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=-1.0 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS 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 5A926C43441 for ; Mon, 19 Nov 2018 18:27:42 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 23500206BA for ; Mon, 19 Nov 2018 18:27:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 23500206BA Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=none smtp.mailfrom=linux-kernel-owner@vger.kernel.org Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730345AbeKTEwW (ORCPT ); Mon, 19 Nov 2018 23:52:22 -0500 Received: from mga05.intel.com ([192.55.52.43]:43979 "EHLO mga05.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730128AbeKTEwW (ORCPT ); Mon, 19 Nov 2018 23:52:22 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga105.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 19 Nov 2018 10:27:39 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,253,1539673200"; d="scan'208";a="109843882" Received: from schen9-desk.jf.intel.com (HELO [10.54.74.144]) ([10.54.74.144]) by orsmga002.jf.intel.com with ESMTP; 19 Nov 2018 10:27:39 -0800 Subject: Re: [Patch v5 11/16] x86/speculation: Add Spectre v2 app to app protection modes To: Thomas Gleixner Cc: Jiri Kosina , Tom Lendacky , Ingo Molnar , Peter Zijlstra , Josh Poimboeuf , Andrea Arcangeli , David Woodhouse , Andi Kleen , Dave Hansen , Casey Schaufler , Asit Mallick , Arjan van de Ven , Jon Masters , Waiman Long , linux-kernel@vger.kernel.org, x86@kernel.org References: From: Tim Chen Openpgp: preference=signencrypt Autocrypt: addr=tim.c.chen@linux.intel.com; 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Linux x86_64; rv:52.0) Gecko/20100101 Thunderbird/52.1.0 MIME-Version: 1.0 In-Reply-To: Content-Type: text/plain; charset=utf-8 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 11/19/2018 07:00 AM, Thomas Gleixner wrote: > On Fri, 16 Nov 2018, Tim Chen wrote: >> +DEFINE_STATIC_KEY_FALSE(spectre_v2_app_lite); >> +EXPORT_SYMBOL_GPL(spectre_v2_app_lite); > > Why would this be exported? The only usage site outside of this code is in > tlb.c which is hardly modular. That was my initial thought too. Ingo suggested to export it in review of v2. Wonder Ingo has some reason? https://lore.kernel.org/patchwork/patch/991759/ > >> @@ -328,14 +411,19 @@ static bool stibp_needed(void) >> /* >> * Determine if STIBP should be always on. >> * Using enhanced IBRS makes using STIBP unnecessary. >> + * For lite option, STIBP is used only for task with >> + * TIF_STIBP flag. STIBP is not always on for that case. > > Having the comment detached from the code is really not helpful. > Sorry, would have the comment moved. Tim