From patchwork Sat Mar 13 16:01:18 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Jarkko Sakkinen X-Patchwork-Id: 12136853 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=-19.2 required=3.0 tests=BAYES_00,DKIMWL_WL_HIGH, DKIM_SIGNED,DKIM_VALID,DKIM_VALID_AU,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,USER_AGENT_GIT autolearn=ham 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 3A1F4C433DB for ; Sat, 13 Mar 2021 16:02:38 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id E4D5D64F1A for ; Sat, 13 Mar 2021 16:02:37 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S234010AbhCMQCD (ORCPT ); Sat, 13 Mar 2021 11:02:03 -0500 Received: from mail.kernel.org ([198.145.29.99]:48106 "EHLO mail.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S233877AbhCMQBx (ORCPT ); Sat, 13 Mar 2021 11:01:53 -0500 Received: by mail.kernel.org (Postfix) with ESMTPSA id 3BD1764F1F; Sat, 13 Mar 2021 16:01:52 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=kernel.org; s=k20201202; t=1615651312; bh=wmiEWoBzQNM3kPcwlo3+3IWPepCWiqpC8Zche8xBDYY=; h=From:To:Cc:Subject:Date:In-Reply-To:References:From; b=IM6sBEa8fGiwbXLenDS/vV4tPQvACmAhui6k27fpOxzCFX+gWm++txshNnyhPcbtK TICkUL39V6AJpSW9TYyO8wbCpVuGDKzA19vz6qSBelNmDCUSgh3C5CeywjUOAxWy+D XDSvugAm+OUehdlXbJOMuidYSfN3NxkfZjJuL93JJPXu7R3eMyX5qVbfH+4ro/PrmW oqB3815FNbu2txcdAhTlIv0iv2Jis5+6r6FUcuLgklflOS0VH94CRubQvaYFAfFzrJ 7Xm6QKhSOxmLewWU/L+VbtNvIfIdMcKQcb3y4KLAdfdX8qrEJS+cMc9OC046lgk9oc QfD/h91OdJpwQ== From: Jarkko Sakkinen To: linux-sgx@vger.kernel.org Cc: Jarkko Sakkinen , Dave Hansen , Thomas Gleixner , Ingo Molnar , Borislav Petkov , x86@kernel.org, "H. Peter Anvin" , linux-kernel@vger.kernel.org Subject: [PATCH v4 2/3] x86/sgx: Replace section local dirty page lists with a global list Date: Sat, 13 Mar 2021 18:01:18 +0200 Message-Id: <20210313160119.1318533-3-jarkko@kernel.org> X-Mailer: git-send-email 2.30.2 In-Reply-To: <20210313160119.1318533-1-jarkko@kernel.org> References: <20210313160119.1318533-1-jarkko@kernel.org> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org Reset initialized EPC pages in sgx_dirty_page_list to uninitialized state, and free them using sgx_free_epc_page(). Do two passes, as for SECS pages the first round can fail, if all child pages have not yet been removed. The driver puts all pages on startup first to sgx_dirty_page_list, as the initialization could be triggered by kexec(), meaning that pages have been reserved for active enclaves before the operation. The section local lists are redundant, as sgx_free_epc_page() figures out the correction by using epc_page->section. Signed-off-by: Jarkko Sakkinen --- v4: * Open coded sgx_santize_section() to ksgxd(). * Rewrote the commit message. arch/x86/kernel/cpu/sgx/main.c | 81 ++++++++++++++++------------------ arch/x86/kernel/cpu/sgx/sgx.h | 7 --- 2 files changed, 37 insertions(+), 51 deletions(-) diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c index 65004fb8a91f..cb4561444b96 100644 --- a/arch/x86/kernel/cpu/sgx/main.c +++ b/arch/x86/kernel/cpu/sgx/main.c @@ -27,39 +27,10 @@ static LIST_HEAD(sgx_active_page_list); static DEFINE_SPINLOCK(sgx_reclaimer_lock); /* - * Reset dirty EPC pages to uninitialized state. Laundry can be left with SECS - * pages whose child pages blocked EREMOVE. + * When the driver initialized, EPC pages go first here, as they could be + * initialized to an active enclave, on kexec entry. */ -static void sgx_sanitize_section(struct sgx_epc_section *section) -{ - struct sgx_epc_page *page; - LIST_HEAD(dirty); - int ret; - - /* init_laundry_list is thread-local, no need for a lock: */ - while (!list_empty(§ion->init_laundry_list)) { - if (kthread_should_stop()) - return; - - /* needed for access to ->page_list: */ - spin_lock(§ion->lock); - - page = list_first_entry(§ion->init_laundry_list, - struct sgx_epc_page, list); - - ret = __eremove(sgx_get_epc_virt_addr(page)); - if (!ret) - list_move(&page->list, §ion->page_list); - else - list_move_tail(&page->list, &dirty); - - spin_unlock(§ion->lock); - - cond_resched(); - } - - list_splice(&dirty, §ion->init_laundry_list); -} +static LIST_HEAD(sgx_dirty_page_list); static bool sgx_reclaimer_age(struct sgx_epc_page *epc_page) { @@ -400,25 +371,48 @@ static bool sgx_should_reclaim(unsigned long watermark) static int ksgxd(void *p) { - int i; + struct sgx_epc_page *page; + LIST_HEAD(dirty); + int i, ret; set_freezable(); /* - * Sanitize pages in order to recover from kexec(). The 2nd pass is - * required for SECS pages, whose child pages blocked EREMOVE. + * Reset initialized EPC pages in sgx_dirty_page_list to uninitialized state, + * and free them using sgx_free_epc_page(). Do two passes, as for SECS pages the + * first round can fail, if all child pages have not yet been removed. The + * driver puts all pages on startup first to sgx_dirty_page_list, as the + * initialization could be triggered by kexec(), meaning that pages have been + * reserved for active enclaves before the operation. */ - for (i = 0; i < sgx_nr_epc_sections; i++) - sgx_sanitize_section(&sgx_epc_sections[i]); - for (i = 0; i < sgx_nr_epc_sections; i++) { - sgx_sanitize_section(&sgx_epc_sections[i]); + /* sgx_dirty_page_list is thread-local to ksgxd, no need for a lock: */ + for (i = 0; i < 2 && !list_empty(&sgx_dirty_page_list); i++) { + while (!list_empty(&sgx_dirty_page_list)) { + if (kthread_should_stop()) + return 0; + + page = list_first_entry(&sgx_dirty_page_list, struct sgx_epc_page, list); + + ret = __eremove(sgx_get_epc_virt_addr(page)); + if (!ret) { + /* The page is clean - move to the free list. */ + list_del(&page->list); + sgx_free_epc_page(page); + } else { + /* The page is not yet clean - move to the dirty list. */ + list_move_tail(&page->list, &dirty); + } + + cond_resched(); + } - /* Should never happen. */ - if (!list_empty(&sgx_epc_sections[i].init_laundry_list)) - WARN(1, "EPC section %d has unsanitized pages.\n", i); + list_splice(&dirty, &sgx_dirty_page_list); } + if (!list_empty(&sgx_dirty_page_list)) + WARN(1, "EPC section %d has unsanitized pages.\n", i); + while (!kthread_should_stop()) { if (try_to_freeze()) continue; @@ -632,13 +626,12 @@ static bool __init sgx_setup_epc_section(u64 phys_addr, u64 size, section->phys_addr = phys_addr; spin_lock_init(§ion->lock); INIT_LIST_HEAD(§ion->page_list); - INIT_LIST_HEAD(§ion->init_laundry_list); for (i = 0; i < nr_pages; i++) { section->pages[i].section = index; section->pages[i].flags = 0; section->pages[i].owner = NULL; - list_add_tail(§ion->pages[i].list, §ion->init_laundry_list); + list_add_tail(§ion->pages[i].list, &sgx_dirty_page_list); } section->free_cnt = nr_pages; diff --git a/arch/x86/kernel/cpu/sgx/sgx.h b/arch/x86/kernel/cpu/sgx/sgx.h index 5fa42d143feb..bc8af0428640 100644 --- a/arch/x86/kernel/cpu/sgx/sgx.h +++ b/arch/x86/kernel/cpu/sgx/sgx.h @@ -45,13 +45,6 @@ struct sgx_epc_section { spinlock_t lock; struct list_head page_list; unsigned long free_cnt; - - /* - * Pages which need EREMOVE run on them before they can be - * used. Only safe to be accessed in ksgxd and init code. - * Not protected by locks. - */ - struct list_head init_laundry_list; }; extern struct sgx_epc_section sgx_epc_sections[SGX_MAX_EPC_SECTIONS];