[PATCH] cpufreq: intel_pstate: fix pstate limits enforcement for adjust_perf call back

From: Doug Smythies
Date: Sat Feb 17 2024 - 16:30:25 EST


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@xxxxxxxxx>
---
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