For system with X86_FEATURE_TOPOEXT, current logic use APIC ID to calculate shared_cpu_map. However, since APIC IDs are not guaranteed to be contiguous for cores across different L3 (e.g. family17h system w/ downcore configuration). This breaks the logic, and results in incorrect L3 shared_cpu_map.
Instead, always use the previously calculated cpu_llc_shared_mask of each cpu to derive L3 shared_cpu_map. This has been tested on family15h and family17h systems, which has L3 and support X86_FEATURE_TOPOEXT. Signed-off-by: Suravee Suthikulpanit <suravee.suthikulpa...@amd.com> --- arch/x86/kernel/cpu/intel_cacheinfo.c | 32 ++++++++++++++++++-------------- 1 file changed, 18 insertions(+), 14 deletions(-) diff --git a/arch/x86/kernel/cpu/intel_cacheinfo.c b/arch/x86/kernel/cpu/intel_cacheinfo.c index c55fb2c..24f74932 100644 --- a/arch/x86/kernel/cpu/intel_cacheinfo.c +++ b/arch/x86/kernel/cpu/intel_cacheinfo.c @@ -811,7 +811,24 @@ static int __cache_amd_cpumap_setup(unsigned int cpu, int index, struct cacheinfo *this_leaf; int i, sibling; - if (boot_cpu_has(X86_FEATURE_TOPOEXT)) { + /* + * For L3, always use the pre-calculated cpu_llc_shared_mask + * to derive shared_cpu_map. + */ + if (index == 3) { + for_each_cpu(i, cpu_llc_shared_mask(cpu)) { + this_cpu_ci = get_cpu_cacheinfo(i); + if (!this_cpu_ci->info_list) + continue; + this_leaf = this_cpu_ci->info_list + index; + for_each_cpu(sibling, cpu_llc_shared_mask(cpu)) { + if (!cpu_online(sibling)) + continue; + cpumask_set_cpu(sibling, + &this_leaf->shared_cpu_map); + } + } + } else if (boot_cpu_has(X86_FEATURE_TOPOEXT)) { unsigned int apicid, nshared, first, last; this_leaf = this_cpu_ci->info_list + index; @@ -839,19 +856,6 @@ static int __cache_amd_cpumap_setup(unsigned int cpu, int index, &this_leaf->shared_cpu_map); } } - } else if (index == 3) { - for_each_cpu(i, cpu_llc_shared_mask(cpu)) { - this_cpu_ci = get_cpu_cacheinfo(i); - if (!this_cpu_ci->info_list) - continue; - this_leaf = this_cpu_ci->info_list + index; - for_each_cpu(sibling, cpu_llc_shared_mask(cpu)) { - if (!cpu_online(sibling)) - continue; - cpumask_set_cpu(sibling, - &this_leaf->shared_cpu_map); - } - } } else return 0; -- 2.7.4