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=-5.8 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 CB5F9C64E75 for ; Thu, 19 Nov 2020 14:15:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4238122256 for ; Thu, 19 Nov 2020 14:15:34 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="MV5CpmAS" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727901AbgKSOPW (ORCPT ); Thu, 19 Nov 2020 09:15:22 -0500 Received: from mail.skyhub.de ([5.9.137.197]:42512 "EHLO mail.skyhub.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727824AbgKSOPU (ORCPT ); Thu, 19 Nov 2020 09:15:20 -0500 Received: from zn.tnic (p200300ec2f0caf00568863aa7ed02326.dip0.t-ipconnect.de [IPv6:2003:ec:2f0c:af00:5688:63aa:7ed0:2326]) (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 71F171EC04D1; Thu, 19 Nov 2020 15:15:18 +0100 (CET) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1605795318; 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:in-reply-to:in-reply-to: references:references; bh=ekf+AUaJ3paDxpFiCZgS74VrJkyt6cyk/9NBpR/fvyU=; b=MV5CpmASljlCO/YUmy8/kf5qcI6xkATuS2O4eC3ZQj5p6yYsvQfVuwzXod7Rr28soYo+vm KBmiQ6VLJJHgwtAp357XiE4VCK4f0OkctgXHYFxueSARLR8U8cOddqvZ9j3yl1mizcKXpO 7Onh/kRnf+CmvoYBWvMVhUjxEN2PV5g= Date: Thu, 19 Nov 2020 15:15:12 +0100 From: Borislav Petkov To: Feng Tang Cc: Peter Zijlstra , Thomas Gleixner , Ingo Molnar , "H . Peter Anvin" , Dave Hansen , x86@kernel.org, linux-kernel@vger.kernel.org, nivedita@alum.mit.edu, thomas.lendacky@amd.com, yazen.ghannam@amd.com, wei.huang2@amd.com Subject: Re: [RFC PATCH v3] tools/x86: add kcpuid tool to show raw CPU features Message-ID: <20201119141512.GB3769@zn.tnic> References: <1603344083-100742-1-git-send-email-feng.tang@intel.com> <20201118191529.GN7472@zn.tnic> <20201119072055.GA112648@shbuild999.sh.intel.com> <20201119091815.GA3769@zn.tnic> <20201119135010.GC112648@shbuild999.sh.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: <20201119135010.GC112648@shbuild999.sh.intel.com> Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Thu, Nov 19, 2020 at 09:50:10PM +0800, Feng Tang wrote: > That's really odd. I tried on 3 baremetal machines: one Skylake NUC device, > one Xeon E5-2699 and one Xeon E5-2680. Ah, sorry, not virt, virt is 0x4000_0000. Yeah, I remember now. It is function 4 which AMD doesn't implement and I'm running this on AMD: $ cpuid -1r CPU: 0x00000000 0x00: eax=0x0000000d ebx=0x68747541 ecx=0x444d4163 edx=0x69746e65 0x00000001 0x00: eax=0x00800f82 ebx=0x0c100800 ecx=0x7ed8320b edx=0x178bfbff 0x00000002 0x00: eax=0x00000000 ebx=0x00000000 ecx=0x00000000 edx=0x00000000 0x00000003 0x00: eax=0x00000000 ebx=0x00000000 ecx=0x00000000 edx=0x00000000 <-- no function 4. 0x00000005 0x00: eax=0x00000040 ebx=0x00000040 ecx=0x00000003 edx=0x00000011 ... That's why. :-) Btw, there are other funny ranges on Intel: ./cpuid -1r CPU: 0x20000000 0x00: eax=0x00000000 ebx=0x00000001 ecx=0x00000001 edx=0x00000000 That one has 2 bits set. 0x80860000 0x00: eax=0x00000000 ebx=0x00000001 ecx=0x00000001 edx=0x00000000 0xc0000000 0x00: eax=0x00000000 ebx=0x00000001 ecx=0x00000001 edx=0x00000000 And those too. Fun. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette