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vfio: Whitelist PCI bridges

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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: Alex Williamson <alex.williamson@redhat.com>
This commit is contained in:
Alex Williamson 2015-10-27 14:53:04 -06:00
parent 32b88194f7
commit 5f096b14d4
1 changed files with 25 additions and 6 deletions
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31
drivers/vfio/vfio.c
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@ -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);