feat: add pcieroot as a device attribute

[michaelasp]

kubernetes/enhancements#5316 provides a standardized device attribute for pcieroot. Use that definition. Fixes #111

[michaelasp]

/cc @aojea

[aojea]

have you validate this is the correct format expected by all drivers?

[michaelasp]

I'm using the definition from the kep, although I realized I used the wrong values in the sprintf. Good catch!

 1. `resource.kubernetes.io/pcieRoot`: A string value in the format
//     `pci<domain>:<bus>`, referring to a PCIe (Peripheral Component
//     Interconnect Express) Root Complex. This attribute can be used to
//     identify devices that share the same PCIe Root Complex. DRA drivers MAY
//     determine this value by inspecting the hierarchical path of the device's
//     entry in sysfs (e.g., `/sys/devices/pci0000:00/0000:00:01.0/0000:01:00.0`),
//     where the `pci<domain>:<bus>` segment at the beginning of the real path
//     identifies the Root Complex (e.g., `pci0000:00`).

[michaelasp]

Based on discussion in kubernetes/kubernetes#132296 this needs some update because the root pci device may have a different hub than the device itself.

[michaelasp]

Updated, PTAL again whenever you have a chance!

[michaelasp]

I'm using the definition from the kep, although I realized I used the wrong values in the sprintf. Good catch!

 1. `resource.kubernetes.io/pcieRoot`: A string value in the format
//     `pci<domain>:<bus>`, referring to a PCIe (Peripheral Component
//     Interconnect Express) Root Complex. This attribute can be used to
//     identify devices that share the same PCIe Root Complex. DRA drivers MAY
//     determine this value by inspecting the hierarchical path of the device's
//     entry in sysfs (e.g., `/sys/devices/pci0000:00/0000:00:01.0/0000:01:00.0`),
//     where the `pci<domain>:<bus>` segment at the beginning of the real path
//     identifies the Root Complex (e.g., `pci0000:00`).

[michaelasp]

Based on discussion in kubernetes/kubernetes#132296 this needs some update because the root pci device may have a different hub than the device itself.

[michaelasp]

Tested locally, looks like it's working as expected:

      name: eth3
    - basic:
        attributes:
          ...
          dra.net/pciAddressBus:
            string: "08"
          dra.net/pciAddressDevice:
            string: "00"
          dra.net/pciAddressDomain:
            string: "0000"
          dra.net/pciAddressFunction:
            string: "0"
          dra.net/pciVendor:
            string: Google, Inc.
          dra.net/rdma:
            bool: false
          dra.net/sriov:
            bool: false
          dra.net/state:
            string: up
          dra.net/tcxProgramNames:
            string: ""
          dra.net/type:
            string: device
          dra.net/virtual:
            bool: false
          gce.dra.net/networkName:
            string: maspinwall-test-dra-net-net-4
          gce.dra.net/networkProjectNumber:
            int: 455207029971
          resource.kubernetes.io/pcieRoot:
            string: pci0000:08

[aojea]

@gauravkghildiyal please review and once you LGTM I merge

[aojea]

We know need to document how to use this with an example