intel_pstate: Fix MSR_CONFIG_TDP_x addressing in core_get_max_pstate()

jan-kiszka · rafaeljw · commit 5fc8f707a2aa · 2016-07-11T15:12:30.000+02:00
If MSR_CONFIG_TDP_CONTROL is locked, we currently try to address some
MSR 0x80000648 or so. Mask out the relevant level bits 0 and 1.

Found while running over the Jailhouse hypervisor which became upset
about this strange MSR index.

Signed-off-by: Jan Kiszka &lt;jan.kiszka@siemens.com&gt;
Acked-by: Srinivas Pandruvada &lt;srinivas.pandruvada@linux.intel.com&gt;
Cc: 4.4+ &lt;stable@vger.kernel.org&gt; # 4.4+
Signed-off-by: Rafael J. Wysocki &lt;rafael.j.wysocki@intel.com&gt;
diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
@@ -945,7 +945,7 @@ static int core_get_max_pstate(void)
 			if (err)
 				goto skip_tar;
 
-			tdp_msr = MSR_CONFIG_TDP_NOMINAL + tdp_ctrl;
+			tdp_msr = MSR_CONFIG_TDP_NOMINAL + (tdp_ctrl & 0x3);
 			err = rdmsrl_safe(tdp_msr, &tdp_ratio);
 			if (err)
 				goto skip_tar;
