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 */ 14 static 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 */ 32 void kvm_set_pmu_events(u32 set, struct perf_event_attr *attr) 33 { 34 struct kvm_host_data *ctx = this_cpu_ptr(&kvm_host_data); 35 36 if (!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 */ 48 void kvm_clr_pmu_events(u32 clr) 49 { 50 struct kvm_host_data *ctx = this_cpu_ptr(&kvm_host_data); 51 52 ctx->pmu_events.events_host &= ~clr; 53 ctx->pmu_events.events_guest &= ~clr; 54 } 55 56 #define PMEVTYPER_READ_CASE(idx) \ 57 case idx: \ 58 return read_sysreg(pmevtyper##idx##_el0) 59 60 #define PMEVTYPER_WRITE_CASE(idx) \ 61 case idx: \ 62 write_sysreg(val, pmevtyper##idx##_el0); \ 63 break 64 65 #define PMEVTYPER_CASES(readwrite) \ 66 PMEVTYPER_##readwrite##_CASE(0); \ 67 PMEVTYPER_##readwrite##_CASE(1); \ 68 PMEVTYPER_##readwrite##_CASE(2); \ 69 PMEVTYPER_##readwrite##_CASE(3); \ 70 PMEVTYPER_##readwrite##_CASE(4); \ 71 PMEVTYPER_##readwrite##_CASE(5); \ 72 PMEVTYPER_##readwrite##_CASE(6); \ 73 PMEVTYPER_##readwrite##_CASE(7); \ 74 PMEVTYPER_##readwrite##_CASE(8); \ 75 PMEVTYPER_##readwrite##_CASE(9); \ 76 PMEVTYPER_##readwrite##_CASE(10); \ 77 PMEVTYPER_##readwrite##_CASE(11); \ 78 PMEVTYPER_##readwrite##_CASE(12); \ 79 PMEVTYPER_##readwrite##_CASE(13); \ 80 PMEVTYPER_##readwrite##_CASE(14); \ 81 PMEVTYPER_##readwrite##_CASE(15); \ 82 PMEVTYPER_##readwrite##_CASE(16); \ 83 PMEVTYPER_##readwrite##_CASE(17); \ 84 PMEVTYPER_##readwrite##_CASE(18); \ 85 PMEVTYPER_##readwrite##_CASE(19); \ 86 PMEVTYPER_##readwrite##_CASE(20); \ 87 PMEVTYPER_##readwrite##_CASE(21); \ 88 PMEVTYPER_##readwrite##_CASE(22); \ 89 PMEVTYPER_##readwrite##_CASE(23); \ 90 PMEVTYPER_##readwrite##_CASE(24); \ 91 PMEVTYPER_##readwrite##_CASE(25); \ 92 PMEVTYPER_##readwrite##_CASE(26); \ 93 PMEVTYPER_##readwrite##_CASE(27); \ 94 PMEVTYPER_##readwrite##_CASE(28); \ 95 PMEVTYPER_##readwrite##_CASE(29); \ 96 PMEVTYPER_##readwrite##_CASE(30) 97 98 /* 99 * Read a value direct from PMEVTYPER<idx> where idx is 0-30 100 * or PMCCFILTR_EL0 where idx is ARMV8_PMU_CYCLE_IDX (31). 101 */ 102 static u64 kvm_vcpu_pmu_read_evtype_direct(int idx) 103 { 104 switch (idx) { 105 PMEVTYPER_CASES(READ); 106 case ARMV8_PMU_CYCLE_IDX: 107 return read_sysreg(pmccfiltr_el0); 108 default: 109 WARN_ON(1); 110 } 111 112 return 0; 113 } 114 115 /* 116 * Write a value direct to PMEVTYPER<idx> where idx is 0-30 117 * or PMCCFILTR_EL0 where idx is ARMV8_PMU_CYCLE_IDX (31). 118 */ 119 static void kvm_vcpu_pmu_write_evtype_direct(int idx, u32 val) 120 { 121 switch (idx) { 122 PMEVTYPER_CASES(WRITE); 123 case ARMV8_PMU_CYCLE_IDX: 124 write_sysreg(val, pmccfiltr_el0); 125 break; 126 default: 127 WARN_ON(1); 128 } 129 } 130 131 /* 132 * Modify ARMv8 PMU events to include EL0 counting 133 */ 134 static void kvm_vcpu_pmu_enable_el0(unsigned long events) 135 { 136 u64 typer; 137 u32 counter; 138 139 for_each_set_bit(counter, &events, 32) { 140 typer = kvm_vcpu_pmu_read_evtype_direct(counter); 141 typer &= ~ARMV8_PMU_EXCLUDE_EL0; 142 kvm_vcpu_pmu_write_evtype_direct(counter, typer); 143 } 144 } 145 146 /* 147 * Modify ARMv8 PMU events to exclude EL0 counting 148 */ 149 static void kvm_vcpu_pmu_disable_el0(unsigned long events) 150 { 151 u64 typer; 152 u32 counter; 153 154 for_each_set_bit(counter, &events, 32) { 155 typer = kvm_vcpu_pmu_read_evtype_direct(counter); 156 typer |= ARMV8_PMU_EXCLUDE_EL0; 157 kvm_vcpu_pmu_write_evtype_direct(counter, typer); 158 } 159 } 160 161 /* 162 * On VHE ensure that only guest events have EL0 counting enabled. 163 * This is called from both vcpu_{load,put} and the sysreg handling. 164 * Since the latter is preemptible, special care must be taken to 165 * disable preemption. 166 */ 167 void kvm_vcpu_pmu_restore_guest(struct kvm_vcpu *vcpu) 168 { 169 struct kvm_host_data *host; 170 u32 events_guest, events_host; 171 172 if (!has_vhe()) 173 return; 174 175 preempt_disable(); 176 host = this_cpu_ptr(&kvm_host_data); 177 events_guest = host->pmu_events.events_guest; 178 events_host = host->pmu_events.events_host; 179 180 kvm_vcpu_pmu_enable_el0(events_guest); 181 kvm_vcpu_pmu_disable_el0(events_host); 182 preempt_enable(); 183 } 184 185 /* 186 * On VHE ensure that only host events have EL0 counting enabled 187 */ 188 void kvm_vcpu_pmu_restore_host(struct kvm_vcpu *vcpu) 189 { 190 struct kvm_host_data *host; 191 u32 events_guest, events_host; 192 193 if (!has_vhe()) 194 return; 195 196 host = this_cpu_ptr(&kvm_host_data); 197 events_guest = host->pmu_events.events_guest; 198 events_host = host->pmu_events.events_host; 199 200 kvm_vcpu_pmu_enable_el0(events_host); 201 kvm_vcpu_pmu_disable_el0(events_guest); 202 } 203