The virtual channel subsystem
The KVM hypervisor provides a virtual channel subsystem (CSS) to its guests.
This virtual channel subsystem connects paravirtualized 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 the
same 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.