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 CDD5BC54E41 for ; Tue, 5 Mar 2024 13:58:05 +0000 (UTC) Received: from localhost ([::1] helo=lists1p.gnu.org) by lists.gnu.org with esmtp (Exim 4.90_1) (envelope-from ) id 1rhVIp-0004Mh-Df; Tue, 05 Mar 2024 08:57:55 -0500 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 1rhVIn-00042h-AE for qemu-devel@nongnu.org; Tue, 05 Mar 2024 08:57:53 -0500 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 1rhVIl-0006qQ-9U for qemu-devel@nongnu.org; Tue, 05 Mar 2024 08:57:52 -0500 DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=redhat.com; s=mimecast20190719; t=1709647070; 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=R+5CJuO59jm3H0HA8beka8VW7L6jr5umZrJG+B8qOSo=; b=EeQYpPWneLbP+EILFqkR18D1vsBworFD6OnZmWSfdgy2rL1Sdy3FyD1+j6ZaYwsG1IQ1KR vYIBHFlG94jcc3e44aBa2sJz9YZKJPFkZAZS9SUQrThAMGHTHu0rmuWcDOcwzdpNh63Pl3 FeNwdnw0G6JR0c6UdMUHuq/Yo29OojI= 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-136-qJZceKIsPrS6v-jt2LjrBQ-1; Tue, 05 Mar 2024 08:57:49 -0500 X-MC-Unique: qJZceKIsPrS6v-jt2LjrBQ-1 Received: from smtp.corp.redhat.com (int-mx05.intmail.prod.int.rdu2.redhat.com [10.11.54.5]) (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 11CB2185A789 for ; Tue, 5 Mar 2024 13:57:49 +0000 (UTC) Received: from redhat.com (unknown [10.42.28.66]) by smtp.corp.redhat.com (Postfix) with ESMTPS id 0C97F10E4F; Tue, 5 Mar 2024 13:57:47 +0000 (UTC) Date: Tue, 5 Mar 2024 13:57:46 +0000 From: Daniel =?utf-8?B?UC4gQmVycmFuZ8Op?= To: Anthony Harivel Cc: pbonzini@redhat.com, mtosatti@redhat.com, qemu-devel@nongnu.org, vchundur@redhat.com Subject: Re: [PATCH v3 3/3] Add support for RAPL MSRs in KVM/Qemu Message-ID: References: <20240125072214.318382-1-aharivel@redhat.com> <20240125072214.318382-4-aharivel@redhat.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 10.11.54.5 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: -26 X-Spam_score: -2.7 X-Spam_bar: -- X-Spam_report: (-2.7 / 5.0 requ) BAYES_00=-1.9, DKIMWL_WL_HIGH=-0.568, 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, T_SCC_BODY_TEXT_LINE=-0.01 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 Tue, Mar 05, 2024 at 02:25:09PM +0100, Anthony Harivel wrote: > Daniel P. Berrangé, Mar 04, 2024 at 15:48: > > On Mon, Mar 04, 2024 at 03:41:02PM +0100, Anthony Harivel wrote: > > > > > > Hi Daniel, > > > > > > > > + if (s->msr_energy.enable == true) { > > > > > > > > This looks to be where we need to check that both the host CPU > > > > vendor is intel, and the guest CPU vendor is intel, and that > > > > the host CPU has the RAPL feature we're using. > > > > > > Checking for the host cpu and RAPL enable is fine and done. > > > > > > But checking for guest CPU is confusing me. > > > The RAPL feature is enable only with KVM enable. > > > This means "-cpu" can only be "host" or its derivative that essentially > > > copy the host CPU definition, no? > > > > KVM can use any named CPU. > > > > > That means if we are already checking the host cpu we don't need to do > > > anything for the guest, do we ? > > > > When I first wrote this I though it would be as simple as checknig a > > CPUID feature flag. That appears to not be the case, however, as Linux > > is just checking for various CPU models directly. With that in mind > > perhaps we should just check of the guest CPU model vendor > > == CPUID_VENDOR_INTEL and leave it at that. > > > > eg, create an error if running an AMD CPU such as $QEMU -cpu EPYC > > The idea looks good to me. Now the hiccups of this solution is that > I cannot find a way to reach CPUArchState at this level of code (i.e > kvm_arch_init() ) with only the MachineState or the KVMState. > I can only reach the topology with x86_possible_cpu_arch_ids(). > > CPUArchState struct is holding the cpuid_vendor variables where we can > use IS_INTEL_CPU() for checking. > > Maybe you know the trick that I miss ? I think perhaps you can do a check in kvm_cpu_realizefn() from target/i386/kvm/kvm-cpu.c, as you have CPUX86State state which is what IS_INTEL_CPU wants. 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 :|