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 X-Spam-Level: X-Spam-Status: No, score=-8.2 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_SANE_1 autolearn=ham autolearn_force=no version=3.4.0 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 7EFF8C432C3 for ; Thu, 21 Nov 2019 10:45:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 52D2B2088F for ; Thu, 21 Nov 2019 10:45:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726270AbfKUKpp (ORCPT ); Thu, 21 Nov 2019 05:45:45 -0500 Received: from mga14.intel.com ([192.55.52.115]:47098 "EHLO mga14.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726014AbfKUKpo (ORCPT ); Thu, 21 Nov 2019 05:45:44 -0500 X-Amp-Result: UNKNOWN X-Amp-Original-Verdict: FILE UNKNOWN X-Amp-File-Uploaded: False Received: from fmsmga006.fm.intel.com ([10.253.24.20]) by fmsmga103.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 21 Nov 2019 02:45:44 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.69,224,1571727600"; d="scan'208";a="408473585" Received: from jsakkine-mobl1.tm.intel.com (HELO localhost) ([10.237.50.162]) by fmsmga006.fm.intel.com with ESMTP; 21 Nov 2019 02:45:38 -0800 Date: Thu, 21 Nov 2019 12:45:38 +0200 From: Jarkko Sakkinen To: Sean Christopherson Cc: Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , Peter Zijlstra , Arnaldo Carvalho de Melo , Mark Rutland , Alexander Shishkin , Jiri Olsa , Namhyung Kim , Paolo Bonzini , Radim =?utf-8?B?S3LEjW3DocWZ?= , Vitaly Kuznetsov , Wanpeng Li , Jim Mattson , Joerg Roedel , Tony Luck , Tony W Wang-oc , Shuah Khan , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, linux-edac@vger.kernel.org, linux-kselftest@vger.kernel.org, Borislav Petkov Subject: Re: [PATCH v3 05/19] x86/mce: WARN once if IA32_FEATURE_CONTROL MSR is left unlocked Message-ID: <20191121104538.GD20907@linux.intel.com> References: <20191119031240.7779-1-sean.j.christopherson@intel.com> <20191119031240.7779-6-sean.j.christopherson@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20191119031240.7779-6-sean.j.christopherson@intel.com> Organization: Intel Finland Oy - BIC 0357606-4 - Westendinkatu 7, 02160 Espoo User-Agent: Mutt/1.10.1 (2018-07-13) Sender: linux-edac-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-edac@vger.kernel.org On Mon, Nov 18, 2019 at 07:12:26PM -0800, Sean Christopherson wrote: > WARN if the IA32_FEATURE_CONTROL MSR is somehow left unlocked now that > CPU initialization unconditionally locks the MSR. > > Reviewed-by: Borislav Petkov > Signed-off-by: Sean Christopherson > --- > arch/x86/kernel/cpu/mce/intel.c | 7 +++---- > 1 file changed, 3 insertions(+), 4 deletions(-) > > diff --git a/arch/x86/kernel/cpu/mce/intel.c b/arch/x86/kernel/cpu/mce/intel.c > index 3e5b29acd301..5abc55a67fce 100644 > --- a/arch/x86/kernel/cpu/mce/intel.c > +++ b/arch/x86/kernel/cpu/mce/intel.c > @@ -119,11 +119,10 @@ static bool lmce_supported(void) > * generate a #GP fault. > */ > rdmsrl(MSR_IA32_FEATURE_CONTROL, tmp); > - if ((tmp & (FEAT_CTL_LOCKED | FEAT_CTL_LMCE_ENABLED)) == > - (FEAT_CTL_LOCKED | FEAT_CTL_LMCE_ENABLED)) > - return true; I'd add a prepending comment: /* * FEAT_CTL_LOCKED should have been always set either by * BIOS before handover to the kernel or init_feature_control_msr(). */ > + if (WARN_ON_ONCE(!(tmp & FEAT_CTL_LOCKED))) > + return false; > > - return false; > + return tmp & FEAT_CTL_LMCE_ENABLED; > } > > bool mce_intel_cmci_poll(void) > -- > 2.24.0 > /Jarkko