On 27.05.2025 10:48, Penny Zheng wrote:
> +int set_amd_cppc_para(struct cpufreq_policy *policy,
> + const struct xen_set_cppc_para *set_cppc)
> +{
> + unsigned int cpu = policy->cpu;
> + struct amd_cppc_drv_data *data = per_cpu(amd_cppc_drv_data, cpu);
> + uint8_t max_perf, min_perf, des_perf = 0, epp;
> +
> + if ( data == NULL )
> + return -ENOENT;
> +
> + /* Validate all parameters */
> + if ( set_cppc->minimum > UINT8_MAX || set_cppc->maximum > UINT8_MAX ||
> + set_cppc->desired > UINT8_MAX || set_cppc->energy_perf > UINT8_MAX )
> + return -EINVAL;
> +
> + /* 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;
> +
> + /* Activity window not supported in MSR */
> + if ( set_cppc->set_params & XEN_SYSCTL_CPPC_SET_ACT_WINDOW )
> + return -EOPNOTSUPP;
> +
> + /* Return if there is nothing to do. */
> + if ( set_cppc->set_params == 0 )
> + return 0;
> +
> + epp = per_cpu(epp_init, cpu);
> + /*
> + * Apply presets:
> + * XEN_SYSCTL_CPPC_SET_DESIRED reflects whether desired perf is set,
> which
> + * is also the flag to distinguish between passive mode and active mode.
> + * When it is set, CPPC in passive mode, only
> + * XEN_SYSCTL_CPPC_SET_PRESET_NONE could be chosen.
> + * when it is not set, CPPC in active mode, three different profile
> + * XEN_SYSCTL_CPPC_SET_PRESET_POWERSAVE/PERFORMANCE/BALANCE are provided,
> + */
> + switch ( set_cppc->set_params & XEN_SYSCTL_CPPC_SET_PRESET_MASK )
> + {
> + case XEN_SYSCTL_CPPC_SET_PRESET_POWERSAVE:
> + if ( set_cppc->set_params & XEN_SYSCTL_CPPC_SET_DESIRED )
> + return -EINVAL;
> + policy->policy = CPUFREQ_POLICY_POWERSAVE;
> + min_perf = data->caps.lowest_perf;
> + /* Lower max frequency to lowest */
> + max_perf = data->caps.lowest_perf;
> + epp = CPPC_ENERGY_PERF_MAX_POWERSAVE;
> + break;
> +
> + case XEN_SYSCTL_CPPC_SET_PRESET_PERFORMANCE:
> + if ( set_cppc->set_params & XEN_SYSCTL_CPPC_SET_DESIRED )
> + return -EINVAL;
> + /* Increase idle frequency to highest */
> + policy->policy = CPUFREQ_POLICY_PERFORMANCE;
> + min_perf = data->caps.highest_perf;
> + max_perf = data->caps.highest_perf;
> + epp = CPPC_ENERGY_PERF_MAX_PERFORMANCE;
> + break;
> +
> + case XEN_SYSCTL_CPPC_SET_PRESET_BALANCE:
> + if ( set_cppc->set_params & XEN_SYSCTL_CPPC_SET_DESIRED )
> + return -EINVAL;
> + policy->policy = CPUFREQ_POLICY_BALANCE;
> + min_perf = data->caps.lowest_perf;
> + max_perf = data->caps.highest_perf;
> + epp = CPPC_ENERGY_PERF_BALANCE;
> + break;
> +
> + case XEN_SYSCTL_CPPC_SET_PRESET_NONE:
> + /*
> + * In paasive mode, Xen governor is responsible for perfomance
> tuning.
> + * we shall set lowest_perf with "lowest_nonlinear_perf" to ensure
> + * governoring performance in P-states range.
> + */
> + min_perf = data->caps.lowest_nonlinear_perf;
> + max_perf = data->caps.highest_perf;
> + break;
Oh, also - can you really leave policy->policy unaltered here?
Jan
