+static int intel_pstate_msrs_not_valid(void)
+{
+ /* Check that all the msr's we are using are valid. */
+ u64 aperf, mperf, tmp;
+
+ rdmsrl(MSR_IA32_APERF, aperf);
+ rdmsrl(MSR_IA32_MPERF, mperf);
+
+ if (!intel_pstate_min_pstate() ||
+ !intel_pstate_max_pstate() ||
+ !intel_pstate_turbo_pstate())
+ return -ENODEV;
+
+ rdmsrl(MSR_IA32_APERF, tmp);
+ if (!(tmp - aperf))
+ return -ENODEV;
+
+ rdmsrl(MSR_IA32_MPERF, tmp);
+ if (!(tmp - mperf))
+ return -ENODEV;
+
+ return 0;
+}