| XENBUS(4) | Device Drivers Manual (xen) | XENBUS(4) | 
xenbus —
xenbus* at hypervisor?
xenbus interface offers an abstraction layer used
  for communications between domains. xenbus is mainly
  used by split paravirtualized drivers, so backend and frontend devices can
  exchange configuration information, properties, and statistics.
xenbus is not used for data transfer
    (network frames, blocks, PCI commands, ...). This functionality is
    implemented by each paravirtualized driver independently, typically via
    shared memory pages and an event channel that serves as a virtual interrupt,
    for signaling.
The xenbus abstraction offers guests the
    possibility to read and write information directly from and to XenStore, a
    centralized database accessible to all domains. For this reason, it also has
    an event channel associated to it, so that domains can post messages to the
    XenStore facility.
xenbus
      interface, for communication with the XenStore database.xenbus driver first appeared in
  NetBSD 3.0.
xenbus driver was written by Manuel
  Bouyer
  <bouyer@NetBSD.org>.
| January 8, 2011 | NetBSD 9.4 |