Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1751630Ab3EJHF6 (ORCPT ); Fri, 10 May 2013 03:05:58 -0400 Received: from mga09.intel.com ([134.134.136.24]:32579 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750825Ab3EJHF5 (ORCPT ); Fri, 10 May 2013 03:05:57 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="4.87,646,1363158000"; d="scan'208";a="334718048" From: "Ren, Qiaowei" To: Matthew Garrett CC: "linux-kernel@vger.kernel.org" , "platform-driver-x86@vger.kernel.org" , "Wei, Gang" Subject: RE: [PATCH 4/4] driver: provide sysfs interfaces to access SMX parameter Thread-Topic: [PATCH 4/4] driver: provide sysfs interfaces to access SMX parameter Thread-Index: AQHOSvE+ysMfIHdI9EqG5gcExdaKwpj6wt+AgAMpG0A= Date: Fri, 10 May 2013 07:05:53 +0000 Message-ID: <9E0BE1322F2F2246BD820DA9FC397ADE9AC926@SHSMSX102.ccr.corp.intel.com> References: <1367938519-840-1-git-send-email-qiaowei.ren@intel.com> <1367938519-840-5-git-send-email-qiaowei.ren@intel.com> <1367990697.2425.33.camel@x230> In-Reply-To: <1367990697.2425.33.camel@x230> Accept-Language: zh-CN, en-US Content-Language: en-US X-MS-Has-Attach: X-MS-TNEF-Correlator: x-originating-ip: [10.239.127.40] Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Transfer-Encoding: 8bit X-MIME-Autoconverted: from base64 to 8bit by mail.home.local id r4A766cr020623 Content-Length: 2070 Lines: 50 On 2013-05-08, Matthew Garrett wrote: > On Tue, 2013-05-07 at 22:55 +0800, Qiaowei Ren wrote: > > > +What: /sys/devices/platform/intel_txt/parameter/acm_max_size > > +Date: May 2013 > > +KernelVersion: 3.9 > > +Contact: "Qiaowei Ren" > > +Description: The "acm_max_size" property will show max size of > > + authenticated code execution area. > > What would userspace use this for? These sysfs files are just export SMX & TXT related information to userspace. So that other developers (or OSV & ISV) can be able to develop txt related applications or tools based on these information. > > +What: /sys/devices/platform/intel_txt/parameter/acm_mem_types > > +Date: May 2013 > > +KernelVersion: 3.9 > > +Contact: "Qiaowei Ren" > > +Description: The "acm_max_types" property will show external memory > > + types supported during AC mode. > > Or this? And what's AC mode? It means that the property will show supportable memory types for memory mapped outside of the authenticated code execution area. > > + __asm__ __volatile__ (IA32_GETSEC_OPCODE "\n" > > + : "=a"(eax), "=b"(ebx), "=c"(ecx) > > + : "a"(IA32_GETSEC_PARAMETERS), "b"(index)); > > + > > + *param_type = eax & 0x1f; > > + *peax = eax; > > + *pebx = ebx; > > + *pecx = ecx; > > Should there be a check for failure here? Is it possible for this operation to fail? You mean GETSEC instruction? I don't notice related description in manual. Next function get_parameters() will process return eax/ebx/ecx returned by this instruction. > > + write_cr4(read_cr4() | CR4_SMXE); > > Whoo. This needs at least a giant comment and probably some locking, but if > this is supposed to be set during runtime then it should be done in core > architecture code rather than just in this driver. Oh. This code should be removed, because tboot code have set SMXE bit. Thanks, Qiaowei ????{.n?+???????+%?????ݶ??w??{.n?+????{??G?????{ay?ʇڙ?,j??f???h?????????z_??(?階?ݢj"???m??????G????????????&???~???iO???z??v?^?m???? ????????I?