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authorAlex Williamson <alex.williamson@redhat.com>2015-10-27 14:53:04 -0600
committerAlex Williamson <alex.williamson@redhat.com>2015-10-27 14:53:04 -0600
commit5f096b14d421ba23249b752e41989ecfaa6ae226 (patch)
tree6fdfa589dc0888699202d9545779b52fab71a976 /drivers/vfio
parent32b88194f71d6ae7768a29f87fbba454728273ee (diff)
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: Alex Williamson <alex.williamson@redhat.com>
Diffstat (limited to 'drivers/vfio')
-rw-r--r--drivers/vfio/vfio.c31
1 files changed, 25 insertions, 6 deletions
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 563c510f285c..1c0f98c2f634 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -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);