LXR linux/arch/arm64/kvm/pmu.c

   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Copyright 2019 Arm Limited
   4 * Author: Andrew Murray <Andrew.Murray@arm.com>
   5 */
   6#include <linux/kvm_host.h>
   7#include <linux/perf_event.h>
   8#include <asm/kvm_hyp.h>
   9
  10/*
  11 * Given the perf event attributes and system type, determine
  12 * if we are going to need to switch counters at guest entry/exit.
  13 */
  14static bool kvm_pmu_switch_needed(struct perf_event_attr *attr)
  15{
  16        /**
  17         * With VHE the guest kernel runs at EL1 and the host at EL2,
  18         * where user (EL0) is excluded then we have no reason to switch
  19         * counters.
  20         */
  21        if (has_vhe() && attr->exclude_user)
  22                return false;
  23
  24        /* Only switch if attributes are different */
  25        return (attr->exclude_host != attr->exclude_guest);
  26}
  27
  28/*
  29 * Add events to track that we may want to switch at guest entry/exit
  30 * time.
  31 */
  32void kvm_set_pmu_events(u32 set, struct perf_event_attr *attr)
  33{
  34        struct kvm_host_data *ctx = this_cpu_ptr_hyp_sym(kvm_host_data);
  35
  36        if (!ctx || !kvm_pmu_switch_needed(attr))
  37                return;
  38
  39        if (!attr->exclude_host)
  40                ctx->pmu_events.events_host |= set;
  41        if (!attr->exclude_guest)
  42                ctx->pmu_events.events_guest |= set;
  43}
  44
  45/*
  46 * Stop tracking events
  47 */
  48void kvm_clr_pmu_events(u32 clr)
  49{
  50        struct kvm_host_data *ctx = this_cpu_ptr_hyp_sym(kvm_host_data);
  51
  52        if (!ctx)
  53                return;
  54
  55        ctx->pmu_events.events_host &= ~clr;
  56        ctx->pmu_events.events_guest &= ~clr;
  57}
  58
  59#define PMEVTYPER_READ_CASE(idx)                                \
  60        case idx:                                               \
  61                return read_sysreg(pmevtyper##idx##_el0)
  62
  63#define PMEVTYPER_WRITE_CASE(idx)                               \
  64        case idx:                                               \
  65                write_sysreg(val, pmevtyper##idx##_el0);        \
  66                break
  67
  68#define PMEVTYPER_CASES(readwrite)                              \
  69        PMEVTYPER_##readwrite##_CASE(0);                        \
  70        PMEVTYPER_##readwrite##_CASE(1);                        \
  71        PMEVTYPER_##readwrite##_CASE(2);                        \
  72        PMEVTYPER_##readwrite##_CASE(3);                        \
  73        PMEVTYPER_##readwrite##_CASE(4);                        \
  74        PMEVTYPER_##readwrite##_CASE(5);                        \
  75        PMEVTYPER_##readwrite##_CASE(6);                        \
  76        PMEVTYPER_##readwrite##_CASE(7);                        \
  77        PMEVTYPER_##readwrite##_CASE(8);                        \
  78        PMEVTYPER_##readwrite##_CASE(9);                        \
  79        PMEVTYPER_##readwrite##_CASE(10);                       \
  80        PMEVTYPER_##readwrite##_CASE(11);                       \
  81        PMEVTYPER_##readwrite##_CASE(12);                       \
  82        PMEVTYPER_##readwrite##_CASE(13);                       \
  83        PMEVTYPER_##readwrite##_CASE(14);                       \
  84        PMEVTYPER_##readwrite##_CASE(15);                       \
  85        PMEVTYPER_##readwrite##_CASE(16);                       \
  86        PMEVTYPER_##readwrite##_CASE(17);                       \
  87        PMEVTYPER_##readwrite##_CASE(18);                       \
  88        PMEVTYPER_##readwrite##_CASE(19);                       \
  89        PMEVTYPER_##readwrite##_CASE(20);                       \
  90        PMEVTYPER_##readwrite##_CASE(21);                       \
  91        PMEVTYPER_##readwrite##_CASE(22);                       \
  92        PMEVTYPER_##readwrite##_CASE(23);                       \
  93        PMEVTYPER_##readwrite##_CASE(24);                       \
  94        PMEVTYPER_##readwrite##_CASE(25);                       \
  95        PMEVTYPER_##readwrite##_CASE(26);                       \
  96        PMEVTYPER_##readwrite##_CASE(27);                       \
  97        PMEVTYPER_##readwrite##_CASE(28);                       \
  98        PMEVTYPER_##readwrite##_CASE(29);                       \
  99        PMEVTYPER_##readwrite##_CASE(30)
 100
 101/*
 102 * Read a value direct from PMEVTYPER<idx> where idx is 0-30
 103 * or PMCCFILTR_EL0 where idx is ARMV8_PMU_CYCLE_IDX (31).
 104 */
 105static u64 kvm_vcpu_pmu_read_evtype_direct(int idx)
 106{
 107        switch (idx) {
 108        PMEVTYPER_CASES(READ);
 109        case ARMV8_PMU_CYCLE_IDX:
 110                return read_sysreg(pmccfiltr_el0);
 111        default:
 112                WARN_ON(1);
 113        }
 114
 115        return 0;
 116}
 117
 118/*
 119 * Write a value direct to PMEVTYPER<idx> where idx is 0-30
 120 * or PMCCFILTR_EL0 where idx is ARMV8_PMU_CYCLE_IDX (31).
 121 */
 122static void kvm_vcpu_pmu_write_evtype_direct(int idx, u32 val)
 123{
 124        switch (idx) {
 125        PMEVTYPER_CASES(WRITE);
 126        case ARMV8_PMU_CYCLE_IDX:
 127                write_sysreg(val, pmccfiltr_el0);
 128                break;
 129        default:
 130                WARN_ON(1);
 131        }
 132}
 133
 134/*
 135 * Modify ARMv8 PMU events to include EL0 counting
 136 */
 137static void kvm_vcpu_pmu_enable_el0(unsigned long events)
 138{
 139        u64 typer;
 140        u32 counter;
 141
 142        for_each_set_bit(counter, &events, 32) {
 143                typer = kvm_vcpu_pmu_read_evtype_direct(counter);
 144                typer &= ~ARMV8_PMU_EXCLUDE_EL0;
 145                kvm_vcpu_pmu_write_evtype_direct(counter, typer);
 146        }
 147}
 148
 149/*
 150 * Modify ARMv8 PMU events to exclude EL0 counting
 151 */
 152static void kvm_vcpu_pmu_disable_el0(unsigned long events)
 153{
 154        u64 typer;
 155        u32 counter;
 156
 157        for_each_set_bit(counter, &events, 32) {
 158                typer = kvm_vcpu_pmu_read_evtype_direct(counter);
 159                typer |= ARMV8_PMU_EXCLUDE_EL0;
 160                kvm_vcpu_pmu_write_evtype_direct(counter, typer);
 161        }
 162}
 163
 164/*
 165 * On VHE ensure that only guest events have EL0 counting enabled.
 166 * This is called from both vcpu_{load,put} and the sysreg handling.
 167 * Since the latter is preemptible, special care must be taken to
 168 * disable preemption.
 169 */
 170void kvm_vcpu_pmu_restore_guest(struct kvm_vcpu *vcpu)
 171{
 172        struct kvm_host_data *host;
 173        u32 events_guest, events_host;
 174
 175        if (!has_vhe())
 176                return;
 177
 178        preempt_disable();
 179        host = this_cpu_ptr_hyp_sym(kvm_host_data);
 180        events_guest = host->pmu_events.events_guest;
 181        events_host = host->pmu_events.events_host;
 182
 183        kvm_vcpu_pmu_enable_el0(events_guest);
 184        kvm_vcpu_pmu_disable_el0(events_host);
 185        preempt_enable();
 186}
 187
 188/*
 189 * On VHE ensure that only host events have EL0 counting enabled
 190 */
 191void kvm_vcpu_pmu_restore_host(struct kvm_vcpu *vcpu)
 192{
 193        struct kvm_host_data *host;
 194        u32 events_guest, events_host;
 195
 196        if (!has_vhe())
 197                return;
 198
 199        host = this_cpu_ptr_hyp_sym(kvm_host_data);
 200        events_guest = host->pmu_events.events_guest;
 201        events_host = host->pmu_events.events_host;
 202
 203        kvm_vcpu_pmu_enable_el0(events_host);
 204        kvm_vcpu_pmu_disable_el0(events_guest);
 205}
 206