Messages in this thread Patch in this message | | | From | Vikas Shivappa <> | Subject | [PATCH 1/7] x86/intel_rdt: Intel Cache Allocation detection | Date | Mon, 11 May 2015 12:02:50 -0700 |
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This patch adds support for Cache Allocation Technology feature found in future Intel Xeon processors. Cache allocation is a sub-feature of Intel Resource Director Technology(RDT) which enables sharing of processor resources. This patch includes CPUID enumeration routines for Cache allocation and new values to track resources to the cpuinfo_x86 structure.
Cache allocation provides a way for the Software (OS/VMM) to restrict cache allocation to a defined 'subset' of cache which may be overlapping with other 'subsets'. This feature is used when allocating a line in cache ie when pulling new data into the cache. The programming of the h/w is done via programming MSRs.
More information about Cache allocation be found in the Intel (R) x86 Architecture Software Developer Manual,Volume 3, section 17.15.
Signed-off-by: Vikas Shivappa <vikas.shivappa@linux.intel.com> --- arch/x86/include/asm/cpufeature.h | 6 +++++- arch/x86/include/asm/processor.h | 3 +++ arch/x86/kernel/cpu/Makefile | 1 + arch/x86/kernel/cpu/common.c | 15 +++++++++++++ arch/x86/kernel/cpu/intel_rdt.c | 44 +++++++++++++++++++++++++++++++++++++++ init/Kconfig | 11 ++++++++++ 6 files changed, 79 insertions(+), 1 deletion(-) create mode 100644 arch/x86/kernel/cpu/intel_rdt.c
diff --git a/arch/x86/include/asm/cpufeature.h b/arch/x86/include/asm/cpufeature.h index 3d6606f..ae5ae9d 100644 --- a/arch/x86/include/asm/cpufeature.h +++ b/arch/x86/include/asm/cpufeature.h @@ -12,7 +12,7 @@ #include <asm/disabled-features.h> #endif -#define NCAPINTS 13 /* N 32-bit words worth of info */ +#define NCAPINTS 14 /* N 32-bit words worth of info */ #define NBUGINTS 1 /* N 32-bit bug flags */ /* @@ -229,6 +229,7 @@ #define X86_FEATURE_RTM ( 9*32+11) /* Restricted Transactional Memory */ #define X86_FEATURE_CQM ( 9*32+12) /* Cache QoS Monitoring */ #define X86_FEATURE_MPX ( 9*32+14) /* Memory Protection Extension */ +#define X86_FEATURE_RDT ( 9*32+15) /* Resource Allocation */ #define X86_FEATURE_AVX512F ( 9*32+16) /* AVX-512 Foundation */ #define X86_FEATURE_RDSEED ( 9*32+18) /* The RDSEED instruction */ #define X86_FEATURE_ADX ( 9*32+19) /* The ADCX and ADOX instructions */ @@ -252,6 +253,9 @@ /* Intel-defined CPU QoS Sub-leaf, CPUID level 0x0000000F:1 (edx), word 12 */ #define X86_FEATURE_CQM_OCCUP_LLC (12*32+ 0) /* LLC occupancy monitoring if 1 */ +/* Intel-defined CPU features, CPUID level 0x00000010:0 (ebx), word 13 */ +#define X86_FEATURE_CAT_L3 (13*32 + 1) /* Cache Allocation L3 */ + /* * BUG word(s) */ diff --git a/arch/x86/include/asm/processor.h b/arch/x86/include/asm/processor.h index 23ba676..e84de35 100644 --- a/arch/x86/include/asm/processor.h +++ b/arch/x86/include/asm/processor.h @@ -114,6 +114,9 @@ struct cpuinfo_x86 { int x86_cache_occ_scale; /* scale to bytes */ int x86_power; unsigned long loops_per_jiffy; + /* Resource Allocation values */ + u16 x86_rdt_max_cbm_len; + u16 x86_rdt_max_closid; /* cpuid returned max cores value: */ u16 x86_max_cores; u16 apicid; diff --git