2024-02-17 21:31:20

by Doug Smythies

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 <[email protected]>
---
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

2024-02-22 19:24:43

by Rafael J. Wysocki

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

On Sat, Feb 17, 2024 at 10:30 PM Doug Smythies <[email protected]> wrote:
>
> 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 <[email protected]>
> ---
> 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;
> --

Applied as 6.9 material, thanks!