From patchwork Wed May 25 10:07:49 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zhiquan Li X-Patchwork-Id: 12860943 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 vger.kernel.org (vger.kernel.org [23.128.96.18]) by smtp.lore.kernel.org (Postfix) with ESMTP id 1C949C433F5 for ; Wed, 25 May 2022 10:07:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S241630AbiEYKHm (ORCPT ); Wed, 25 May 2022 06:07:42 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:33282 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S242146AbiEYKHk (ORCPT ); Wed, 25 May 2022 06:07:40 -0400 Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 6A034939F7 for ; Wed, 25 May 2022 03:07:07 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1653473227; x=1685009227; h=from:to:cc:subject:date:message-id:mime-version: content-transfer-encoding; bh=2T7wMCj0vBNOd+xYIeo5hX9DR1sX3Spod4zmEXVot5M=; b=OEot9vb1Y1Ns2sOPM+l4y2fKFVRMnVFMKRE4Y8jalBSSCSgApVrQ3IpQ Ru+XCxkT686MwnmJYRpvOwOau9bicFVgByIxmY9edXHv3EW//5sbjVQFD 5P7B4r4xOKHi4eIrXgqNs8AbJl/PxwHeHw/FQ5IXxnvTvu8NfaxKss1xN ucOThidhUtpKQi+sc+xugcCZ3kUuB2JzGCs1daoUcfwYMbDZBjtKRQdwg kXvQufq547lD0Oy+AN0yfQVmnJghmempiMh1qydFgm4036DogUdkKRiza 5NvAbnMbeD685MC5QmZZ+GLr5UObcxQHe/i9yf1HcW1FzRAOQoRHmPhnO A==; X-IronPort-AV: E=McAfee;i="6400,9594,10357"; a="273501150" X-IronPort-AV: E=Sophos;i="5.91,250,1647327600"; d="scan'208";a="273501150" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 25 May 2022 03:07:07 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.91,250,1647327600"; d="scan'208";a="717573084" Received: from zhiquan-linux-dev.bj.intel.com ([10.238.155.101]) by fmsmga001.fm.intel.com with ESMTP; 25 May 2022 03:07:04 -0700 From: Zhiquan Li To: linux-sgx@vger.kernel.org, tony.luck@intel.com Cc: jarkko@kernel.org, dave.hansen@linux.intel.com, seanjc@google.com, kai.huang@intel.com, fan.du@intel.com, zhiquan1.li@intel.com Subject: [PATCH v3 3/3] x86/sgx: Fine grained SGX MCA behavior for normal case Date: Wed, 25 May 2022 18:07:49 +0800 Message-Id: <20220525100749.760864-1-zhiquan1.li@intel.com> X-Mailer: git-send-email 2.25.1 MIME-Version: 1.0 Precedence: bulk List-ID: X-Mailing-List: linux-sgx@vger.kernel.org When the application accesses a SGX EPC page with memory failure, the task will receive a SIGBUS signal without any extra info, unless the EPC page has SGX_EPC_PAGE_KVM_GUEST flag. However, in some cases, we only use SGX in sub-task and we don't expect the entire task group be killed due to a SGX EPC page for a sub-task has memory failure. To fix it, we extend the solution for normal case. That is, the SGX regular EPC page with memory failure will trigger a SIGBUS signal with code BUS_MCEERR_AR and additional info, so that the user has opportunity to make further decision. Suppose an enclave is shared by multiple processes, when an enclave page triggers a machine check, the enclave will be disabled so that it couldn't be entered again. Killing other processes with the same enclave mapped would perhaps be overkill, but they are going to find that the enclave is "dead" next time they try to use it. Thanks for Jarkko's head up and Tony's clarification on this point. Our intension is to provide additional info so that the application has more choices. Current behavior looks gently, and we don't want to change it. Signed-off-by: Zhiquan Li --- Changes since V2: - Adapted the code since struct sgx_vepc_page was discarded. - Replace EPC page flag SGX_EPC_PAGE_IS_VEPC with SGX_EPC_PAGE_KVM_GUEST as they are duplicated. Changes since V1: - Add valuable information from Jarkko and Tony the into commit message. --- arch/x86/kernel/cpu/sgx/main.c | 7 +++++-- 1 file changed, 5 insertions(+), 2 deletions(-) diff --git a/arch/x86/kernel/cpu/sgx/main.c b/arch/x86/kernel/cpu/sgx/main.c index faca7f73b06d..69a2a29c8957 100644 --- a/arch/x86/kernel/cpu/sgx/main.c +++ b/arch/x86/kernel/cpu/sgx/main.c @@ -739,12 +739,15 @@ int arch_memory_failure(unsigned long pfn, int flags) * decision but not simply kill it. This is quite useful for * virtualization case. */ - if (page->flags & SGX_EPC_PAGE_KVM_GUEST) { + if (page->owner) { /* * The "owner" field is repurposed as the virtual address * of virtual EPC page. */ - vaddr = (unsigned long)page->owner & PAGE_MASK; + if (page->flags & SGX_EPC_PAGE_KVM_GUEST) + vaddr = (unsigned long)page->owner & PAGE_MASK; + else + vaddr = (unsigned long)page->owner->desc & PAGE_MASK; ret = force_sig_mceerr(BUS_MCEERR_AR, (void __user *)vaddr, PAGE_SHIFT); if (ret < 0)