x86/resctrl: Enumerate per-thread MBA controls

Some systems support per-thread Memory Bandwidth Allocation (MBA) which
applies a throttling delay value to each hardware thread instead of to
a core. Per-thread MBA is enumerated by CPUID.

No feature flag is shown in /proc/cpuinfo. User applications need to
check a resctrl throttling mode info file to know if the feature is
supported.

Signed-off-by: Fenghua Yu <fenghua.yu@intel.com>
Signed-off-by: Borislav Petkov <bp@suse.de>
Reviewed-by: Babu Moger <babu.moger@amd.com>
Reviewed-by: Reinette Chatre <reinette.chatre@intel.com>
Link: https://lkml.kernel.org/r/1598296281-127595-2-git-send-email-fenghua.yu@intel.com

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 2901d5d..4a7473a 100644 (file)
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -288,6 +288,7 @@
 #define X86_FEATURE_FENCE_SWAPGS_USER  (11*32+ 4) /* "" LFENCE in user entry SWAPGS path */
 #define X86_FEATURE_FENCE_SWAPGS_KERNEL        (11*32+ 5) /* "" LFENCE in kernel entry SWAPGS path */
 #define X86_FEATURE_SPLIT_LOCK_DETECT  (11*32+ 6) /* #AC for split lock */
+#define X86_FEATURE_PER_THREAD_MBA     (11*32+ 7) /* "" Per-thread Memory Bandwidth Allocation */
 
 /* Intel-defined CPU features, CPUID level 0x00000007:1 (EAX), word 12 */
 #define X86_FEATURE_AVX512_BF16                (12*32+ 5) /* AVX512 BFLOAT16 instructions */

diff --git a/arch/x86/kernel/cpu/cpuid-deps.c b/arch/x86/kernel/cpu/cpuid-deps.c
index 3cbe24c..3e30b26 100644 (file)
--- a/arch/x86/kernel/cpu/cpuid-deps.c
+++ b/arch/x86/kernel/cpu/cpuid-deps.c
@@ -69,6 +69,7 @@ static const struct cpuid_dep cpuid_deps[] = {
        { X86_FEATURE_CQM_MBM_TOTAL,            X86_FEATURE_CQM_LLC   },
        { X86_FEATURE_CQM_MBM_LOCAL,            X86_FEATURE_CQM_LLC   },
        { X86_FEATURE_AVX512_BF16,              X86_FEATURE_AVX512VL  },
+       { X86_FEATURE_PER_THREAD_MBA,           X86_FEATURE_MBA       },
        {}
 };
 

diff --git a/arch/x86/kernel/cpu/scattered.c b/arch/x86/kernel/cpu/scattered.c
index 62b137c..bccfc9f 100644 (file)
--- a/arch/x86/kernel/cpu/scattered.c
+++ b/arch/x86/kernel/cpu/scattered.c
@@ -35,6 +35,7 @@ static const struct cpuid_bit cpuid_bits[] = {
        { X86_FEATURE_CDP_L3,           CPUID_ECX,  2, 0x00000010, 1 },
        { X86_FEATURE_CDP_L2,           CPUID_ECX,  2, 0x00000010, 2 },
        { X86_FEATURE_MBA,              CPUID_EBX,  3, 0x00000010, 0 },
+       { X86_FEATURE_PER_THREAD_MBA,   CPUID_ECX,  0, 0x00000010, 3 },
        { X86_FEATURE_HW_PSTATE,        CPUID_EDX,  7, 0x80000007, 0 },
        { X86_FEATURE_CPB,              CPUID_EDX,  9, 0x80000007, 0 },
        { X86_FEATURE_PROC_FEEDBACK,    CPUID_EDX, 11, 0x80000007, 0 },