[PATCH v2 1/2] timekeeping: add EXPORT_SYMBOL_GPL for do_adjtimex()

Jeff Epler jepler at unpythonic.net
Tue Oct 21 04:02:13 UTC 2014

On Tue, Oct 21, 2014 at 03:18:58AM +0000, Thomas Shao wrote:
> In some situation, the user is not able to enable guest VM to sync with external 
> time source, like NTP. But the host is still synced with a trusted time source. 
> In this case, host-guest time synchronization is useful.

It's interesting to imagine that a virtualization host could present a
time service to the guest *userspace*, even when the guest is not
otherwise exposed to the internet at large.  This could take the form of
an NTP server on a private network, or as an implementation of a time
source directly usable by ntpd in the guest, for instance as an emulated
serial port with synthetic NEMA GPS signal + PPS signal, for instance.

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