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19#include <linux/cpu.h>
20#include <linux/of_irq.h>
21#include <linux/kvm.h>
22#include <linux/kvm_host.h>
23#include <linux/interrupt.h>
24
25#include <clocksource/arm_arch_timer.h>
26#include <asm/arch_timer.h>
27
28#include <kvm/arm_vgic.h>
29#include <kvm/arm_arch_timer.h>
30
31static struct timecounter *timecounter;
32static struct workqueue_struct *wqueue;
33static unsigned int host_vtimer_irq;
34
35static cycle_t kvm_phys_timer_read(void)
36{
37 return timecounter->cc->read(timecounter->cc);
38}
39
40static bool timer_is_armed(struct arch_timer_cpu *timer)
41{
42 return timer->armed;
43}
44
45
46static void timer_arm(struct arch_timer_cpu *timer, u64 ns)
47{
48 timer->armed = true;
49 hrtimer_start(&timer->timer, ktime_add_ns(ktime_get(), ns),
50 HRTIMER_MODE_ABS);
51}
52
53static void timer_disarm(struct arch_timer_cpu *timer)
54{
55 if (timer_is_armed(timer)) {
56 hrtimer_cancel(&timer->timer);
57 cancel_work_sync(&timer->expired);
58 timer->armed = false;
59 }
60}
61
62static void kvm_timer_inject_irq(struct kvm_vcpu *vcpu)
63{
64 int ret;
65 struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
66
67 timer->cntv_ctl |= ARCH_TIMER_CTRL_IT_MASK;
68 ret = kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id,
69 timer->irq->irq,
70 timer->irq->level);
71 WARN_ON(ret);
72}
73
74static irqreturn_t kvm_arch_timer_handler(int irq, void *dev_id)
75{
76 struct kvm_vcpu *vcpu = *(struct kvm_vcpu **)dev_id;
77
78
79
80
81
82
83
84 pr_warn("Unexpected interrupt %d on vcpu %p\n", irq, vcpu);
85 return IRQ_HANDLED;
86}
87
88
89
90
91
92static void kvm_timer_inject_irq_work(struct work_struct *work)
93{
94 struct kvm_vcpu *vcpu;
95
96 vcpu = container_of(work, struct kvm_vcpu, arch.timer_cpu.expired);
97 vcpu->arch.timer_cpu.armed = false;
98
99
100
101
102
103 kvm_vcpu_kick(vcpu);
104}
105
106static enum hrtimer_restart kvm_timer_expire(struct hrtimer *hrt)
107{
108 struct arch_timer_cpu *timer;
109 timer = container_of(hrt, struct arch_timer_cpu, timer);
110 queue_work(wqueue, &timer->expired);
111 return HRTIMER_NORESTART;
112}
113
114bool kvm_timer_should_fire(struct kvm_vcpu *vcpu)
115{
116 struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
117 cycle_t cval, now;
118
119 if ((timer->cntv_ctl & ARCH_TIMER_CTRL_IT_MASK) ||
120 !(timer->cntv_ctl & ARCH_TIMER_CTRL_ENABLE))
121 return false;
122
123 cval = timer->cntv_cval;
124 now = kvm_phys_timer_read() - vcpu->kvm->arch.timer.cntvoff;
125
126 return cval <= now;
127}
128
129
130
131
132
133
134
135
136void kvm_timer_flush_hwstate(struct kvm_vcpu *vcpu)
137{
138 struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
139
140
141
142
143
144
145 timer_disarm(timer);
146
147
148
149
150
151 if (kvm_timer_should_fire(vcpu))
152 kvm_timer_inject_irq(vcpu);
153}
154
155
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158
159
160
161
162void kvm_timer_sync_hwstate(struct kvm_vcpu *vcpu)
163{
164 struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
165 cycle_t cval, now;
166 u64 ns;
167
168 BUG_ON(timer_is_armed(timer));
169
170 if (kvm_timer_should_fire(vcpu)) {
171
172
173
174
175 kvm_timer_inject_irq(vcpu);
176 return;
177 }
178
179 cval = timer->cntv_cval;
180 now = kvm_phys_timer_read() - vcpu->kvm->arch.timer.cntvoff;
181
182 ns = cyclecounter_cyc2ns(timecounter->cc, cval - now, timecounter->mask,
183 &timecounter->frac);
184 timer_arm(timer, ns);
185}
186
187void kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu,
188 const struct kvm_irq_level *irq)
189{
190 struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
191
192
193
194
195
196
197
198 timer->irq = irq;
199}
200
