385  * the other that uses the TSC reference page feature as defined in the
387  * Hyper-V and 32-bit x86.  The TSC reference page version is preferred.
416 	 * subsection Refererence Counter, guarantees that the TSC and MSR  in read_hv_clock_tsc()
418 	 * to the MSR in case the TSC page indicates unavailability.  in read_hv_clock_tsc()
441 	/* Disable the TSC page */  in suspend_hv_clock_tsc()
452 	/* Re-enable the TSC page */  in resume_hv_clock_tsc()
525 	 * If Hyper-V offers TSC_INVARIANT, then the virtualized TSC correctly  in hv_init_tsc_clocksource()
528 	 * Hyper-V Reference TSC rating, causing the generic TSC to be used.  in hv_init_tsc_clocksource()
530 	 * TSC will be preferred over the virtualized ARM64 arch counter.  in hv_init_tsc_clocksource()
543 	 * TSC page mapping works differently in root compared to guest.  in hv_init_tsc_clocksource()
552 	 * It worth mentioning, that TSC clocksource read function  in hv_init_tsc_clocksource()
554 	 * TSC page is zeroed (which is the case until the PFN is remapped) and  in hv_init_tsc_clocksource()
555 	 * thus TSC clocksource will work even without the real TSC page  in hv_init_tsc_clocksource()
570 	 * If TSC is invariant, then let it stay as the sched clock since it  in hv_init_tsc_clocksource()
571 	 * will be faster than reading the TSC page. But if not invariant, use  in hv_init_tsc_clocksource()
572 	 * the TSC page so that live migrations across hosts with different  in hv_init_tsc_clocksource()
584 	 * Try to set up the TSC page clocksource, then the MSR clocksource.  in hv_init_clocksource()
605 		WARN(1, "%s: attempt to remap TSC page in guest partition\n",  in hv_remap_tsc_clocksource()
613 		pr_err("Failed to remap Hyper-V TSC page.\n");  in hv_remap_tsc_clocksource()