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 = this_cpu_ptr_hyp_sym(kvm_host_data);
35
36 if (!kvm_arm_support_pmu_v3() || !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 */
kvm_clr_pmu_events(u32 clr)48 void kvm_clr_pmu_events(u32 clr)
49 {
50 struct kvm_host_data *ctx = this_cpu_ptr_hyp_sym(kvm_host_data);
51
52 if (!kvm_arm_support_pmu_v3() || !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 */
kvm_vcpu_pmu_read_evtype_direct(int idx)105 static 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 */
kvm_vcpu_pmu_write_evtype_direct(int idx,u32 val)122 static 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 */
kvm_vcpu_pmu_enable_el0(unsigned long events)137 static 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 */
kvm_vcpu_pmu_disable_el0(unsigned long events)152 static 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 */
kvm_vcpu_pmu_restore_guest(struct kvm_vcpu * vcpu)170 void 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 (!kvm_arm_support_pmu_v3() || !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 */
kvm_vcpu_pmu_restore_host(struct kvm_vcpu * vcpu)191 void 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 (!kvm_arm_support_pmu_v3() || !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