[PATCH] intel_pstate: Fix MSR_CONFIG_TDP_x addressing in core_get_max_pstate

From: Jan Kiszka
Date: Fri Jul 08 2016 - 14:42:23 EST


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 <jan.kiszka@xxxxxxxxxxx>
---
drivers/cpufreq/intel_pstate.c | 2 +-
1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index 1fa1a32..1b15917 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -944,7 +944,7 @@ 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;
--
2.1.4