From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1753866AbaACWG3 (ORCPT ); Fri, 3 Jan 2014 17:06:29 -0500 Received: from mail-ea0-f181.google.com ([209.85.215.181]:61518 "EHLO mail-ea0-f181.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753814AbaACWG0 (ORCPT ); Fri, 3 Jan 2014 17:06:26 -0500 Message-ID: <52C7345D.30603@redhat.com> Date: Fri, 03 Jan 2014 23:06:21 +0100 From: Paolo Bonzini User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130923 Thunderbird/17.0.9 MIME-Version: 1.0 To: Dirk Brandewie CC: Gleb Natapov , "Rafael J. Wysocki" , Kashyap Chamarthy , Josh Boyer , One Thousand Gnomes , Viresh Kumar , "cpufreq@vger.kernel.org" , Linux PM list , "Linux-Kernel@Vger. Kernel. Org" , "Richard W.M. Jones" Subject: Re: intel_pstate divide error with v3.13-rc4-256-gb7000ad References: <4794554.Hmd2RUNYDT@vostro.rjw.lan> <52C18A23.10703@redhat.com> <3710588.K8glfx1cYs@vostro.rjw.lan> <52C6F3B4.3050904@gmail.com> <20140103180435.GK10961@minantech.com> <52C716C1.6070704@gmail.com> In-Reply-To: <52C716C1.6070704@gmail.com> X-Enigmail-Version: 1.6 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Il 03/01/2014 21:00, Dirk Brandewie ha scritto: > + case MSR_IA32_MPERF: > + case MSR_IA32_APERF: These should never be accessed. A KVM VM will always have CPUID[06H].ECX = 0, and the Intel manual says that the MSRs are only present if CPUID returns that value with bit 0 set. I think the actual bug is that intel_pstate_init does not check the feature bits in CPUID (either manually or via x86_match_cpu). Paolo