The following commit has been merged into the perf/core branch of tip: Commit-ID: 32451614da2a9cf4296f90d3606ac77814fb519d Gitweb: https://git.kernel.org/tip/32451614da2a9cf4296f90d3606ac77814fb519d Author: Kan Liang <kan.li...@linux.intel.com> AuthorDate: Thu, 28 Jan 2021 14:40:11 -08:00 Committer: Peter Zijlstra <pet...@infradead.org> CommitterDate: Mon, 01 Feb 2021 15:31:37 +01:00
perf/x86/intel: Support CPUID 10.ECX to disable fixed counters With Architectural Performance Monitoring Version 5, CPUID 10.ECX cpu leaf indicates the fixed counter enumeration. This extends the previous count to a bitmap which allows disabling even lower fixed counters. It could be used by a Hypervisor. The existing intel_ctrl variable is used to remember the bitmask of the counters. All code that reads all counters is fixed to check this extra bitmask. Suggested-by: Peter Zijlstra (Intel) <pet...@infradead.org> Originally-by: Andi Kleen <a...@linux.intel.com> Signed-off-by: Kan Liang <kan.li...@linux.intel.com> Signed-off-by: Peter Zijlstra (Intel) <pet...@infradead.org> Link: https://lkml.kernel.org/r/1611873611-156687-6-git-send-email-kan.li...@linux.intel.com --- arch/x86/events/core.c | 8 +++++++- arch/x86/events/intel/core.c | 34 ++++++++++++++++++++++++---------- arch/x86/events/perf_event.h | 5 +++++ 3 files changed, 36 insertions(+), 11 deletions(-) diff --git a/arch/x86/events/core.c b/arch/x86/events/core.c index cf0a52c..6ddeed3 100644 --- a/arch/x86/events/core.c +++ b/arch/x86/events/core.c @@ -255,6 +255,8 @@ static bool check_hw_exists(void) if (ret) goto msr_fail; for (i = 0; i < x86_pmu.num_counters_fixed; i++) { + if (fixed_counter_disabled(i)) + continue; if (val & (0x03 << i*4)) { bios_fail = 1; val_fail = val; @@ -1531,6 +1533,8 @@ void perf_event_print_debug(void) cpu, idx, prev_left); } for (idx = 0; idx < x86_pmu.num_counters_fixed; idx++) { + if (fixed_counter_disabled(idx)) + continue; rdmsrl(MSR_ARCH_PERFMON_FIXED_CTR0 + idx, pmc_count); pr_info("CPU#%d: fixed-PMC%d count: %016llx\n", @@ -2012,7 +2016,9 @@ static int __init init_hw_perf_events(void) pr_info("... generic registers: %d\n", x86_pmu.num_counters); pr_info("... value mask: %016Lx\n", x86_pmu.cntval_mask); pr_info("... max period: %016Lx\n", x86_pmu.max_period); - pr_info("... fixed-purpose events: %d\n", x86_pmu.num_counters_fixed); + pr_info("... fixed-purpose events: %lu\n", + hweight64((((1ULL << x86_pmu.num_counters_fixed) - 1) + << INTEL_PMC_IDX_FIXED) & x86_pmu.intel_ctrl)); pr_info("... event mask: %016Lx\n", x86_pmu.intel_ctrl); if (!x86_pmu.read) diff --git a/arch/x86/events/intel/core.c b/arch/x86/events/intel/core.c index 58cd64e..67a7246 100644 --- a/arch/x86/events/intel/core.c +++ b/arch/x86/events/intel/core.c @@ -2723,8 +2723,11 @@ static void intel_pmu_reset(void) wrmsrl_safe(x86_pmu_config_addr(idx), 0ull); wrmsrl_safe(x86_pmu_event_addr(idx), 0ull); } - for (idx = 0; idx < x86_pmu.num_counters_fixed; idx++) + for (idx = 0; idx < x86_pmu.num_counters_fixed; idx++) { + if (fixed_counter_disabled(idx)) + continue; wrmsrl_safe(MSR_ARCH_PERFMON_FIXED_CTR0 + idx, 0ull); + } if (ds) ds->bts_index = ds->bts_buffer_base; @@ -5042,7 +5045,7 @@ __init int intel_pmu_init(void) union cpuid10_eax eax; union cpuid10_ebx ebx; struct event_constraint *c; - unsigned int unused; + unsigned int fixed_mask; struct extra_reg *er; bool pmem = false; int version, i; @@ -5064,7 +5067,7 @@ __init int intel_pmu_init(void) * Check whether the Architectural PerfMon supports * Branch Misses Retired hw_event or not. */ - cpuid(10, &eax.full, &ebx.full, &unused, &edx.full); + cpuid(10, &eax.full, &ebx.full, &fixed_mask, &edx.full); if (eax.split.mask_length < ARCH_PERFMON_EVENTS_COUNT) return -ENODEV; @@ -5088,12 +5091,15 @@ __init int intel_pmu_init(void) * Quirk: v2 perfmon does not report fixed-purpose events, so * assume at least 3 events, when not running in a hypervisor: */ - if (version > 1) { + if (version > 1 && version < 5) { int assume = 3 * !boot_cpu_has(X86_FEATURE_HYPERVISOR); x86_pmu.num_counters_fixed = max((int)edx.split.num_counters_fixed, assume); - } + + fixed_mask = (1L << x86_pmu.num_counters_fixed) - 1; + } else if (version >= 5) + x86_pmu.num_counters_fixed = fls(fixed_mask); if (boot_cpu_has(X86_FEATURE_PDCM)) { u64 capabilities; @@ -5680,8 +5686,7 @@ __init int intel_pmu_init(void) x86_pmu.num_counters_fixed = INTEL_PMC_MAX_FIXED; } - x86_pmu.intel_ctrl |= - ((1LL << x86_pmu.num_counters_fixed)-1) << INTEL_PMC_IDX_FIXED; + x86_pmu.intel_ctrl |= (u64)fixed_mask << INTEL_PMC_IDX_FIXED; /* AnyThread may be deprecated on arch perfmon v5 or later */ if (x86_pmu.intel_cap.anythread_deprecated) @@ -5698,13 +5703,22 @@ __init int intel_pmu_init(void) * events to the generic counters. */ if (c->idxmsk64 & INTEL_PMC_MSK_TOPDOWN) { + /* + * Disable topdown slots and metrics events, + * if slots event is not in CPUID. + */ + if (!(INTEL_PMC_MSK_FIXED_SLOTS & x86_pmu.intel_ctrl)) + c->idxmsk64 = 0; c->weight = hweight64(c->idxmsk64); continue; } - if (c->cmask == FIXED_EVENT_FLAGS - && c->idxmsk64 != INTEL_PMC_MSK_FIXED_REF_CYCLES) { - c->idxmsk64 |= (1ULL << x86_pmu.num_counters) - 1; + if (c->cmask == FIXED_EVENT_FLAGS) { + /* Disabled fixed counters which are not in CPUID */ + c->idxmsk64 &= x86_pmu.intel_ctrl; + + if (c->idxmsk64 != INTEL_PMC_MSK_FIXED_REF_CYCLES) + c->idxmsk64 |= (1ULL << x86_pmu.num_counters) - 1; } c->idxmsk64 &= ~(~0ULL << (INTEL_PMC_IDX_FIXED + x86_pmu.num_counters_fixed)); diff --git a/arch/x86/events/perf_event.h b/arch/x86/events/perf_event.h index b8bf2ce..53b2b5f 100644 --- a/arch/x86/events/perf_event.h +++ b/arch/x86/events/perf_event.h @@ -1068,6 +1068,11 @@ ssize_t events_sysfs_show(struct device *dev, struct device_attribute *attr, ssize_t events_ht_sysfs_show(struct device *dev, struct device_attribute *attr, char *page); +static inline bool fixed_counter_disabled(int i) +{ + return !(x86_pmu.intel_ctrl >> (i + INTEL_PMC_IDX_FIXED)); +} + #ifdef CONFIG_CPU_SUP_AMD int amd_pmu_init(void);
