On 28.08.2025 06:06, Penny, Zheng wrote:
>> -----Original Message-----
>> From: Jan Beulich <jbeul...@suse.com>
>> Sent: Tuesday, August 26, 2025 12:03 AM
>>
>> On 22.08.2025 12:52, Penny Zheng wrote:
>>> --- a/xen/arch/x86/acpi/cpufreq/amd-cppc.c
>>> +++ b/xen/arch/x86/acpi/cpufreq/amd-cppc.c
>>> + /* Only allow values if params bit is set. */
>>> + if ( (!(set_cppc->set_params & XEN_SYSCTL_CPPC_SET_DESIRED) &&
>>> + set_cppc->desired) ||
>>> + (!(set_cppc->set_params & XEN_SYSCTL_CPPC_SET_MINIMUM) &&
>>> + set_cppc->minimum) ||
>>> + (!(set_cppc->set_params & XEN_SYSCTL_CPPC_SET_MAXIMUM) &&
>>> + set_cppc->maximum) ||
>>> + (!(set_cppc->set_params &
>> XEN_SYSCTL_CPPC_SET_ENERGY_PERF) &&
>>> + set_cppc->energy_perf) )
>>> + return -EINVAL;
>>
>> ... all the errors checked here are to be ignored when no flag is set at all?
>
> Yes, values are only meaningful when according flag is properly set, which
> has been described in the comment for "struct xen_set_cppc_para"
Especially since you stripped the initial part of this comment of mine, it feels
as if you misunderstood my request. What it boils down to is the question
whether
"if ( set_cppc->set_params == 0 )" shouldn't move after the if() you left in
context above.
>>> + /*
>>> + * Validate all parameters
>>> + * Maximum performance may be set to any performance value in the range
>>> + * [Nonlinear Lowest Performance, Highest Performance], inclusive but
>> must
>>> + * be set to a value that is larger than or equal to minimum
>>> Performance.
>>> + */
>>> + if ( (set_cppc->set_params & XEN_SYSCTL_CPPC_SET_MAXIMUM) &&
>>> + (set_cppc->maximum > data->caps.highest_perf ||
>>> + set_cppc->maximum <
>>> + (set_cppc->set_params &
>> XEN_SYSCTL_CPPC_SET_MINIMUM
>>> + ? set_cppc->minimum
>>> + : data->req.min_perf)) )
>>
>> Too deep indentation (more of this throughout the function), and seeing ...
>
> Maybe four indention is more proper
> ```
> if ( (set_cppc->set_params & XEN_SYSCTL_CPPC_SET_MAXIMUM) &&
> (set_cppc->maximum > data->caps.highest_perf ||
> (set_cppc->maximum <
> (set_cppc->set_params & XEN_SYSCTL_CPPC_SET_MINIMUM
> ? set_cppc->minimum
> : data->req.min_perf))) )
> ```
No. In expressions you always want to indent according to pending open
parentheses:
if ( (set_cppc->set_params & XEN_SYSCTL_CPPC_SET_MAXIMUM) &&
(set_cppc->maximum > data->caps.highest_perf ||
(set_cppc->maximum <
(set_cppc->set_params & XEN_SYSCTL_CPPC_SET_MINIMUM
? set_cppc->minimum
: data->req.min_perf))) )
>>> + case XEN_SYSCTL_CPPC_SET_PRESET_NONE:
>>> + if ( active_mode )
>>> + policy->policy = CPUFREQ_POLICY_UNKNOWN;
>>> + break;
>>> +
>>> + default:
>>> + return -EINVAL;
>>> + }
>>
>> Much of this looks very similar to what patch 09 introduces in
>> amd_cppc_epp_set_policy(). Is it not possible to reduce the redundancy?
>>
>
> I'll add a new helper to amd_cppc_prepare_policy() to extract common
>
>>> --- a/xen/include/public/sysctl.h
>>> +++ b/xen/include/public/sysctl.h
>>> @@ -336,8 +336,14 @@ struct xen_ondemand {
>>> uint32_t up_threshold;
>>> };
>>>
>>> +#define CPUFREQ_POLICY_UNKNOWN 0
>>> +#define CPUFREQ_POLICY_POWERSAVE 1
>>> +#define CPUFREQ_POLICY_PERFORMANCE 2
>>> +#define CPUFREQ_POLICY_ONDEMAND 3
>>
>> Without XEN_ prefixes they shouldn't appear in a public header. But do we
>> need ...
>>
>>> struct xen_get_cppc_para {
>>> /* OUT */
>>> + uint32_t policy; /* CPUFREQ_POLICY_xxx */
>>
>> ... the new field at all? Can't you synthesize the kind-of-governor into
>> struct
>> xen_get_cpufreq_para's respective field? You invoke both sub-ops from xenpm
>> now anyway ...
>>
>
> Maybe I could borrow governor field to indicate policy info, like the
> following in print_cpufreq_para(), then we don't need to add the new filed
> "policy"
> ```
> + /* Translate governor info to policy info in CPPC active mode */
> + if ( is_cppc_active )
> + {
> + if ( !strncmp(p_cpufreq->u.s.scaling_governor,
> + "ondemand", CPUFREQ_NAME_LEN) )
> + printf("cppc policy : ondemand\n");
> + else if ( !strncmp(p_cpufreq->u.s.scaling_governor,
> + "performance", CPUFREQ_NAME_LEN) )
> + printf("cppc policy : performance\n");
> +
> + else if ( !strncmp(p_cpufreq->u.s.scaling_governor,
> + "powersave", CPUFREQ_NAME_LEN) )
> + printf("cppc policy : powersave\n");
> + else
> + printf("cppc policy : unknown\n");
> + }
> +
> ```
Something like this is what I was thinking of, yes.
Jan
