Commit 0c487010 authored by Perry Yuan's avatar Perry Yuan Committed by Borislav Petkov (AMD)
Browse files

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: default avatarPerry Yuan <perry.yuan@amd.com>
Signed-off-by: default avatarMario Limonciello <mario.limonciello@amd.com>
Signed-off-by: default avatarBorislav Petkov (AMD) <bp@alien8.de>
Reviewed-by: default avatarGautham R. Shenoy <gautham.shenoy@amd.com>
Link: https://lore.kernel.org/r/20241028020251.8085-4-mario.limonciello@amd.com
parent 3eef25ab

arch/x86/include/asm/cpufeatures.h

+1 −0
Original line number Diff line number Diff line
@@ -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)

arch/x86/kernel/cpu/scattered.c

+1 −0
Original line number Diff line number Diff line
@@ -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 },