kernel/arch/x86/kvm/pmu_amd.c

   1 /*
   2  * KVM PMU support for AMD
   3  *
   4  * Copyright 2015, Red Hat, Inc. and/or its affiliates.
   5  *
   6  * Author:
   7  *   Wei Huang <wei@redhat.com>
   8  *
   9  * This work is licensed under the terms of the GNU GPL, version 2.  See
  10  * the COPYING file in the top-level directory.
  11  *
  12  * Implementation is based on pmu_intel.c file
  13  */
  14 #include <linux/types.h>
  15 #include <linux/kvm_host.h>
  16 #include <linux/perf_event.h>
  17 #include "x86.h"
  18 #include "cpuid.h"
  19 #include "lapic.h"
  20 #include "pmu.h"
  21
  22 /* duplicated from amd_perfmon_event_map, K7 and above should work. */
  23 static struct kvm_event_hw_type_mapping amd_event_mapping[] = {
  24         [0] = { 0x76, 0x00, PERF_COUNT_HW_CPU_CYCLES },
  25         [1] = { 0xc0, 0x00, PERF_COUNT_HW_INSTRUCTIONS },
  26         [2] = { 0x80, 0x00, PERF_COUNT_HW_CACHE_REFERENCES },
  27         [3] = { 0x81, 0x00, PERF_COUNT_HW_CACHE_MISSES },
  28         [4] = { 0xc2, 0x00, PERF_COUNT_HW_BRANCH_INSTRUCTIONS },
  29         [5] = { 0xc3, 0x00, PERF_COUNT_HW_BRANCH_MISSES },
  30         [6] = { 0xd0, 0x00, PERF_COUNT_HW_STALLED_CYCLES_FRONTEND },
  31         [7] = { 0xd1, 0x00, PERF_COUNT_HW_STALLED_CYCLES_BACKEND },
  32 };
  33
  34 static unsigned amd_find_arch_event(struct kvm_pmu *pmu,
  35                                     u8 event_select,
  36                                     u8 unit_mask)
  37 {
  38         int i;
  39
  40         for (i = 0; i < ARRAY_SIZE(amd_event_mapping); i++)
  41                 if (amd_event_mapping[i].eventsel == event_select
  42                     && amd_event_mapping[i].unit_mask == unit_mask)
  43                         break;
  44
  45         if (i == ARRAY_SIZE(amd_event_mapping))
  46                 return PERF_COUNT_HW_MAX;
  47
  48         return amd_event_mapping[i].event_type;
  49 }
  50
  51 /* return PERF_COUNT_HW_MAX as AMD doesn't have fixed events */
  52 static unsigned amd_find_fixed_event(int idx)
  53 {
  54         return PERF_COUNT_HW_MAX;
  55 }
  56
  57 /* check if a PMC is enabled by comparing it against global_ctrl bits. Because
  58  * AMD CPU doesn't have global_ctrl MSR, all PMCs are enabled (return TRUE).
  59  */
  60 static bool amd_pmc_is_enabled(struct kvm_pmc *pmc)
  61 {
  62         return true;
  63 }
  64
  65 static struct kvm_pmc *amd_pmc_idx_to_pmc(struct kvm_pmu *pmu, int pmc_idx)
  66 {
  67         return get_gp_pmc(pmu, MSR_K7_EVNTSEL0 + pmc_idx, MSR_K7_EVNTSEL0);
  68 }
  69
  70 /* returns 0 if idx's corresponding MSR exists; otherwise returns 1. */
  71 static int amd_is_valid_msr_idx(struct kvm_vcpu *vcpu, unsigned idx)
  72 {
  73         struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
  74
  75         idx &= ~(3u << 30);
  76
  77         return (idx >= pmu->nr_arch_gp_counters);
  78 }
  79
  80 /* idx is the ECX register of RDPMC instruction */
  81 static struct kvm_pmc *amd_msr_idx_to_pmc(struct kvm_vcpu *vcpu, unsigned idx)
  82 {
  83         struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
  84         struct kvm_pmc *counters;
  85
  86         idx &= ~(3u << 30);
  87         if (idx >= pmu->nr_arch_gp_counters)
  88                 return NULL;
  89         counters = pmu->gp_counters;
  90
  91         return &counters[idx];
  92 }
  93
  94 static bool amd_is_valid_msr(struct kvm_vcpu *vcpu, u32 msr)
  95 {
  96         struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
  97         int ret = false;
  98
  99         ret = get_gp_pmc(pmu, msr, MSR_K7_PERFCTR0) ||
 100                 get_gp_pmc(pmu, msr, MSR_K7_EVNTSEL0);
