linux-kernel - [PATCH 09/32] x86/intel_rdt: Intel Code Data Prioritization detection

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Date:	Tue, 12 Jul 2016 18:02:42 -0700
From:	"Fenghua Yu" <fenghua.yu@...el.com>
To:	"Thomas Gleixner" <tglx@...utronix.de>,
	"Ingo Molnar" <mingo@...e.hu>,
	"H. Peter Anvin" <h.peter.anvin@...el.com>,
	"Tony Luck" <tony.luck@...el.com>, "Tejun Heo" <tj@...nel.org>,
	"Borislav Petkov" <bp@...e.de>,
	"Stephane Eranian" <eranian@...gle.com>,
	"Peter Zijlstra" <peterz@...radead.org>,
	"Marcelo Tosatti" <mtosatti@...hat.com>,
	"David Carrillo-Cisneros" <davidcc@...gle.com>,
	"Ravi V Shankar" <ravi.v.shankar@...el.com>,
	"Vikas Shivappa" <vikas.shivappa@...ux.intel.com>,
	"Sai Prakhya" <sai.praneeth.prakhya@...el.com>
Cc:	"linux-kernel" <linux-kernel@...r.kernel.org>,
	"x86" <x86@...nel.org>, "Fenghua Yu" <fenghua.yu@...el.com>
Subject: [PATCH 09/32] x86/intel_rdt: Intel Code Data Prioritization detection

From: Vikas Shivappa <vikas.shivappa@...ux.intel.com>

This patch adds enumeration support for Code Data Prioritization(CDP)
feature found in future Intel Xeon processors. It includes CPUID
enumeration routines for CDP.

CDP is an extension to Cache Allocation and lets threads allocate subset
of L3 cache for code and data separately. The allocation is represented
by the code or data cache capacity bit mask(cbm) MSRs
IA32_L3_QOS_MASK_n. Each Class of service would be associated with one
dcache_cbm and one icache_cbm MSR and hence the number of available
CLOSids is halved with CDP. The association for a CLOSid 'n' is shown
below :

data_cbm_address (n) = base + (n <<1)
code_cbm_address (n) = base + (n <<1) +1.
During scheduling the kernel writes the CLOSid
of the thread to IA32_PQR_ASSOC_MSR.

Signed-off-by: Vikas Shivappa <vikas.shivappa@...ux.intel.com>
Signed-off-by: Fenghua Yu <fenghua.yu@...el.com>
Reviewed-by: Tony Luck <tony.luck@...el.com>
---
 arch/x86/include/asm/cpufeatures.h | 5 ++++-
 arch/x86/kernel/cpu/common.c       | 3 ++-
 arch/x86/kernel/cpu/intel_rdt.c    | 2 ++
 3 files changed, 8 insertions(+), 2 deletions(-)

diff --git a/arch/x86/include/asm/cpufeatures.h b/arch/x86/include/asm/cpufeatures.h
index 667acf3..16489b3 100644
--- a/arch/x86/include/asm/cpufeatures.h
+++ b/arch/x86/include/asm/cpufeatures.h
@@ -12,7 +12,7 @@
 /*
  * Defines x86 CPU feature bits
  */
-#define NCAPINTS	19	/* N 32-bit words worth of info */
+#define NCAPINTS	20	/* N 32-bit words worth of info */
 #define NBUGINTS	1	/* N 32-bit bug flags */
 
 /*
@@ -291,6 +291,9 @@
 /* Intel-defined CPU features, CPUID level 0x00000010:0 (ebx), word 18 */
 #define X86_FEATURE_CAT_L3      (18*32+ 1) /* Cache Allocation L3 */
 
+/* Intel-defined CPU QoS Sub-leaf, CPUID level 0x00000010:1 (ecx), word 19 */
+#define X86_FEATURE_CDP_L3	(19*32+ 2) /* Code data prioritization L3 */
+
 /*
  * BUG word(s)
  */
diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c
index 42c90cb..a695e58 100644
--- a/arch/x86/kernel/cpu/common.c
+++ b/arch/x86/kernel/cpu/common.c
@@ -716,13 +716,14 @@ void get_cpu_cap(struct cpuinfo_x86 *c)
 		u32 eax, ebx, ecx, edx;
 
 		cpuid_count(0x00000010, 0, &eax, &ebx, &ecx, &edx);
-		c->x86_capability[14] = ebx;
+		c->x86_capability[17] = ebx;
 
 		if (cpu_has(c, X86_FEATURE_CAT_L3)) {
 
 			cpuid_count(0x00000010, 1, &eax, &ebx, &ecx, &edx);
 			c->x86_cache_max_closid = edx + 1;
 			c->x86_cache_max_cbm_len = eax + 1;
+			c->x86_capability[18] = ecx;
 		}
 	}
 
diff --git a/arch/x86/kernel/cpu/intel_rdt.c b/arch/x86/kernel/cpu/intel_rdt.c
index 525390a..5fa0f9d 100644
--- a/arch/x86/kernel/cpu/intel_rdt.c
+++ b/arch/x86/kernel/cpu/intel_rdt.c
@@ -399,6 +399,8 @@ static int __init intel_rdt_late_init(void)
 
 	static_key_slow_inc(&rdt_enable_key);
 	pr_info("Intel cache allocation enabled\n");
+	if (cpu_has(c, X86_FEATURE_CDP_L3))
+		pr_info("Intel code data prioritization detected\n");
 out_err:
 
 	return err;
-- 
2.5.0