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=-4.1 required=3.0 tests=BAYES_00,DKIM_SIGNED, DKIM_VALID,DKIM_VALID_AU,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 3E18CC433E7 for ; Wed, 2 Sep 2020 16:52:24 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 14DEC20767 for ; Wed, 2 Sep 2020 16:52:24 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="Y2GqRyjf" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728130AbgIBQwW (ORCPT ); Wed, 2 Sep 2020 12:52:22 -0400 Received: from mail.skyhub.de ([5.9.137.197]:32828 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726467AbgIBQwV (ORCPT ); Wed, 2 Sep 2020 12:52:21 -0400 Received: from zn.tnic (p200300ec2f0d7a00acdede37bac547d6.dip0.t-ipconnect.de [IPv6:2003:ec:2f0d:7a00:acde:de37:bac5:47d6]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.skyhub.de (SuperMail on ZX Spectrum 128k) with ESMTPSA id 5DACA1EC0493; Wed, 2 Sep 2020 18:52:20 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1599065540; h=from:from:reply-to:subject:subject:date:date:message-id:message-id: to:to:cc:cc:mime-version:mime-version:content-type:content-type: content-transfer-encoding:content-transfer-encoding: in-reply-to:in-reply-to:references:references; bh=agIwxdotGavgVufm8ANMtee53aatZqrnYawgSob6eFk=; b=Y2GqRyjfLNTXQuTlPTxaGp+ZwJv27pxB4vLUxlBX8N4T0WRughh3gBbwJTXeWM+qMAZtIM T9Ni8FYGCoDo42PsL1/2CZBDEoowB7Aaq+jeFsUgZysm9kxiuUWO8zkLwtYJN8Jzep6lt0 Ke/TsD4kT81Atku75LkW91oqTZQ03wo= Date: Wed, 2 Sep 2020 18:52:16 +0200 From: Borislav Petkov To: Dave Hansen Cc: Feng Tang , Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" , Peter Zijlstra , x86@kernel.org, linux-kernel@vger.kernel.org Subject: Re: [RFC PATCH] tools/x86: add kcpuid tool to show raw CPU features Message-ID: <20200902165216.GB21537@zn.tnic> References: <1598514543-90152-1-git-send-email-feng.tang@intel.com> <20200902154018.GA21537@zn.tnic> <5ef17179-7557-b609-2e72-20caa1369d46@intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline Content-Transfer-Encoding: 8bit In-Reply-To: <5ef17179-7557-b609-2e72-20caa1369d46@intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Wed, Sep 02, 2020 at 09:25:17AM -0700, Dave Hansen wrote: > Ugh. I hate text parsers. But, I do see what you're getting at. That's why it'll be a simple one. Nothing fancy. I'm hoping the final version would be somewhat readable to humans too. > If we do this, I bet having each value on its own line, I bet this would > be a bit less painful to parse. It'll be a _bit_ harder to read, but > not really. Maybe: > > LEAF[07],SUBLEAF[00],EAX[31:0],max_value, Max input value for supported > subleafs > LEAF[07],SUBLEAF[00],EBX[ 0],FSGSBASE, > RDFSBASE/RDGSBASE/WRFSBASE/WRGSBASE if 1. > LEAF[07],SUBLEAF[00],EBX[ 1],TSC_ADJUST, IA32_TSC_ADJUST MSR is > supported if 1. > LEAF[07],SUBLEAF[00],EBX[ 2],SGX, Supports Intel® Software Guard > Extensions (Intel® SGX Extensions) if 1. Yeah, this was just a stupid example to start the conversation. > I was *really* hoping that we could eventually feed kcpuid and the > X86_FEATURE_* bits from the same source. But X86_FEATURE_* won't be all bits in all CPUID leafs - only the ones the kernel has enabled/use for/needs/... Also you have CPUID fields which are multi-bit and which cannot be X86_FEATURE_* things. So you need a place which has the whole CPUID space and X86_FEATURE_* simply cannot represent it all. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette