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 Received: from mail.kernel.org (mail.kernel.org [198.145.29.99]) by smtp.lore.kernel.org (Postfix) with ESMTP id 28C90C43217 for ; Tue, 26 Oct 2021 22:01:44 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id 0E8EF61177 for ; Tue, 26 Oct 2021 22:01:44 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S239762AbhJZWEH (ORCPT ); Tue, 26 Oct 2021 18:04:07 -0400 Received: from mga18.intel.com ([134.134.136.126]:57935 "EHLO mga18.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S239739AbhJZWEC (ORCPT ); Tue, 26 Oct 2021 18:04:02 -0400 X-IronPort-AV: E=McAfee;i="6200,9189,10149"; a="216934491" X-IronPort-AV: E=Sophos;i="5.87,184,1631602800"; d="scan'208";a="216934491" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by orsmga106.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Oct 2021 15:01:00 -0700 X-IronPort-AV: E=Sophos;i="5.87,184,1631602800"; d="scan'208";a="497555769" Received: from agluck-desk2.sc.intel.com ([10.3.52.146]) by orsmga008-auth.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 26 Oct 2021 15:01:00 -0700 From: Tony Luck To: Borislav Petkov , x86@kernel.org Cc: "Rafael J. Wysocki" , naoya.horiguchi@nec.com, Andrew Morton , Sean Christopherson , Jarkko Sakkinen , Dave Hansen , Cathy Zhang , linux-sgx@vger.kernel.org, linux-acpi@vger.kernel.org, linux-mm@kvack.org, linux-kernel@vger.kernel.org, Tony Luck , Reinette Chatre Subject: [PATCH v11 4/7] x86/sgx: Add SGX infrastructure to recover from poison Date: Tue, 26 Oct 2021 15:00:47 -0700 Message-Id: <20211026220050.697075-5-tony.luck@intel.com> X-Mailer: git-send-email 2.31.1 In-Reply-To: <20211026220050.697075-1-tony.luck@intel.com> References: <20211018202542.584115-1-tony.luck@intel.com> <20211026220050.697075-1-tony.luck@intel.com> MIME-Version: 1.0 Content-Transfer-Encoding: 8bit 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 per-node poison page list. Reviewed-by: Jarkko Sakkinen Tested-by: Reinette Chatre Signed-off-by: Tony Luck --- arch/x86/kernel/cpu/sgx/main.c | 76 ++++++++++++++++++++++++++++++++++ 1 file changed, 76 insertions(+) diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c index e5fcb8354bcc..231c494dfd40 100644 --- a/arch/x86/kernel/cpu/sgx/main.c +++ b/arch/x86/kernel/cpu/sgx/main.c @@ -693,6 +693,82 @@ 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 the page is on a free list, move it to the per-node + * poison page list. + */ + if (page->flags & SGX_EPC_PAGE_IS_FREE) { + list_move(&page->list, &node->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 -- 2.31.1