Re: [PATCH] cpufreq/amd-pstate-ut: Fix amd_pstate_ut_check_freq failure with 'Requested CPU Min frequency' BIOS option

[Mario Limonciello <mario.limonciello@amd.com>]

On 9/9/26 05:26, K Prateek Nayak wrote:
> Since commit 608a76b65288 ("cpufreq/amd-pstate: Add support for the
> "Requested CPU Min frequency" BIOS option"), amd-pstate driver sets
> policy->min to frequency corresponding to bios_min_perf if a valid BIOS
> programmed min frequency value is detected.
> 
> amd_pstate_ut_check_freq expects policy->min to always match
> lowest_nonlinear_freq which does not hold true on platforms with user
> configured BIOS min freq.
> 
> Update the test case to compare policy->min to bios_min_freq on
> platforms that set it. Final comparison is adjusted to account for
> insane values by clamping the result within the supported frequency
> range.
> 
> While at it, move freq_to_perf() and perf_to_freq() helpers to internal
> header to allow their use from amd-pstate-ut.
> 
> Fixes: 608a76b65288 ("cpufreq/amd-pstate: Add support for the "Requested CPU Min frequency" BIOS option")
> Signed-off-by: K Prateek Nayak <kprateek.nayak@amd.com>

Reviewed-by: Mario Limonciello (AMD) <superm1@kernel.org>

Applied to my bleeding-edge branch.

FYI - as this is for unit tests only I'll plan to include this with 7.4 
material.

> ---
>   drivers/cpufreq/amd-pstate-ut.c | 23 ++++++++++++++++++++++-
>   drivers/cpufreq/amd-pstate.c    | 13 -------------
>   drivers/cpufreq/amd-pstate.h    | 14 ++++++++++++++
>   3 files changed, 36 insertions(+), 14 deletions(-)
> 
> diff --git a/drivers/cpufreq/amd-pstate-ut.c b/drivers/cpufreq/amd-pstate-ut.c
> index e23773680e05..c2c1a166b3a9 100644
> --- a/drivers/cpufreq/amd-pstate-ut.c
> +++ b/drivers/cpufreq/amd-pstate-ut.c
> @@ -226,11 +226,14 @@ static int amd_pstate_ut_check_freq(u32 index)
>   	for_each_online_cpu(cpu) {
>   		struct cpufreq_policy *policy __free(put_cpufreq_policy) = NULL;
>   		struct amd_cpudata *cpudata;
> +		union perf_cached perf;
>   
>   		policy = cpufreq_cpu_get(cpu);
>   		if (!policy)
>   			continue;
> +
>   		cpudata = policy->driver_data;
> +		perf = READ_ONCE(cpudata->perf);
>   
>   		if (!((policy->cpuinfo.max_freq >= cpudata->nominal_freq) &&
>   			(cpudata->nominal_freq > cpudata->lowest_nonlinear_freq) &&
> @@ -242,7 +245,25 @@ static int amd_pstate_ut_check_freq(u32 index)
>   			return -EINVAL;
>   		}
>   
> -		if (cpudata->lowest_nonlinear_freq != policy->min) {
> +		if (perf.bios_min_perf) {
> +			u32 bios_min_freq = perf_to_freq(perf, cpudata->nominal_freq,
> +							 perf.bios_min_perf);
> +
> +			/*
> +			 * User set bios_min_freq cannot be trusted to
> +			 * be within the driver limits. Clamp it similar
> +			 * to cpufreq_verify_within_cpu_limits().
> +			 */
> +			bios_min_freq = clamp_t(u32, bios_min_freq,
> +						     policy->cpuinfo.min_freq,
> +						     policy->cpuinfo.max_freq);
> +
> +			if (bios_min_freq != policy->min) {
> +				pr_err("%s cpu%d bios_min_freq=%d policy_min=%d, they should be equal!\n",
> +					__func__, cpu, bios_min_freq, policy->min);
> +				return -EINVAL;
> +			}
> +		} else if (cpudata->lowest_nonlinear_freq != policy->min) {
>   			pr_err("%s cpu%d cpudata_lowest_nonlinear_freq=%d policy_min=%d, they should be equal!\n",
>   				__func__, cpu, cpudata->lowest_nonlinear_freq, policy->min);
>   			return -EINVAL;
> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
> index ea6cc072121f..a5daabc2edcd 100644
> --- a/drivers/cpufreq/amd-pstate.c
> +++ b/drivers/cpufreq/amd-pstate.c
> @@ -145,19 +145,6 @@ static struct quirk_entry quirk_amd_7k62 = {
>   	.lowest_freq = 550,
>   };
>   
> -static inline u8 freq_to_perf(union perf_cached perf, u32 nominal_freq, unsigned int freq_val)
> -{
> -	u32 perf_val = DIV_ROUND_UP_ULL((u64)freq_val * perf.nominal_perf, nominal_freq);
> -
> -	return (u8)clamp(perf_val, perf.lowest_perf, perf.highest_perf);
> -}
> -
> -static inline u32 perf_to_freq(union perf_cached perf, u32 nominal_freq, u8 perf_val)
> -{
> -	return DIV_ROUND_UP_ULL((u64)nominal_freq * perf_val,
> -				perf.nominal_perf);
> -}
> -
>   static int __init dmi_matched_7k62_bios_bug(const struct dmi_system_id *dmi)
>   {
>   	/**
> diff --git a/drivers/cpufreq/amd-pstate.h b/drivers/cpufreq/amd-pstate.h
> index 9f5a81976eae..578465187b7a 100644
> --- a/drivers/cpufreq/amd-pstate.h
> +++ b/drivers/cpufreq/amd-pstate.h
> @@ -159,6 +159,20 @@ enum amd_pstate_mode {
>   	AMD_PSTATE_GUIDED,
>   	AMD_PSTATE_MAX,
>   };
> +
> +static inline u8 freq_to_perf(union perf_cached perf, u32 nominal_freq, unsigned int freq_val)
> +{
> +	u32 perf_val = DIV_ROUND_UP_ULL((u64)freq_val * perf.nominal_perf, nominal_freq);
> +
> +	return (u8)clamp(perf_val, perf.lowest_perf, perf.highest_perf);
> +}
> +
> +static inline u32 perf_to_freq(union perf_cached perf, u32 nominal_freq, u8 perf_val)
> +{
> +	return DIV_ROUND_UP_ULL((u64)nominal_freq * perf_val,
> +				perf.nominal_perf);
> +}
> +
>   const char *amd_pstate_get_mode_string(enum amd_pstate_mode mode);
>   int amd_pstate_get_status(void);
>   int amd_pstate_update_status(const char *buf, size_t size);
> 
> base-commit: d06c75c22d5c95ee27e01fedcaa07231c9bd5c88