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=-4.0 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS autolearn=no 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 76C97C433E0 for ; Wed, 29 Jul 2020 22:07:17 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 59A1F206D8 for ; Wed, 29 Jul 2020 22:07:17 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727883AbgG2WHQ (ORCPT ); Wed, 29 Jul 2020 18:07:16 -0400 Received: from mga02.intel.com ([134.134.136.20]:21934 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726628AbgG2WHP (ORCPT ); Wed, 29 Jul 2020 18:07:15 -0400 IronPort-SDR: 8fpMMl/Ic870kAW6sFiHdtf3VzsEJ2Wsfo6B40IWq8DrcSlo/Php+ZWeqg6Z3gjiYz3F1yZuZ9 lY5KntjafGfw== X-IronPort-AV: E=McAfee;i="6000,8403,9697"; a="139511045" X-IronPort-AV: E=Sophos;i="5.75,412,1589266800"; d="scan'208";a="139511045" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 29 Jul 2020 15:07:14 -0700 IronPort-SDR: sWuxLoWojkxjsr4BOfxDQrzxADpJPxark3spRp2R6u6StfOBIgnrH2GmW9peBdrAju1I4SeHzj 3fv01O4nRsHg== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.75,412,1589266800"; d="scan'208";a="313183177" Received: from otcwcpicx6.sc.intel.com ([172.25.55.29]) by fmsmga004.fm.intel.com with ESMTP; 29 Jul 2020 15:07:14 -0700 Date: Wed, 29 Jul 2020 22:07:14 +0000 From: Fenghua Yu To: Sean Christopherson Cc: Fenghua Yu , Thomas Gleixner , Borislav Petkov , Ingo Molnar , Peter Zijlstra , "Shanbhogue, Vedvyas" , "Luck, Tony" , H Peter Anvin , Andy Lutomirski , "Shankar, Ravi V" , "Li, Xiaoyao" , x86 , linux-kernel Subject: Re: [PATCH RFC] x86/bus_lock: Enable bus lock detection Message-ID: <20200729220714.GA318659@otcwcpicx6.sc.intel.com> References: <1595021700-68460-1-git-send-email-fenghua.yu@intel.com> <20200729030232.GE5583@linux.intel.com> <20200729184614.GI27751@linux.intel.com> <20200729194259.GA318576@otcwcpicx6.sc.intel.com> <20200729200033.GJ27751@linux.intel.com> <20200729203557.GA318595@otcwcpicx6.sc.intel.com> <20200729203905.GN27751@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <20200729203905.GN27751@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Hi, Sean, On Wed, Jul 29, 2020 at 01:39:05PM -0700, Sean Christopherson wrote: > On Wed, Jul 29, 2020 at 08:35:57PM +0000, Fenghua Yu wrote: > > If sld=fatal and bld=ratelimit (both sld and bld are enabled in hw), > > a split lock always generates #AC and kills the app and bld will never have > > a chance to trigger #DB for split lock. So effectively the combination makes > > the kernel to take two different actions after detecting a bus lock: if the > > bus lock comes from a split lock, fatal (sld); if the bus lock comes from > > lock to non-WB memory, ratelimit (bld). Seems this is not a useful combination > > and is not what the user really wants to do because the user wants ratelimit > > for BLD, right? > > I understood all off that. And as I user I want to run sld=fatal and > bld=ratelimit to provide maximum protection, i.e. disallow split locks at > all times, and ratelimit the crud SLD #AC can't catch. Then this will expand the current usages and do need two options. Let me work on adding a new "bus_lock_detect=" option as you suggested. Thanks. -Fenghua