CCW device specifications for virtio devices

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On z/Architecture®, virtual servers access virtio devices as virtual channel subsystem (CCW) devices. Virtual CCW devices have common specifications in the device configuration.

Virtual servers access virtual CCW devices through a virtual channel subsystem, with channel subsystem-ID 0x00. In device configurations, this channel subsystem is specified through the reserved channel subsystem-ID 0xfe.

Virtual CCW devices are all of channel path type 0x32 and virtual control unit type 0x3832. Device types for virtio devices are specified as control unit models as listed in Table 1.

Table 1. Device types and models in the virtual channel subsystem
Device Device type
Virtual channel subsystem-ID 0x00
Virtual channel path type 0x32
Virtual control unit type 0x3832
Virtual control unit model for:  
  • Network (virtio-net) devices
 0x01
  • Block (virtio-block) devices
 0x02
  • Serial devices

    For z/Architecture, this device type is not well suited for a console device. The preferred option is an SCLP based console.

 0x03
  • Random number generators (RNGs)

    Do not configure a virtual random number generator for a virtual server, unless the host is equipped with a hardware random number generator, such as the secure IBM® CCA coprocessor of a Crypto Express adapter.

 0x04
  • Balloon devices

    This device can be suppressed in the configuration of the virtual server

 0x05
  • SCSI Host Bus Adapter (virtio-scsi)
 0x08
  • Virtual graphic card, GPU (virtio-gpu)
 0x10
  • Virtual human input interface (virtio-input)
 0x12
  • Device for communication with the host (virtio-vsock)
 0x13