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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,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 01CE9C48BE5 for ; Fri, 11 Jun 2021 12:26:33 +0000 (UTC) Received: from vger.kernel.org (vger.kernel.org [23.128.96.18]) by mail.kernel.org (Postfix) with ESMTP id BCFA3613D3 for ; Fri, 11 Jun 2021 12:26:32 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S231669AbhFKM23 (ORCPT ); Fri, 11 Jun 2021 08:28:29 -0400 Received: from frasgout.his.huawei.com ([185.176.79.56]:3214 "EHLO frasgout.his.huawei.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S231614AbhFKM2X (ORCPT ); Fri, 11 Jun 2021 08:28:23 -0400 Received: from fraeml702-chm.china.huawei.com (unknown [172.18.147.226]) by frasgout.his.huawei.com (SkyGuard) with ESMTP id 4G1fzZ148tz6K5rk; Fri, 11 Jun 2021 20:19:38 +0800 (CST) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by fraeml702-chm.china.huawei.com (10.206.15.51) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2176.2; Fri, 11 Jun 2021 14:26:24 +0200 Received: from localhost.localdomain (10.69.192.58) by lhreml724-chm.china.huawei.com (10.201.108.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Fri, 11 Jun 2021 13:26:21 +0100 From: John Garry To: , , , , CC: , , , , , John Garry Subject: [PATCH v12 2/5] iommu: Enhance IOMMU default DMA mode build options Date: Fri, 11 Jun 2021 20:20:40 +0800 Message-ID: <1623414043-40745-3-git-send-email-john.garry@huawei.com> X-Mailer: git-send-email 2.8.1 In-Reply-To: <1623414043-40745-1-git-send-email-john.garry@huawei.com> References: <1623414043-40745-1-git-send-email-john.garry@huawei.com> MIME-Version: 1.0 Content-Type: text/plain X-Originating-IP: [10.69.192.58] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected Precedence: bulk List-ID: X-Mailing-List: linux-kernel@vger.kernel.org From: Zhen Lei First, add build options IOMMU_DEFAULT_{LAZY|STRICT}, so that we have the opportunity to set {lazy|strict} mode as default at build time. Then put the two config options in an choice, as they are mutually exclusive. [jpg: Make choice between strict and lazy only (and not passthrough)] Signed-off-by: Zhen Lei Signed-off-by: John Garry --- drivers/iommu/Kconfig | 38 ++++++++++++++++++++++++++++++++++++++ drivers/iommu/iommu.c | 3 ++- 2 files changed, 40 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig index 1f111b399bca..2a71347611d4 100644 --- a/drivers/iommu/Kconfig +++ b/drivers/iommu/Kconfig @@ -90,6 +90,44 @@ config IOMMU_DEFAULT_PASSTHROUGH If unsure, say N here. +choice + prompt "IOMMU default DMA mode" + depends on IOMMU_DMA + + default IOMMU_DEFAULT_STRICT + help + This option allows an IOMMU DMA mode to be chosen at build time, to + override the default DMA mode of each ARCH, removing the need to + pass in kernel parameters through command line. It is still possible + to provide ARCH-specific or common boot options to override this + option. + + If unsure, keep the default. + +config IOMMU_DEFAULT_STRICT + bool "strict" + help + For every IOMMU DMA unmap operation, the flush operation of IOTLB and + the free operation of IOVA are guaranteed to be done in the unmap + function. + +config IOMMU_DEFAULT_LAZY + bool "lazy" + help + Support lazy mode, where for every IOMMU DMA unmap operation, the + flush operation of IOTLB and the free operation of IOVA are deferred. + They are only guaranteed to be done before the related IOVA will be + reused. + + The isolation provided in this mode is not as secure as STRICT mode, + such that a vulnerable time window may be created between the DMA + unmap and the mapping finally being torn down in the IOMMU, where the + device can still access the system memory. However this mode may + provide better performance in high throughput scenarios, and is still + considerably more secure than passthrough mode or no IOMMU. + +endchoice + config OF_IOMMU def_bool y depends on OF && IOMMU_API diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index cf58949cc2f3..ccbd5d4c1a50 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -29,7 +29,8 @@ static struct kset *iommu_group_kset; static DEFINE_IDA(iommu_group_ida); static unsigned int iommu_def_domain_type __read_mostly; -static bool iommu_dma_strict __read_mostly = true; +static bool iommu_dma_strict __read_mostly = + IS_ENABLED(CONFIG_IOMMU_DEFAULT_STRICT); static u32 iommu_cmd_line __read_mostly; struct iommu_group { -- 2.26.2 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=-16.8 