Re: [PATCH 08/11] platform/x86/: hfi: add online and offline callback support

["Ilpo Järvinen" <ilpo.jarvinen@linux.intel.com>]

On Tue, 27 Aug 2024, Perry Yuan wrote:

> From: Perry Yuan <Perry.Yuan@amd.com>
> 
> There are some firmware parameters that need to be configured
> when a CPU core is brought online or offline.
> 
> when CPU is online, it will initialize the workload classification
> parameters to CPU firmware which will trigger the workload class ID
> updating function.
> 
> Once the CPU is going to offline, it will need to disable the workload
> classification function and clear the history.
> 
> Signed-off-by: Perry Yuan <Perry.Yuan@amd.com>
> ---
>  drivers/platform/x86/amd/hfi/hfi.c | 90 ++++++++++++++++++++++++++++++
>  1 file changed, 90 insertions(+)
> 
> diff --git a/drivers/platform/x86/amd/hfi/hfi.c b/drivers/platform/x86/amd/hfi/hfi.c
> index cd5f2b708ebf..57b642c4c522 100644
> --- a/drivers/platform/x86/amd/hfi/hfi.c
> +++ b/drivers/platform/x86/amd/hfi/hfi.c
> @@ -154,6 +154,7 @@ static int __percpu *amd_hfi_ipcc_scores;
>  
>  static int amd_set_hfi_ipcc_score(struct amd_hfi_cpuinfo *info, int cpu);
>  static int update_hfi_ipcc_scores(struct amd_hfi_data *amd_hfi_data);
> +static int amd_hfi_set_state(unsigned int cpu, bool state);

Unnecessary.

>  static int find_cpu_index_by_apicid(unsigned int target_apicid)
>  {
> @@ -318,6 +319,87 @@ static int amd_set_hfi_ipcc_score(struct amd_hfi_cpuinfo *hfi_cpuinfo, int cpu)
>  	return 0;
>  }
>  
> +static int amd_hfi_set_state(unsigned int cpu, bool state)
> +{
> +	int ret;
> +
> +	ret = wrmsrl_on_cpu(cpu, AMD_WORKLOAD_CLASS_CONFIG, state);
> +	if (ret)
> +		return ret;
> +
> +	return wrmsrl_on_cpu(cpu, AMD_WORKLOAD_HRST, 0x1);
> +}
> +
> +/*
> + * amd_hfi_online() - Enable workload classification on @cpu
> + * @cpu: CPU in which the workload classification will be enabled
> + *
> + */
> +static int amd_hfi_online(unsigned int cpu)
> +{
> +	struct amd_hfi_cpuinfo *hfi_info = per_cpu_ptr(&amd_hfi_cpuinfo, cpu);
> +	struct amd_hfi_classes *hfi_classes;
> +	int ret;
> +
> +	if (WARN_ON_ONCE(!hfi_info))

Can this ever trigger??

> +		return -EINVAL;

Definitely wrong error code to return since this has nothing to do with 
user input being invalid.

> +	if (!zalloc_cpumask_var(&hfi_info->cpus, GFP_KERNEL))
> +		return -ENOMEM;
> +
> +	mutex_lock(&hfi_cpuinfo_lock);

Use guard().

> +	cpumask_set_cpu(cpu, hfi_info->cpus);
> +
> +	/*
> +	 * Check if @cpu as an associated, initialized and ranking data must be filled
> +	 */
> +	hfi_classes = hfi_info->amd_hfi_classes;
> +	if (!hfi_classes)
> +		goto unlock;
> +
> +	/* Enable the workload classification interface */
> +	ret = amd_hfi_set_state(cpu, true);
> +	if (ret)
> +		pr_err("wct enable failed for cpu %d\n", cpu);

Use %u for unsigned int.

> +
> +	mutex_unlock(&hfi_cpuinfo_lock);
> +	return 0;
> +
> +unlock:
> +	free_cpumask_var(hfi_info->cpus);
> +	mutex_unlock(&hfi_cpuinfo_lock);
> +	return ret;
> +}
> +
> +/*
> + * amd_hfi_offline() - Disable workload classification on @cpu
> + * @cpu: CPU in which the workload classification will be disabled
> + *
> + * Remove @cpu from those covered by its HFI instance.
> + *
> + */
> +static int amd_hfi_offline(unsigned int cpu)
> +{
> +	struct amd_hfi_cpuinfo *hfi_info = &per_cpu(amd_hfi_cpuinfo, cpu);
> +	int ret;
> +
> +	if (WARN_ON_ONCE(!hfi_info))
> +		return -EINVAL;
> +
> +	mutex_lock(&hfi_cpuinfo_lock);
> +
> +	/* Disable the workload classification interface */
> +	ret = amd_hfi_set_state(cpu, false);
> +	if (ret)
> +		pr_err("wct disable failed for cpu %d\n", cpu);

%u

> +
> +	mutex_unlock(&hfi_cpuinfo_lock);
> +
> +	free_cpumask_var(hfi_info->cpus);
> +
> +	return 0;
> +}
> +
>  static int update_hfi_ipcc_scores(struct amd_hfi_data *amd_hfi_data)
>  {
>  	int cpu;
> @@ -467,6 +549,14 @@ static int amd_hfi_probe(struct platform_device *pdev)
>  	if (ret)
>  		goto err_exit;
>  
> +	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "x86/amd_hfi:online",
> +			amd_hfi_online,
> +			amd_hfi_offline);
> +	if (ret < 0) {
> +		pr_warn("failed to setup cpuhp state! (%d)\n", ret);
> +		return ret;
> +	}
> +
>  	dev_dbg(&pdev->dev, "%s driver registered.\n", pdev->name);
>  
>  	return 0;
> 

-- 
 i.