From patchwork Wed Mar 20 16:21:06 2019 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jarkko Sakkinen X-Patchwork-Id: 10862173 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 6D7851708 for ; Wed, 20 Mar 2019 16:24:14 +0000 (UTC) Received: from mail.wl.linuxfoundation.org (localhost [127.0.0.1]) by mail.wl.linuxfoundation.org (Postfix) with ESMTP id 5309A28880 for ; Wed, 20 Mar 2019 16:24:14 +0000 (UTC) Received: by mail.wl.linuxfoundation.org (Postfix, from userid 486) id 46E622894E; Wed, 20 Mar 2019 16:24:14 +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 BFFA828880 for ; Wed, 20 Mar 2019 16:24:13 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1727582AbfCTQYN (ORCPT ); Wed, 20 Mar 2019 12:24:13 -0400 Received: from mga01.intel.com ([192.55.52.88]:41432 "EHLO mga01.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1726860AbfCTQYN (ORCPT ); Wed, 20 Mar 2019 12:24:13 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga003.jf.intel.com ([10.7.209.27]) by fmsmga101.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 20 Mar 2019 09:24:12 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.60,249,1549958400"; d="scan'208";a="135715279" Received: from sorenthe-mobl1.ger.corp.intel.com (HELO localhost) ([10.249.254.203]) by orsmga003.jf.intel.com with ESMTP; 20 Mar 2019 09:24:00 -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, 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,RESEND 14/27] x86/sgx: Add functions to allocate and free EPC pages Date: Wed, 20 Mar 2019 18:21:06 +0200 Message-Id: <20190320162119.4469-15-jarkko.sakkinen@linux.intel.com> X-Mailer: git-send-email 2.19.1 In-Reply-To: <20190320162119.4469-1-jarkko.sakkinen@linux.intel.com> References: <20190320162119.4469-1-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 At this time there is no support for reclaiming pages prior to the owner explicitly freeing the page. As for freeing pages, because freeing a page is expected to succeed in the vast majority of cases and because most call sites will not be equipped to handle failure, provide a variant for freeing a page that warns on failure, e.g. due to ENCLS[EREMOVE] failing. Signed-off-by: Jarkko Sakkinen Co-developed-by: Sean Christopherson Signed-off-by: Sean Christopherson --- arch/x86/kernel/cpu/sgx/main.c | 89 ++++++++++++++++++++++++++++++++++ arch/x86/kernel/cpu/sgx/sgx.h | 4 ++ 2 files changed, 93 insertions(+) diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c index 18ce4acdd7ef..f88c8d86c2a8 100644 --- a/arch/x86/kernel/cpu/sgx/main.c +++ b/arch/x86/kernel/cpu/sgx/main.c @@ -9,6 +9,7 @@ #include #include #include "arch.h" +#include "encls.h" #include "sgx.h" struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS]; @@ -23,6 +24,94 @@ static void sgx_section_put_page(struct sgx_epc_section *section, section->free_cnt++; } +static struct sgx_epc_page *sgx_section_get_page( + struct sgx_epc_section *section) +{ + struct sgx_epc_page *page; + + if (!section->free_cnt) + return NULL; + + page = list_first_entry(§ion->page_list, + struct sgx_epc_page, list); + list_del_init(&page->list); + section->free_cnt--; + return page; +} + +/** + * sgx_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_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_section_get_page(section); + spin_unlock(§ion->lock); + + if (page) + return page; + } + + return ERR_PTR(-ENOMEM); +} +EXPORT_SYMBOL_GPL(sgx_alloc_page); + +/** + * __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. + * + * Return: + * 0 on success + * SGX error code if EREMOVE fails + */ +int __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 (ret) + return ret; + + spin_lock(§ion->lock); + sgx_section_put_page(section, page); + spin_unlock(§ion->lock); + + return 0; +} +EXPORT_SYMBOL_GPL(__sgx_free_page); + +/** + * sgx_free_page - Free an EPC page and WARN on failure + * @page: pointer to a previously allocated EPC page + * + * EREMOVE an EPC page and insert it back to the list of free pages, and WARN + * if EREMOVE fails. For use when the call site cannot (or chooses not to) + * handle failure, i.e. the page is leaked on failure. + */ +void sgx_free_page(struct sgx_epc_page *page) +{ + int ret; + + ret = __sgx_free_page(page); + WARN(ret > 0, "sgx: EREMOVE returned %d (0x%x)", ret, ret); +} +EXPORT_SYMBOL_GPL(sgx_free_page); + static __init void 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 228e3dae360d..86b4c74b6089 100644 --- a/arch/x86/kernel/cpu/sgx/sgx.h +++ b/arch/x86/kernel/cpu/sgx/sgx.h @@ -59,4 +59,8 @@ static inline void *sgx_epc_addr(struct sgx_epc_page *page) return section->va + (page->desc & PAGE_MASK) - section->pa; } +struct sgx_epc_page *sgx_alloc_page(void); +int __sgx_free_page(struct sgx_epc_page *page); +void sgx_free_page(struct sgx_epc_page *page); + #endif /* _X86_SGX_H */