From patchwork Tue Jan 26 09:31:06 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Huang, Kai" X-Patchwork-Id: 12047203 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 EEE18C4332D for ; Tue, 26 Jan 2021 15:29:54 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BEF9B23101 for ; Tue, 26 Jan 2021 15:29:54 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2406048AbhAZP3m (ORCPT ); Tue, 26 Jan 2021 10:29:42 -0500 Received: from mga03.intel.com ([134.134.136.65]:12823 "EHLO mga03.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1727430AbhAZJdW (ORCPT ); Tue, 26 Jan 2021 04:33:22 -0500 IronPort-SDR: FluIt0koWGRaW2TgsJfC/reKmHtkWkl9tDZF6dhSZUuyo8b9HUZn21GNIAW0IEEUSZx0gNriDb sXgSYE2QPh3A== X-IronPort-AV: E=McAfee;i="6000,8403,9875"; a="179954933" X-IronPort-AV: E=Sophos;i="5.79,375,1602572400"; d="scan'208";a="179954933" Received: from fmsmga005.fm.intel.com ([10.253.24.32]) by orsmga103.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Jan 2021 01:31:43 -0800 IronPort-SDR: 0/fIr8Rq8J4cWleJ2/+rvJdTyqMUrpxXdCwCJUJbcWZuf9tbW4bXDblo8TgbL/0gaFslx6ztP/ RNjC+D85kxAg== X-IronPort-AV: E=Sophos;i="5.79,375,1602572400"; d="scan'208";a="577747757" 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 01:31:40 -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, Kai Huang Subject: [RFC PATCH v3 14/27] x86/sgx: Add helpers to expose ECREATE and EINIT to KVM Date: Tue, 26 Jan 2021 22:31:06 +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 bare-metal kernel must intercept ECREATE to be able to impose policies on guests. When it does this, the bare-metal kernel runs ECREATE against the userspace mapping of the virtualized EPC. Provide wrappers around __ecreate() and __einit() to hide the ugliness of overloading the ENCLS return value to encode multiple error formats in a single int. KVM will trap-and-execute ECREATE and EINIT as part of SGX virtualization, and on an exception, KVM needs the trapnr so that it can inject the correct fault into the guest. Signed-off-by: Sean Christopherson Signed-off-by: Kai Huang --- v2->v3: - Added kdoc for sgx_virt_ecreate() and sgx_virt_einit(), per Jarkko. - Changed to use CONFIG_X86_SGX_KVM. --- arch/x86/include/asm/sgx.h | 16 ++++++ arch/x86/kernel/cpu/sgx/virt.c | 93 ++++++++++++++++++++++++++++++++++ 2 files changed, 109 insertions(+) create mode 100644 arch/x86/include/asm/sgx.h diff --git a/arch/x86/include/asm/sgx.h b/arch/x86/include/asm/sgx.h new file mode 100644 index 000000000000..8a3ea3e1efbe --- /dev/null +++ b/arch/x86/include/asm/sgx.h @@ -0,0 +1,16 @@ +/* SPDX-License-Identifier: GPL-2.0 */ +#ifndef _ASM_X86_SGX_H +#define _ASM_X86_SGX_H + +#include + +#ifdef CONFIG_X86_SGX_KVM +struct sgx_pageinfo; + +int sgx_virt_ecreate(struct sgx_pageinfo *pageinfo, void __user *secs, + int *trapnr); +int sgx_virt_einit(void __user *sigstruct, void __user *token, + void __user *secs, u64 *lepubkeyhash, int *trapnr); +#endif + +#endif /* _ASM_X86_SGX_H */ diff --git a/arch/x86/kernel/cpu/sgx/virt.c b/arch/x86/kernel/cpu/sgx/virt.c index e1ad7856d878..0f5b0e4e33dd 100644 --- a/arch/x86/kernel/cpu/sgx/virt.c +++ b/arch/x86/kernel/cpu/sgx/virt.c @@ -252,3 +252,96 @@ int __init sgx_vepc_init(void) return misc_register(&sgx_vepc_dev); } + +/** + * sgx_virt_ecreate() - Run ECREATE on behalf of guest + * @pageinfo: Pointer to PAGEINFO structure + * @secs: Userspace pointer to SECS page + * @trapnr: trap number injected to guest in case of ECREATE error + * + * Run ECREATE on behalf of guest after KVM traps ECREATE for the purpose + * of enforcing policies of guest's enclaves, and return the trap number + * which should be injected to guest in case of any ECREATE error. + * + * Return: + * - 0: ECREATE was successful. + * - -EFAULT: ECREATE returned error. + */ +int sgx_virt_ecreate(struct sgx_pageinfo *pageinfo, void __user *secs, + int *trapnr) +{ + int ret; + + /* + * @secs is userspace address, and it's not guaranteed @secs points at + * an actual EPC page. It's also possible to generate a kernel mapping + * to physical EPC page by resolving PFN but using __uaccess_xx() is + * simpler. + */ + __uaccess_begin(); + ret = __ecreate(pageinfo, (void *)secs); + __uaccess_end(); + + if (encls_faulted(ret)) { + *trapnr = ENCLS_TRAPNR(ret); + return -EFAULT; + } + + /* ECREATE doesn't return an error code, it faults or succeeds. */ + WARN_ON_ONCE(ret); + return 0; +} +EXPORT_SYMBOL_GPL(sgx_virt_ecreate); + +static int __sgx_virt_einit(void __user *sigstruct, void __user *token, + void __user *secs) +{ + int ret; + + __uaccess_begin(); + ret = __einit((void *)sigstruct, (void *)token, (void *)secs); + __uaccess_end(); + return ret; +} + +/** + * sgx_virt_ecreate() - Run EINIT on behalf of guest + * @sigstruct: Userspace pointer to SIGSTRUCT structure + * @token: Userspace pointer to EINITTOKEN structure + * @secs: Userspace pointer to SECS page + * @lepubkeyhash: Pointer to guest's *virtual* SGX_LEPUBKEYHASH MSR + * values + * @trapnr: trap number injected to guest in case of EINIT error + * + * Run EINIT on behalf of guest after KVM traps EINIT. If SGX_LC is available + * in host, bare-metal driver may rewrite the hardware values, therefore KVM + * needs to update hardware values to guest's virtual MSR values in order to + * ensure EINIT is executed with expected hardware values. + * + * Return: + * - 0: EINIT was successful. + * - -EFAULT: EINIT returned error. + */ +int sgx_virt_einit(void __user *sigstruct, void __user *token, + void __user *secs, u64 *lepubkeyhash, int *trapnr) +{ + int ret; + + if (!boot_cpu_has(X86_FEATURE_SGX_LC)) { + ret = __sgx_virt_einit(sigstruct, token, secs); + } else { + preempt_disable(); + + sgx_update_lepubkeyhash(lepubkeyhash); + + ret = __sgx_virt_einit(sigstruct, token, secs); + preempt_enable(); + } + + if (encls_faulted(ret)) { + *trapnr = ENCLS_TRAPNR(ret); + return -EFAULT; + } + return ret; +} +EXPORT_SYMBOL_GPL(sgx_virt_einit);