linux-kernel - Re: [PATCH 2/2] cpufreq: amd-pstate: Use amd_get_highest

lists.openwall.net		lists / announce owl-users owl-dev john-users john-dev passwdqc-users yescrypt popa3d-users / oss-security kernel-hardening musl sabotage tlsify passwords / crypt-dev xvendor / Bugtraq Full-Disclosure linux-kernel linux-netdev linux-ext4 linux-hardening linux-cve-announce PHC
Open Source and information security mailing list archives

Hash Suite: Windows password security audit tool. GUI, reports in PDF.

[<prev] [next>] [<thread-prev] [thread-next>] [day] [month] [year] [list]

Date: Wed, 26 Jun 2024 13:19:56 -0500
From: Mario Limonciello <mario.limonciello@....com>
To: Borislav Petkov <bp@...en8.de>
Cc: "Gautham R . Shenoy" <gautham.shenoy@....com>,
 Perry Yuan <perry.yuan@....com>, Thomas Gleixner <tglx@...utronix.de>,
 Ingo Molnar <mingo@...hat.com>, Dave Hansen <dave.hansen@...ux.intel.com>,
 "maintainer:X86 ARCHITECTURE (32-BIT AND 64-BIT)" <x86@...nel.org>,
 "H . Peter Anvin" <hpa@...or.com>, Huang Rui <ray.huang@....com>,
 "Rafael J . Wysocki" <rafael@...nel.org>,
 Viresh Kumar <viresh.kumar@...aro.org>,
 Nikolay Borisov <nik.borisov@...e.com>, Peter Zijlstra
 <peterz@...radead.org>,
 "open list:X86 ARCHITECTURE (32-BIT AND 64-BIT)"
 <linux-kernel@...r.kernel.org>,
 "open list:AMD PSTATE DRIVER" <linux-pm@...r.kernel.org>
Subject: Re: [PATCH 2/2] cpufreq: amd-pstate: Use amd_get_highest_perf() to
 lookup perf values

On 6/26/2024 12:18, Borislav Petkov wrote:
> On Tue, Jun 25, 2024 at 11:20:43PM -0500, Mario Limonciello wrote:
>> +	/*
>> +	 * For AMD CPUs with Family ID 19H and Model ID range 0x70 to 0x7f,
>> +	 * the highest performance level is set to 196.
>> +	 * https://bugzilla.kernel.org/show_bug.cgi?id=218759
>> +	 */
>> +	if (cpu_feature_enabled(X86_FEATURE_ZEN4)) {
>> +		switch (c->x86_model) {
>> +		case 0x70 ... 0x7f:
> 
> Aha, so here it is non-inclusive - "<" and not "<=".
> 
> So you need to check the model ranges first.
> 
>> +			return CPPC_HIGHEST_PERF_PERFORMANCE;
>> +		default:
>> +			return CPPC_HIGHEST_PERF_DEFAULT;
> 
> As for patch 1.
> 
>> +		}
>> +	}
>> +
>> +	return CPPC_HIGHEST_PERF_DEFAULT;
>>   }
>>   EXPORT_SYMBOL_GPL(amd_get_highest_perf);
>>   
>> diff --git a/drivers/cpufreq/amd-pstate.c b/drivers/cpufreq/amd-pstate.c
>> index 80eaa58f1405..f468d8562e17 100644
>> --- a/drivers/cpufreq/amd-pstate.c
>> +++ b/drivers/cpufreq/amd-pstate.c
>> @@ -52,8 +52,6 @@
>>   #define AMD_PSTATE_TRANSITION_LATENCY	20000
>>   #define AMD_PSTATE_TRANSITION_DELAY	1000
>>   #define AMD_PSTATE_FAST_CPPC_TRANSITION_DELAY 600
>> -#define CPPC_HIGHEST_PERF_PERFORMANCE	196
>> -#define CPPC_HIGHEST_PERF_DEFAULT	166
>>   
>>   #define AMD_CPPC_EPP_PERFORMANCE		0x00
>>   #define AMD_CPPC_EPP_BALANCE_PERFORMANCE	0x80
> 
> This already doesn't apply:
> 
> checking file arch/x86/kernel/cpu/amd.c
> checking file drivers/cpufreq/amd-pstate.c
> Hunk #1 FAILED at 52.
> 

I was thinking we would take this patch through superm1/linux-next or 
linux-pm/linux-next as there is other amd-pstate stuff for the next 
merge window, but if you'd rather go through x86 then we can wait until 
after the merge window on this series.