linux-kernel - [PATCH] cpufreq: intel_pstate: fix pstate limits enforcement for adjust

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Date: Sat, 17 Feb 2024 13:30:10 -0800
From: Doug Smythies <dsmythies@...us.net>
To: srinivas.pandruvada@...ux.intel.com,
	rafael@...nel.org,
	lenb@...nel.org
Cc: linux-kernel@...r.kernel.org,
	linux-pm@...r.kernel.org,
	vincent.guittot@...aro.org,
	dsmythies@...us.net
Subject: [PATCH] cpufreq: intel_pstate: fix pstate limits enforcement for adjust_perf call back

There is a loophole in pstate limit clamping for the intel_cpufreq CPU
frequency scaling driver (intel_pstate in passive mode), schedutil CPU
frequency scaling governor, HWP (HardWare Pstate) control enabled, when
the adjust_perf call back path is used.

Fix it.

Signed-off-by: Doug Smythies <dsmythies@...us.net>
---
 drivers/cpufreq/intel_pstate.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/cpufreq/intel_pstate.c b/drivers/cpufreq/intel_pstate.c
index ca94e60e705a..79619227ea51 100644
--- a/drivers/cpufreq/intel_pstate.c
+++ b/drivers/cpufreq/intel_pstate.c
@@ -2987,6 +2987,9 @@ static void intel_cpufreq_adjust_perf(unsigned int cpunum,
 	if (min_pstate < cpu->min_perf_ratio)
 		min_pstate = cpu->min_perf_ratio;
 
+	if (min_pstate > cpu->max_perf_ratio)
+		min_pstate = cpu->max_perf_ratio;
+
 	max_pstate = min(cap_pstate, cpu->max_perf_ratio);
 	if (max_pstate < min_pstate)
 		max_pstate = min_pstate;
-- 
2.25.1