From patchwork Fri Oct 1 16:47:21 2021 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: "Luck, Tony" X-Patchwork-Id: 12531073 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.0 (2014-02-07) on aws-us-west-2-korg-lkml-1.web.codeaurora.org Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1BA59C43217 for ; Fri, 1 Oct 2021 16:47:34 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0928461AE3 for ; Fri, 1 Oct 2021 16:47:34 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1355232AbhJAQtR (ORCPT ); Fri, 1 Oct 2021 12:49:17 -0400 Received: from mga11.intel.com ([192.55.52.93]:19801 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1355195AbhJAQtR (ORCPT ); Fri, 1 Oct 2021 12:49:17 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10124"; a="222290388" X-IronPort-AV: E=Sophos;i="5.85,339,1624345200"; d="scan'208";a="222290388" Received: from fmsmga004.fm.intel.com ([10.253.24.48]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Oct 2021 09:47:32 -0700 X-IronPort-AV: E=Sophos;i="5.85,339,1624345200"; d="scan'208";a="540357500" Received: from agluck-desk2.sc.intel.com ([10.3.52.146]) by fmsmga004-auth.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 01 Oct 2021 09:47:31 -0700 From: Tony Luck To: Sean Christopherson , Jarkko Sakkinen , Dave Hansen Cc: Cathy Zhang , linux-sgx@vger.kernel.org, Tony Luck Subject: [PATCH v8 4/7] x86/sgx: Add SGX infrastructure to recover from poison Date: Fri, 1 Oct 2021 09:47:21 -0700 Message-Id: <20211001164724.220532-5-tony.luck@intel.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20211001164724.220532-1-tony.luck@intel.com> References: <20210927213452.212470-1-tony.luck@intel.com> <20211001164724.220532-1-tony.luck@intel.com> MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org Provide a recovery function sgx_memory_failure(). If the poison was consumed synchronously then send a SIGBUS. Note that the virtual address of the access is not included with the SIGBUS as is the case for poison outside of SGX enclaves. This doesn't matter as addresses of code/data inside an enclave is of little to no use to code executing outside the (now dead) enclave. Poison found in a free page results in the page being moved from the free list to the poison page list. Signed-off-by: Tony Luck Reviewed-by: Jarkko Sakkinen --- arch/x86/kernel/cpu/sgx/main.c | 77 ++++++++++++++++++++++++++++++++++ 1 file changed, 77 insertions(+) diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c index 653bace26100..398c9749e4d1 100644 --- a/arch/x86/kernel/cpu/sgx/main.c +++ b/arch/x86/kernel/cpu/sgx/main.c @@ -682,6 +682,83 @@ bool arch_is_platform_page(u64 paddr) } EXPORT_SYMBOL_GPL(arch_is_platform_page); +static struct sgx_epc_page *sgx_paddr_to_page(u64 paddr) +{ + struct sgx_epc_section *section; + + section = xa_load(&sgx_epc_address_space, paddr); + if (!section) + return NULL; + + return §ion->pages[PFN_DOWN(paddr - section->phys_addr)]; +} + +/* + * Called in process context to handle a hardware reported + * error in an SGX EPC page. + * If the MF_ACTION_REQUIRED bit is set in flags, then the + * context is the task that consumed the poison data. Otherwise + * this is called from a kernel thread unrelated to the page. + */ +int arch_memory_failure(unsigned long pfn, int flags) +{ + struct sgx_epc_page *page = sgx_paddr_to_page(pfn << PAGE_SHIFT); + struct sgx_epc_section *section; + struct sgx_numa_node *node; + + /* + * mm/memory-failure.c calls this routine for all errors + * where there isn't a "struct page" for the address. But that + * includes other address ranges besides SGX. + */ + if (!page) + return -ENXIO; + + /* + * If poison was consumed synchronously. Send a SIGBUS to + * the task. Hardware has already exited the SGX enclave and + * will not allow re-entry to an enclave that has a memory + * error. The signal may help the task understand why the + * enclave is broken. + */ + if (flags & MF_ACTION_REQUIRED) + force_sig(SIGBUS); + + section = &sgx_epc_sections[page->section]; + node = section->node; + + spin_lock(&node->lock); + + /* Already poisoned? Nothing more to do */ + if (page->poison) + goto out; + + page->poison = 1; + + /* + * If flags is zero, then the page is on a free list. + * Move it to the poison page list. + */ + if (!page->flags) { + list_del(&page->list); + list_add(&page->list, &sgx_poison_page_list); + goto out; + } + + /* + * TBD: Add additional plumbing to enable pre-emptive + * action for asynchronous poison notification. Until + * then just hope that the poison: + * a) is not accessed - sgx_free_epc_page() will deal with it + * when the user gives it back + * b) results in a recoverable machine check rather than + * a fatal one + */ +out: + spin_unlock(&node->lock); + return 0; +} + /** * A section metric is concatenated in a way that @low bits 12-31 define the * bits 12-31 of the metric and @high bits 0-19 define the bits 32-51 of the