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=-12.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY, SPF_HELO_NONE,SPF_PASS,URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 7D685C43461 for ; Mon, 7 Sep 2020 17:29:06 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 4ECE82067C for ; Mon, 7 Sep 2020 17:29:06 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1731284AbgIGR3E (ORCPT ); Mon, 7 Sep 2020 13:29:04 -0400 Received: from 8bytes.org ([81.169.241.247]:43570 "EHLO theia.8bytes.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1729518AbgIGNTh (ORCPT ); Mon, 7 Sep 2020 09:19:37 -0400 Received: from cap.home.8bytes.org (p549add56.dip0.t-ipconnect.de [84.154.221.86]) (using TLSv1.3 with cipher TLS_AES_256_GCM_SHA384 (256/256 bits)) (No client certificate requested) by theia.8bytes.org (Postfix) with ESMTPSA id 793183AB2; Mon, 7 Sep 2020 15:17:20 +0200 (CEST) From: Joerg Roedel To: x86@kernel.org Cc: Joerg Roedel , Joerg Roedel , Martin Radev , Kees Cook , hpa@zytor.com, Andy Lutomirski , Dave Hansen , Peter Zijlstra , Jiri Slaby , Dan Williams , Tom Lendacky , Juergen Gross , David Rientjes , Cfir Cohen , Erdem Aktas , Masami Hiramatsu , Mike Stunes , Sean Christopherson , linux-kernel@vger.kernel.org, kvm@vger.kernel.org, virtualization@lists.linux-foundation.org Subject: [PATCH v7 72/72] x86/sev-es: Check required CPU features for SEV-ES Date: Mon, 7 Sep 2020 15:16:13 +0200 Message-Id: <20200907131613.12703-73-joro@8bytes.org> X-Mailer: git-send-email 2.28.0 In-Reply-To: <20200907131613.12703-1-joro@8bytes.org> References: <20200907131613.12703-1-joro@8bytes.org> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Martin Radev Make sure the machine supports RDRAND, otherwise there is no trusted source of of randomness in the system. To also check this in the pre-decompression stage, make has_cpuflag not depend on CONFIG_RANDOMIZE_BASE anymore. Signed-off-by: Martin Radev Signed-off-by: Joerg Roedel Reviewed-by: Kees Cook --- arch/x86/boot/compressed/cpuflags.c | 4 ---- arch/x86/boot/compressed/misc.h | 5 +++-- arch/x86/boot/compressed/sev-es.c | 3 +++ arch/x86/kernel/sev-es-shared.c | 15 +++++++++++++++ arch/x86/kernel/sev-es.c | 3 +++ 5 files changed, 24 insertions(+), 6 deletions(-) diff --git a/arch/x86/boot/compressed/cpuflags.c b/arch/x86/boot/compressed/cpuflags.c index 6448a8196d32..0cc1323896d1 100644 --- a/arch/x86/boot/compressed/cpuflags.c +++ b/arch/x86/boot/compressed/cpuflags.c @@ -1,6 +1,4 @@ // SPDX-License-Identifier: GPL-2.0 -#ifdef CONFIG_RANDOMIZE_BASE - #include "../cpuflags.c" bool has_cpuflag(int flag) @@ -9,5 +7,3 @@ bool has_cpuflag(int flag) return test_bit(flag, cpu.flags); } - -#endif diff --git a/arch/x86/boot/compressed/misc.h b/arch/x86/boot/compressed/misc.h index c0e0ffeee50a..6d31f1b4c4d1 100644 --- a/arch/x86/boot/compressed/misc.h +++ b/arch/x86/boot/compressed/misc.h @@ -85,8 +85,6 @@ void choose_random_location(unsigned long input, unsigned long *output, unsigned long output_size, unsigned long *virt_addr); -/* cpuflags.c */ -bool has_cpuflag(int flag); #else static inline void choose_random_location(unsigned long input, unsigned long input_size, @@ -97,6 +95,9 @@ static inline void choose_random_location(unsigned long input, } #endif +/* cpuflags.c */ +bool has_cpuflag(int flag); + #ifdef CONFIG_X86_64 extern int set_page_decrypted(unsigned long address); extern int set_page_encrypted(unsigned long address); diff --git a/arch/x86/boot/compressed/sev-es.c b/arch/x86/boot/compressed/sev-es.c index 0a9a248ca33d..3c66dad4e62e 100644 --- a/arch/x86/boot/compressed/sev-es.c +++ b/arch/x86/boot/compressed/sev-es.c @@ -145,6 +145,9 @@ void sev_es_shutdown_ghcb(void) if (!boot_ghcb) return; + if (!sev_es_check_cpu_features()) + error("SEV-ES CPU Features missing."); + /* * GHCB Page must be flushed from the cache and mapped encrypted again. * Otherwise the running kernel will see strange cache effects when diff --git a/arch/x86/kernel/sev-es-shared.c b/arch/x86/kernel/sev-es-shared.c index 92d77b725ccb..ce86d2c9ca7b 100644 --- a/arch/x86/kernel/sev-es-shared.c +++ b/arch/x86/kernel/sev-es-shared.c @@ -9,6 +9,21 @@ * and is included directly into both code-bases. */ +#ifndef __BOOT_COMPRESSED +#define error(v) pr_err(v) +#define has_cpuflag(f) boot_cpu_has(f) +#endif + +static bool __init sev_es_check_cpu_features(void) +{ + if (!has_cpuflag(X86_FEATURE_RDRAND)) { + error("RDRAND instruction not supported - no trusted source of randomness available\n"); + return false; + } + + return true; +} + static void sev_es_terminate(unsigned int reason) { u64 val = GHCB_SEV_TERMINATE; diff --git a/arch/x86/kernel/sev-es.c b/arch/x86/kernel/sev-es.c index 4e2b7e4d9b87..70623bbce062 100644 --- a/arch/x86/kernel/sev-es.c +++ b/arch/x86/kernel/sev-es.c @@ -665,6 +665,9 @@ void __init sev_es_init_vc_handling(void) if (!sev_es_active()) return; + if (!sev_es_check_cpu_features()) + panic("SEV-ES CPU Features missing"); + /* Enable SEV-ES special handling */ static_branch_enable(&sev_es_enable_key); -- 2.28.0