a/arch/x86/kernel/cpu/Makefile b/arch/x86/kernel/cpu/Makefile index 9bff687..4ff7a1f 100644 --- a/arch/x86/kernel/cpu/Makefile +++ b/arch/x86/kernel/cpu/Makefile @@ -48,6 +48,7 @@ obj-$(CONFIG_PERF_EVENTS_INTEL_UNCORE) += perf_event_intel_uncore.o \ perf_event_intel_uncore_nhmex.o endif +obj-$(CONFIG_CGROUP_RDT) += intel_rdt.o obj-$(CONFIG_X86_MCE) += mcheck/ obj-$(CONFIG_MTRR) += mtrr/ diff --git a/arch/x86/kernel/cpu/common.c b/arch/x86/kernel/cpu/common.c index a62cf04..4133d3c 100644 --- a/arch/x86/kernel/cpu/common.c +++ b/arch/x86/kernel/cpu/common.c @@ -670,6 +670,21 @@ void get_cpu_cap(struct cpuinfo_x86 *c) } } + /* Additional Intel-defined flags: level 0x00000010 */ + if (c->cpuid_level >= 0x00000010) { + u32 eax, ebx, ecx, edx; + + cpuid_count(0x00000010, 0, &eax, &ebx, &ecx, &edx); + c->x86_capability[13] = ebx; + + if (cpu_has(c, X86_FEATURE_CAT_L3)) { + + cpuid_count(0x00000010, 1, &eax, &ebx, &ecx, &edx); + c->x86_rdt_max_closid = edx + 1; + c->x86_rdt_max_cbm_len = eax + 1; + } + } + /* AMD-defined flags: level 0x80000001 */ xlvl = cpuid_eax(0x80000000); c->extended_cpuid_level = xlvl; diff --git a/arch/x86/kernel/cpu/intel_rdt.c b/arch/x86/kernel/cpu/intel_rdt.c new file mode 100644 index 0000000..f393d3e --- /dev/null +++ b/arch/x86/kernel/cpu/intel_rdt.c @@ -0,0 +1,44 @@ +/* + * Resource Director Technology(RDT) + * - Cache Allocation code. + * + * Copyright (C) 2014 Intel Corporation + * + * 2014-09-10 Written by + * Vikas Shivappa <vikas.shivappa@intel.com> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms and conditions of the GNU General Public License, + * version 2, as published by the Free Software Foundation. + * + * This program is distributed in the hope it will be useful, but WITHOUT + * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or + * FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for + * more details. + * + * More information about RDT be found in the Intel (R) x86 Architecture + * Software Developer Manual, volume 3, section 17.15. + */ + +#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt + +#include <linux/slab.h> +#include <linux/err.h> + +static int __init intel_rdt_late_init(void) +{ + struct cpuinfo_x86 *c = &boot_cpu_data; + int maxid, max_cbm_len; + + if (!cpu_has(c, X86_FEATURE_CAT_L3)) + return -ENODEV; + + maxid = c->x86_rdt_max_closid; + max_cbm_len = c->x86_rdt_max_cbm_len; + + pr_info("Max bitmask length:%u,Max ClosIds: %u\n", max_cbm_len, maxid); + + return 0; +} + +late_initcall(intel_rdt_late_init); diff --git a/init/Kconfig b/init/Kconfig index dc24dec..d97ff5e 100644 --- a/init/Kconfig +++ b/init/Kconfig @@ -983,6 +983,17 @@ config CPUSETS Say N if unsure. +config CGROUP_RDT + bool "Resource Director Technology cgroup subsystem" + depends on X86_64 && CPU_SUP_INTEL + help + This option provides a cgroup to allocate Platform shared + resources. Among the shared resources, current implementation + focuses on L3 Cache. Using the interface user can specify the + amount of L3 cache space into which an application can fill. + + Say N if unsure. + config PROC_PID_CPUSET bool "Include legacy /proc/<pid>/cpuset file" depends on CPUSETS -- 1.9.1
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