Re: [PATCH v5 1/4] x86/cpu/topology: Always try cpu_parse_topology_ext() on AMD/Hygon

On 9/11/2025 10:07 AM, K Prateek Nayak wrote:

/*

•  * In case leaf B is available, use it to derive
  

•  * topology information.
  

•  * If the extended topology leaf 0xb leaf doesn't exits,
  

•  * derive CORE and DIE information from the 0x8000001e leaf.
  

  */

• err = detect_extended_topology(c);
  

• if (!err)
  

• 	c->x86_coreid_bits = get_count_order(c->x86_max_cores);
  

• if (!has_extended_topology) {
  

• 	c->cpu_die_id  = ecx & 0xff;
  

Just noticed that we still need that "cpu_die_id" from 0x8000001e since 0xb on AMD does not implement the LEVEL_TYPE of DIE_TYPE (5).

• 	if (c->x86 >= 0x17) {
  

• 		c->cpu_core_id = ebx & 0xff;
  

• 		if (smp_num_siblings > 1)
  

• 			c->x86_max_cores /= smp_num_siblings;
  

• 	}
  

• }