201void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu)
202{
203 struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
204
205 INIT_WORK(&timer->expired, kvm_timer_inject_irq_work);
206 hrtimer_init(&timer->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
207 timer->timer.function = kvm_timer_expire;
208}
209
210static void kvm_timer_init_interrupt(void *info)
211{
212 enable_percpu_irq(host_vtimer_irq, 0);
213}
214
215int kvm_arm_timer_set_reg(struct kvm_vcpu *vcpu, u64 regid, u64 value)
216{
217 struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
218
219 switch (regid) {
220 case KVM_REG_ARM_TIMER_CTL:
221 timer->cntv_ctl = value;
222 break;
223 case KVM_REG_ARM_TIMER_CNT:
224 vcpu->kvm->arch.timer.cntvoff = kvm_phys_timer_read() - value;
225 break;
226 case KVM_REG_ARM_TIMER_CVAL:
227 timer->cntv_cval = value;
228 break;
229 default:
230 return -1;
231 }
232 return 0;
233}
234
235u64 kvm_arm_timer_get_reg(struct kvm_vcpu *vcpu, u64 regid)
236{
237 struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
238
239 switch (regid) {
240 case KVM_REG_ARM_TIMER_CTL:
241 return timer->cntv_ctl;
242 case KVM_REG_ARM_TIMER_CNT:
243 return kvm_phys_timer_read() - vcpu->kvm->arch.timer.cntvoff;
244 case KVM_REG_ARM_TIMER_CVAL:
245 return timer->cntv_cval;
246 }
247 return (u64)-1;
248}
249
250static int kvm_timer_cpu_notify(struct notifier_block *self,
251 unsigned long action, void *cpu)
252{
253 switch (action) {
254 case CPU_STARTING:
255 case CPU_STARTING_FROZEN:
256 kvm_timer_init_interrupt(NULL);
257 break;
258 case CPU_DYING:
259 case CPU_DYING_FROZEN:
260 disable_percpu_irq(host_vtimer_irq);
261 break;
262 }
263
264 return NOTIFY_OK;
265}
266
267static struct notifier_block kvm_timer_cpu_nb = {
268 .notifier_call = kvm_timer_cpu_notify,
269};
270
271static const struct of_device_id arch_timer_of_match[] = {
272 { .compatible = "arm,armv7-timer", },
273 { .compatible = "arm,armv8-timer", },
274 {},
275};
276
277int kvm_timer_hyp_init(void)
278{
279 struct device_node *np;
280 unsigned int ppi;
281 int err;
282
283 timecounter = arch_timer_get_timecounter();
284 if (!timecounter)
285 return -ENODEV;
286
287 np = of_find_matching_node(NULL, arch_timer_of_match);
288 if (!np) {
289 kvm_err("kvm_arch_timer: can't find DT node\n");
290 return -ENODEV;
291 }
292
293 ppi = irq_of_parse_and_map(np, 2);
294 if (!ppi) {
295 kvm_err("kvm_arch_timer: no virtual timer interrupt\n");
296 err = -EINVAL;
297 goto out;
298 }
299
300 err = request_percpu_irq(ppi, kvm_arch_timer_handler,
301 "kvm guest timer", kvm_get_running_vcpus());
302 if (err) {
303 kvm_err("kvm_arch_timer: can't request interrupt %d (%d)\n",
304 ppi, err);
305 goto out;
306 }
307
308 host_vtimer_irq = ppi;
309
310 err = __register_cpu_notifier(&kvm_timer_cpu_nb);
311 if (err) {
312 kvm_err("Cannot register timer CPU notifier\n");
313 goto out_free;
314 }
315
316 wqueue = create_singlethread_workqueue("kvm_arch_timer");
317 if (!wqueue) {
318 err = -ENOMEM;
319 goto out_free;
320 }
321
322 kvm_info("%s IRQ%d\n", np->name, ppi);
323 on_each_cpu(kvm_timer_init_interrupt, NULL, 1);
324
325 goto out;
326out_free:
327 free_percpu_irq(ppi, kvm_get_running_vcpus());
328out:
329 of_node_put(np);
330 return err;
331}
332
333void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu)
334{
335 struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
336
337 timer_disarm(timer);
338}
339
340void kvm_timer_enable(struct kvm *kvm)
341{
342 if (kvm->arch.timer.enabled)
343 return;
344
345
346
347
348
349
350
351
352
353 if (timecounter && wqueue)
354 kvm->arch.timer.enabled = 1;
355}
356
357void kvm_timer_init(struct kvm *kvm)
358{
359 kvm->arch.timer.cntvoff = kvm_phys_timer_read();
360}
361