From patchwork Wed Jun 22 09:37:05 2022 Content-Type: text/plain; charset="utf-8" MIME-Version: 1.0 Content-Transfer-Encoding: 7bit X-Patchwork-Submitter: Zhiquan Li X-Patchwork-Id: 12890407 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 9CFE2C433EF for ; Wed, 22 Jun 2022 09:37:08 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S237523AbiFVJhI (ORCPT ); Wed, 22 Jun 2022 05:37:08 -0400 Received: from lindbergh.monkeyblade.net ([23.128.96.19]:35494 "EHLO lindbergh.monkeyblade.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S235328AbiFVJhH (ORCPT ); Wed, 22 Jun 2022 05:37:07 -0400 Received: from mga09.intel.com (mga09.intel.com [134.134.136.24]) by lindbergh.monkeyblade.net (Postfix) with ESMTPS id 0AA7B35AAD for ; Wed, 22 Jun 2022 02:37:05 -0700 (PDT) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1655890625; x=1687426625; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=yhD4nyL4iV+PuCrN/tauAdoGztq7IpEcKdrueIrGy+Q=; b=knb/QfP70dljdWYwAJgkloXOQsXfGGXYLahSpUrl5jq4cCSJUAVuO3hT 84BfaAshnCvwfG0aXIqnRop4UL5oPei3X69H0odPTcjEy/Nr39f5KV9Pd iMnv29GC9Axc+2kbp9tkgK/1tfpyjsTDL2NOhqF+/i9t3JyGSQbrlsrmd Fk5NZHtP96yE1ucANgqZgircvQ/VIfZhjSGuInE71iUZiWccHtSLyidar FhxqYlX6uqbtSbJPE+vxuiHCoWChyJJRhHhvU0goTUaJ3nY+N/Iy2qCQt pxHQw8uVJMVbEx7PXUvTv6kFrd+WxJ4K+Q3KRh4Xfo7Hukr9dJ3/foQx7 Q==; X-IronPort-AV: E=McAfee;i="6400,9594,10385"; a="281100622" X-IronPort-AV: E=Sophos;i="5.92,212,1650956400"; d="scan'208";a="281100622" Received: from fmsmga003.fm.intel.com ([10.253.24.29]) by orsmga102.jf.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 22 Jun 2022 02:37:04 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.92,212,1650956400"; d="scan'208";a="677448881" Received: from zhiquan-linux-dev.bj.intel.com ([10.238.155.101]) by FMSMGA003.fm.intel.com with ESMTP; 22 Jun 2022 02:37:02 -0700 From: Zhiquan Li To: linux-sgx@vger.kernel.org, tony.luck@intel.com, jarkko@kernel.org, dave.hansen@linux.intel.com Cc: seanjc@google.com, kai.huang@intel.com, fan.du@intel.com, cathy.zhang@intel.com, zhiquan1.li@intel.com Subject: [PATCH v5 3/3] x86/sgx: Fine grained SGX MCA behavior for normal case Date: Wed, 22 Jun 2022 17:37:05 +0800 Message-Id: <20220622093705.2891642-4-zhiquan1.li@intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220622093705.2891642-1-zhiquan1.li@intel.com> References: <20220622093705.2891642-1-zhiquan1.li@intel.com> 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 --- No changes since V4. 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 4507c2302348..7c55dcdb2b7c 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)