1ef3342a93
get_pf_vdev() tries to check if a PF is a VFIO PF by looking at the driver:
if (pci_dev_driver(physfn) != pci_dev_driver(vdev->pdev)) {
However now that we have multiple VF and PF drivers this is no longer
reliable.
This means that security tests realted to vf_token can be skipped by
mixing and matching different VFIO PCI drivers.
Instead of trying to use the driver core to find the PF devices maintain a
linked list of all PF vfio_pci_core_device's that we have called
pci_enable_sriov() on.
When registering a VF just search the list to see if the PF is present and
record the match permanently in the struct. PCI core locking prevents a PF
from passing pci_disable_sriov() while VF drivers are attached so the VFIO
owned PF becomes a static property of the VF.
In common cases where vfio does not own the PF the global list remains
empty and the VF's pointer is statically NULL.
This also fixes a lockdep splat from recursive locking of the
vfio_group::device_lock between vfio_device_get_from_name() and
vfio_device_get_from_dev(). If the VF and PF share the same group this
would deadlock.
Fixes: ff53edf6d6ab ("vfio/pci: Split the pci_driver code out of vfio_pci_core.c")
Signed-off-by: Jason Gunthorpe <jgg@nvidia.com>
Link: https://lore.kernel.org/r/0-v3-876570980634+f2e8-vfio_vf_token_jgg@nvidia.com
Signed-off-by: Alex Williamson <alex.williamson@redhat.com>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.