The virtual channel subsystem
The KVM hypervisor provides a virtual channel
subsystem (CSS) with a subchannel, CHPID 00, for
paravirtualized CCW devices.
This virtual channel subsystem connects paravirtualized CCW devices and pass-through CCW devices
to the virtual server. In the virtual channel subsystem:
- All paravirtualized CCW devices have control unit type
3832/<nn>, where <nn> is a two-digit hexadecimal number that indicates the device type. - All paravirtualized CCW devices use a single virtual channel path with CHPID
00. The availability of all paravirtualized CCW devices depends on this channel path being operational.
For general information about the channel subsystem, see z/Architecture® Principles of Operation, SA22-7832.