- A Host devices tab on the VM page lists the VM's USB host devices, each
once: how it is chosen (its address, or any device of its model), the
device the running VM holds and whether its next start has it; its other
host devices (PCI, SCSI, mediated) are listed for the XML editor.
- Superusers add a USB device of the host and take it back, on a running
VM too. The add form is loaded when the tab opens, as its choices read
every VM of the host; a hub, a device the host has its own disks or
network interfaces on, or one another VM names is not offered, with the
reason, and refused on the server under the compute's claim. A device is
chosen by model when the host has one of it, else by its address.
- A VM without a USB controller is refused; a device is taken from each
definition as that definition describes it.
- A clone gets none of the VM's host devices (the clone form says so), and
a VM with host devices is not migrated. A snapshot revert is refused when
it would give the VM a device another VM names or the host uses.
- A NIC that is a host device is no longer edited or removed from the
Network tab: the XML editor changes it.
- A Devices section of each host lists its PCI devices by IOMMU group and
its USB devices: what each is (vendor, product, IDs, class, driver), what
the host itself has on it (its network interfaces, disks and graphics
card, anywhere below it) and the VMs whose definitions name it.
- A VM names a PCI device by its address, a USB device by its address or
by its model only; a VM that names a model only is shown on every device
of that model, which one it takes is known only when it starts.
- A host without IOMMU groups says that no PCI device can be given to a VM
and how to turn the IOMMU on.
- One listing of the host's node devices, one XML read each (a device gone
meanwhile is left out), and the VMs' definitions read once; nothing is
shown when they cannot be read, as a device would look free.
- Read only: giving devices to VMs comes in the next layers.
