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=-2.5 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,SPF_PASS,USER_AGENT_MUTT 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 689B0C282C4 for ; Mon, 4 Feb 2019 19:09:58 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id 410802080A for ; Mon, 4 Feb 2019 19:09:58 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1729851AbfBDTJ4 (ORCPT ); Mon, 4 Feb 2019 14:09:56 -0500 Received: from mga17.intel.com ([192.55.52.151]:50620 "EHLO mga17.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727544AbfBDTJ4 (ORCPT ); Mon, 4 Feb 2019 14:09:56 -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 fmsmga107.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 04 Feb 2019 11:09:56 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.56,560,1539673200"; d="scan'208";a="316261243" Received: from romley-ivt3.sc.intel.com ([172.25.110.60]) by fmsmga006.fm.intel.com with ESMTP; 04 Feb 2019 11:09:55 -0800 Date: Mon, 4 Feb 2019 11:03:44 -0800 From: Fenghua Yu To: Dave Hansen Cc: Thomas Gleixner , Ingo Molnar , H Peter Anvin , Ashok Raj , Peter Zijlstra , Michael Chan , Ravi V Shankar , Ricardo Neri , linux-kernel , x86 Subject: Re: [PATCH v3 09/10] x86/split_lock: Define #AC for split lock feature Message-ID: <20190204190344.GA69898@romley-ivt3.sc.intel.com> References: <1549084491-57808-1-git-send-email-fenghua.yu@intel.com> <1549084491-57808-10-git-send-email-fenghua.yu@intel.com> <2d1c4c93-6ea9-5a0d-9a36-641fc01b14f5@intel.com> <20190204184549.GA69755@romley-ivt3.sc.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: User-Agent: Mutt/1.5.23 (2014-03-12) Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Mon, Feb 04, 2019 at 11:00:03AM -0800, Dave Hansen wrote: > On 2/4/19 10:45 AM, Fenghua Yu wrote: > > On Mon, Feb 04, 2019 at 10:41:40AM -0800, Dave Hansen wrote: > >> On 2/1/19 9:14 PM, Fenghua Yu wrote: > >>> --- a/arch/x86/include/asm/cpufeatures.h > >>> +++ b/arch/x86/include/asm/cpufeatures.h > >>> @@ -221,6 +221,7 @@ > >>> #define X86_FEATURE_ZEN ( 7*32+28) /* "" CPU is AMD family 0x17 (Zen) */ > >>> #define X86_FEATURE_L1TF_PTEINV ( 7*32+29) /* "" L1TF workaround PTE inversion */ > >>> #define X86_FEATURE_IBRS_ENHANCED ( 7*32+30) /* Enhanced IBRS */ > >>> +#define X86_FEATURE_AC_SPLIT_LOCK ( 7*32+31) /* #AC for split lock */ > >> > >> The last time this was posted, we (Intel) promised to go get the proper > >> (CPUID or MSR-based) enumeration of this feature documented. Did we do > >> that? If so, where is that documentation? > > > > As said in the cover patch: > > "Please note: The feature could be enumerated through > > MSR IA32_CORE_CAPABILITY (0xCF). But the enumeration is not completely > > published yet. So this patch set doesn't include the method." > > FWIW, I think we (Intel) promised to get this documented _before_ we > came back asking our intrepid x86 maintainers to accept something like > setcpuid=. While I generally applaud the post-early-post-often > attitude, we might have been a bit trigger-happy on this one. > > This is awfully crucial information to bury in a massive cover letter, > especially when the patch description is a rather anemic two lines. > Hi, Dave, I do have two pathes available to enumerate IA32_CORE_CAPABILITY itself and to enumerate #AC for split lock by bit 5 in the MSR. But because the enumeration for the MSR is not published, I cannot release the two patches in this patch set. Hopefully this patch set without the two enumeration patches is a meaningful set. Thanks. -Fenghua