From patchwork Sun Mar 17 21:14:37 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jarkko Sakkinen X-Patchwork-Id: 10856609 Return-Path: Received: from mail.wl.linuxfoundation.org (pdx-wl-mail.web.codeaurora.org [172.30.200.125]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id B43C51390 for ; Sun, 17 Mar 2019 21:16:36 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 9B8DA291EE for ; Sun, 17 Mar 2019 21:16:36 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 8F9E529214; Sun, 17 Mar 2019 21:16:36 +0000 (UTC) X-Spam-Checker-Version: SpamAssassin 3.3.1 (2010-03-16) on pdx-wl-mail.web.codeaurora.org X-Spam-Level: X-Spam-Status: No, score=-7.9 required=2.0 tests=BAYES_00,MAILING_LIST_MULTI, RCVD_IN_DNSWL_HI autolearn=ham version=3.3.1 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 28FB9291EE for ; Sun, 17 Mar 2019 21:16:36 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727425AbfCQVQg (ORCPT ); Sun, 17 Mar 2019 17:16:36 -0400 Received: from mga03.intel.com ([134.134.136.65]:57841 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726735AbfCQVQf (ORCPT ); Sun, 17 Mar 2019 17:16:35 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga103.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 17 Mar 2019 14:16:35 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.58,491,1544515200"; d="scan'208";a="142816733" Received: from vanderss-mobl1.ger.corp.intel.com (HELO localhost) ([10.249.254.193]) by orsmga002.jf.intel.com with ESMTP; 17 Mar 2019 14:16:26 -0700 From: Jarkko Sakkinen To: x86@kernel.org, linux-sgx@vger.kernel.org Cc: akpm@linux-foundation.org, dave.hansen@intel.com, sean.j.christopherson@intel.com, nhorman@redhat.com, npmccallum@redhat.com, serge.ayoun@intel.com, shay.katz-zamir@intel.com, haitao.huang@intel.com, andriy.shevchenko@linux.intel.com, tglx@linutronix.de, kai.svahn@intel.com, bp@alien8.de, josh@joshtriplett.org, luto@kernel.org, kai.huang@intel.com, rientjes@google.com, Jarkko Sakkinen Subject: [PATCH v19 08/27] x86/cpu/intel: Detect SGX support and update caps appropriately Date: Sun, 17 Mar 2019 23:14:37 +0200 Message-Id: <20190317211456.13927-9-jarkko.sakkinen@linux.intel.com> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190317211456.13927-1-jarkko.sakkinen@linux.intel.com> References: <20190317211456.13927-1-jarkko.sakkinen@linux.intel.com> MIME-Version: 1.0 Sender: linux-sgx-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org X-Virus-Scanned: ClamAV using ClamSMTP From: Sean Christopherson Similar to other large Intel features such as VMX and TXT, SGX must be explicitly enabled in IA32_FEATURE_CONTROL MSR to be truly usable. Clear all SGX related capabilities if SGX is not fully enabled in IA32_FEATURE_CONTROL or if the SGX1 instruction set isn't supported (impossible on bare metal, theoretically possible in a VM if the VMM is doing something weird). Like SGX itself, SGX Launch Control must be explicitly enabled via a flag in IA32_FEATURE_CONTROL. Clear the SGX_LC capability if Launch Control is not fully enabled (or obviously if SGX itself is disabled). Note that clearing X86_FEATURE_SGX_LC creates a bit of a conundrum regarding the SGXLEPUBKEYHASH MSRs, as it may be desirable to read the MSRs even if they are not writable, e.g. to query the configured key, but clearing the capability leaves no breadcrum for discerning whether or not the MSRs exist. But, such usage will be rare (KVM is the only known case at this time) and not performance critical, so it's not unreasonable to require the use of rdmsr_safe(). Clearing the cap bit eliminates the need for an additional flag to track whether or not Launch Control is truly enabled, which is what we care about the vast majority of the time. Signed-off-by: Sean Christopherson Co-developed-by: Jarkko Sakkinen Signed-off-by: Jarkko Sakkinen --- arch/x86/kernel/cpu/intel.c | 39 +++++++++++++++++++++++++++++++++++++ 1 file changed, 39 insertions(+) diff --git a/arch/x86/kernel/cpu/intel.c b/arch/x86/kernel/cpu/intel.c index fc3c07fe7df5..702497f34a96 100644 --- a/arch/x86/kernel/cpu/intel.c +++ b/arch/x86/kernel/cpu/intel.c @@ -596,6 +596,42 @@ static void detect_tme(struct cpuinfo_x86 *c) c->x86_phys_bits -= keyid_bits; } +static void __maybe_unused detect_sgx(struct cpuinfo_x86 *c) +{ + unsigned long long fc; + + rdmsrl(MSR_IA32_FEATURE_CONTROL, fc); + if (!(fc & FEATURE_CONTROL_LOCKED)) { + pr_err_once("sgx: The feature control MSR is not locked\n"); + goto err_unsupported; + } + + if (!(fc & FEATURE_CONTROL_SGX_ENABLE)) { + pr_err_once("sgx: SGX is not enabled in IA32_FEATURE_CONTROL MSR\n"); + goto err_unsupported; + } + + if (!cpu_has(c, X86_FEATURE_SGX1)) { + pr_err_once("sgx: SGX1 instruction set is not supported\n"); + goto err_unsupported; + } + + if (!(fc & FEATURE_CONTROL_SGX_LE_WR)) { + pr_info_once("sgx: The launch control MSRs are not writable\n"); + goto err_msrs_rdonly; + } + + return; + +err_unsupported: + setup_clear_cpu_cap(X86_FEATURE_SGX); + setup_clear_cpu_cap(X86_FEATURE_SGX1); + setup_clear_cpu_cap(X86_FEATURE_SGX2); + +err_msrs_rdonly: + setup_clear_cpu_cap(X86_FEATURE_SGX_LC); +} + static void init_intel_energy_perf(struct cpuinfo_x86 *c) { u64 epb; @@ -763,6 +799,9 @@ static void init_intel(struct cpuinfo_x86 *c) if (cpu_has(c, X86_FEATURE_TME)) detect_tme(c); + if (IS_ENABLED(CONFIG_INTEL_SGX) && cpu_has(c, X86_FEATURE_SGX)) + detect_sgx(c); + init_intel_energy_perf(c); init_intel_misc_features(c);