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 5213BC433F5 for ; Sun, 28 Nov 2021 02:51:22 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id EB709607AC; Sun, 28 Nov 2021 02:51:21 +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 r2vFjJjOsk8B; Sun, 28 Nov 2021 02:51:21 +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 CCDAA607CF; Sun, 28 Nov 2021 02:51:20 +0000 (UTC) Received: from lf-lists.osuosl.org (localhost [127.0.0.1]) by lists.linuxfoundation.org (Postfix) with ESMTP id B7B6FC001C; Sun, 28 Nov 2021 02:51:20 +0000 (UTC) Received: from smtp3.osuosl.org (smtp3.osuosl.org [140.211.166.136]) by lists.linuxfoundation.org (Postfix) with ESMTP id 32A3AC000A for ; Sun, 28 Nov 2021 02:51:19 +0000 (UTC) Received: from localhost (localhost [127.0.0.1]) by smtp3.osuosl.org (Postfix) with ESMTP id 14417607CF for ; Sun, 28 Nov 2021 02:51:19 +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 qN5tiDqQJsJM for ; Sun, 28 Nov 2021 02:51:18 +0000 (UTC) X-Greylist: domain auto-whitelisted by SQLgrey-1.8.0 Received: from mga14.intel.com (mga14.intel.com [192.55.52.115]) by smtp3.osuosl.org (Postfix) with ESMTPS id 36DA2607AC for ; Sun, 28 Nov 2021 02:51:18 +0000 (UTC) X-IronPort-AV: E=McAfee;i="6200,9189,10181"; a="236040193" X-IronPort-AV: E=Sophos;i="5.87,270,1631602800"; d="scan'208";a="236040193" Received: from fmsmga001.fm.intel.com ([10.253.24.23]) by fmsmga103.fm.intel.com with ESMTP/TLS/ECDHE-RSA-AES256-GCM-SHA384; 27 Nov 2021 18:51:17 -0800 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.87,270,1631602800"; d="scan'208";a="652488940" Received: from allen-box.sh.intel.com ([10.239.159.118]) by fmsmga001.fm.intel.com with ESMTP; 27 Nov 2021 18:51:10 -0800 From: Lu Baolu To: Greg Kroah-Hartman , Joerg Roedel , Alex Williamson , Bjorn Helgaas , Jason Gunthorpe , Christoph Hellwig , Kevin Tian , Ashok Raj Subject: [PATCH v2 02/17] driver core: Add dma_unconfigure callback in bus_type Date: Sun, 28 Nov 2021 10:50:36 +0800 Message-Id: <20211128025051.355578-3-baolu.lu@linux.intel.com> X-Mailer: git-send-email 2.25.1 In-Reply-To: <20211128025051.355578-1-baolu.lu@linux.intel.com> References: <20211128025051.355578-1-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 , 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_unconfigure() 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. Suggested-by: Jason Gunthorpe Link: https://lore.kernel.org/linux-iommu/20210922123931.GI327412@nvidia.com/ Link: https://lore.kernel.org/linux-iommu/20210928115751.GK964074@nvidia.com/ Signed-off-by: Lu Baolu --- include/linux/device/bus.h | 3 +++ drivers/base/dd.c | 7 ++++++- 2 files changed, 9 insertions(+), 1 deletion(-) diff --git a/include/linux/device/bus.h b/include/linux/device/bus.h index a039ab809753..ef54a71e5f8f 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_unconfigure: 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_unconfigure)(struct device *dev); const struct dev_pm_ops *pm; diff --git a/drivers/base/dd.c b/drivers/base/dd.c index 68ea1f949daa..a37aafff5fde 100644 --- a/drivers/base/dd.c +++ b/drivers/base/dd.c @@ -577,7 +577,7 @@ static int really_probe(struct device *dev, struct device_driver *drv) if (dev->bus->dma_configure) { ret = dev->bus->dma_configure(dev); if (ret) - goto probe_failed; + goto pinctrl_bind_failed; } ret = driver_sysfs_add(dev); @@ -660,6 +660,8 @@ 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->dma_unconfigure) + dev->bus->dma_unconfigure(dev); pinctrl_bind_failed: device_links_no_driver(dev); devres_release_all(dev); @@ -1204,6 +1206,9 @@ static void __device_release_driver(struct device *dev, struct device *parent) else if (drv->remove) drv->remove(dev); + if (dev->bus->dma_unconfigure) + dev->bus->dma_unconfigure(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