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 Received: from smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) (using TLSv1.2 with cipher ECDHE-RSA-AES256-GCM-SHA384 (256/256 bits)) (No client certificate requested) by smtp.lore.kernel.org (Postfix) with ESMTPS id D6F20C433F5 for ; Mon, 28 Feb 2022 00:53:00 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id 7DC6B60D94; Mon, 28 Feb 2022 00:53:00 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Received: from smtp3.osuosl.org ([127.0.0.1]) by localhost (smtp3.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id EAOr9rFaaj45; Mon, 28 Feb 2022 00:52:59 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [IPv6:2605:bc80:3010:104::8cd3:938]) by smtp3.osuosl.org (Postfix) with ESMTPS id 393A460D79; Mon, 28 Feb 2022 00:52:59 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 13BE4C0077; Mon, 28 Feb 2022 00:52:59 +0000 (UTC) Received: from smtp4.osuosl.org (smtp4.osuosl.org [IPv6:2605:bc80:3010::137]) by lists.linuxfoundation.org (Postfix) with ESMTP id 2153AC001A for ; Mon, 28 Feb 2022 00:52:58 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id 0FD074011F for ; Mon, 28 Feb 2022 00:52:58 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Authentication-Results: smtp4.osuosl.org (amavisd-new); dkim=pass (2048-bit key) header.d=intel.com Received: from smtp4.osuosl.org ([127.0.0.1]) by localhost (smtp4.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id rtbRGdbjaxnC for ; Mon, 28 Feb 2022 00:52:55 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 Received: from mga11.intel.com (mga11.intel.com [192.55.52.93]) by smtp4.osuosl.org (Postfix) with ESMTPS id 597624095F for ; Mon, 28 Feb 2022 00:52:55 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1646009575; x=1677545575; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=TTb5uTpvyMenyURqmVAtinXx9YdD8xnnaNld1DpmwaY=; b=PwFTGNAXCEFla0HyXSQ+5QIxy3/HK1TcW5yQ2iZeSHxIUJKNEG/0MNSN 0wTWQWqay8L4+pkItBhsI4JuZB3+/ycKDcwTswFpM9mPs644aRfv9dS7C efyL9Qpi2R9B9y26kwps0TMxrfj9pLPr05U59Q5cJZXQYwN6irJZzf+31 knAC7C3rsysz9y8XEcTgSL80sscO5lplkxR9eYxVbaAOFrBHr1j2oH6yw CTFlrdw0TLW01lKhnDSdVvO93CPT8S1B0SFYZxY2l41iwW7Hqr8xiWjWB eU/wmWLKNT58NQ3gUJ7zMwC84HTOlhuBNlTIgPAF1ltBn/U35R/WBDvZM g==; X-IronPort-AV: E=McAfee;i="6200,9189,10271"; a="250354863" X-IronPort-AV: E=Sophos;i="5.90,142,1643702400"; d="scan'208";a="250354863" Received: from orsmga008.jf.intel.com ([10.7.209.65]) by fmsmga102.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Feb 2022 16:52:54 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.90,142,1643702400"; d="scan'208";a="550020162" Received: from allen-box.sh.intel.com ([10.239.159.118]) by orsmga008.jf.intel.com with ESMTP; 27 Feb 2022 16:52:47 -0800 From: Lu Baolu To: Greg Kroah-Hartman , Joerg Roedel , Alex Williamson , Bjorn Helgaas , Jason Gunthorpe , Christoph Hellwig , Kevin Tian , Ashok Raj Subject: [PATCH v7 02/11] driver core: Add dma_cleanup callback in bus_type Date: Mon, 28 Feb 2022 08:50:47 +0800 Message-Id: <20220228005056.599595-3-baolu.lu@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220228005056.599595-1-baolu.lu@linux.intel.com> References: <20220228005056.599595-1-baolu.lu@linux.intel.com> MIME-Version: 1.0 Cc: kvm@vger.kernel.org, rafael@kernel.org, David Airlie , linux-pci@vger.kernel.org, Thierry Reding , Diana Craciun , Dmitry Osipenko , Will Deacon , Stuart Yoder , Jonathan Hunter , Chaitanya Kulkarni , Dan Williams , Cornelia Huck , linux-kernel@vger.kernel.org, Li Yang , iommu@lists.linux-foundation.org, Jacob jun Pan , Daniel Vetter , Robin Murphy 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" The bus_type structure defines dma_configure() callback for bus drivers to configure DMA on the devices. This adds the paired dma_cleanup() callback and calls it during driver unbinding so that bus drivers can do some cleanup work. One use case for this paired DMA callbacks is for the bus driver to check for DMA ownership conflicts during driver binding, where multiple devices belonging to a same IOMMU group (the minimum granularity of isolation and protection) may be assigned to kernel drivers or user space respectively. Without this change, for example, the vfio driver has to listen to a bus BOUND_DRIVER event and then BUG_ON() in case of dma ownership conflict. This leads to bad user experience since careless driver binding operation may crash the system if the admin overlooks the group restriction. Aside from bad design, this leads to a security problem as a root user, even with lockdown=integrity, can force the kernel to BUG. With this change, the bus driver could check and set the DMA ownership in driver binding process and fail on ownership conflicts. The DMA ownership should be released during driver unbinding. Signed-off-by: Lu Baolu Reviewed-by: Greg Kroah-Hartman Reviewed-by: Jason Gunthorpe --- include/linux/device/bus.h | 3 +++ drivers/base/dd.c | 5 +++++ 2 files changed, 8 insertions(+) diff --git a/include/linux/device/bus.h b/include/linux/device/bus.h index a039ab809753..d8b29ccd07e5 100644 --- a/include/linux/device/bus.h +++ b/include/linux/device/bus.h @@ -59,6 +59,8 @@ struct fwnode_handle; * bus supports. * @dma_configure: Called to setup DMA configuration on a device on * this bus. + * @dma_cleanup: Called to cleanup DMA configuration on a device on + * this bus. * @pm: Power management operations of this bus, callback the specific * device driver's pm-ops. * @iommu_ops: IOMMU specific operations for this bus, used to attach IOMMU @@ -103,6 +105,7 @@ struct bus_type { int (*num_vf)(struct device *dev); int (*dma_configure)(struct device *dev); + void (*dma_cleanup)(struct device *dev); const struct dev_pm_ops *pm; diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 9eaaff2f556c..de05c5c60c6b 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -662,6 +662,8 @@ static int really_probe(struct device *dev, struct device_driver *drv) if (dev->bus) blocking_notifier_call_chain(&dev->bus->p->bus_notifier, BUS_NOTIFY_DRIVER_NOT_BOUND, dev); + if (dev->bus && dev->bus->dma_cleanup) + dev->bus->dma_cleanup(dev); pinctrl_bind_failed: device_links_no_driver(dev); devres_release_all(dev); @@ -1205,6 +1207,9 @@ static void __device_release_driver(struct device *dev, struct device *parent) else if (drv->remove) drv->remove(dev); + if (dev->bus && dev->bus->dma_cleanup) + dev->bus->dma_cleanup(dev); + device_links_driver_cleanup(dev); devres_release_all(dev); -- 2.25.1 _______________________________________________ iommu mailing list iommu@lists.linux-foundation.org https://lists.linuxfoundation.org/mailman/listinfo/iommu