From 0c487010cb4f79e451ac9e7cc47494cb21ac3566 Mon Sep 17 00:00:00 2001 From: Perry Yuan Date: Sun, 27 Oct 2024 21:02:41 -0500 Subject: [PATCH] x86/cpufeatures: Add X86_FEATURE_AMD_WORKLOAD_CLASS feature bit Add a new feature bit that indicates support for workload-based heuristic feedback to OS for scheduling decisions. When the bit set, threads are classified during runtime into enumerated classes. The classes represent thread performance/power characteristics that may benefit from special scheduling behaviors. Signed-off-by: Perry Yuan Signed-off-by: Mario Limonciello Signed-off-by: Borislav Petkov (AMD) Reviewed-by: Gautham R. Shenoy Link: https://lore.kernel.org/r/20241028020251.8085-4-mario.limonciello@amd.com --- arch/x86/include/asm/cpufeatures.h | 1 + arch/x86/kernel/cpu/scattered.c | 1 + 2 files changed, 2 insertions(+) diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h index 1216a0588ba8e..05e985ce9880d 100644 --- a/arch/x86/include/asm/cpufeatures.h +++ b/arch/x86/include/asm/cpufeatures.h @@ -474,6 +474,7 @@ #define X86_FEATURE_CLEAR_BHB_LOOP_ON_VMEXIT (21*32+ 4) /* Clear branch history at vmexit using SW loop */ #define X86_FEATURE_AMD_FAST_CPPC (21*32 + 5) /* Fast CPPC */ #define X86_FEATURE_AMD_HETEROGENEOUS_CORES (21*32 + 6) /* Heterogeneous Core Topology */ +#define X86_FEATURE_AMD_WORKLOAD_CLASS (21*32 + 7) /* Workload Classification */ /* * BUG word(s) diff --git a/arch/x86/kernel/cpu/scattered.c b/arch/x86/kernel/cpu/scattered.c index 307a917415343..1e54332594443 100644 --- a/arch/x86/kernel/cpu/scattered.c +++ b/arch/x86/kernel/cpu/scattered.c @@ -49,6 +49,7 @@ static const struct cpuid_bit cpuid_bits[] = { { X86_FEATURE_MBA, CPUID_EBX, 6, 0x80000008, 0 }, { X86_FEATURE_SMBA, CPUID_EBX, 2, 0x80000020, 0 }, { X86_FEATURE_BMEC, CPUID_EBX, 3, 0x80000020, 0 }, + { X86_FEATURE_AMD_WORKLOAD_CLASS, CPUID_EAX, 22, 0x80000021, 0 }, { X86_FEATURE_PERFMON_V2, CPUID_EAX, 0, 0x80000022, 0 }, { X86_FEATURE_AMD_LBR_V2, CPUID_EAX, 1, 0x80000022, 0 }, { X86_FEATURE_AMD_LBR_PMC_FREEZE, CPUID_EAX, 2, 0x80000022, 0 },