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 /** 57 * Disable host events, enable guest events 58 */ 59 bool __hyp_text __pmu_switch_to_guest(struct kvm_cpu_context *host_ctxt) 60 { 61 struct kvm_host_data *host; 62 struct kvm_pmu_events *pmu; 63 64 host = container_of(host_ctxt, struct kvm_host_data, host_ctxt); 65 pmu = &host->pmu_events; 66 67 if (pmu->events_host) 68 write_sysreg(pmu->events_host, pmcntenclr_el0); 69 70 if (pmu->events_guest) 71 write_sysreg(pmu->events_guest, pmcntenset_el0); 72 73 return (pmu->events_host || pmu->events_guest); 74 } 75 76 /** 77 * Disable guest events, enable host events 78 */ 79 void __hyp_text __pmu_switch_to_host(struct kvm_cpu_context *host_ctxt) 80 { 81 struct kvm_host_data *host; 82 struct kvm_pmu_events *pmu; 83 84 host = container_of(host_ctxt, struct kvm_host_data, host_ctxt); 85 pmu = &host->pmu_events; 86 87 if (pmu->events_guest) 88 write_sysreg(pmu->events_guest, pmcntenclr_el0); 89 90 if (pmu->events_host) 91 write_sysreg(pmu->events_host, pmcntenset_el0); 92 } 93 94 #define PMEVTYPER_READ_CASE(idx) \ 95 case idx: \ 96 return read_sysreg(pmevtyper##idx##_el0) 97 98 #define PMEVTYPER_WRITE_CASE(idx) \ 99 case idx: \ 100 write_sysreg(val, pmevtyper##idx##_el0); \ 101 break 102 103 #define PMEVTYPER_CASES(readwrite) \ 104 PMEVTYPER_##readwrite##_CASE(0); \ 105 PMEVTYPER_##readwrite##_CASE(1); \ 106 PMEVTYPER_##readwrite##_CASE(2); \ 107 PMEVTYPER_##readwrite##_CASE(3); \ 108 PMEVTYPER_##readwrite##_CASE(4); \ 109 PMEVTYPER_##readwrite##_CASE(5); \ 110 PMEVTYPER_##readwrite##_CASE(6); \ 111 PMEVTYPER_##readwrite##_CASE(7); \ 112 PMEVTYPER_##readwrite##_CASE(8); \ 113 PMEVTYPER_##readwrite##_CASE(9); \ 114 PMEVTYPER_##readwrite##_CASE(10); \ 115 PMEVTYPER_##readwrite##_CASE(11); \ 116 PMEVTYPER_##readwrite##_CASE(12); \ 117 PMEVTYPER_##readwrite##_CASE(13); \ 118 PMEVTYPER_##readwrite##_CASE(14); \ 119 PMEVTYPER_##readwrite##_CASE(15); \ 120 PMEVTYPER_##readwrite##_CASE(16); \ 121 PMEVTYPER_##readwrite##_CASE(17); \ 122 PMEVTYPER_##readwrite##_CASE(18); \ 123 PMEVTYPER_##readwrite##_CASE(19); \ 124 PMEVTYPER_##readwrite##_CASE(20); \ 125 PMEVTYPER_##readwrite##_CASE(21); \ 126 PMEVTYPER_##readwrite##_CASE(22); \ 127 PMEVTYPER_##readwrite##_CASE(23); \ 128 PMEVTYPER_##readwrite##_CASE(24); \ 129 PMEVTYPER_##readwrite##_CASE(25); \ 130 PMEVTYPER_##readwrite##_CASE(26); \ 131 PMEVTYPER_##readwrite##_CASE(27); \ 132 PMEVTYPER_##readwrite##_CASE(28); \ 133 PMEVTYPER_##readwrite##_CASE(29); \ 134 PMEVTYPER_##readwrite##_CASE(30) 135 136 /* 137 * Read a value direct from PMEVTYPER<idx> where idx is 0-30 138 * or PMCCFILTR_EL0 where idx is ARMV8_PMU_CYCLE_IDX (31). 139 */ 140 static u64 kvm_vcpu_pmu_read_evtype_direct(int idx) 141 { 142 switch (idx) { 143 PMEVTYPER_CASES(READ); 144 case ARMV8_PMU_CYCLE_IDX: 145 return read_sysreg(pmccfiltr_el0); 146 default: 147 WARN_ON(1); 148 } 149 150 return 0; 151 } 152 153 /* 154 * Write a value direct to PMEVTYPER<idx> where idx is 0-30 155 * or PMCCFILTR_EL0 where idx is ARMV8_PMU_CYCLE_IDX (31). 156 */ 157 static void kvm_vcpu_pmu_write_evtype_direct(int idx, u32 val) 158 { 159 switch (idx) { 160 PMEVTYPER_CASES(WRITE); 161 case ARMV8_PMU_CYCLE_IDX: 162 write_sysreg(val, pmccfiltr_el0); 163 break; 164 default: 165 WARN_ON(1); 166 } 167 } 168 169 /* 170 * Modify ARMv8 PMU events to include EL0 counting 171 */ 172 static void kvm_vcpu_pmu_enable_el0(unsigned long events) 173 { 174 u64 typer; 175 u32 counter; 176 177 for_each_set_bit(counter, &events, 32) { 178 typer = kvm_vcpu_pmu_read_evtype_direct(counter); 179 typer &= ~ARMV8_PMU_EXCLUDE_EL0; 180 kvm_vcpu_pmu_write_evtype_direct(counter, typer); 181 } 182 } 183 184 /* 185 * Modify ARMv8 PMU events to exclude EL0 counting 186 */ 187 static void kvm_vcpu_pmu_disable_el0(unsigned long events) 188 { 189 u64 typer; 190 u32 counter; 191 192 for_each_set_bit(counter, &events, 32) { 193 typer = kvm_vcpu_pmu_read_evtype_direct(counter); 194 typer |= ARMV8_PMU_EXCLUDE_EL0; 195 kvm_vcpu_pmu_write_evtype_direct(counter, typer); 196 } 197 } 198 199 /* 200 * On VHE ensure that only guest events have EL0 counting enabled 201 */ 202 void kvm_vcpu_pmu_restore_guest(struct kvm_vcpu *vcpu) 203 { 204 struct kvm_cpu_context *host_ctxt; 205 struct kvm_host_data *host; 206 u32 events_guest, events_host; 207 208 if (!has_vhe()) 209 return; 210 211 host_ctxt = vcpu->arch.host_cpu_context; 212 host = container_of(host_ctxt, struct kvm_host_data, host_ctxt); 213 events_guest = host->pmu_events.events_guest; 214 events_host = host->pmu_events.events_host; 215 216 kvm_vcpu_pmu_enable_el0(events_guest); 217 kvm_vcpu_pmu_disable_el0(events_host); 218 } 219 220 /* 221 * On VHE ensure that only host events have EL0 counting enabled 222 */ 223 void kvm_vcpu_pmu_restore_host(struct kvm_vcpu *vcpu) 224 { 225 struct kvm_cpu_context *host_ctxt; 226 struct kvm_host_data *host; 227 u32 events_guest, events_host; 228 229 if (!has_vhe()) 230 return; 231 232 host_ctxt = vcpu->arch.host_cpu_context; 233 host = container_of(host_ctxt, struct kvm_host_data, host_ctxt); 234 events_guest = host->pmu_events.events_guest; 235 events_host = host->pmu_events.events_host; 236 237 kvm_vcpu_pmu_enable_el0(events_host); 238 kvm_vcpu_pmu_disable_el0(events_guest); 239 } 240