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_BLOCKED,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 6AFDFC56202 for ; Sat, 21 Nov 2020 14:04:13 +0000 (UTC) Received: from fraxinus.osuosl.org (smtp4.osuosl.org [140.211.166.137]) (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 1E8432224A for ; Sat, 21 Nov 2020 14:04:12 +0000 (UTC) DMARC-Filter: OpenDMARC Filter v1.3.2 mail.kernel.org 1E8432224A 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 localhost (localhost [127.0.0.1]) by fraxinus.osuosl.org (Postfix) with ESMTP id E698086126; Sat, 21 Nov 2020 14:04:12 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from fraxinus.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id yW3W8Cc62_9b; Sat, 21 Nov 2020 14:04:10 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by fraxinus.osuosl.org (Postfix) with ESMTP id 1CED1850E0; Sat, 21 Nov 2020 14:04:10 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 08528C163C; Sat, 21 Nov 2020 14:04:10 +0000 (UTC) Received: from hemlock.osuosl.org (smtp2.osuosl.org [140.211.166.133]) by lists.linuxfoundation.org (Postfix) with ESMTP id DA43CC0891 for ; Sat, 21 Nov 2020 14:04:07 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by hemlock.osuosl.org (Postfix) with ESMTP id D15B087476 for ; Sat, 21 Nov 2020 14:04:07 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from hemlock.osuosl.org ([127.0.0.1]) by localhost (.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id Pq4LnCgPXQAO for ; Sat, 21 Nov 2020 14:04:07 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.7.6 Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by hemlock.osuosl.org (Postfix) with ESMTPS id 2ACBB87428 for ; Sat, 21 Nov 2020 14:04:07 +0000 (UTC) IronPort-SDR: ds6QFEEi092Sa+krRcx6MFbJpprgQauVAdzn4NbZtVVXlfSEOWaXsfMthF+vyGxR+f+Na/6c8T w9IwAXTy1JfA== X-IronPort-AV: E=McAfee;i="6000,8403,9811"; a="168083759" X-IronPort-AV: E=Sophos;i="5.78,359,1599548400"; d="scan'208";a="168083759" X-Amp-Result: SKIPPED(no attachment in message) X-Amp-File-Uploaded: False Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 21 Nov 2020 06:04:07 -0800 IronPort-SDR: DD6vw02tildfIuN5c0qtC0NZD51DyHrj4vlTxxsPUk7usjtVUG8EE93Dj8NPGGl7lIvRWTNzWW vyXuFOycGoKA== X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.78,359,1599548400"; d="scan'208";a="431852787" Received: from allen-box.sh.intel.com ([10.239.159.28]) by fmsmga001.fm.intel.com with ESMTP; 21 Nov 2020 06:04:04 -0800 From: Lu Baolu To: Will Deacon , Joerg Roedel Subject: [PATCH v9 4/4] iommu: Document usage of "/sys/kernel/iommu_groups//type" file Date: Sat, 21 Nov 2020 21:56:20 +0800 Message-Id: <20201121135620.3496419-5-baolu.lu@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20201121135620.3496419-1-baolu.lu@linux.intel.com> References: <20201121135620.3496419-1-baolu.lu@linux.intel.com> MIME-Version: 1.0 Cc: Ashok Raj , Will Deacon , linux-kernel@vger.kernel.org, Sai Praneeth Prakhya , iommu@lists.linux-foundation.org, Robin Murphy , Christoph Hellwig 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: Sai Praneeth Prakhya The default domain type of an iommu group can be changed by writing to "/sys/kernel/iommu_groups//type" file. Hence, document it's usage and more importantly spell out its limitations. Cc: Christoph Hellwig Cc: Joerg Roedel Cc: Ashok Raj Cc: Will Deacon Cc: Sohil Mehta Cc: Robin Murphy Cc: Jacob Pan Signed-off-by: Sai Praneeth Prakhya Signed-off-by: Lu Baolu --- .../ABI/testing/sysfs-kernel-iommu_groups | 29 +++++++++++++++++++ 1 file changed, 29 insertions(+) diff --git a/Documentation/ABI/testing/sysfs-kernel-iommu_groups b/Documentation/ABI/testing/sysfs-kernel-iommu_groups index 017f5bc3920c..407b1628d7fd 100644 --- a/Documentation/ABI/testing/sysfs-kernel-iommu_groups +++ b/Documentation/ABI/testing/sysfs-kernel-iommu_groups @@ -33,3 +33,32 @@ Description: In case an RMRR is used only by graphics or USB devices it is now exposed as "direct-relaxable" instead of "direct". In device assignment use case, for instance, those RMRR are considered to be relaxable and safe. + +What: /sys/kernel/iommu_groups//type +Date: November 2020 +KernelVersion: v5.11 +Contact: Sai Praneeth Prakhya +Description: /sys/kernel/iommu_groups//type shows the type of default + domain in use by iommu for this group. See include/linux/iommu.h + for possible values. A privileged user could request kernel to + change the group type by writing to this file. Presently, only + three types of request are supported: + 1. DMA: All the DMA transactions from the device in this group + are translated by the iommu. + 2. identity: All the DMA transactions from the device in this + group are *not* translated by the iommu. + 3. auto: Change to the type the device was booted with. + Note: + ----- + The default domain type of a group may be modified only when + 1. The group has *only* one device + 2. The device in the group is not bound to any device driver. + So, the users must unbind the appropriate driver before + changing the default domain type. + Caution: + -------- + Unbinding a device driver will take away the driver's control + over the device and if done on devices that host root file + system could lead to catastrophic effects (the users might + need to reboot the machine to get it to normal state). So, it's + expected that the users understand what they're doing. -- 2.25.1 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu