Hi Babu,
On 7/8/25 3:17 PM, Babu Moger wrote:
> diff --git a/arch/x86/kernel/cpu/resctrl/core.c b/arch/x86/kernel/cpu/resctrl/core.c
> index 267e9206a999..b48cc67cbbe3 100644
> --- a/arch/x86/kernel/cpu/resctrl/core.c
> +++ b/arch/x86/kernel/cpu/resctrl/core.c
> @@ -990,7 +990,8 @@ void resctrl_cpu_detect(struct cpuinfo_x86 *c)
>
> if (cpu_has(c, X86_FEATURE_CQM_OCCUP_LLC) ||
> cpu_has(c, X86_FEATURE_CQM_MBM_TOTAL) ||
> - cpu_has(c, X86_FEATURE_CQM_MBM_LOCAL)) {
> + cpu_has(c, X86_FEATURE_CQM_MBM_LOCAL) ||
> + cpu_has(c, X86_FEATURE_ABMC)) {
I interpret this to mean that ABMC does not depend on any of the
"legacy" monitoring features.
> u32 eax, ebx, ecx, edx;
>
> /* QoS sub-leaf, EAX=0Fh, ECX=1 */
> diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c
> index 2558b1bdef8b..0a695ce68f46 100644
> --- a/arch/x86/kernel/cpu/resctrl/monitor.c
> +++ b/arch/x86/kernel/cpu/resctrl/monitor.c
> @@ -339,6 +339,7 @@ int __init rdt_get_mon_l3_config(struct rdt_resource *r)
> unsigned int mbm_offset = boot_cpu_data.x86_cache_mbm_width_offset;
> struct rdt_hw_resource *hw_res = resctrl_to_arch_res(r);
> unsigned int threshold;
> + u32 eax, ebx, ecx, edx;
>
> snc_nodes_per_l3_cache = snc_get_config();
>
> @@ -368,14 +369,18 @@ int __init rdt_get_mon_l3_config(struct rdt_resource *r)
rdt_get_mon_l3_config() is only called when one or more of the "legacy" monitoring
features are supported ...
> */
> resctrl_rmid_realloc_threshold = resctrl_arch_round_mon_val(threshold);
>
> - if (rdt_cpu_has(X86_FEATURE_BMEC)) {
> - u32 eax, ebx, ecx, edx;
> -
> + if (rdt_cpu_has(X86_FEATURE_BMEC) || rdt_cpu_has(X86_FEATURE_ABMC)) {
> /* Detect list of bandwidth sources that can be tracked */
> cpuid_count(0x80000020, 3, &eax, &ebx, &ecx, &edx);
> r->mon.mbm_cfg_mask = ecx & MAX_EVT_CONFIG_BITS;
> }
>
> + if (rdt_cpu_has(X86_FEATURE_ABMC)) {
... so having this check within rdt_get_mon_l3_config() implies that ABMC depends
on the "legacy" monitoring features. This contradicts the change to resctrl_cpu_detect()
though so it seems that get_rdt_mon_resources() is missing a check for ABMC to ensure
rdt_get_mon_l3_config() is called when ABMC is supported (but "legacy" monitoring features
are not)?
Reinette
