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 D9BA6D0C609 for ; Fri, 25 Oct 2024 13:31:47 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1t4KPV-00082T-P8; Fri, 25 Oct 2024 09:31:25 -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 1t4KPU-00082H-Gt for qemu-devel@nongnu.org; Fri, 25 Oct 2024 09:31:24 -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 1t4KPS-000221-V4 for qemu-devel@nongnu.org; Fri, 25 Oct 2024 09:31:24 -0400 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1729863082; 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=waoi+b8XH0c3xLVAJPFetdqTvj+3eqZAdduWa1Fv1LI=; b=Prc2WF4FfH668QMDoqoWfwuBnU5vQjBhloCJWLYoImI7GbyAVbcQv/UNM0Mz3RpDlpfV8E lUoI9Fo5IOY8NyxDHaIazNdoc5E6hr4BYkgf6IfgYyx2a6Z5+sV8nd6WIQCAqGBvQkg7YT zt/HNbVneSd7gNM9u22Eq7QdWceQlM0= Received: from mx-prod-mc-05.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-38-Rd7mrFVRPGm__spTrUcptA-1; Fri, 25 Oct 2024 09:31:18 -0400 X-MC-Unique: Rd7mrFVRPGm__spTrUcptA-1 Received: from mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com [10.30.177.4]) (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-05.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 00F3819560A2; Fri, 25 Oct 2024 13:31:14 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.164]) by mx-prod-int-01.mail-002.prod.us-west-2.aws.redhat.com (Postfix) with ESMTPS id 2F9F430001A9; Fri, 25 Oct 2024 13:31:06 +0000 (UTC) Date: Fri, 25 Oct 2024 14:31:03 +0100 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Eric Auger Cc: eric.auger.pro@gmail.com, cohuck@redhat.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> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <0700af51-a1a6-4b11-a4bf-0eaf6e279c6d@redhat.com> User-Agent: Mutt/2.2.12 (2023-09-09) X-Scanned-By: MIMEDefang 3.4.1 on 10.30.177.4 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: -24 X-Spam_score: -2.5 X-Spam_bar: -- X-Spam_report: (-2.5 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.454, 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=ham 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 Fri, Oct 25, 2024 at 03:28:35PM +0200, Eric Auger wrote: > Hi Daniel, > > On 10/25/24 15:13, Daniel P. Berrangé wrote: > > On Fri, Oct 25, 2024 at 12:17:40PM +0200, Eric Auger wrote: > >> From: Cornelia Huck > >> > >> Add some documentation for the custom model. > >> > >> Signed-off-by: Eric Auger > >> Signed-off-by: Cornelia Huck > >> --- > >> docs/system/arm/cpu-features.rst | 55 +++++++++++++++++++++++++++----- > >> 1 file changed, 47 insertions(+), 8 deletions(-) > > > >> @@ -167,6 +196,16 @@ disabling many SVE vector lengths would be quite verbose, the ``sve`` CPU > >> properties have special semantics (see "SVE CPU Property Parsing > >> Semantics"). > >> > >> +The ``custom`` CPU model needs to be configured via individual ID register > >> +field properties, for example:: > >> + > >> + $ qemu-system-aarch64 -M virt -cpu custom,SYSREG_ID_AA64ISAR0_EL1_DP=0x0 > >> + > >> +This forces ID_AA64ISAR0_EL1 DP field to 0. > > What is the "baseline" featureset implied by 'custom' ? > there is no baseline at the moment. By default this is a host > passthrough model. Why do we need to create "custom" at all, as opposed to just letting users toggle features on "-cpu host" ? 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 :|