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 X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,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 C8BFAC7618E for ; Tue, 30 Jul 2019 04:53:45 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by mail.kernel.org (Postfix) with ESMTP id A36972089E for ; Tue, 30 Jul 2019 04:53:45 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1728983AbfG3Exo (ORCPT ); Tue, 30 Jul 2019 00:53:44 -0400 Received: from mga04.intel.com ([192.55.52.120]:50253 "EHLO mga04.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1728401AbfG3Exk (ORCPT ); Tue, 30 Jul 2019 00:53:40 -0400 X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by fmsmga104.fm.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 29 Jul 2019 21:53:40 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,325,1559545200"; d="scan'208";a="183007175" Received: from allen-box.sh.intel.com ([10.239.159.136]) by orsmga002.jf.intel.com with ESMTP; 29 Jul 2019 21:53:36 -0700 From: Lu Baolu To: David Woodhouse , Joerg Roedel , Bjorn Helgaas , Christoph Hellwig Cc: ashok.raj@intel.com, jacob.jun.pan@intel.com, alan.cox@intel.com, kevin.tian@intel.com, mika.westerberg@linux.intel.com, Ingo Molnar , Greg Kroah-Hartman , pengfei.xu@intel.com, Konrad Rzeszutek Wilk , Marek Szyprowski , Robin Murphy , Jonathan Corbet , Boris Ostrovsky , Juergen Gross , Stefano Stabellini , Steven Rostedt , iommu@lists.linux-foundation.org, linux-kernel@vger.kernel.org, Lu Baolu , Jacob Pan Subject: [PATCH v6 6/8] iommu/vt-d: Check whether device requires bounce buffer Date: Tue, 30 Jul 2019 12:52:27 +0800 Message-Id: <20190730045229.3826-7-baolu.lu@linux.intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190730045229.3826-1-baolu.lu@linux.intel.com> References: <20190730045229.3826-1-baolu.lu@linux.intel.com> Sender: linux-kernel-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org This adds a helper to check whether a device needs to use bounce buffer. It also provides a boot time option to disable the bounce buffer. Users can use this to prevent the iommu driver from using the bounce buffer for performance gain. Cc: Ashok Raj Cc: Jacob Pan Cc: Kevin Tian Signed-off-by: Lu Baolu Tested-by: Xu Pengfei Tested-by: Mika Westerberg --- Documentation/admin-guide/kernel-parameters.txt | 5 +++++ drivers/iommu/intel-iommu.c | 6 ++++++ 2 files changed, 11 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 7ccd158b3894..09b83df0e24d 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1732,6 +1732,11 @@ Note that using this option lowers the security provided by tboot because it makes the system vulnerable to DMA attacks. + nobounce [Default off] + Disable bounce buffer for unstrusted devices such as + the Thunderbolt devices. This will treat the untrusted + devices as the trusted ones, hence might expose security + risks of DMA attacks. intel_idle.max_cstate= [KNL,HW,ACPI,X86] 0 disables intel_idle and fall back on acpi_idle. diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index 8064af607d3b..fcbbf8de07e7 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -360,6 +360,7 @@ static int dmar_forcedac; static int intel_iommu_strict; static int intel_iommu_superpage = 1; static int iommu_identity_mapping; +static int intel_no_bounce; #define IDENTMAP_ALL 1 #define IDENTMAP_GFX 2 @@ -373,6 +374,8 @@ EXPORT_SYMBOL_GPL(intel_iommu_gfx_mapped); static DEFINE_SPINLOCK(device_domain_lock); static LIST_HEAD(device_domain_list); +#define device_needs_bounce(d) (!intel_no_bounce && dev_is_untrusted(d)) + /* * Iterate over elements in device_domain_list and call the specified * callback @fn against each element. @@ -455,6 +458,9 @@ static int __init intel_iommu_setup(char *str) printk(KERN_INFO "Intel-IOMMU: not forcing on after tboot. This could expose security risk for tboot\n"); intel_iommu_tboot_noforce = 1; + } else if (!strncmp(str, "nobounce", 8)) { + pr_info("Intel-IOMMU: No bounce buffer. This could expose security risks of DMA attacks\n"); + intel_no_bounce = 1; } str += strcspn(str, ","); -- 2.17.1 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 X-Spam-Level: X-Spam-Status: No, score=-9.8 required=3.