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,URIBL_BLOCKED, 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 A242BC10DCE for ; Wed, 25 Mar 2020 00:31:30 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 75A4220719 for ; Wed, 25 Mar 2020 00:31:30 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727262AbgCYAb3 (ORCPT ); Tue, 24 Mar 2020 20:31:29 -0400 Received: from mga02.intel.com ([134.134.136.20]:50410 "EHLO mga02.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727099AbgCYAb3 (ORCPT ); Tue, 24 Mar 2020 20:31:29 -0400 IronPort-SDR: cJLDkC3wCpyVIDqxd/RlQc1sxSrdn77yTQ0+nsEmn/cpy7pRLStIGZj/0247dIXo0kDdCiZ6Tq FhDhlGj7vm5A== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga101.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 24 Mar 2020 17:31:28 -0700 IronPort-SDR: IjDW8Fh1RUSOFjUVHr7o4ibU5xKTGeVUQee9K8tvntMfUqnWaInjyv5w2zhX6vi475LzLbiXuF rufpamoCH23A== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.72,302,1580803200"; d="scan'208";a="446451454" Received: from xiaoyaol-mobl.ccr.corp.intel.com (HELO [10.249.170.28]) ([10.249.170.28]) by fmsmga005.fm.intel.com with ESMTP; 24 Mar 2020 17:31:25 -0700 Subject: Re: [PATCH v6 4/8] kvm: x86: Emulate split-lock access as a write in emulator To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , hpa@zytor.com, Paolo Bonzini , Sean Christopherson Cc: x86@kernel.org, kvm@vger.kernel.org, linux-kernel@vger.kernel.org, Andy Lutomirski , Peter Zijlstra , Arvind Sankar , Fenghua Yu , Tony Luck References: <20200324151859.31068-1-xiaoyao.li@intel.com> <20200324151859.31068-5-xiaoyao.li@intel.com> <87lfnpz4k2.fsf@nanos.tec.linutronix.de> From: Xiaoyao Li Message-ID: Date: Wed, 25 Mar 2020 08:31:24 +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: <87lfnpz4k2.fsf@nanos.tec.linutronix.de> 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 3/25/2020 8:00 AM, Thomas Gleixner wrote: > Xiaoyao Li writes: >> >> +bool split_lock_detect_on(void) >> +{ >> + return sld_state != sld_off; >> +} >> +EXPORT_SYMBOL_GPL(split_lock_detect_on); > > 1) You export this function here > > 2) You change that in one of the next patches to something else > > 3) According to patch 1/8 X86_FEATURE_SPLIT_LOCK_DETECT is not set when > sld_state == sld_off. FYI, I did that on purpose. > > AFAICT #1 and #2 are just historical leftovers of your previous patch > series and the extra step was just adding more changed lines per patch > for no value. > > #3 changed the detection mechanism and at the same time the semantics of > the feature flag. > > So what's the point of this exercise? Right. In this series, setting X86_FEATURE_SPLIT_LOCK_DETECT flag means SLD is turned on. Need to remove split_lock_detect_on(). Thanks for pointing out this. > Thanks, > > tglx >