From patchwork Wed Nov 4 14:54:13 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Jarkko Sakkinen X-Patchwork-Id: 11880841 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=-12.7 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=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 B6AF5C2D0A3 for ; Wed, 4 Nov 2020 14:55:26 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 7938B221E2 for ; Wed, 4 Nov 2020 14:55:25 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1730386AbgKDOzY (ORCPT ); Wed, 4 Nov 2020 09:55:24 -0500 Received: from mail.kernel.org ([198.145.29.99]:49128 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1730245AbgKDOzX (ORCPT ); Wed, 4 Nov 2020 09:55:23 -0500 Received: from suppilovahvero.lan (83-245-197-237.elisa-laajakaista.fi [83.245.197.237]) (using TLSv1.2 with cipher ECDHE-RSA-AES128-GCM-SHA256 (128/128 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPSA id CC62222228; Wed, 4 Nov 2020 14:55:15 +0000 (UTC) From: Jarkko Sakkinen To: x86@kernel.org, linux-sgx@vger.kernel.org Cc: linux-kernel@vger.kernel.org, Sean Christopherson , Jethro Beekman , Darren Kenny , Jarkko Sakkinen , akpm@linux-foundation.org, andriy.shevchenko@linux.intel.com, asapek@google.com, bp@alien8.de, cedric.xing@intel.com, chenalexchen@google.com, conradparker@google.com, cyhanish@google.com, dave.hansen@intel.com, haitao.huang@intel.com, kai.huang@intel.com, kai.svahn@intel.com, kmoy@google.com, ludloff@google.com, luto@kernel.org, nhorman@redhat.com, npmccallum@redhat.com, puiterwijk@redhat.com, rientjes@google.com, tglx@linutronix.de, yaozhangx@google.com, mikko.ylinen@intel.com Subject: [PATCH v40 07/24] x86/cpu/intel: Detect SGX support Date: Wed, 4 Nov 2020 16:54:13 +0200 Message-Id: <20201104145430.300542-8-jarkko.sakkinen@linux.intel.com> X-Mailer: git-send-email 2.27.0 In-Reply-To: <20201104145430.300542-1-jarkko.sakkinen@linux.intel.com> References: <20201104145430.300542-1-jarkko.sakkinen@linux.intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org From: Sean Christopherson Kernel support for SGX is ultimately decided by the state of the launch control bits in the feature control MSR (MSR_IA32_FEAT_CTL). If the hardware supports SGX, but neglects to support flexible launch control, the kernel will not enable SGX. Enable SGX at feature control MSR initialization and update the associated X86_FEATURE flags accordingly. Disable X86_FEATURE_SGX (and all derivatives) if the kernel is not able to establish itself as the authority over SGX Launch Control. All checks are performed for each logical CPU (not just boot CPU) in order to verify that MSR_IA32_FEATURE_CONTROL is correctly configured on all CPUs. All SGX code in this series expects the same configuration from all CPUs. This differs from VMX where X86_FEATURE_VMX is intentionally cleared only for the current CPU so that KVM can provide additional information if KVM fails to load like which CPU doesn't support VMX. There’s not much the kernel or an administrator can do to fix the situation, so SGX neglects to convey additional details about these kinds of failures if they occur. Acked-by: Jethro Beekman Reviewed-by: Darren Kenny Signed-off-by: Sean Christopherson Co-developed-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen --- arch/x86/kernel/cpu/feat_ctl.c | 29 ++++++++++++++++++++++++++++- 1 file changed, 28 insertions(+), 1 deletion(-) diff --git a/arch/x86/kernel/cpu/feat_ctl.c b/arch/x86/kernel/cpu/feat_ctl.c index 29a3bedabd06..d38e97325018 100644 --- a/arch/x86/kernel/cpu/feat_ctl.c +++ b/arch/x86/kernel/cpu/feat_ctl.c @@ -93,16 +93,32 @@ static void init_vmx_capabilities(struct cpuinfo_x86 *c) } #endif /* CONFIG_X86_VMX_FEATURE_NAMES */ +static void clear_sgx_caps(void) +{ + setup_clear_cpu_cap(X86_FEATURE_SGX); + setup_clear_cpu_cap(X86_FEATURE_SGX_LC); +} + void init_ia32_feat_ctl(struct cpuinfo_x86 *c) { bool tboot = tboot_enabled(); + bool enable_sgx; u64 msr; if (rdmsrl_safe(MSR_IA32_FEAT_CTL, &msr)) { clear_cpu_cap(c, X86_FEATURE_VMX); + clear_sgx_caps(); return; } + /* + * 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 = cpu_has(c, X86_FEATURE_SGX) && + cpu_has(c, X86_FEATURE_SGX_LC) && + IS_ENABLED(CONFIG_X86_SGX); + if (msr & FEAT_CTL_LOCKED) goto update_caps; @@ -124,13 +140,16 @@ void init_ia32_feat_ctl(struct cpuinfo_x86 *c) msr |= FEAT_CTL_VMX_ENABLED_INSIDE_SMX; } + if (enable_sgx) + msr |= FEAT_CTL_SGX_ENABLED | FEAT_CTL_SGX_LC_ENABLED; + wrmsrl(MSR_IA32_FEAT_CTL, msr); update_caps: set_cpu_cap(c, X86_FEATURE_MSR_IA32_FEAT_CTL); if (!cpu_has(c, X86_FEATURE_VMX)) - return; + goto update_sgx; if ( (tboot && !(msr & FEAT_CTL_VMX_ENABLED_INSIDE_SMX)) || (!tboot && !(msr & FEAT_CTL_VMX_ENABLED_OUTSIDE_SMX))) { @@ -143,4 +162,12 @@ void init_ia32_feat_ctl(struct cpuinfo_x86 *c) init_vmx_capabilities(c); #endif } + +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"); + clear_sgx_caps(); + } }