access to tsc calibration info

x86-specific question: Is there a generic way to get access to the TSC frequency calibration information, as provided by modern x86 CPUs in MSRs? (User mode components cannot directly read these.)

The information is readily available in Nova's hypervisor information page (Hip), conveniently exported as a ROM. But I am not spotting a similar export for (e.g.) seL4. The data is present in the sel4 boot info structure (in core)--maybe this is accessible to components in some manner? Suggests a possible platform API, if not already present...

Suggestions?

// Steve Harp