VMT(4) (x86)

VMT(4) | Kernel Interfaces Manual (x86) | VMT(4)

# NAME

vmt — VMware Tools driver

# SYNOPSIS

vmt0 at cpu0

# DESCRIPTION

The vmt driver is a kernel level implementation of VMware Tools. VMware Tools are intended to provide better support for operating systems running inside virtual machines.

vmt handles shutdown, reboot, resume requests from the host by sending events using sysmon_pswitch(9) of type PSWITCH_TYPE_POWER, PSWITCH_TYPE_RESET, and PSWITCH_TYPE_SLEEP that can be handled by powerd(8). vmt will log notifications that the guest has been suspended or resumed by the host.

vmt reports the guest's hostname and first non-loopback IP address to the host.

## Clock synchronization

The vmt driver synchronizes the virtual machine's clock with the host clock in the following situations:

- When the virtual machine resumes after having been suspended.
- Periodically with the interval indicated by the machdep.vmt0.clock_sync.period sysctl(8) variable. This is done so that the virtual machine can keep its clock synchronized when the host is suspended, because in this case the vmt driver receives no notification of such an event. Setting this tunable to zero disables clock synchronization.

# SEE ALSO

powerd(8)

# HISTORY

The vmt driver first appeared in OpenBSD 4.4 and was then ported to NetBSD 6.0.

# AUTHORS

The vmt driver was written by David Gwynne <dlg@openbsd.org>.

October 6, 2013 | NetBSD 7.0