VMT(4) | Device Drivers Manual (x86) | VMT(4)

# NAME

`vmt` —
VMware Tools driver

# SYNOPSIS

`vmt0 at cpu0`
`vmt0 at fdt?`

# 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 10.1