 101
 102         return ret;
 103 }
 104
 105 static int amd_pmu_get_msr(struct kvm_vcpu *vcpu, u32 msr, u64 *data)
 106 {
 107         struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
 108         struct kvm_pmc *pmc;
 109
 110         /* MSR_K7_PERFCTRn */
 111         pmc = get_gp_pmc(pmu, msr, MSR_K7_PERFCTR0);
 112         if (pmc) {
 113                 *data = pmc_read_counter(pmc);
 114                 return 0;
 115         }
 116         /* MSR_K7_EVNTSELn */
 117         pmc = get_gp_pmc(pmu, msr, MSR_K7_EVNTSEL0);
 118         if (pmc) {
 119                 *data = pmc->eventsel;
 120                 return 0;
 121         }
 122
 123         return 1;
 124 }
 125
 126 static int amd_pmu_set_msr(struct kvm_vcpu *vcpu, struct msr_data *msr_info)
 127 {
 128         struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
 129         struct kvm_pmc *pmc;
 130         u32 msr = msr_info->index;
 131         u64 data = msr_info->data;
 132
 133         /* MSR_K7_PERFCTRn */
 134         pmc = get_gp_pmc(pmu, msr, MSR_K7_PERFCTR0);
 135         if (pmc) {
 136                 pmc->counter += data - pmc_read_counter(pmc);
 137                 return 0;
 138         }
 139         /* MSR_K7_EVNTSELn */
 140         pmc = get_gp_pmc(pmu, msr, MSR_K7_EVNTSEL0);
 141         if (pmc) {
 142                 if (data == pmc->eventsel)
 143                         return 0;
 144                 if (!(data & pmu->reserved_bits)) {
 145                         reprogram_gp_counter(pmc, data);
 146                         return 0;
 147                 }
 148         }
 149
 150         return 1;
 151 }
 152
 153 static void amd_pmu_refresh(struct kvm_vcpu *vcpu)
 154 {
 155         struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
 156
 157         pmu->nr_arch_gp_counters = AMD64_NUM_COUNTERS;
 158         pmu->counter_bitmask[KVM_PMC_GP] = ((u64)1 << 48) - 1;
 159         pmu->reserved_bits = 0xffffffff00200000ull;
 160         /* not applicable to AMD; but clean them to prevent any fall out */
 161         pmu->counter_bitmask[KVM_PMC_FIXED] = 0;
 162         pmu->nr_arch_fixed_counters = 0;
 163         pmu->version = 0;
 164         pmu->global_status = 0;
 165 }
 166
 167 static void amd_pmu_init(struct kvm_vcpu *vcpu)
 168 {
 169         struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
 170         int i;
 171
 172         for (i = 0; i < AMD64_NUM_COUNTERS ; i++) {
 173                 pmu->gp_counters[i].type = KVM_PMC_GP;
 174                 pmu->gp_counters[i].vcpu = vcpu;
 175                 pmu->gp_counters[i].idx = i;
 176         }
 177 }
 178
 179 static void amd_pmu_reset(struct kvm_vcpu *vcpu)
 180 {
 181         struct kvm_pmu *pmu = vcpu_to_pmu(vcpu);
 182         int i;
 183
 184         for (i = 0; i < AMD64_NUM_COUNTERS; i++) {
 185                 struct kvm_pmc *pmc = &pmu->gp_counters[i];
 186
 187                 pmc_stop_counter(pmc);
 188                 pmc->counter = pmc->eventsel = 0;
 189         }
 190 }
 191
 192 struct kvm_pmu_ops amd_pmu_ops = {
 193         .find_arch_event = amd_find_arch_event,
 194         .find_fixed_event = amd_find_fixed_event,
 195         .pmc_is_enabled = amd_pmc_is_enabled,
 196         .pmc_idx_to_pmc = amd_pmc_idx_to_pmc,
 197         .msr_idx_to_pmc = amd_msr_idx_to_pmc,
 198         .is_valid_msr_idx = amd_is_valid_msr_idx,
 199         .is_valid_msr = amd_is_valid_msr,
 200         .get_msr = amd_pmu_get_msr,
 201         .set_msr = amd_pmu_set_msr,
 202         .refresh = amd_pmu_refresh,
 203         .init = amd_pmu_init,
 204         .reset = amd_pmu_reset,
 205 };