def _get_sysfs_netdev_path(pci_addr, pf_interface):
    """Get the sysfs path based on the PCI address of the device.

    Assumes a networking device - will not check for the existence of the path.
    """
    if pf_interface:
        return '/sys/bus/pci/devices/%s/physfn/net' % pci_addr
    return '/sys/bus/pci/devices/%s/net' % pci_addr