required=3.0 tests=BAYES_00, HEADER_FROM_DIFFERENT_DOMAINS,INCLUDES_CR_TRAILER,INCLUDES_PATCH, MAILING_LIST_MULTI,SPF_HELO_NONE,SPF_PASS,URIBL_RED,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 2E6C4C48BE0 for ; 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Fri, 11 Jun 2021 20:19:38 +0800 (CST) Received: from lhreml724-chm.china.huawei.com (10.201.108.75) by fraeml702-chm.china.huawei.com (10.206.15.51) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_CBC_SHA256_P256) id 15.1.2176.2; Fri, 11 Jun 2021 14:26:24 +0200 Received: from localhost.localdomain (10.69.192.58) by lhreml724-chm.china.huawei.com (10.201.108.75) with Microsoft SMTP Server (version=TLS1_2, cipher=TLS_ECDHE_RSA_WITH_AES_128_GCM_SHA256) id 15.1.2176.2; Fri, 11 Jun 2021 13:26:21 +0100 From: John Garry To: , , , , Subject: [PATCH v12 2/5] iommu: Enhance IOMMU default DMA mode build options Date: Fri, 11 Jun 2021 20:20:40 +0800 Message-ID: <1623414043-40745-3-git-send-email-john.garry@huawei.com> X-Mailer: git-send-email 2.8.1 In-Reply-To: <1623414043-40745-1-git-send-email-john.garry@huawei.com> References: <1623414043-40745-1-git-send-email-john.garry@huawei.com> MIME-Version: 1.0 X-Originating-IP: [10.69.192.58] X-ClientProxiedBy: dggems704-chm.china.huawei.com (10.3.19.181) To lhreml724-chm.china.huawei.com (10.201.108.75) X-CFilter-Loop: Reflected Cc: linux-kernel@vger.kernel.org, linuxarm@huawei.com, iommu@lists.linux-foundation.org X-BeenThere: iommu@lists.linux-foundation.org X-Mailman-Version: 2.1.15 Precedence: list List-Id: Development issues for Linux IOMMU support List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , Content-Type: text/plain; charset="us-ascii" Content-Transfer-Encoding: 7bit Errors-To: iommu-bounces@lists.linux-foundation.org Sender: "iommu" From: Zhen Lei First, add build options IOMMU_DEFAULT_{LAZY|STRICT}, so that we have the opportunity to set {lazy|strict} mode as default at build time. Then put the two config options in an choice, as they are mutually exclusive. [jpg: Make choice between strict and lazy only (and not passthrough)] Signed-off-by: Zhen Lei Signed-off-by: John Garry --- drivers/iommu/Kconfig | 38 ++++++++++++++++++++++++++++++++++++++ drivers/iommu/iommu.c | 3 ++- 2 files changed, 40 insertions(+), 1 deletion(-) diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig index 1f111b399bca..2a71347611d4 100644 --- a/drivers/iommu/Kconfig +++ b/drivers/iommu/Kconfig @@ -90,6 +90,44 @@ config IOMMU_DEFAULT_PASSTHROUGH If unsure, say N here. +choice + prompt "IOMMU default DMA mode" + depends on IOMMU_DMA + + default IOMMU_DEFAULT_STRICT + help + This option allows an IOMMU DMA mode to be chosen at build time, to + override the default DMA mode of each ARCH, removing the need to + pass in kernel parameters through command line. It is still possible + to provide ARCH-specific or common boot options to override this + option. + + If unsure, keep the default. + +config IOMMU_DEFAULT_STRICT + bool "strict" + help + For every IOMMU DMA unmap operation, the flush operation of IOTLB and + the free operation of IOVA are guaranteed to be done in the unmap + function. + +config IOMMU_DEFAULT_LAZY + bool "lazy" + help + Support lazy mode, where for every IOMMU DMA unmap operation, the + flush operation of IOTLB and the free operation of IOVA are deferred. + They are only guaranteed to be done before the related IOVA will be + reused. + + The isolation provided in this mode is not as secure as STRICT mode, + such that a vulnerable time window may be created between the DMA + unmap and the mapping finally being torn down in the IOMMU, where the + device can still access the system memory. However this mode may + provide better performance in high throughput scenarios, and is still + considerably more secure than passthrough mode or no IOMMU. + +endchoice + config OF_IOMMU def_bool y depends on OF && IOMMU_API diff --git a/drivers/iommu/iommu.c b/drivers/iommu/iommu.c index cf58949cc2f3..ccbd5d4c1a50 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -29,7 +29,8 @@ static struct kset *iommu_group_kset; static DEFINE_IDA(iommu_group_ida); static unsigned int iommu_def_domain_type __read_mostly; -static bool iommu_dma_strict __read_mostly = true; +static bool iommu_dma_strict __read_mostly = + IS_ENABLED(CONFIG_IOMMU_DEFAULT_STRICT); static u32 iommu_cmd_line __read_mostly; struct iommu_group { -- 2.26.2 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu