Index: sys/x86/include/pvclock.h
===================================================================
--- sys/x86/include/pvclock.h
+++ sys/x86/include/pvclock.h
@@ -50,6 +50,7 @@
 } __packed;
 
 void		pvclock_resume(void);
+uint64_t	pvclock_tsc_freq(struct pvclock_vcpu_time_info *ti);
 uint64_t	pvclock_get_timecount(struct pvclock_vcpu_time_info *ti);
 void		pvclock_get_wallclock(struct pvclock_wall_clock *wc,
 		    struct timespec *ts);
Index: sys/x86/x86/pvclock.c
===================================================================
--- sys/x86/x86/pvclock.c
+++ sys/x86/x86/pvclock.c
@@ -51,6 +51,21 @@
 	atomic_store_rel_64(&pvclock_last_cycles, 0);
 }
 
+uint64_t
+pvclock_tsc_freq(struct pvclock_vcpu_time_info *ti)
+{
+	uint64_t freq;
+
+	freq = (1000000000ULL << 32) / ti->tsc_to_system_mul;
+
+	if (ti->tsc_shift < 0)
+		freq <<= -ti->tsc_shift;
+	else
+		freq >>= ti->tsc_shift;
+
+	return (freq);
+}
+
 /*
  * Scale a 64-bit delta by scaling and multiplying by a 32-bit fraction,
  * yielding a 64-bit result.