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Linux kernel mirror (for testing)
git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
kernel
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linux
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(&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 */
48void 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 */
102static 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 */
119static 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 */
134static 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 */
149static 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 */
167void 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 */
188void 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}