From mboxrd@z Thu Jan 1 00:00:00 1970 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=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, 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 D9E93C3F2D7 for ; Tue, 3 Mar 2020 23:38:08 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id B8C3C21739 for ; Tue, 3 Mar 2020 23:38:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728738AbgCCXiH (ORCPT ); Tue, 3 Mar 2020 18:38:07 -0500 Received: from mga04.intel.com ([192.55.52.120]:46848 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728387AbgCCXiH (ORCPT ); Tue, 3 Mar 2020 18:38:07 -0500 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 03 Mar 2020 15:38:06 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.70,511,1574150400"; d="scan'208";a="229117436" Received: from kwasilew-mobl.ger.corp.intel.com (HELO localhost) ([10.251.88.57]) by orsmga007.jf.intel.com with ESMTP; 03 Mar 2020 15:37:56 -0800 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 Subject: [PATCH v28 09/22] x86/sgx: Add functions to allocate and free EPC pages Date: Wed, 4 Mar 2020 01:35:56 +0200 Message-Id: <20200303233609.713348-10-jarkko.sakkinen@linux.intel.com> X-Mailer: git-send-email 2.25.0 In-Reply-To: <20200303233609.713348-1-jarkko.sakkinen@linux.intel.com> References: <20200303233609.713348-1-jarkko.sakkinen@linux.intel.com> MIME-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 8bit Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@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 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 */ -- 2.25.0