From patchwork Fri Aug 6 00:09:39 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Kuppuswamy Sathyanarayanan X-Patchwork-Id: 12422347 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT 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 90413C4320A for ; Fri, 6 Aug 2021 00:10:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 73075610FB for ; Fri, 6 Aug 2021 00:10:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S242714AbhHFAKT (ORCPT ); Thu, 5 Aug 2021 20:10:19 -0400 Received: from mga04.intel.com ([192.55.52.120]:45281 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242703AbhHFAKR (ORCPT ); Thu, 5 Aug 2021 20:10:17 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10067"; a="212422358" X-IronPort-AV: E=Sophos;i="5.84,299,1620716400"; d="scan'208";a="212422358" Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Aug 2021 17:10:02 -0700 X-IronPort-AV: E=Sophos;i="5.84,299,1620716400"; d="scan'208";a="420562704" Received: from rmgular-mobl2.amr.corp.intel.com (HELO skuppusw-desk1.amr.corp.intel.com) ([10.251.138.25]) by orsmga003-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 05 Aug 2021 17:10:00 -0700 From: Kuppuswamy Sathyanarayanan To: Thomas Gleixner , Ingo Molnar , Borislav Petkov , Peter Zijlstra , Andy Lutomirski , Hans de Goede , Mark Gross , Alexei Starovoitov , Daniel Borkmann , Andrii Nakryiko Cc: Peter H Anvin , Dave Hansen , Tony Luck , Dan Williams , Andi Kleen , Kirill Shutemov , Sean Christopherson , Kuppuswamy Sathyanarayanan , x86@kernel.org, linux-kernel@vger.kernel.org, platform-driver-x86@vger.kernel.org, bpf@vger.kernel.org, netdev@vger.kernel.org Subject: [PATCH v4 1/7] x86/tdx: Add tdg_debug_enabled() interface Date: Thu, 5 Aug 2021 17:09:39 -0700 Message-Id: <20210806000946.2951441-2-sathyanarayanan.kuppuswamy@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20210806000946.2951441-1-sathyanarayanan.kuppuswamy@linux.intel.com> References: <20210806000946.2951441-1-sathyanarayanan.kuppuswamy@linux.intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: bpf@vger.kernel.org A guest TD is defined as debuggable if its ATTRIBUTES.DEBUG bit is 1. In this mode, the host VMM can use Intel TDX functions to access secret TD state that is not accessible for non-debuggable TDs. A debuggable TD is, by nature, untrusted. Since the TD’s ATTRIBUTES are included in the TDG.MR.REPORT, the TD’s debuggability state can be known to any third party to which the TD attests. TD Attributes are initialized during TD INIT call. For more details about debug features, check Intel Trust Domain Extensions (Intel TDX) Module Architecture specification, sec 13.3. Add a new interface to detect the TDX debug mode. This will be used by follow-on patches. Examples of its usage are, when adding command line debug options to disable TDX features like driver or port filter, tdg_debug_enabled() is used to make sure it is used only in debug mode. https://software.intel.com/content/dam/develop/external/us/en/documents/tdx-module-1eas-v0.85.039.pdf Reviewed-by: Tony Luck Reviewed-by: Andi Kleen Signed-off-by: Kuppuswamy Sathyanarayanan --- arch/x86/include/asm/tdx.h | 2 ++ arch/x86/kernel/tdx.c | 5 +++++ 2 files changed, 7 insertions(+) diff --git a/arch/x86/include/asm/tdx.h b/arch/x86/include/asm/tdx.h index dd5459ece9aa..50693bd6f0dd 100644 --- a/arch/x86/include/asm/tdx.h +++ b/arch/x86/include/asm/tdx.h @@ -69,6 +69,8 @@ enum tdx_map_type { extern unsigned int tdg_disable_prot; +bool tdg_debug_enabled(void); + void __init tdx_early_init(void); bool tdx_prot_guest_has(unsigned long flag); diff --git a/arch/x86/kernel/tdx.c b/arch/x86/kernel/tdx.c index bfa168f3f09c..c71049cd2255 100644 --- a/arch/x86/kernel/tdx.c +++ b/arch/x86/kernel/tdx.c @@ -135,6 +135,11 @@ phys_addr_t tdg_shared_mask(void) return 1ULL << (td_info.gpa_width - 1); } +bool tdg_debug_enabled(void) +{ + return td_info.attributes & BIT(0); +} + static void tdg_get_info(void) { u64 ret;