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authorAlex Williamson <alex.williamson@redhat.com>2018-07-12 16:33:04 -0600
committerAlex Williamson <alex.williamson@redhat.com>2018-08-06 12:23:19 -0600
commit0dd0e297f0ec780b6b3484ba38b27d18c8ca7af9 (patch)
tree7ca25cc8284c0a53355f710582cc3b66f2f1905a /drivers/vfio
parent544c05a60aef7de34ef60eebaf46582ca2bf05f9 (diff)
downloadlinux-0dd0e297f0ec780b6b3484ba38b27d18c8ca7af9.tar.bz2
vfio-pci: Disable binding to PFs with SR-IOV enabled
We expect to receive PFs with SR-IOV disabled, however some host drivers leave SR-IOV enabled at unbind. This puts us in a state where we can potentially assign both the PF and the VF, leading to both functionality as well as security concerns due to lack of managing the SR-IOV state as well as vendor dependent isolation from the PF to VF. If we were to attempt to actively disable SR-IOV on driver probe, we risk VF bound drivers blocking, potentially risking live lock scenarios. Therefore simply refuse to bind to PFs with SR-IOV enabled with a warning message indicating the issue. Users can resolve this by re-binding to the host driver and disabling SR-IOV before attempting to use the device with vfio-pci. Reviewed-by: David Gibson <david@gibson.dropbear.id.au> Reviewed-by: Peter Xu <peterx@redhat.com> Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Diffstat (limited to 'drivers/vfio')
-rw-r--r--drivers/vfio/pci/vfio_pci.c13
1 files changed, 13 insertions, 0 deletions
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c
index 7fe2748ba101..9979d3ba9e52 100644
--- a/drivers/vfio/pci/vfio_pci.c
+++ b/drivers/vfio/pci/vfio_pci.c
@@ -1193,6 +1193,19 @@ static int vfio_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)
if (pdev->hdr_type != PCI_HEADER_TYPE_NORMAL)
return -EINVAL;
+ /*
+ * Prevent binding to PFs with VFs enabled, this too easily allows
+ * userspace instance with VFs and PFs from the same device, which
+ * cannot work. Disabling SR-IOV here would initiate removing the
+ * VFs, which would unbind the driver, which is prone to blocking
+ * if that VF is also in use by vfio-pci. Just reject these PFs
+ * and let the user sort it out.
+ */
+ if (pci_num_vf(pdev)) {
+ pci_warn(pdev, "Cannot bind to PF with SR-IOV enabled\n");
+ return -EBUSY;
+ }
+
group = vfio_iommu_group_get(&pdev->dev);
if (!group)
return -EINVAL;