Node devices XML format

Node Device XML

There are several libvirt functions, all with the prefix virNodeDevice, which deal with management of host devices that can be handed to guests via passthrough as <hostdev> elements in the domain XML. These devices are represented as a hierarchy, where a device on a bus has a parent of the bus controller device; the root of the hierarchy is the node named "computer".

When represented in XML, a node device uses the top-level device element, with the following elements present according to the type of device:

name

The name for this device. The name will be alphanumeric, with words separated by underscore. For many devices, the name is just the bus type and address, as in "pci_0000_00_02_1" or "usb_1_5_3", but some devices are able to provide more specific names, such as "net_eth1_00_27_13_6a_fe_00".

parent

If this element is present, it names the parent device (that is, a controller to which this node belongs).

capability

This node appears for each capability that libvirt associates with a node. A mandatory attribute type lists which category the device belongs to, and controls which further subelements will be present to describe the node:

system

Describes the overall host. Sub-elements include:

product: If present, a simple text string giving the product name of the system.
hardware: Describes the hardware of the system, including sub-elements for vendor, version, serial, and uuid.
firmware: Describes the firmware of the system, including sub-elements for vendor, version, and release_date.

pci

Describes a device on the host's PCI bus. Sub-elements include:

domain: Which domain the device belongs to.
bus: Which bus within the domain.
slot: Which slot within the bus.
function: Which function within the slot.
product: Product details from the device ROM, including an attribute id with the hexadecimal product id, and an optional text description of that id.
vendor: Vendor details from the device ROM, including an attribute id with the hexadecimal vendor id, and an optional text name of that vendor.

usb_device

Describes a device on the host's USB bus, based on its location within the bus. Sub-elements include:

bus: Which bus the device belongs to.
device: Which device within the bus.
product: Product details from the device ROM, including an attribute id with the hexadecimal product id, and an optional text description of that id.
vendor: Vendor details from the device ROM, including an attribute id with the hexadecimal vendor id, and an optional text name of that vendor.

usb

Describes a USB device, based on its advertised driver interface. Sub-elements include:

number: The device number.
number: The device class.
number: The device subclass.
number: The device protocol.
description: If present, a description of the device.

net

Describes a device capable for use as a network interface. Sub-elements include:

interface: The interface name tied to this device.
address: If present, the MAC address of the device.
capability: A network protocol exposed by the device, where the attribute type can be "80203" for IEEE 802.3, or "80211" for various flavors of IEEE 802.11.

scsi_host

Describes a SCSI host device. Sub-elements include:

host: The SCSI host number.
capability: Current capabilities include "vports_ops" (indicates vport operations are supported) and "fc_host", the later implies following sub-elements: wwnn, wwpn, fabric_wwn.

scsi

Desribes a SCSI device. Sub-elements include:

host: The SCSI host containing the device.
bus: The bus within the host.
target: The target within the bus.
lun: The lun within the target.
type: The type of SCSI device.

storage

Describes a device usable for storage. Sub-elements include:

block: A block device file name that accesses the storage present on the device.
bus: If present, the name of the bus the device is found on.
drive_type: The type of the drive, such as "disk" or "cdrom".
model: Any model information available from the device.
vendor: Any vendor information available from the device.
serial: Any serial number information available from the device.
size: For fixed-size storage, the amount of storage available.
capability: If present, an additional capability is listed via the attribute type. Current capabilites include "hotpluggable" and "removable", with the latter implying the following sub-elements: media_available (0 or 1), media_size, and media_label.

Examples

The following are some example node device XML outputs:

<device>
  <name>computer</name>
  <capability type='system'>
    <product>2241B36</product>
    <hardware>
      <vendor>LENOVO</vendor>
      <version>ThinkPad T500</version>
      <serial>R89055N</serial>
      <uuid>c9488981-5049-11cb-9c1c-993d0230b4cd</uuid>
    </hardware>
    <firmware>
      <vendor>LENOVO</vendor>
      <version>6FET82WW (3.12 )</version>
      <release_date>11/26/2009</release_date>
    </firmware>
  </capability>
</device>

<device>
  <name>net_eth1_00_27_13_6a_fe_00</name>
  <parent>pci_0000_00_19_0</parent>
  <capability type='net'>
    <interface>eth1</interface>
    <address>00:27:13:6a:fe:00</address>
    <capability type='80203'/>
  </capability>
</device>