Add pcirebind extension

[mwdomino]

The pcirebind extension is a simple helper that attempts to rebind the drivers of a given PCI Bus ID during the boot process using a writable sysfs.

This is done by passing kernel args like:

machine:
  install:
    extensions:
      extraKernelArgs:
        - pcirebind.rebind=0000:04:00.00_ixgbe+vfio-pci

The above kernel args would generate actions similar to:

echo "vfio-pci" > /sys/bus/pci/devices/0000:04:00.0/driver_override
echo "0000:04:00.0" > /sys/bus/pci/drivers/ixgbe/unbind
echo "0000:04:00.0" > /sys/bus/pci/drivers/vfio-pci/bind

We're currently using this internally to rebind some NICs to use vfio-pci so that we can utilize them for VPP.

Let me know if you all have any questions, suggestions, or additions you'd like me to make on this!

[mwdomino]

I'm not sure what any of those CI errors mean so just let me know if I need to make any changes to placate the bots :)

[frezbo]

this could probably use go-procfs from here: https://github.com/siderolabs/go-procfs

[frezbo]

@smira i wonder if this needs to be an extension or core talos? 🤔

[smira]

yes, I almost wonder if that should be actually a controller, and operate on a proper machine config document

[smira]

I wonder if that should be a Talos controller which accepts the configuration like:

kind: PCIRebindConfig
apiVersion: v1alpha1
name: 0000:04:00.00
drivers:
  old: ixgbe
  new: vfio-pci