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=-0.8 required=3.0 tests=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 EAC86C433DF for ; Fri, 19 Jun 2020 13:22:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id C86802184D for ; Fri, 19 Jun 2020 13:22:54 +0000 (UTC) Authentication-Results: mail.kernel.org; dkim=pass (1024-bit key) header.d=alien8.de header.i=@alien8.de header.b="d6JTVPWK" Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1732121AbgFSNWx (ORCPT ); Fri, 19 Jun 2020 09:22:53 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:40570 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726124AbgFSNWw (ORCPT ); Fri, 19 Jun 2020 09:22:52 -0400 Received: from mail.skyhub.de (mail.skyhub.de [IPv6:2a01:4f8:190:11c2::b:1457]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 1DE3EC06174E for ; Fri, 19 Jun 2020 06:22:52 -0700 (PDT) Received: from zn.tnic (p200300ec2f0bac004d57d24caa4a0e33.dip0.t-ipconnect.de [IPv6:2003:ec:2f0b:ac00:4d57:d24c:aa4a:e33]) (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 1747A1EC03D0; Fri, 19 Jun 2020 15:22:50 +0200 (CEST) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/relaxed; d=alien8.de; s=dkim; t=1592572970; 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=gEMLO6KVm1oIKIAxLPOc4rRHgVZxc+y/BwsFuOfLTRE=; b=d6JTVPWK6JBiDGrITcwYYDhlXhKkzeVLRPbq6uoLnES4BND4yX3uHsRq2vAbtGeY+Bb0W/ myqVvLmlEO0kJ8Y3l1WCGAo+w8vke9bE3kRcXsw3/H72OQFnS3DmGmp5Nzv/YTO3+5O5bv jwUx6ekS+qY6Y5iL8MGHE4RcWxm2mBQ= Date: Fri, 19 Jun 2020 15:22:43 +0200 From: Borislav Petkov To: Daniel Gutson Cc: Dave Hansen , Thomas Gleixner , Ingo Molnar , x86@kernel.org, "H. Peter Anvin" , Arnd Bergmann , Greg Kroah-Hartman , Peter Zijlstra , "David S. Miller" , Rob Herring , Tony Luck , Rahul Tanwar , Xiaoyao Li , Sean Christopherson , Dave Hansen , linux-kernel@vger.kernel.org, Richard Hughes Subject: Re: [PATCH] Ability to read the MKTME status from userspace Message-ID: <20200619132243.GC32683@zn.tnic> References: <20200618210215.23602-1-daniel.gutson@eclypsium.com> <589c89ae-620e-36f8-2be5-4afc727c2911@intel.com> <20200618220139.GH27951@zn.tnic> <20200619074053.GA32683@zn.tnic> MIME-Version: 1.0 Content-Type: text/plain; charset=utf-8 Content-Disposition: inline In-Reply-To: Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org On Fri, Jun 19, 2020 at 10:01:36AM -0300, Daniel Gutson wrote: > Then the user will not know that he/she could improve the security of the > system by enabling the feature in the BIOS. And how is the user going to know from your "module"? AFAICT, your module loads on any system - not only on ones which have MKTME in CPUID. > The fact that the CPU has the cap and the BIOS disables it, can > trigger a prevention action. I can only venture guesses what "prevention action" is - you'll have to be more verbose here. -- Regards/Gruss, Boris. https://people.kernel.org/tglx/notes-about-netiquette