linux-kernel - [tip:x86/cpu] x86/intel_rdt/mba: Memory bandwith allocation feature detect

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Message-ID: <tip-ab66a33b032eb5b8186aeaf648127bce829c9efd@git.kernel.org>
Date:   Fri, 14 Apr 2017 07:19:17 -0700
From:   tip-bot for Vikas Shivappa <tipbot@...or.com>
To:     linux-tip-commits@...r.kernel.org
Cc:     hpa@...or.com, linux-kernel@...r.kernel.org, mingo@...nel.org,
        vikas.shivappa@...ux.intel.com, tglx@...utronix.de
Subject: [tip:x86/cpu] x86/intel_rdt/mba: Memory bandwith allocation feature
 detect

Commit-ID:  ab66a33b032eb5b8186aeaf648127bce829c9efd
Gitweb:     http://git.kernel.org/tip/ab66a33b032eb5b8186aeaf648127bce829c9efd
Author:     Vikas Shivappa <vikas.shivappa@...ux.intel.com>
AuthorDate: Fri, 7 Apr 2017 17:33:52 -0700
Committer:  Thomas Gleixner <tglx@...utronix.de>
CommitDate: Fri, 14 Apr 2017 16:10:07 +0200

x86/intel_rdt/mba: Memory bandwith allocation feature detect

Detect MBA feature if CPUID.(EAX=10H, ECX=0):EBX.L2[bit 3] = 1.
Add supporting data structures to detect feature details which is done
in later patch using CPUID with EAX=10H, ECX= 3.

Signed-off-by: Vikas Shivappa <vikas.shivappa@...ux.intel.com>
Cc: ravi.v.shankar@...el.com
Cc: tony.luck@...el.com
Cc: fenghua.yu@...el.com
Cc: vikas.shivappa@...el.com
Link: http://lkml.kernel.org/r/1491611637-20417-4-git-send-email-vikas.shivappa@linux.intel.com
Signed-off-by: Thomas Gleixner <tglx@...utronix.de>

---
 arch/x86/include/asm/cpufeatures.h | 2 ++
 arch/x86/include/asm/intel_rdt.h   | 8 ++++++++
 arch/x86/kernel/cpu/intel_rdt.c    | 4 ++++
 arch/x86/kernel/cpu/scattered.c    | 1 +
 4 files changed, 15 insertions(+)

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index b04bb6d..25d7f52 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -201,6 +201,8 @@
 #define X86_FEATURE_AVX512_4VNNIW (7*32+16) /* AVX-512 Neural Network Instructions */
 #define X86_FEATURE_AVX512_4FMAPS (7*32+17) /* AVX-512 Multiply Accumulation Single precision */
 
+#define X86_FEATURE_MBA         ( 7*32+18) /* Memory Bandwidth Allocation */
+
 /* Virtualization flags: Linux defined, word 8 */
 #define X86_FEATURE_TPR_SHADOW  ( 8*32+ 0) /* Intel TPR Shadow */
 #define X86_FEATURE_VNMI        ( 8*32+ 1) /* Intel Virtual NMI */
diff --git a/arch/x86/include/asm/intel_rdt.h b/arch/x86/include/asm/intel_rdt.h
index 51e4a1c..6295594 100644
--- a/arch/x86/include/asm/intel_rdt.h
+++ b/arch/x86/include/asm/intel_rdt.h
@@ -184,6 +184,14 @@ union cpuid_0x10_1_eax {
 	unsigned int full;
 };
 
+/* CPUID.(EAX=10H, ECX=ResID=3).EAX */
+union cpuid_0x10_3_eax {
+	struct {
+		unsigned int max_delay:12;
+	} split;
+	unsigned int full;
+};
+
 /* CPUID.(EAX=10H, ECX=ResID).EDX */
 union cpuid_0x10_x_edx {
 	struct {
diff --git a/arch/x86/kernel/cpu/intel_rdt.c b/arch/x86/kernel/cpu/intel_rdt.c
index 8486abe..82eafd6 100644
--- a/arch/x86/kernel/cpu/intel_rdt.c
+++ b/arch/x86/kernel/cpu/intel_rdt.c
@@ -430,6 +430,10 @@ static __init bool get_rdt_resources(void)
 		rdt_get_cache_config(2, &rdt_resources_all[RDT_RESOURCE_L2]);
 		ret = true;
 	}
+
+	if (boot_cpu_has(X86_FEATURE_MBA))
+		ret = true;
+
 	return ret;
 }
 
diff --git a/arch/x86/kernel/cpu/scattered.c b/arch/x86/kernel/cpu/scattered.c
index d979406..23c2350 100644
--- a/arch/x86/kernel/cpu/scattered.c
+++ b/arch/x86/kernel/cpu/scattered.c
@@ -27,6 +27,7 @@ static const struct cpuid_bit cpuid_bits[] = {
 	{ X86_FEATURE_CAT_L3,		CPUID_EBX,  1, 0x00000010, 0 },
 	{ X86_FEATURE_CAT_L2,		CPUID_EBX,  2, 0x00000010, 0 },
 	{ X86_FEATURE_CDP_L3,		CPUID_ECX,  2, 0x00000010, 1 },
+	{ X86_FEATURE_MBA,		CPUID_EBX,  3, 0x00000010, 0 },
 	{ 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 },