[libvirt] HELP: after host upgrade to F11, guest runs extremely slow

I upgraded the host from F10 to F11 (x86_64) with no issues. Now when I start a F10 (i386) guest it runs very very slow. I also see messages on the guest boot console about "clocksource tsc unstable" and some kernel oops. Once it got far enough to start network I logged in and checked the clocksource and it currently is 'acpi_pm' even though the kernel line says clocksource=pit. The available clocksources are acpi_pm, jiffies, and tsc. I do not see 'pit' in the list. How do I fix this issue? Regards, Gerry