From patchwork Fri May 15 00:43:58 2020 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 8bit X-Patchwork-Submitter: Jarkko Sakkinen X-Patchwork-Id: 11550165 Return-Path: Received: from mail.kernel.org (pdx-korg-mail-1.web.codeaurora.org [172.30.200.123]) by pdx-korg-patchwork-2.web.codeaurora.org (Postfix) with ESMTP id 71A0A90 for ; Fri, 15 May 2020 00:45:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 63B7320709 for ; Fri, 15 May 2020 00:45:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728280AbgEOApo (ORCPT ); Thu, 14 May 2020 20:45:44 -0400 Received: from mga09.intel.com ([134.134.136.24]:63259 "EHLO mga09.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726170AbgEOApn (ORCPT ); Thu, 14 May 2020 20:45:43 -0400 IronPort-SDR: 5EX4rDW6/3GM19S5AIGlVBo2E16vixzyTN1LwLAAALjhePuusqduUmvuE0qnjyrBB/cbDk8NPq lC16m3feXcnQ== X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga008.fm.intel.com ([10.253.24.58]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 14 May 2020 17:45:43 -0700 IronPort-SDR: ZbcrqZTNWyse2c2kvB+HM45ArxZmSwVRvs+JuESD4ZdBGykoZ6by/U4sDyrL8mJVZ97tYO6e6u yONlLLhntIcw== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.73,393,1583222400"; d="scan'208";a="253644196" Received: from ashadrin-mobl1.ccr.corp.intel.com (HELO localhost) ([10.249.38.112]) by fmsmga008.fm.intel.com with ESMTP; 14 May 2020 17:45:35 -0700 From: Jarkko Sakkinen To: linux-kernel@vger.kernel.org, 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, 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, cedric.xing@intel.com, puiterwijk@redhat.com, Jarkko Sakkinen , Jethro Beekman Subject: [PATCH v30 08/20] x86/sgx: Add functions to allocate and free EPC pages Date: Fri, 15 May 2020 03:43:58 +0300 Message-Id: <20200515004410.723949-9-jarkko.sakkinen@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20200515004410.723949-1-jarkko.sakkinen@linux.intel.com> References: <20200515004410.723949-1-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 Add functions for allocating page from Enclave Page Cache (EPC). A page is allocated by going through the EPC sections and returning the first free page. When a page is freed, it might have a valid state, which means that the callee has assigned it to an enclave, which are protected memory ares used to run code protected from outside access. The page is returned back to the invalid state with ENCLS[EREMOVE] [1]. [1] Intel SDM: 40.3 INTEL® SGX SYSTEM LEAF FUNCTION REFERENCE Co-developed-by: Sean Christopherson Signed-off-by: Sean Christopherson Acked-by: Jethro Beekman Signed-off-by: Jarkko Sakkinen --- arch/x86/kernel/cpu/sgx/main.c | 60 ++++++++++++++++++++++++++++++++++ arch/x86/kernel/cpu/sgx/sgx.h | 3 ++ 2 files changed, 63 insertions(+) diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c index 38424c1e8341..60d82e7537c8 100644 --- a/arch/x86/kernel/cpu/sgx/main.c +++ b/arch/x86/kernel/cpu/sgx/main.c @@ -13,6 +13,66 @@ struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS]; int sgx_nr_epc_sections; +static struct sgx_epc_page *__sgx_try_alloc_page(struct sgx_epc_section *section) +{ + struct sgx_epc_page *page; + + if (list_empty(§ion->page_list)) + return NULL; + + page = list_first_entry(§ion->page_list, struct sgx_epc_page, list); + list_del_init(&page->list); + return page; +} + +/** + * sgx_try_alloc_page() - Allocate an EPC page + * + * Try to grab a page from the free EPC page list. + * + * Return: + * a pointer to a &struct sgx_epc_page instance, + * -errno on error + */ +struct sgx_epc_page *sgx_try_alloc_page(void) +{ + struct sgx_epc_section *section; + struct sgx_epc_page *page; + int i; + + for (i = 0; i < sgx_nr_epc_sections; i++) { + section = &sgx_epc_sections[i]; + spin_lock(§ion->lock); + page = __sgx_try_alloc_page(section); + spin_unlock(§ion->lock); + + if (page) + return page; + } + + return ERR_PTR(-ENOMEM); +} + +/** + * sgx_free_page() - Free an EPC page + * @page: pointer a previously allocated EPC page + * + * EREMOVE an EPC page and insert it back to the list of free pages. + */ +void sgx_free_page(struct sgx_epc_page *page) +{ + struct sgx_epc_section *section = sgx_epc_section(page); + int ret; + + ret = __eremove(sgx_epc_addr(page)); + if (WARN_ONCE(ret, "EREMOVE returned %d (0x%x)", ret, ret)) + return; + + spin_lock(§ion->lock); + list_add_tail(&page->list, §ion->page_list); + spin_unlock(§ion->lock); +} + static void __init sgx_free_epc_section(struct sgx_epc_section *section) { struct sgx_epc_page *page; diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h index aad30980be32..aa85f85412d8 100644 --- a/arch/x86/kernel/cpu/sgx/sgx.h +++ b/arch/x86/kernel/cpu/sgx/sgx.h @@ -67,4 +67,7 @@ extern struct task_struct *ksgxswapd_tsk; bool __init sgx_page_reclaimer_init(void); +struct sgx_epc_page *sgx_try_alloc_page(void); +void sgx_free_page(struct sgx_epc_page *page); + #endif /* _X86_SGX_H */