linux-kernel - [PATCH 1/4] cpufreq/amd-pstate: Use nominal perf for limits when boost is disabled

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Message-ID: <20241012174519.897-1-mario.limonciello@amd.com>
Date: Sat, 12 Oct 2024 12:45:16 -0500
From: Mario Limonciello <mario.limonciello@....com>
To: "Gautham R . Shenoy" <gautham.shenoy@....com>
CC: Perry Yuan <perry.yuan@....com>, <linux-kernel@...r.kernel.org>,
	<linux-pm@...r.kernel.org>, Dhananjay Ugwekar <Dhananjay.Ugwekar@....com>,
	Mario Limonciello <mario.limonciello@....com>, Peter Jung
	<ptr1337@...hyos.org>
Subject: [PATCH 1/4] cpufreq/amd-pstate: Use nominal perf for limits when boost is disabled

When boost has been disabled the limit for perf should be nominal perf not
the highest perf.  Using the latter to do calculations will lead to
incorrect values that are still above nominal.

Fixes: ad4caad58d91 ("cpufreq: amd-pstate: Merge amd_pstate_highest_perf_set() into amd_get_boost_ratio_numerator()")
Reported-by: Peter Jung <ptr1337@...hyos.org>
Closes: https://bugzilla.kernel.org/show_bug.cgi?id=219348
Signed-off-by: Mario Limonciello <mario.limonciello@....com>
---
 drivers/cpufreq/amd-pstate.c | 20 ++++++++++++++------
 1 file changed, 14 insertions(+), 6 deletions(-)

diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
index 30415c30d8b4..dfa9a146769b 100644
--- a/drivers/cpufreq/amd-pstate.c
+++ b/drivers/cpufreq/amd-pstate.c
@@ -536,11 +536,16 @@ static int amd_pstate_verify(struct cpufreq_policy_data *policy)
 
 static int amd_pstate_update_min_max_limit(struct cpufreq_policy *policy)
 {
-	u32 max_limit_perf, min_limit_perf, lowest_perf;
+	u32 max_limit_perf, min_limit_perf, lowest_perf, max_perf;
 	struct amd_cpudata *cpudata = policy->driver_data;
 
-	max_limit_perf = div_u64(policy->max * cpudata->highest_perf, cpudata->max_freq);
-	min_limit_perf = div_u64(policy->min * cpudata->highest_perf, cpudata->max_freq);
+	if (cpudata->boost_supported && !policy->boost_enabled)
+		max_perf = READ_ONCE(cpudata->nominal_perf);
+	else
+		max_perf = READ_ONCE(cpudata->highest_perf);
+
+	max_limit_perf = div_u64(policy->max * max_perf, policy->cpuinfo.max_freq);
+	min_limit_perf = div_u64(policy->min * max_perf, policy->cpuinfo.max_freq);
 
 	lowest_perf = READ_ONCE(cpudata->lowest_perf);
 	if (min_limit_perf < lowest_perf)
@@ -1506,10 +1511,13 @@ static int amd_pstate_epp_update_limit(struct cpufreq_policy *policy)
 	u64 value;
 	s16 epp;
 
-	max_perf = READ_ONCE(cpudata->highest_perf);
+	if (cpudata->boost_supported && !policy->boost_enabled)
+		max_perf = READ_ONCE(cpudata->nominal_perf);
+	else
+		max_perf = READ_ONCE(cpudata->highest_perf);
 	min_perf = READ_ONCE(cpudata->lowest_perf);
-	max_limit_perf = div_u64(policy->max * cpudata->highest_perf, cpudata->max_freq);
-	min_limit_perf = div_u64(policy->min * cpudata->highest_perf, cpudata->max_freq);
+	max_limit_perf = div_u64(policy->max * max_perf, policy->cpuinfo.max_freq);
+	min_limit_perf = div_u64(policy->min * max_perf, policy->cpuinfo.max_freq);
 
 	if (min_limit_perf < min_perf)
 		min_limit_perf = min_perf;
-- 
2.43.0