Re: [PATCH] platform/x86: TPMI: clean up CPU mappings on offline

[Srinivas Pandruvada <srinivas.pandruvada@linux.intel.com>]

On Wed, 2026-11-04 at 11:27 +0800, lirongqing wrote:
> From: Li RongQing <lirongqing@baidu.com>
> 
> The TPMI power domain driver adds each online CPU to a hash table and
> its power domain mask, but does not remove either entry when the CPU
> goes offline. Bringing a CPU back online can therefore insert the
> same
> hlist node again and leave stale CPU mask state.
> 
> Register an offline callback that removes the hash entry and clears
> the
> CPU from its power domain mask.
> 

Hi RonQing,

Thanks for the patch.

TPMI feature doesn't depend on CPU online/offline and can update MMIO
while CPU is offline.

Instead of adding a offline callback, can we just do the below if the
cost of search is not high?

diff --git a/drivers/platform/x86/intel/tpmi_power_domains.c
b/drivers/platform/x86/intel/tpmi_power_domains.c
index d89b9894c42a..dadd5fc5719f 100644
--- a/drivers/platform/x86/intel/tpmi_power_domains.c
+++ b/drivers/platform/x86/intel/tpmi_power_domains.c
@@ -201,6 +201,8 @@ static int tpmi_get_logical_id(unsigned int cpu,
struct tpmi_cpu_info *info)
 static int tpmi_cpu_online(unsigned int cpu)
 {
        struct tpmi_cpu_info *info = &per_cpu(tpmi_cpu_info, cpu);
+       struct tpmi_cpu_info *entry;
+       bool found = false;
        int ret, index;
 
        /* Don't fail CPU online for some bad mapping of CPUs */
@@ -212,7 +214,14 @@ static int tpmi_cpu_online(unsigned int cpu)
 
        guard(mutex)(&tpmi_lock);
        cpumask_set_cpu(cpu, &tpmi_power_domain_mask[index]);
-       hash_add(tpmi_cpu_hash, &info->hnode, info->punit_core_id);
+       hash_for_each_possible(tpmi_cpu_hash, entry, hnode, info-
>punit_core_id) {
+               if (entry == info) {
+                       found = true;
+                       break;
+               }
+       }
+       if (!found)
+               hash_add(tpmi_cpu_hash, &info->hnode, info-
>punit_core_id);
 
        domain_die_map[info->pkg_id * MAX_POWER_DOMAINS + info-
>punit_domain_id] =
                        topology_die_id(cpu);
Thanks,
Srinivas

> Fixes: 17ca2780458c ("platform/x86/intel: TPMI domain id and CPU
> mapping")
> Signed-off-by: Li RongQing <lirongqing@baidu.com>
> ---
>  drivers/platform/x86/intel/tpmi_power_domains.c | 19
> ++++++++++++++++++-
>  1 file changed, 18 insertions(+), 1 deletion(-)
> 
> diff --git a/drivers/platform/x86/intel/tpmi_power_domains.c
> b/drivers/platform/x86/intel/tpmi_power_domains.c
> index d89b989..c3fd1bd 100644
> --- a/drivers/platform/x86/intel/tpmi_power_domains.c
> +++ b/drivers/platform/x86/intel/tpmi_power_domains.c
> @@ -220,6 +220,23 @@ static int tpmi_cpu_online(unsigned int cpu)
>  	return 0;
>  }
>  
> +static int tpmi_cpu_offline(unsigned int cpu)
> +{
> +	struct tpmi_cpu_info *info = &per_cpu(tpmi_cpu_info, cpu);
> +	int index;
> +
> +	if (hlist_unhashed(&info->hnode) ||
> !tpmi_domain_is_valid(info))
> +		return 0;
> +
> +	index = info->pkg_id * MAX_POWER_DOMAINS + info-
> >punit_domain_id;
> +
> +	guard(mutex)(&tpmi_lock);
> +	cpumask_clear_cpu(cpu, &tpmi_power_domain_mask[index]);
> +	hash_del(&info->hnode);
> +
> +	return 0;
> +}
> +
>  static int __init tpmi_init(void)
>  {
>  	const struct x86_cpu_id *id;
> @@ -249,7 +266,7 @@ static int __init tpmi_init(void)
>  
>  	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN,
>  				"platform/x86/tpmi_power_domains:onl
> ine",
> -				tpmi_cpu_online, NULL);
> +				tpmi_cpu_online, tpmi_cpu_offline);
>  	if (ret < 0)
>  		goto free_domain_map;
>