Hi Reinette, On 5/22/25 15:54, Reinette Chatre wrote: > Hi Babu, > > On 5/15/25 3:51 PM, Babu Moger wrote: >> ABMC feature details are reported via CPUID Fn8000_0020_EBX_x5. >> Bits Description >> 15:0 MAX_ABMC Maximum Supported Assignable Bandwidth >> Monitoring Counter ID + 1 >> >> The feature details are documented in APM listed below [1]. >> [1] AMD64 Architecture Programmer's Manual Volume 2: System Programming >> Publication # 24593 Revision 3.41 section 19.3.3.3 Assignable Bandwidth >> Monitoring (ABMC). >> >> Detect the feature and number of assignable monitoring counters supported. >> >> Link: https://bugzilla.kernel.org/show_bug.cgi?id=206537 >> Signed-off-by: Babu Moger <babu.moger@xxxxxxx> >> --- > > ... > >> --- >> arch/x86/kernel/cpu/resctrl/monitor.c | 9 +++++++-- >> include/linux/resctrl.h | 4 ++++ >> 2 files changed, 11 insertions(+), 2 deletions(-) >> >> diff --git a/arch/x86/kernel/cpu/resctrl/monitor.c b/arch/x86/kernel/cpu/resctrl/monitor.c >> index aeb2a9283069..fd2761d9f3f7 100644 >> --- a/arch/x86/kernel/cpu/resctrl/monitor.c >> +++ b/arch/x86/kernel/cpu/resctrl/monitor.c >> @@ -345,6 +345,7 @@ 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(); >> >> @@ -375,13 +376,17 @@ int __init rdt_get_mon_l3_config(struct rdt_resource *r) >> resctrl_rmid_realloc_threshold = resctrl_arch_round_mon_val(threshold); >> >> if (rdt_cpu_has(X86_FEATURE_BMEC)) { >> - u32 eax, ebx, ecx, edx; >> - >> /* 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)) { >> + r->mon.mbm_cntr_assignable = true; >> + cpuid_count(0x80000020, 5, &eax, &ebx, &ecx, &edx); >> + r->mon.num_mbm_cntrs = (ebx & GENMASK(15, 0)) + 1; >> + } >> + > > Shouldn't ABMC detection also include enumeration of which configurations > are supported? From what I can tell, looking ahead patch #18 hardcodes definitions > of all known "bandwidth types" (which term to use TBD) and then patch #20 allows > *any* of these types to be configured irrespective of whether system > supports it. > AMD spec mentions "The types of L3 transactions that ABMC can track are > configurable and identified by CPUID Fn8000_0020_ECX_x3." It thus looks > like the enumeration of r->mon.mbm_cfg_mask when BMEC is enabled is > required for ABMC also and used by this implementation. > >> r->mon_capable = true; >> >> return 0; >> diff --git a/include/linux/resctrl.h b/include/linux/resctrl.h >> index 2a8fa454d3e6..065fb6e38933 100644 >> --- a/include/linux/resctrl.h >> +++ b/include/linux/resctrl.h >> @@ -260,11 +260,15 @@ enum resctrl_schema_fmt { >> * @num_rmid: Number of RMIDs available >> * @mbm_cfg_mask: Bandwidth sources that can be tracked when bandwidth >> * monitoring events can be configured. >> + * @num_mbm_cntrs: Number of assignable monitoring counters >> + * @mbm_cntr_assignable:Is system capable of supporting monitor assignment? > > "monitor assignment" has not been used so far, was this intended to be > "counter assignment"? Missed to respond to this comment. Yes. Sure. Will correct it. -- Thanks Babu Moger
