[Qemu-devel] guest freezes when host clock is advanced

[James Ko]

Hi,

I have a linux guest running in qemu-kvm which freezes temporarily whenever the host clock is advanced.  The freezing is ~1s/month of advance.  So advancing the host clock by 1 year the guest will be frozen for about 12 seconds.  There appears to be no impact when the clock is wound back however.

The guest is using kvm-clock source if that matters.
#uname -a
Linux NO-HOSTNAME 2.6.32.59.cge #1 SMP PREEMPT Tue Jan 28 14:38:11 PST 2014 x86_64 GNU/Linux

Also during the freeze it also appears that some signals may be lost.  For example, the acpid failed to respond to the system_powerdown command in the qemu shell.

I know this is an unusual scenario but one for which I would like an explanation.
Has anyone else experienced this behaviour or can explain what may be going on here?

James