70693f4708
Claim group dma ownership when an IOMMU group is set to a container,
and release the dma ownership once the iommu group is unset from the
container.
This change disallows some unsafe bridge drivers to bind to non-ACS
bridges while devices under them are assigned to user space. This is an
intentional enhancement and possibly breaks some existing
configurations. The recommendation to such an affected user would be
that the previously allowed host bridge driver was unsafe for this use
case and to continue to enable assignment of devices within that group,
the driver should be unbound from the bridge device or replaced with the
pci-stub driver.
For any bridge driver, we consider it unsafe if it satisfies any of the
following conditions:
1) The bridge driver uses DMA. Calling pci_set_master() or calling any
kernel DMA API (dma_map_*() and etc.) is an indicate that the
driver is doing DMA.
2) If the bridge driver uses MMIO, it should be tolerant to hostile
userspace also touching the same MMIO registers via P2P DMA
attacks.
If the bridge driver turns out to be a safe one, it could be used as
before by setting the driver's .driver_managed_dma field, just like what
we have done in the pcieport driver.
Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
Reviewed-by: Jason Gunthorpe <jgg@nvidia.com>
Acked-by: Alex Williamson <alex.williamson@redhat.com>
Link: https://lore.kernel.org/r/20220418005000.897664-8-baolu.lu@linux.intel.com
Signed-off-by: Joerg Roedel <jroedel@suse.de>
88 lines
2.2 KiB
C
88 lines
2.2 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* Copyright (C) 2013 - Virtual Open Systems
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* Author: Antonios Motakis <a.motakis@virtualopensystems.com>
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*/
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#include <linux/module.h>
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#include <linux/slab.h>
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#include <linux/vfio.h>
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#include <linux/platform_device.h>
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#include "vfio_platform_private.h"
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#define DRIVER_VERSION "0.10"
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#define DRIVER_AUTHOR "Antonios Motakis <a.motakis@virtualopensystems.com>"
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#define DRIVER_DESC "VFIO for platform devices - User Level meta-driver"
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static bool reset_required = true;
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module_param(reset_required, bool, 0444);
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MODULE_PARM_DESC(reset_required, "override reset requirement (default: 1)");
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/* probing devices from the linux platform bus */
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static struct resource *get_platform_resource(struct vfio_platform_device *vdev,
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int num)
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{
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struct platform_device *dev = (struct platform_device *) vdev->opaque;
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return platform_get_mem_or_io(dev, num);
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}
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static int get_platform_irq(struct vfio_platform_device *vdev, int i)
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{
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struct platform_device *pdev = (struct platform_device *) vdev->opaque;
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return platform_get_irq_optional(pdev, i);
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}
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static int vfio_platform_probe(struct platform_device *pdev)
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{
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struct vfio_platform_device *vdev;
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int ret;
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vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
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if (!vdev)
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return -ENOMEM;
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vdev->opaque = (void *) pdev;
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vdev->name = pdev->name;
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vdev->flags = VFIO_DEVICE_FLAGS_PLATFORM;
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vdev->get_resource = get_platform_resource;
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vdev->get_irq = get_platform_irq;
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vdev->reset_required = reset_required;
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ret = vfio_platform_probe_common(vdev, &pdev->dev);
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if (ret) {
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kfree(vdev);
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return ret;
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}
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dev_set_drvdata(&pdev->dev, vdev);
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return 0;
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}
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static int vfio_platform_remove(struct platform_device *pdev)
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{
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struct vfio_platform_device *vdev = dev_get_drvdata(&pdev->dev);
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vfio_platform_remove_common(vdev);
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kfree(vdev);
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return 0;
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}
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static struct platform_driver vfio_platform_driver = {
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.probe = vfio_platform_probe,
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.remove = vfio_platform_remove,
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.driver = {
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.name = "vfio-platform",
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},
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.driver_managed_dma = true,
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};
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module_platform_driver(vfio_platform_driver);
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MODULE_VERSION(DRIVER_VERSION);
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MODULE_LICENSE("GPL v2");
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MODULE_AUTHOR(DRIVER_AUTHOR);
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MODULE_DESCRIPTION(DRIVER_DESC);
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