Update: setting to jiffies on my guest seems to be the most stable (no lockups yet in the last 24 hours)
I googled around and by adding clocksource=jiffies to my kernel i fixed it. Instead of jiffies you could also try "pit". This is for the guest OS. You can also use kvm-clock if that is available to you. To check, run the following commands and see whether kvm-clock is available
Some people say that the best option for a precise clock on the guest is to use the
kvm-clocksource (pvclock) which is synchronized with clock's host.
There are also reports of disabling C-states in the BIOS.