from mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (ec2-54-186-198-63.us-west-2.compute.amazonaws.com [54.186.198.63]) by relay.mimecast.com with ESMTP with STARTTLS (version=TLSv1.3, cipher=TLS_AES_256_GCM_SHA384) id us-mta-410-oLV_MKhvOJit6ANUPC0mtw-1; Thu, 31 Oct 2024 08:24:51 -0400 X-MC-Unique: oLV_MKhvOJit6ANUPC0mtw-1 Received: from mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.40]) (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 mx-prod-mc-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 562F919560BC; Thu, 31 Oct 2024 12:24:48 +0000 (UTC) Received: from pinwheel (unknown [10.39.194.127]) by mx-prod-int-04.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id AB1821956054; Thu, 31 Oct 2024 12:24:40 +0000 (UTC) Date: Thu, 31 Oct 2024 13:24:37 +0100 From: Kashyap Chamarthy To: Cornelia Huck Cc: Daniel =?iso-8859-1?Q?P=2E_Berrang=E9?= , Eric Auger , eric.auger.pro@gmail.com, qemu-devel@nongnu.org, qemu-arm@nongnu.org, kvmarm@lists.linux.dev, peter.maydell@linaro.org, richard.henderson@linaro.org, alex.bennee@linaro.org, maz@kernel.org, oliver.upton@linux.dev, sebott@redhat.com, shameerali.kolothum.thodi@huawei.com, armbru@redhat.com, abologna@redhat.com, jdenemar@redhat.com, shahuang@redhat.com, mark.rutland@arm.com, philmd@linaro.org, pbonzini@redhat.com Subject: Re: [RFC 21/21] arm/cpu-features: Document custom vcpu model Message-ID: References: <20241025101959.601048-1-eric.auger@redhat.com> <20241025101959.601048-22-eric.auger@redhat.com> <0700af51-a1a6-4b11-a4bf-0eaf6e279c6d@redhat.com> <87y128nrfr.fsf@redhat.com> <87plnknqco.fsf@redhat.com> MIME-Version: 1.0 Content-Type: text/plain; charset=iso-8859-1 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <87plnknqco.fsf@redhat.com> X-Scanned-By: MIMEDefang 3.0 on 10.30.177.40 Received-SPF: pass client-ip=170.10.133.124; envelope-from=kchamart@redhat.com; helo=us-smtp-delivery-124.mimecast.com X-Spam_score_int: -24 X-Spam_score: -2.5 X-Spam_bar: -- X-Spam_report: (-2.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.366, 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_H3=0.001, RCVD_IN_MSPIKE_WL=0.001, RCVD_IN_VALIDITY_CERTIFIED_BLOCKED=0.001, RCVD_IN_VALIDITY_RPBL_BLOCKED=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, Oct 28, 2024 at 05:29:11PM +0100, Cornelia Huck wrote: > On Mon, Oct 28 2024, Daniel P. Berrangé wrote: [...] > >> We could consolidate that to the current "host" model, once we figure > >> out how to handle the currently already existing properties. Models > >> based on the different architecture extensions would probably be more > >> useable in the long run; maybe "custom" has a place for testing. > > > > If you can set the features against "host", then any testing could > > be done with "host" surely, making 'custom' pointless ? > > We might differentiate between "do some consistency checks" and "allow > a completely weird wolpertinger"; if we agree that we don't need it, > then we surely could drop it again. Yeah, FWIW, I agree that it's best to drop "custom" if all the meaningful tests can be handled by being able to add/remove CPU flags from `-cpu host`. Related: I don't see any mention of `-cpu max` here. Is it not relevant? It is currently defined as: "enables all features supported by the accelerator in the current host". Does it make sense for `max` to allow disabling features? Or is the idea that, why would you choose `-cpu max` if you want to disable features? In that case, go with either: -cpu host,feat1=off Or: -cpu some_future_named_model,$feat1=off ? -- /kashyap