Assigning and removing devices of a VM

Once a VM is initialized, individual peripheral devices can be assigned to it.

This section examines individual devices. Information on pubset devices is provided in the section "Assigning and removing pubsets of a VM".

Devices can be assigned to the VMs and thus to the guest systems:

• by the VM2000 or VM administrator using ADMIN-PRIVILEGES=*MAX (explicit assignment, see "Explicit device assignment and removal")

• by a guest system whose VM has the privilege ASSIGN-BY-GUEST=*YES for the relevant assignment set to which the device is assigned (implicit assignment, see "Assignment sets, implicit device assignment and release")

In the case of explicit device assignment, the VM2000 or VM administrator specifies a VM’s set of devices. Implicit device assignment permits guest system operators to provide the required (free) devices themselves without having to call on an administrator. Both types of device assignment can be used in parallel.

The monitor VM must already have been assigned the devices required for the startup before the monitor system is started up.

	For SU /390 this is implemented in the configuration file for the monitor VM
	For SU x86 this is implemented via the SE manager (startup settings for the monitor VM)

Devices can be released from the VMs and the guest systems

• by the VM2000 or VM administrator (explicit removal using /REMOVE-VM-DEVICES or /SWITCH-VM-DEVICES, see "Explicit device assignment and removal"

• by a guest system (implicit release of implicitly assigned devices using BS2000 command /DETACH-DEVICE, see "Assignment sets, implicit device assignment and release"

Device name

Each device is referred to in the VM2000 commands by its mnemonic device name, analogously to the BS2000 operating system. The mnemonic device name can be 2-digit (alphanumeric) or 4-digit (hexadecimal).

Access to a device

A guest system cannot access a device until the device is assigned to the VM (implicitly, explicitly, see above) and attached in the guest system (see "Explicit device assignment and removal").

Accounting for devices

The use of devices is displayed in the VM2000 accounting record for devices (see "Accounting record for devices").