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=-1.3 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, HK_RANDOM_FROM,MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_SANE_1 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 E8494C10DCE for ; Wed, 18 Mar 2020 12:58:03 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id C1A8E2076D for ; Wed, 18 Mar 2020 12:58:03 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1726894AbgCRM6C (ORCPT ); Wed, 18 Mar 2020 08:58:02 -0400 Received: from mga06.intel.com ([134.134.136.31]:63424 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726765AbgCRM6C (ORCPT ); Wed, 18 Mar 2020 08:58:02 -0400 IronPort-SDR: RvbxxRczG7WdWNhsPeOiqSYS0RGD/fPyhXC4R2xRalk0a9iBIIj7CUjhJZ6TjUMxfsctqPkjhR T/LEyM0wB2tw== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 18 Mar 2020 05:58:02 -0700 IronPort-SDR: aEOQ2pm0rO6THLoXW9F6ereX9BgMU5ud7ETZSpylp/E5z87zJyoffb+Rd2xI1jypSAHrkD+RmY Pay+mPtT4FmQ== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,567,1574150400"; d="scan'208";a="238598966" Received: from xiaoyaol-mobl.ccr.corp.intel.com (HELO [10.255.29.88]) ([10.255.29.88]) by orsmga008.jf.intel.com with ESMTP; 18 Mar 2020 05:57:59 -0700 Subject: Re: [PATCH] x86/cpufeatures: make bits in cpu_caps_cleared[] and cpu_cpus_set[] exclusive To: Borislav Petkov Cc: Thomas Gleixner , Ingo Molnar , "H. Peter Anvin" , x86@kernel.org, linux-kernel@vger.kernel.org References: <20200318061624.150313-1-xiaoyao.li@intel.com> <20200318103219.GA4377@zn.tnic> From: Xiaoyao Li Message-ID: <42770941-dfdf-628b-3fe8-6ee5a871b1b4@intel.com> Date: Wed, 18 Mar 2020 20:57:58 +0800 User-Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:68.0) Gecko/20100101 Thunderbird/68.6.0 MIME-Version: 1.0 In-Reply-To: <20200318103219.GA4377@zn.tnic> Content-Type: text/plain; charset=utf-8; format=flowed Content-Language: en-US Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On 3/18/2020 6:32 PM, Borislav Petkov wrote: > On Wed, Mar 18, 2020 at 02:16:24PM +0800, Xiaoyao Li wrote: >> In apply_forced_caps(), cpu_caps_set[] overrides cpu_caps_cleared[], so >> that setup_clear_cpu_cap() cannot clear one cap if setup_force_cpu_cap() >> sets the cap before it. > > Context pls: what is the observation, what are you trying to do, > reproducer, etc? Well. I use setup_force_cup_cap(XXX) to set one flag, XXX, during early boot. And use setup_clear_cpu_cap(XXX) to clear this flag when something wrong later. However, it turns out that the flag is still set when I use cpu_has(c, XXX) to check when init each AP. I have to clear the flag XXX explicitly using clear_cpu_cap(c, XXX). However, in /proc/cpuinfo, this XXX flag still presents on every CPU. > Thx. >