From patchwork Tue Jan 26 09:30:54 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Huang, Kai" X-Patchwork-Id: 12047351 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=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 8069AC4332D for ; Tue, 26 Jan 2021 16:13:51 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 5947F207B6 for ; Tue, 26 Jan 2021 16:13:51 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2391188AbhAZQNl (ORCPT ); Tue, 26 Jan 2021 11:13:41 -0500 Received: from mga11.intel.com ([192.55.52.93]:39104 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S2391187AbhAZJbs (ORCPT ); Tue, 26 Jan 2021 04:31:48 -0500 IronPort-SDR: 9jSPVkbUrOWr2TVWinVm9IIydoX6eR5gT/xVS47YxbkLTvEZGDXCJxbqg0i46jEf8/mJQkhRjt qd4M0c14M7/g== X-IronPort-AV: E=McAfee;i="6000,8403,9875"; a="176363313" X-IronPort-AV: E=Sophos;i="5.79,375,1602572400"; d="scan'208";a="176363313" Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Jan 2021 01:31:07 -0800 IronPort-SDR: EX16KSkqm2HrJp68MbE79vNBavTLohW16YfTh8fmaKkT/Fd9RlvARFN2RQXXkFX+3KMqXV3iuW HABU1qZOx5lg== X-IronPort-AV: E=Sophos;i="5.79,375,1602572400"; d="scan'208";a="577747596" Received: from ravivisw-mobl1.amr.corp.intel.com (HELO khuang2-desk.gar.corp.intel.com) ([10.254.124.51]) by fmsmga005-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Jan 2021 01:31:03 -0800 From: Kai Huang To: linux-sgx@vger.kernel.org, kvm@vger.kernel.org, x86@kernel.org Cc: seanjc@google.com, jarkko@kernel.org, luto@kernel.org, dave.hansen@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: [RFC PATCH v3 07/27] x86/cpu/intel: Allow SGX virtualization without Launch Control support Date: Tue, 26 Jan 2021 22:30:54 +1300 Message-Id: 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 Signed-off-by: Kai Huang --- v2->v3: - Added to use 'enable_sgx_any', per Dave. - Changed to call clear_cpu_cap() directly, rather than using clear_sgx_caps() and clear_sgx_lc(). - Changed to use CONFIG_X86_SGX_KVM, instead of CONFIG_X86_SGX_VIRTUALIZATION. v1->v2: - Refined commit message per Dave's comments. - Added check to only enable SGX virtualization when VMX is supported, per Dave's comment. - Refined error msg print to explicitly call out SGX virtualization will be supported when LC is locked by BIOS, per Dave's comment. --- arch/x86/kernel/cpu/feat_ctl.c | 58 ++++++++++++++++++++++++++-------- 1 file changed, 45 insertions(+), 13 deletions(-) diff --git a/arch/x86/kernel/cpu/feat_ctl.c b/arch/x86/kernel/cpu/feat_ctl.c index 27533a6e04fa..0fc202550fcc 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_vmx; + bool enable_sgx_any, enable_sgx_kvm, enable_sgx_driver; u64 msr; if (rdmsrl_safe(MSR_IA32_FEAT_CTL, &msr)) { @@ -114,13 +115,22 @@ 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. + * Enable SGX if and only if the kernel supports SGX. Require Launch + * Control support if SGX virtualization is *not* supported, i.e. + * disable SGX if the LE hash MSRs can't be written and SGX can't be + * exposed to a KVM guest (which might support non-LC configurations). */ - 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) && + cpu_has(c, X86_FEATURE_SGX1) && + 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 +146,18 @@ 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 +180,29 @@ 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); + } } }