From patchwork Mon Mar 1 09:45:02 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Huang, Kai" X-Patchwork-Id: 12109331 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,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 37935C43381 for ; Mon, 1 Mar 2021 09:47:22 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 00A4564E54 for ; Mon, 1 Mar 2021 09:47:21 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234164AbhCAJrC (ORCPT ); Mon, 1 Mar 2021 04:47:02 -0500 Received: from mga06.intel.com ([134.134.136.31]:23944 "EHLO mga06.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S234106AbhCAJp5 (ORCPT ); Mon, 1 Mar 2021 04:45:57 -0500 IronPort-SDR: KymdAsDzbOdaS1YUyQNg2CPTuRgqo+wquBzjif6XnUqHsXbRartPx96ewiaLGWn9fHDAgGr031 Uu+xY6WHRElA== X-IronPort-AV: E=McAfee;i="6000,8403,9909"; a="247822421" X-IronPort-AV: E=Sophos;i="5.81,215,1610438400"; d="scan'208";a="247822421" Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga104.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Mar 2021 01:45:13 -0800 IronPort-SDR: 0apQbZCRaW3T6t4buz1Vkt79cibMH/LqxhE8r2r4aa/GMp0j7FXoREVoKQOnVp3QCKYwYE2V5s pe0xoftsGK5g== X-IronPort-AV: E=Sophos;i="5.81,215,1610438400"; d="scan'208";a="599267426" Received: from jscomeax-mobl.amr.corp.intel.com (HELO khuang2-desk.gar.corp.intel.com) ([10.252.139.76]) by fmsmga005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Mar 2021 01:45:09 -0800 From: Kai Huang To: kvm@vger.kernel.org, x86@kernel.org, linux-sgx@vger.kernel.org Cc: linux-kernel@vger.kernel.org, seanjc@google.com, jarkko@kernel.org, luto@kernel.org, dave.hansen@intel.com, rick.p.edgecombe@intel.com, haitao.huang@intel.com, pbonzini@redhat.com, bp@alien8.de, tglx@linutronix.de, mingo@redhat.com, hpa@zytor.com, jethro@fortanix.com, b.thiel@posteo.de, Kai Huang Subject: [PATCH 06/25] x86/cpu/intel: Allow SGX virtualization without Launch Control support Date: Mon, 1 Mar 2021 22:45:02 +1300 Message-Id: <12541888ae9ac7f517582aa64d9153feede7aed4.1614590788.git.kai.huang@intel.com> X-Mailer: git-send-email 2.29.2 In-Reply-To: References: MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: kvm@vger.kernel.org From: Sean Christopherson The kernel will currently disable all SGX support if the hardware does not support launch control. Make it more permissive to allow SGX virtualization on systems without Launch Control support. This will allow KVM to expose SGX to guests that have less-strict requirements on the availability of flexible launch control. Improve error message to distinguish between three cases. There are two cases where SGX support is completely disabled: 1) SGX has been disabled completely by the BIOS 2) SGX LC is locked by the BIOS. Bare-metal support is disabled because of LC unavailability. SGX virtualization is unavailable (because of Kconfig). One where it is partially available: 3) SGX LC is locked by the BIOS. Bare-metal support is disabled because of LC unavailability. SGX virtualization is supported. Signed-off-by: Sean Christopherson Co-developed-by: Kai Huang Acked-by: Dave Hansen Signed-off-by: Kai Huang --- arch/x86/kernel/cpu/feat_ctl.c | 57 ++++++++++++++++++++++++++-------- 1 file changed, 44 insertions(+), 13 deletions(-) diff --git a/arch/x86/kernel/cpu/feat_ctl.c b/arch/x86/kernel/cpu/feat_ctl.c index 27533a6e04fa..96c370284913 100644 --- a/arch/x86/kernel/cpu/feat_ctl.c +++ b/arch/x86/kernel/cpu/feat_ctl.c @@ -105,7 +105,8 @@ early_param("nosgx", nosgx); void init_ia32_feat_ctl(struct cpuinfo_x86 *c) { bool tboot = tboot_enabled(); - bool enable_sgx; + bool enable_sgx_any, enable_sgx_kvm, enable_sgx_driver; + bool enable_vmx; u64 msr; if (rdmsrl_safe(MSR_IA32_FEAT_CTL, &msr)) { @@ -114,13 +115,21 @@ void init_ia32_feat_ctl(struct cpuinfo_x86 *c) return; } + enable_vmx = cpu_has(c, X86_FEATURE_VMX) && + IS_ENABLED(CONFIG_KVM_INTEL); + /* - * Enable SGX if and only if the kernel supports SGX and Launch Control - * is supported, i.e. disable SGX if the LE hash MSRs can't be written. + * Separate out SGX driver enabling from KVM. This allows KVM + * guests to use SGX even if the kernel SGX driver refuses to + * use it. This happens if flexible Faunch Control is not + * available. */ - enable_sgx = cpu_has(c, X86_FEATURE_SGX) && - cpu_has(c, X86_FEATURE_SGX_LC) && - IS_ENABLED(CONFIG_X86_SGX); + enable_sgx_any = cpu_has(c, X86_FEATURE_SGX) && + IS_ENABLED(CONFIG_X86_SGX); + enable_sgx_driver = enable_sgx_any && + cpu_has(c, X86_FEATURE_SGX_LC); + enable_sgx_kvm = enable_sgx_any && enable_vmx && + IS_ENABLED(CONFIG_X86_SGX_KVM); if (msr & FEAT_CTL_LOCKED) goto update_caps; @@ -136,15 +145,18 @@ void init_ia32_feat_ctl(struct cpuinfo_x86 *c) * i.e. KVM is enabled, to avoid unnecessarily adding an attack vector * for the kernel, e.g. using VMX to hide malicious code. */ - if (cpu_has(c, X86_FEATURE_VMX) && IS_ENABLED(CONFIG_KVM_INTEL)) { + if (enable_vmx) { msr |= FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX; if (tboot) msr |= FEAT_CTL_VMX_ENABLED_INSIDE_SMX; } - if (enable_sgx) - msr |= FEAT_CTL_SGX_ENABLED | FEAT_CTL_SGX_LC_ENABLED; + if (enable_sgx_kvm || enable_sgx_driver) { + msr |= FEAT_CTL_SGX_ENABLED; + if (enable_sgx_driver) + msr |= FEAT_CTL_SGX_LC_ENABLED; + } wrmsrl(MSR_IA32_FEAT_CTL, msr); @@ -167,10 +179,29 @@ void init_ia32_feat_ctl(struct cpuinfo_x86 *c) } update_sgx: - if (!(msr & FEAT_CTL_SGX_ENABLED) || - !(msr & FEAT_CTL_SGX_LC_ENABLED) || !enable_sgx) { - if (enable_sgx) - pr_err_once("SGX disabled by BIOS\n"); + if (!(msr & FEAT_CTL_SGX_ENABLED)) { + if (enable_sgx_kvm || enable_sgx_driver) + pr_err_once("SGX disabled by BIOS.\n"); clear_cpu_cap(c, X86_FEATURE_SGX); + return; + } + + /* + * VMX feature bit may be cleared due to being disabled in BIOS, + * in which case SGX virtualization cannot be supported either. + */ + if (!cpu_has(c, X86_FEATURE_VMX) && enable_sgx_kvm) { + pr_err_once("SGX virtualization disabled due to lack of VMX.\n"); + enable_sgx_kvm = 0; + } + + if (!(msr & FEAT_CTL_SGX_LC_ENABLED) && enable_sgx_driver) { + if (!enable_sgx_kvm) { + pr_err_once("SGX Launch Control is locked. Disable SGX.\n"); + clear_cpu_cap(c, X86_FEATURE_SGX); + } else { + pr_err_once("SGX Launch Control is locked. Support SGX virtualization only.\n"); + clear_cpu_cap(c, X86_FEATURE_SGX_LC); + } } }