From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1754706Ab3L0RVH (ORCPT ); Fri, 27 Dec 2013 12:21:07 -0500 Received: from mx1.redhat.com ([209.132.183.28]:45718 "EHLO mx1.redhat.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754166Ab3L0RVD (ORCPT ); Fri, 27 Dec 2013 12:21:03 -0500 Message-ID: <52BDB63B.70107@redhat.com> Date: Fri, 27 Dec 2013 18:17:47 +0100 From: Kashyap Chamarthy User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:17.0) Gecko/20130923 Thunderbird/17.0.9 MIME-Version: 1.0 To: Gleb Natapov CC: Josh Boyer , One Thousand Gnomes , Viresh Kumar , Dirk Brandewie , "Rafael J. Wysocki" , "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: <20131227122422.62857cec@alan.etchedpixels.co.uk> <20131227124749.GE10961@minantech.com> <52BD8B8B.1050209@redhat.com> <20131227165248.GG10961@minantech.com> <20131227170147.GH10961@minantech.com> In-Reply-To: <20131227170147.GH10961@minantech.com> 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 On 12/27/2013 06:01 PM, Gleb Natapov wrote: > On Fri, Dec 27, 2013 at 06:52:48PM +0200, Gleb Natapov wrote: >> On Fri, Dec 27, 2013 at 03:15:39PM +0100, Kashyap Chamarthy wrote: >>> [. . .] >>> >>>>> KVM does not emulate P-states at all. intel_pstate_init() calls >>>>> intel_pstate_msrs_not_valid() before printing "Intel P-state driver >>>>> initializing." which suppose to fail since it checks that two reads of >>>>> MSR_IA32_APERF return different values, but KVM does not emulate this msr >>>>> at all, so both calls should return zero (KVM suppose to inject #GP, all rdmsrl >>>>> are patched to be rdmsrl_safe in a guest). >>>>> >>>>> Anything interesting in host dmesg? >>> >>> Heya Gleb, >>> >>> Here's the relevant dmesg snippet (full dmesg, refer the attachment below): >> That's guest dmesg. What about host one? Here's host dmesg: https://bugzilla.kernel.org/attachment.cgi?id=119751 >> Can you ftrace the failure? Can try, need some time (rest of the day I'll be away travelling, will try to do it over the weekend, and update the Kernel bugzilla with observations). >> > Ugh, it looks like guest dmesg but there are KVM messages there too ("[ > 281.443662] kvm [2452]: vcpu0 unhandled rdmsr: 0xe8" is unhandled access > to MSR_IA32_APERF I was talking about above), so I guess this is nested > guest invocation? Yeah -- sorry, I forgot to note it's in a nested environment :( > Does it happen in non nested guest? I need to that. Note to self: Also try with a newer Kernel on the host. -- /kashyap