From: Robin Murphy <robin.murphy@arm.com>
To: Lu Baolu <baolu.lu@linux.intel.com>,
Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
Joerg Roedel <joro@8bytes.org>,
Alex Williamson <alex.williamson@redhat.com>,
Bjorn Helgaas <bhelgaas@google.com>,
Jason Gunthorpe <jgg@nvidia.com>,
Christoph Hellwig <hch@infradead.org>,
Kevin Tian <kevin.tian@intel.com>,
Ashok Raj <ashok.raj@intel.com>
Cc: Will Deacon <will@kernel.org>,
Dan Williams <dan.j.williams@intel.com>,
rafael@kernel.org, Diana Craciun <diana.craciun@oss.nxp.com>,
Cornelia Huck <cohuck@redhat.com>,
Eric Auger <eric.auger@redhat.com>, Liu Yi L <yi.l.liu@intel.com>,
Jacob jun Pan <jacob.jun.pan@intel.com>,
Chaitanya Kulkarni <kch@nvidia.com>,
Stuart Yoder <stuyoder@gmail.com>,
Laurentiu Tudor <laurentiu.tudor@nxp.com>,
Thierry Reding <thierry.reding@gmail.com>,
David Airlie <airlied@linux.ie>, Daniel Vetter <daniel@ffwll.ch>,
Jonathan Hunter <jonathanh@nvidia.com>,
Li Yang <leoyang.li@nxp.com>, Dmitry Osipenko <digetx@gmail.com>,
iommu@lists.linux-foundation.org, linux-pci@vger.kernel.org,
kvm@vger.kernel.org, linux-kernel@vger.kernel.org
Subject: Re: [PATCH v8 04/11] bus: platform,amba,fsl-mc,PCI: Add device DMA ownership management
Date: Tue, 8 Mar 2022 13:39:51 +0000 [thread overview]
Message-ID: <400b2dd3-120b-9728-3990-801b53447a2b@arm.com> (raw)
In-Reply-To: <20220308054421.847385-5-baolu.lu@linux.intel.com>
On 2022-03-08 05:44, Lu Baolu wrote:
> The devices on platform/amba/fsl-mc/PCI buses could be bound to drivers
> with the device DMA managed by kernel drivers or user-space applications.
> Unfortunately, multiple devices may be placed in the same IOMMU group
> because they cannot be isolated from each other. The DMA on these devices
> must either be entirely under kernel control or userspace control, never
> a mixture. Otherwise the driver integrity is not guaranteed because they
> could access each other through the peer-to-peer accesses which by-pass
> the IOMMU protection.
>
> This checks and sets the default DMA mode during driver binding, and
> cleanups during driver unbinding. In the default mode, the device DMA is
> managed by the device driver which handles DMA operations through the
> kernel DMA APIs (see Documentation/core-api/dma-api.rst).
>
> For cases where the devices are assigned for userspace control through the
> userspace driver framework(i.e. VFIO), the drivers(for example, vfio_pci/
> vfio_platfrom etc.) may set a new flag (driver_managed_dma) to skip this
> default setting in the assumption that the drivers know what they are
> doing with the device DMA.
>
> Calling iommu_device_use_default_domain() before {of,acpi}_dma_configure
> is currently a problem. As things stand, the IOMMU driver ignored the
> initial iommu_probe_device() call when the device was added, since at
> that point it had no fwspec yet. In this situation,
> {of,acpi}_iommu_configure() are retriggering iommu_probe_device() after
> the IOMMU driver has seen the firmware data via .of_xlate to learn that
> it actually responsible for the given device. As the result, before
> that gets fixed, iommu_use_default_domain() goes at the end, and calls
> arch_teardown_dma_ops() if it fails.
>
> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Cc: Bjorn Helgaas <bhelgaas@google.com>
> Cc: Stuart Yoder <stuyoder@gmail.com>
> Cc: Laurentiu Tudor <laurentiu.tudor@nxp.com>
> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
> Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
> Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Reviewed-by: Robin Murphy <robin.murphy@arm.com>
next prev parent reply other threads:[~2022-03-08 13:40 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2022-03-08 5:44 [PATCH v8 00/11] Fix BUG_ON in vfio_iommu_group_notifier() Lu Baolu
2022-03-08 5:44 ` [PATCH v8 01/11] iommu: Add DMA ownership management interfaces Lu Baolu
2022-03-08 13:37 ` Robin Murphy
2022-03-08 5:44 ` [PATCH v8 02/11] driver core: Add dma_cleanup callback in bus_type Lu Baolu
2022-03-08 5:44 ` [PATCH v8 03/11] amba: Stop sharing platform_dma_configure() Lu Baolu
2022-03-08 5:44 ` [PATCH v8 04/11] bus: platform,amba,fsl-mc,PCI: Add device DMA ownership management Lu Baolu
2022-03-08 13:39 ` Robin Murphy [this message]
2022-03-08 5:44 ` [PATCH v8 05/11] PCI: pci_stub: Set driver_managed_dma Lu Baolu
2022-03-08 5:44 ` [PATCH v8 06/11] PCI: portdrv: " Lu Baolu
2022-03-08 5:44 ` [PATCH v8 07/11] vfio: Set DMA ownership for VFIO devices Lu Baolu
2022-03-08 5:44 ` [PATCH v8 08/11] vfio: Remove use of vfio_group_viable() Lu Baolu
2022-03-08 5:44 ` [PATCH v8 09/11] vfio: Delete the unbound_list Lu Baolu
2022-03-08 5:44 ` [PATCH v8 10/11] vfio: Remove iommu group notifier Lu Baolu
2022-03-08 5:44 ` [PATCH v8 11/11] iommu: Remove iommu group changes notifier Lu Baolu
2022-03-10 9:46 ` [PATCH v8 00/11] Fix BUG_ON in vfio_iommu_group_notifier() Eric Auger
2022-03-15 0:21 ` Jason Gunthorpe
2022-04-08 7:57 ` Joerg Roedel
2022-04-08 12:22 ` Lu Baolu
2022-04-08 12:23 ` Jason Gunthorpe
2022-04-08 14:00 ` Joerg Roedel
2022-04-08 14:17 ` Jason Gunthorpe
2022-04-08 15:37 ` Joerg Roedel
2022-04-08 15:59 ` Bjorn Helgaas
2022-04-08 16:07 ` Alex Williamson
2022-04-08 20:24 ` Jason Gunthorpe
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