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 smtp4.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 smtp.lore.kernel.org (Postfix) with ESMTPS id 14AD7C433FE for ; Tue, 8 Mar 2022 05:46:28 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp4.osuosl.org (Postfix) with ESMTP id C52FA41738; Tue, 8 Mar 2022 05:46:27 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org 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 MuxNSV0oQJ3j; Tue, 8 Mar 2022 05:46:27 +0000 (UTC) Received: from lists.linuxfoundation.org (lf-lists.osuosl.org [140.211.9.56]) by smtp4.osuosl.org (Postfix) with ESMTPS id A488B41733; Tue, 8 Mar 2022 05:46:26 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id 78B67C001D; Tue, 8 Mar 2022 05:46:26 +0000 (UTC) Received: from smtp2.osuosl.org (smtp2.osuosl.org [140.211.166.133]) by lists.linuxfoundation.org (Postfix) with ESMTP id 0E3B5C000B for ; Tue, 8 Mar 2022 05:46:25 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp2.osuosl.org (Postfix) with ESMTP id EF339404C5 for ; Tue, 8 Mar 2022 05:46:24 +0000 (UTC) X-Virus-Scanned: amavisd-new at osuosl.org Authentication-Results: smtp2.osuosl.org (amavisd-new); dkim=pass (2048-bit key) header.d=intel.com Received: from smtp2.osuosl.org ([127.0.0.1]) by localhost (smtp2.osuosl.org [127.0.0.1]) (amavisd-new, port 10024) with ESMTP id PSlRLziq1R3U for ; Tue, 8 Mar 2022 05:46:24 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 Received: from mga04.intel.com (mga04.intel.com [192.55.52.120]) by smtp2.osuosl.org (Postfix) with ESMTPS id 8F8134013D for ; Tue, 8 Mar 2022 05:46:23 +0000 (UTC) DKIM-Signature: v=1; a=rsa-sha256; c=relaxed/simple; d=intel.com; i=@intel.com; q=dns/txt; s=Intel; t=1646718384; x=1678254384; h=from:to:cc:subject:date:message-id:in-reply-to: references:mime-version:content-transfer-encoding; bh=7RqVH7LEIAgp5LCm2Qn1GAJ89sBrOf2aUr2sUfMN69I=; b=nO7LR4mJgr4bwOS+a5hzyAZuWwaxIdBYgCyn22/hg3SKSQJVfBN68GnL 10WAHkn9X0HnAsAfp7f5O1Av+Yt2XyTAAtMxuOfmDKRVl5/oUj/wuc/P7 g5L/pTuPUCpNiDimzWbLwG4KbtfspqkGLCM07mKm2zSb6hit3G+aj/nLy iXoNonvHkitWJYo+FKILENEIhIKpeTYlO2S4EuZ4OJb3hLGj2lilh5xgX 1tuDXLl9Tffjp/NZGwuQkRFuK+hEtoxMin1ymFJUwv/5Qoy4jTrgv2rmo qxuh/azPiWCF88LsLqkwStdPcZ+GLa6djsBdsVsgKEns3BBGdSnfDZrE7 w==; X-IronPort-AV: E=McAfee;i="6200,9189,10279"; a="253427472" X-IronPort-AV: E=Sophos;i="5.90,163,1643702400"; d="scan'208";a="253427472" Received: from orsmga007.jf.intel.com ([10.7.209.58]) by fmsmga104.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 07 Mar 2022 21:46:21 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.90,163,1643702400"; d="scan'208";a="537430035" Received: from allen-box.sh.intel.com ([10.239.159.48]) by orsmga007.jf.intel.com with ESMTP; 07 Mar 2022 21:46:14 -0800 From: Lu Baolu To: Greg Kroah-Hartman , Joerg Roedel , Alex Williamson , Bjorn Helgaas , Jason Gunthorpe , Christoph Hellwig , Kevin Tian , Ashok Raj Subject: [PATCH v8 02/11] driver core: Add dma_cleanup callback in bus_type Date: Tue, 8 Mar 2022 13:44:12 +0800 Message-Id: <20220308054421.847385-3-baolu.lu@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20220308054421.847385-1-baolu.lu@linux.intel.com> References: <20220308054421.847385-1-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 f47cab21430f..7c3c9b4c3deb 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -665,6 +665,8 @@ 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); @@ -1208,6 +1210,9 @@ 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