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, INCLUDES_PATCH,MAILING_LIST_MULTI,SIGNED_OFF_BY,SPF_HELO_NONE,SPF_PASS, URIBL_BLOCKED,USER_AGENT_GIT autolearn=unavailable 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 A68AEC7618E for ; Tue, 30 Jul 2019 04:58:42 +0000 (UTC) Received: from mail.linuxfoundation.org (mail.linuxfoundation.org [140.211.169.12]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by mail.kernel.org (Postfix) with ESMTPS id 84609206A2 for ; Tue, 30 Jul 2019 04:58:42 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 84609206A2 Authentication-Results: mail.kernel.org; dmarc=fail (p=none dis=none) header.from=linux.intel.com Authentication-Results: mail.kernel.org; spf=pass smtp.mailfrom=iommu-bounces@lists.linux-foundation.org Received: from mail.linux-foundation.org (localhost [127.0.0.1]) by mail.linuxfoundation.org (Postfix) with ESMTP id 4D44623AC; Tue, 30 Jul 2019 04:58:22 +0000 (UTC) Received: from smtp1.linuxfoundation.org (smtp1.linux-foundation.org [172.17.192.35]) by mail.linuxfoundation.org (Postfix) with ESMTPS id CED5E21FF for ; Tue, 30 Jul 2019 04:53:41 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga02.intel.com (mga02.intel.com [134.134.136.20]) by smtp1.linuxfoundation.org (Postfix) with ESMTPS id 6A78BA8 for ; Tue, 30 Jul 2019 04:53:40 +0000 (UTC) X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from orsmga002.jf.intel.com ([10.7.209.21]) by orsmga101.jf.intel.com with ESMTP/TLS/DHE-RSA-AES256-GCM-SHA384; 29 Jul 2019 21:53:40 -0700 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.64,325,1559545200"; d="scan'208";a="183007175" Received: from allen-box.sh.intel.com ([10.239.159.136]) by orsmga002.jf.intel.com with ESMTP; 29 Jul 2019 21:53:36 -0700 From: Lu Baolu To: David Woodhouse , Joerg Roedel , Bjorn Helgaas , Christoph Hellwig Subject: [PATCH v6 6/8] iommu/vt-d: Check whether device requires bounce buffer Date: Tue, 30 Jul 2019 12:52:27 +0800 Message-Id: <20190730045229.3826-7-baolu.lu@linux.intel.com> X-Mailer: git-send-email 2.17.1 In-Reply-To: <20190730045229.3826-1-baolu.lu@linux.intel.com> References: <20190730045229.3826-1-baolu.lu@linux.intel.com> Cc: Juergen Gross , kevin.tian@intel.com, Stefano Stabellini , ashok.raj@intel.com, Konrad Rzeszutek Wilk , alan.cox@intel.com, Jonathan Corbet , Robin Murphy , Steven Rostedt , linux-kernel@vger.kernel.org, iommu@lists.linux-foundation.org, pengfei.xu@intel.com, Ingo Molnar , jacob.jun.pan@intel.com, Greg Kroah-Hartman , Boris Ostrovsky , mika.westerberg@linux.intel.com X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.12 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , MIME-Version: 1.0 Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Sender: iommu-bounces@lists.linux-foundation.org Errors-To: iommu-bounces@lists.linux-foundation.org This adds a helper to check whether a device needs to use bounce buffer. It also provides a boot time option to disable the bounce buffer. Users can use this to prevent the iommu driver from using the bounce buffer for performance gain. Cc: Ashok Raj Cc: Jacob Pan Cc: Kevin Tian Signed-off-by: Lu Baolu Tested-by: Xu Pengfei Tested-by: Mika Westerberg --- Documentation/admin-guide/kernel-parameters.txt | 5 +++++ drivers/iommu/intel-iommu.c | 6 ++++++ 2 files changed, 11 insertions(+) diff --git a/Documentation/admin-guide/kernel-parameters.txt b/Documentation/admin-guide/kernel-parameters.txt index 7ccd158b3894..09b83df0e24d 100644 --- a/Documentation/admin-guide/kernel-parameters.txt +++ b/Documentation/admin-guide/kernel-parameters.txt @@ -1732,6 +1732,11 @@ Note that using this option lowers the security provided by tboot because it makes the system vulnerable to DMA attacks. + nobounce [Default off] + Disable bounce buffer for unstrusted devices such as + the Thunderbolt devices. This will treat the untrusted + devices as the trusted ones, hence might expose security + risks of DMA attacks. intel_idle.max_cstate= [KNL,HW,ACPI,X86] 0 disables intel_idle and fall back on acpi_idle. diff --git a/drivers/iommu/intel-iommu.c b/drivers/iommu/intel-iommu.c index 8064af607d3b..fcbbf8de07e7 100644 --- a/drivers/iommu/intel-iommu.c +++ b/drivers/iommu/intel-iommu.c @@ -360,6 +360,7 @@ static int dmar_forcedac; static int intel_iommu_strict; static int intel_iommu_superpage = 1; static int iommu_identity_mapping; +static int intel_no_bounce; #define IDENTMAP_ALL 1 #define IDENTMAP_GFX 2 @@ -373,6 +374,8 @@ EXPORT_SYMBOL_GPL(intel_iommu_gfx_mapped); static DEFINE_SPINLOCK(device_domain_lock); static LIST_HEAD(device_domain_list); +#define device_needs_bounce(d) (!intel_no_bounce && dev_is_untrusted(d)) + /* * Iterate over elements in device_domain_list and call the specified * callback @fn against each element. @@ -455,6 +458,9 @@ static int __init intel_iommu_setup(char *str) printk(KERN_INFO "Intel-IOMMU: not forcing on after tboot. This could expose security risk for tboot\n"); intel_iommu_tboot_noforce = 1; + } else if (!strncmp(str, "nobounce", 8)) { + pr_info("Intel-IOMMU: No bounce buffer. This could expose security risks of DMA attacks\n"); + intel_no_bounce = 1; } str += strcspn(str, ","); -- 2.17.1 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu