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 */
kvm_pmu_switch_needed(struct perf_event_attr * attr)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 */
kvm_set_pmu_events(u32 set,struct perf_event_attr * attr)32 void kvm_set_pmu_events(u32 set, struct perf_event_attr *attr)
33 {
34 struct kvm_host_data *ctx;
35
36 if (!kvm_arm_support_pmu_v3())
37 return;
38
39 ctx = this_cpu_ptr_hyp_sym(kvm_host_data);
40 if (!ctx || !kvm_pmu_switch_needed(attr))
41 return;
42
43 if (!attr->exclude_host)
44 ctx->pmu_events.events_host |= set;
45 if (!attr->exclude_guest)
46 ctx->pmu_events.events_guest |= set;
47 }
48
49 /*
50 * Stop tracking events
51 */
kvm_clr_pmu_events(u32 clr)52 void kvm_clr_pmu_events(u32 clr)
53 {
54 struct kvm_host_data *ctx;
55
56 if (!kvm_arm_support_pmu_v3())
57 return;
58
59 ctx = this_cpu_ptr_hyp_sym(kvm_host_data);
60 if (!ctx)
61 return;
62
63 ctx->pmu_events.events_host &= ~clr;
64 ctx->pmu_events.events_guest &= ~clr;
65 }
66
67 #define PMEVTYPER_READ_CASE(idx) \
68 case idx: \
69 return read_sysreg(pmevtyper##idx##_el0)
70
71 #define PMEVTYPER_WRITE_CASE(idx) \
72 case idx: \
73 write_sysreg(val, pmevtyper##idx##_el0); \
74 break
75
76 #define PMEVTYPER_CASES(readwrite) \
77 PMEVTYPER_##readwrite##_CASE(0); \
78 PMEVTYPER_##readwrite##_CASE(1); \
79 PMEVTYPER_##readwrite##_CASE(2); \
80 PMEVTYPER_##readwrite##_CASE(3); \
81 PMEVTYPER_##readwrite##_CASE(4); \
82 PMEVTYPER_##readwrite##_CASE(5); \
83 PMEVTYPER_##readwrite##_CASE(6); \
84 PMEVTYPER_##readwrite##_CASE(7); \
85 PMEVTYPER_##readwrite##_CASE(8); \
86 PMEVTYPER_##readwrite##_CASE(9); \
87 PMEVTYPER_##readwrite##_CASE(10); \
88 PMEVTYPER_##readwrite##_CASE(11); \
89 PMEVTYPER_##readwrite##_CASE(12); \
90 PMEVTYPER_##readwrite##_CASE(13); \
91 PMEVTYPER_##readwrite##_CASE(14); \
92 PMEVTYPER_##readwrite##_CASE(15); \
93 PMEVTYPER_##readwrite##_CASE(16); \
94 PMEVTYPER_##readwrite##_CASE(17); \
95 PMEVTYPER_##readwrite##_CASE(18); \
96 PMEVTYPER_##readwrite##_CASE(19); \
97 PMEVTYPER_##readwrite##_CASE(20); \
98 PMEVTYPER_##readwrite##_CASE(21); \
99 PMEVTYPER_##readwrite##_CASE(22); \
100 PMEVTYPER_##readwrite##_CASE(23); \
101 PMEVTYPER_##readwrite##_CASE(24); \
102 PMEVTYPER_##readwrite##_CASE(25); \
103 PMEVTYPER_##readwrite##_CASE(26); \
104 PMEVTYPER_##readwrite##_CASE(27); \
105 PMEVTYPER_##readwrite##_CASE(28); \
106 PMEVTYPER_##readwrite##_CASE(29); \
107 PMEVTYPER_##readwrite##_CASE(30)
108
109 /*
110 * Read a value direct from PMEVTYPER<idx> where idx is 0-30
111 * or PMCCFILTR_EL0 where idx is ARMV8_PMU_CYCLE_IDX (31).
