[Qemu-devel] Missing guest clock-sync on Host clock change

[Erik Rull <erik.rull@rdsoftware.de>]

Hi all,

I would like to have the guest "drifting" to a new set clock on the host.

My problem is the following:

- Host System (Linux) starts up, hwclock and kernel time are synced, guest 
starts up with -rtc clock=host,driftfix=slew (which I assume should fix any 
drift issue on ACPI compatible guest OSes)
- Host System kernel time drifts against the hwclock (jiffies timer due to 
no other available useful timer on SMP systems - core2duo has no hpet!)
- calling "hwclock -s" on the host resyncs the kernel time with the 
hwclock, so "date" and "hwclock" show the same again
- the guest stays at the "old" kernel time before the sync - also after 1 
hour the delta is still the same, so no sync or slew is done :-(

My guest OS is Windows 8, which must have ACPI enabled, otherwise it will 
not work.

Any ideas how to proceed? Maybe some command line parameters are wrong?

I need this resync for the guest due to external synchronization - it must 
not be millisecond-precise, but a 9 seconds shift during a run overnight is 
too much!

Thanks.

Best regards,

Erik