From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: X-Spam-Checker-Version: SpamAssassin 3.4.2 (2018-09-13) on archive.lwn.net X-Spam-Level: X-Spam-Status: No, score=-6.0 required=5.0 tests=HEADER_FROM_DIFFERENT_DOMAINS, MAILING_LIST_MULTI,RCVD_IN_DNSWL_HI,SPF_HELO_NONE,SPF_NONE autolearn=ham autolearn_force=no version=3.4.2 Received: from vger.kernel.org (vger.kernel.org [209.132.180.67]) by archive.lwn.net (Postfix) with ESMTP id 4AEC17D922 for ; Thu, 30 May 2019 03:50:40 +0000 (UTC) Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S2387675AbfE3Dt1 (ORCPT ); Wed, 29 May 2019 23:49:27 -0400 Received: from szxga04-in.huawei.com ([45.249.212.190]:18051 "EHLO huawei.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S2387654AbfE3DtZ (ORCPT ); Wed, 29 May 2019 23:49:25 -0400 Received: from DGGEMS403-HUB.china.huawei.com (unknown [172.30.72.59]) by Forcepoint Email with ESMTP id DB4C41F0F32B9FF7AF5D; Thu, 30 May 2019 11:49:22 +0800 (CST) Received: from HGHY4L002753561.china.huawei.com (10.133.215.186) by DGGEMS403-HUB.china.huawei.com (10.3.19.203) with Microsoft SMTP Server id 14.3.439.0; Thu, 30 May 2019 11:49:12 +0800 From: Zhen Lei To: Jean-Philippe Brucker , John Garry , Robin Murphy , Will Deacon , Joerg Roedel , Jonathan Corbet , linux-doc , Sebastian Ott , Gerald Schaefer , "Martin Schwidefsky" , Heiko Carstens , Benjamin Herrenschmidt , Paul Mackerras , "Michael Ellerman" , Tony Luck , Fenghua Yu , Thomas Gleixner , Ingo Molnar , Borislav Petkov , "H . Peter Anvin" , David Woodhouse , iommu , linux-kernel , linux-s390 , linuxppc-dev , x86 , linux-ia64 CC: Zhen Lei , Hanjun Guo Subject: [PATCH v8 1/7] iommu: enhance IOMMU default DMA mode build options Date: Thu, 30 May 2019 11:48:25 +0800 Message-ID: <20190530034831.4184-2-thunder.leizhen@huawei.com> X-Mailer: git-send-email 2.21.0.windows.1 In-Reply-To: <20190530034831.4184-1-thunder.leizhen@huawei.com> References: <20190530034831.4184-1-thunder.leizhen@huawei.com> MIME-Version: 1.0 Content-Transfer-Encoding: 7BIT Content-Type: text/plain; charset=US-ASCII X-Originating-IP: [10.133.215.186] X-CFilter-Loop: Reflected Sender: linux-doc-owner@vger.kernel.org Precedence: bulk List-ID: X-Mailing-List: linux-doc@vger.kernel.org First, add build option IOMMU_DEFAULT_{LAZY|STRICT}, so that we have the opportunity to set {lazy|strict} mode as default at build time. Then put the three config options in an choice, make people can only choose one of the three at a time. Signed-off-by: Zhen Lei --- drivers/iommu/Kconfig | 42 +++++++++++++++++++++++++++++++++++------- drivers/iommu/iommu.c | 3 ++- 2 files changed, 37 insertions(+), 8 deletions(-) diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig index 83664db5221df02..d6a1a45f80ffbf5 100644 --- a/drivers/iommu/Kconfig +++ b/drivers/iommu/Kconfig @@ -75,17 +75,45 @@ config IOMMU_DEBUGFS debug/iommu directory, and then populate a subdirectory with entries as required. -config IOMMU_DEFAULT_PASSTHROUGH - bool "IOMMU passthrough by default" +choice + prompt "IOMMU default DMA mode" depends on IOMMU_API - help - Enable passthrough by default, removing the need to pass in - iommu.passthrough=on or iommu=pt through command line. If this - is enabled, you can still disable with iommu.passthrough=off - or iommu=nopt depending on the architecture. + default IOMMU_DEFAULT_STRICT + help + This option allows IOMMU DMA mode to be chose at build time, to + override the default DMA mode of each ARCHs, removing the need to + pass in kernel parameters through command line. You can still use + ARCHs specific boot options to override this option again. + +config IOMMU_DEFAULT_PASSTHROUGH + bool "passthrough" + help + In this mode, the DMA access through IOMMU without any addresses + translation. That means, the wrong or illegal DMA access can not + be caught, no error information will be reported. If unsure, say N here. +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. + +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. + + This mode is safer than the two above, but it maybe slower in some + high performace scenarios. + +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 67ee6623f9b2a4d..56bce221285b15f 100644 --- a/drivers/iommu/iommu.c +++ b/drivers/iommu/iommu.c @@ -43,7 +43,8 @@ #else static unsigned int iommu_def_domain_type = IOMMU_DOMAIN_DMA; #endif -static bool iommu_dma_strict __read_mostly = true; +static bool iommu_dma_strict __read_mostly = + IS_ENABLED(CONFIG_IOMMU_DEFAULT_STRICT); struct iommu_group { struct kobject kobj; -- 1.8.3