112 */
kvm_vcpu_pmu_read_evtype_direct(int idx)113 static u64 kvm_vcpu_pmu_read_evtype_direct(int idx)
114 {
115 switch (idx) {
116 PMEVTYPER_CASES(READ);
117 case ARMV8_PMU_CYCLE_IDX:
118 return read_sysreg(pmccfiltr_el0);
119 default:
120 WARN_ON(1);
121 }
122
123 return 0;
124 }
125
126 /*
127 * Write a value direct to PMEVTYPER<idx> where idx is 0-30
128 * or PMCCFILTR_EL0 where idx is ARMV8_PMU_CYCLE_IDX (31).
129 */
kvm_vcpu_pmu_write_evtype_direct(int idx,u32 val)130 static void kvm_vcpu_pmu_write_evtype_direct(int idx, u32 val)
131 {
132 switch (idx) {
133 PMEVTYPER_CASES(WRITE);
134 case ARMV8_PMU_CYCLE_IDX:
135 write_sysreg(val, pmccfiltr_el0);
136 break;
137 default:
138 WARN_ON(1);
139 }
140 }
141
142 /*
143 * Modify ARMv8 PMU events to include EL0 counting
144 */
kvm_vcpu_pmu_enable_el0(unsigned long events)145 static void kvm_vcpu_pmu_enable_el0(unsigned long events)
146 {
147 u64 typer;
148 u32 counter;
149
150 for_each_set_bit(counter, &events, 32) {
151 typer = kvm_vcpu_pmu_read_evtype_direct(counter);
152 typer &= ~ARMV8_PMU_EXCLUDE_EL0;
153 kvm_vcpu_pmu_write_evtype_direct(counter, typer);
154 }
155 }
156
157 /*
158 * Modify ARMv8 PMU events to exclude EL0 counting
159 */
kvm_vcpu_pmu_disable_el0(unsigned long events)160 static void kvm_vcpu_pmu_disable_el0(unsigned long events)
161 {
162 u64 typer;
163 u32 counter;
164
165 for_each_set_bit(counter, &events, 32) {
166 typer = kvm_vcpu_pmu_read_evtype_direct(counter);
167 typer |= ARMV8_PMU_EXCLUDE_EL0;
168 kvm_vcpu_pmu_write_evtype_direct(counter, typer);
169 }
170 }
171
172 /*
173 * On VHE ensure that only guest events have EL0 counting enabled.
174 * This is called from both vcpu_{load,put} and the sysreg handling.
175 * Since the latter is preemptible, special care must be taken to
176 * disable preemption.
177 */
kvm_vcpu_pmu_restore_guest(struct kvm_vcpu * vcpu)178 void kvm_vcpu_pmu_restore_guest(struct kvm_vcpu *vcpu)
179 {
180 struct kvm_host_data *host;
181 u32 events_guest, events_host;
182
183 if (!kvm_arm_support_pmu_v3() || !has_vhe())
184 return;
185
186 preempt_disable();
187 host = this_cpu_ptr_hyp_sym(kvm_host_data);
188 events_guest = host->pmu_events.events_guest;
189 events_host = host->pmu_events.events_host;
190
191 kvm_vcpu_pmu_enable_el0(events_guest);
192 kvm_vcpu_pmu_disable_el0(events_host);
193 preempt_enable();
194 }
195
196 /*
197 * On VHE ensure that only host events have EL0 counting enabled
198 */
kvm_vcpu_pmu_restore_host(struct kvm_vcpu * vcpu)199 void kvm_vcpu_pmu_restore_host(struct kvm_vcpu *vcpu)
200 {
201 struct kvm_host_data *host;
202 u32 events_guest, events_host;
203
204 if (!kvm_arm_support_pmu_v3() || !has_vhe())
205 return;
206
207 host = this_cpu_ptr_hyp_sym(kvm_host_data);
208 events_guest = host->pmu_events.events_guest;
209 events_host = host->pmu_events.events_host;
210
211 kvm_vcpu_pmu_enable_el0(events_host);
212 kvm_vcpu_pmu_disable_el0(events_guest);
213 }
214