[PATCH 0/2] rust: pci: expose is_virtfn() and reject VFs in nova-core

[John Hubbard <jhubbard@nvidia.com>]

Post-Kangrejos, the approach for NovaCore + VFIO has changed a bit: the
idea now is that VFIO drivers, for NVIDIA GPUs that are supported by
NovaCore, should bind directly to the GPU's VFs. (An earlier idea was to
let NovaCore bind to the VFs, and then have NovaCore call into the upper
(VFIO) module via Aux Bus, but this turns out to be awkward and is no
longer in favor.) So, in order to support that:

Nova-core must only bind to Physical Functions (PFs) and regular PCI
devices, not to Virtual Functions (VFs) created through SR-IOV.

Add a method to check if a PCI device is a Virtual Function (VF). This
allows Rust drivers to determine whether a device is a VF created
through SR-IOV. This is required in order to implement VFIO, because
drivers such as NovaCore must only bind to Physical Functions (PFs) or
regular PCI devices. The VFs must be left unclaimed, so that a VFIO
kernel module can claim them.

Use is_virtfn() in NovaCore, in preparation for it to be used in a VFIO
scenario.

I've based this on top of today's driver-core-next [1], because the
first patch belongs there, and the second patch applies cleanly to either
driver-core-next or drm-rust-next. So this seems like the easiest to
work with.


[1] https://git.kernel.org/pub/scm/linux/kernel/git/driver-core/driver-core.git/

John Hubbard (2):
  rust: pci: add is_virtfn(), to check for VFs
  gpu: nova-core: reject binding to SR-IOV Virtual Functions

 drivers/gpu/nova-core/driver.rs | 5 +++++
 rust/kernel/pci.rs              | 6 ++++++
 2 files changed, 11 insertions(+)


base-commit: 6d97171ac6585de698df019b0bfea3f123fd8385
-- 
2.51.0