cpufreq: intel_pstate: Clear HWP Status during HWP Interrupt enable

It is possible that some performance excursions happened before OS boot
or enable HWP interrupts. So clear MSR_HWP_STATUS bits when we enable
HWP interrupt. In this way a next excursion will results in a HWP
interrupt.

The status bits of MSR_HWP_STATUS must be cleared (0) by software so
that a new status condition change will cause the hardware to set the
bit again and issue the notification.

Fixes: 57577c9 ("cpufreq: intel_pstate: Process HWP Guaranteed change notification")
Signed-off-by: Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

Author: spandruvada

drivers/cpufreq/intel_pstate.c

@@ -1652,6 +1652,7 @@ static void intel_pstate_enable_hwp_interrupt(struct cpudata *cpudata)
 
 		/* wrmsrl_on_cpu has to be outside spinlock as this can result in IPC */
 		wrmsrl_on_cpu(cpudata->cpu, MSR_HWP_INTERRUPT, 0x01);
+		wrmsrl_on_cpu(cpudata->cpu, MSR_HWP_STATUS, 0);
 	}
 }