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Commit 5f096b14 authored by Alex Williamson's avatar Alex Williamson
Browse files

vfio: Whitelist PCI bridges 



When determining whether a group is viable, we already allow devices
bound to pcieport.  Generalize this to include any PCI bridge device.

Signed-off-by: default avatarAlex Williamson <alex.williamson@redhat.com>
parent 32b88194

drivers/vfio/vfio.c

+25 −6
Original line number Diff line number Diff line
@@ -25,6 +25,7 @@ 
#include <linux/miscdevice.h>

#include <linux/module.h>

#include <linux/mutex.h>

#include <linux/pci.h>

#include <linux/rwsem.h>

#include <linux/sched.h>

#include <linux/slab.h>
@@ -438,16 +439,33 @@ static struct vfio_device *vfio_group_get_device(struct vfio_group *group, 
}



/*

 * Whitelist some drivers that we know are safe (no dma) or just sit on

 * a device.  It's not always practical to leave a device within a group

 * driverless as it could get re-bound to something unsafe.

 * Some drivers, like pci-stub, are only used to prevent other drivers from

 * claiming a device and are therefore perfectly legitimate for a user owned

 * group.  The pci-stub driver has no dependencies on DMA or the IOVA mapping

 * of the device, but it does prevent the user from having direct access to

 * the device, which is useful in some circumstances.

 *

 * We also assume that we can include PCI interconnect devices, ie. bridges.

 * IOMMU grouping on PCI necessitates that if we lack isolation on a bridge

 * then all of the downstream devices will be part of the same IOMMU group as

 * the bridge.  Thus, if placing the bridge into the user owned IOVA space

 * breaks anything, it only does so for user owned devices downstream.  Note

 * that error notification via MSI can be affected for platforms that handle

 * MSI within the same IOVA space as DMA.

 */

static const char * const vfio_driver_whitelist[] = { "pci-stub", "pcieport" };

static const char * const vfio_driver_whitelist[] = { "pci-stub" };



static bool vfio_whitelisted_driver(struct device_driver *drv)

static bool vfio_dev_whitelisted(struct device *dev, struct device_driver *drv)

{

	int i;



	if (dev_is_pci(dev)) {

		struct pci_dev *pdev = to_pci_dev(dev);



		if (pdev->hdr_type != PCI_HEADER_TYPE_NORMAL)

			return true;

	}



	for (i = 0; i < ARRAY_SIZE(vfio_driver_whitelist); i++) {

		if (!strcmp(drv->name, vfio_driver_whitelist[i]))

			return true;
@@ -462,6 +480,7 @@ static bool vfio_whitelisted_driver(struct device_driver *drv) 
 *  - driver-less

 *  - bound to a vfio driver

 *  - bound to a whitelisted driver

 *  - a PCI interconnect device

 *

 * We use two methods to determine whether a device is bound to a vfio

 * driver.  The first is to test whether the device exists in the vfio
@@ -486,7 +505,7 @@ static int vfio_dev_viable(struct device *dev, void *data) 
	}

	mutex_unlock(&group->unbound_lock);



	if (!ret || !drv || vfio_whitelisted_driver(drv))

	if (!ret || !drv || vfio_dev_whitelisted(dev, drv))

		return 0;



	device = vfio_group_get_device(group, dev);