| Message ID | 20180712223243.9593.24855.stgit@gimli.home (mailing list archive) |
|---|---|
| State | New, archived |
| Delegated to: | Bjorn Helgaas |
| Headers | show |
On Thu, Jul 12, 2018 at 04:33:04PM -0600, Alex Williamson wrote: > 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. > > Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Reviewed-by: David Gibson <david@gibson.dropbear.id.au> > --- > drivers/vfio/pci/vfio_pci.c | 13 +++++++++++++ > 1 file changed, 13 insertions(+) > > diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c > index b423a309a6e0..f372f209c5c2 100644 > --- a/drivers/vfio/pci/vfio_pci.c > +++ b/drivers/vfio/pci/vfio_pci.c > @@ -1189,6 +1189,19 @@ 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; >
On Thu, Jul 12, 2018 at 04:33:04PM -0600, Alex Williamson wrote: > 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. > > Signed-off-by: Alex Williamson <alex.williamson@redhat.com> Reviewed-by: Peter Xu <peterx@redhat.com>
diff --git a/drivers/vfio/pci/vfio_pci.c b/drivers/vfio/pci/vfio_pci.c index b423a309a6e0..f372f209c5c2 100644 --- a/drivers/vfio/pci/vfio_pci.c +++ b/drivers/vfio/pci/vfio_pci.c @@ -1189,6 +1189,19 @@ 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;
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. Signed-off-by: Alex Williamson <alex.williamson@redhat.com> --- drivers/vfio/pci/vfio_pci.c | 13 +++++++++++++ 1 file changed, 13 insertions(+)