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Marc Zyngier53e72402013-01-23 13:21:58 -05001/*
2 * Copyright (C) 2012 ARM Ltd.
3 * Author: Marc Zyngier <marc.zyngier@arm.com>
4 *
5 * This program is free software; you can redistribute it and/or modify
6 * it under the terms of the GNU General Public License version 2 as
7 * published by the Free Software Foundation.
8 *
9 * This program is distributed in the hope that it will be useful,
10 * but WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
12 * GNU General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
17 */
18
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
Mark Rutland372b7c12013-03-27 15:56:11 +000025#include <clocksource/arm_arch_timer.h>
Marc Zyngier53e72402013-01-23 13:21:58 -050026#include <asm/arch_timer.h>
27
Marc Zyngier7275acd2013-05-14 14:31:01 +010028#include <kvm/arm_vgic.h>
29#include <kvm/arm_arch_timer.h>
Marc Zyngier53e72402013-01-23 13:21:58 -050030
31static struct timecounter *timecounter;
32static struct workqueue_struct *wqueue;
Anup Patel5ae7f872013-04-30 12:02:15 +053033static unsigned int host_vtimer_irq;
Marc Zyngier53e72402013-01-23 13:21:58 -050034
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/* timer_arm: as in "arm the timer", not as in ARM the company */
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{
Christoffer Dall05971122014-12-12 21:19:23 +010064 int ret;
Marc Zyngier53e72402013-01-23 13:21:58 -050065 struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
66
Marc Zyngierf120cd62014-06-23 13:59:13 +010067 kvm_vgic_set_phys_irq_active(timer->map, true);
68 ret = kvm_vgic_inject_mapped_irq(vcpu->kvm, vcpu->vcpu_id,
69 timer->map,
70 timer->irq->level);
Christoffer Dall05971122014-12-12 21:19:23 +010071 WARN_ON(ret);
Marc Zyngier53e72402013-01-23 13:21:58 -050072}
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 * We disable the timer in the world switch and let it be
80 * handled by kvm_timer_sync_hwstate(). Getting a timer
81 * interrupt at this point is a sure sign of some major
82 * breakage.
83 */
84 pr_warn("Unexpected interrupt %d on vcpu %p\n", irq, vcpu);
85 return IRQ_HANDLED;
86}
87
Christoffer Dall1a748472015-03-13 17:02:55 +000088/*
89 * Work function for handling the backup timer that we schedule when a vcpu is
90 * no longer running, but had a timer programmed to fire in the future.
91 */
Marc Zyngier53e72402013-01-23 13:21:58 -050092static 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;
Christoffer Dall1a748472015-03-13 17:02:55 +000098
99 /*
100 * If the vcpu is blocked we want to wake it up so that it will see
101 * the timer has expired when entering the guest.
102 */
103 kvm_vcpu_kick(vcpu);
Marc Zyngier53e72402013-01-23 13:21:58 -0500104}
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
Christoffer Dall1a748472015-03-13 17:02:55 +0000114bool 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) ||
Marc Zyngierf120cd62014-06-23 13:59:13 +0100120 !(timer->cntv_ctl & ARCH_TIMER_CTRL_ENABLE) ||
121 kvm_vgic_get_phys_irq_active(timer->map))
Christoffer Dall1a748472015-03-13 17:02:55 +0000122 return false;
123
124 cval = timer->cntv_cval;
125 now = kvm_phys_timer_read() - vcpu->kvm->arch.timer.cntvoff;
126
127 return cval <= now;
128}
129
Marc Zyngier53e72402013-01-23 13:21:58 -0500130/**
131 * kvm_timer_flush_hwstate - prepare to move the virt timer to the cpu
132 * @vcpu: The vcpu pointer
133 *
134 * Disarm any pending soft timers, since the world-switch code will write the
135 * virtual timer state back to the physical CPU.
136 */
137void kvm_timer_flush_hwstate(struct kvm_vcpu *vcpu)
138{
139 struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
140
141 /*
142 * We're about to run this vcpu again, so there is no need to
143 * keep the background timer running, as we're about to
144 * populate the CPU timer again.
145 */
146 timer_disarm(timer);
Christoffer Dall1a748472015-03-13 17:02:55 +0000147
148 /*
149 * If the timer expired while we were not scheduled, now is the time
150 * to inject it.
151 */
152 if (kvm_timer_should_fire(vcpu))
153 kvm_timer_inject_irq(vcpu);
Marc Zyngier53e72402013-01-23 13:21:58 -0500154}
155
156/**
157 * kvm_timer_sync_hwstate - sync timer state from cpu
158 * @vcpu: The vcpu pointer
159 *
160 * Check if the virtual timer was armed and either schedule a corresponding
161 * soft timer or inject directly if already expired.
162 */
163void kvm_timer_sync_hwstate(struct kvm_vcpu *vcpu)
164{
165 struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
166 cycle_t cval, now;
167 u64 ns;
168
Marc Zyngier53e72402013-01-23 13:21:58 -0500169 BUG_ON(timer_is_armed(timer));
170
Christoffer Dall1a748472015-03-13 17:02:55 +0000171 if (kvm_timer_should_fire(vcpu)) {
Marc Zyngier53e72402013-01-23 13:21:58 -0500172 /*
173 * Timer has already expired while we were not
174 * looking. Inject the interrupt and carry on.
175 */
176 kvm_timer_inject_irq(vcpu);
177 return;
178 }
179
Christoffer Dall1a748472015-03-13 17:02:55 +0000180 cval = timer->cntv_cval;
181 now = kvm_phys_timer_read() - vcpu->kvm->arch.timer.cntvoff;
182
Richard Cochran2eebdde2014-12-21 19:47:06 +0100183 ns = cyclecounter_cyc2ns(timecounter->cc, cval - now, timecounter->mask,
184 &timecounter->frac);
Marc Zyngier53e72402013-01-23 13:21:58 -0500185 timer_arm(timer, ns);
186}
187
Marc Zyngierf120cd62014-06-23 13:59:13 +0100188int kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu,
189 const struct kvm_irq_level *irq)
Anup Patel5ae7f872013-04-30 12:02:15 +0530190{
191 struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
Marc Zyngierf120cd62014-06-23 13:59:13 +0100192 struct irq_phys_map *map;
Anup Patel5ae7f872013-04-30 12:02:15 +0530193
194 /*
195 * The vcpu timer irq number cannot be determined in
196 * kvm_timer_vcpu_init() because it is called much before
197 * kvm_vcpu_set_target(). To handle this, we determine
198 * vcpu timer irq number when the vcpu is reset.
199 */
200 timer->irq = irq;
Marc Zyngierf120cd62014-06-23 13:59:13 +0100201
202 /*
Christoffer Dall4ad9e162015-09-04 16:24:39 +0200203 * The bits in CNTV_CTL are architecturally reset to UNKNOWN for ARMv8
204 * and to 0 for ARMv7. We provide an implementation that always
205 * resets the timer to be disabled and unmasked and is compliant with
206 * the ARMv7 architecture.
207 */
208 timer->cntv_ctl = 0;
209
210 /*
Marc Zyngierf120cd62014-06-23 13:59:13 +0100211 * Tell the VGIC that the virtual interrupt is tied to a
212 * physical interrupt. We do that once per VCPU.
213 */
214 map = kvm_vgic_map_phys_irq(vcpu, irq->irq, host_vtimer_irq);
215 if (WARN_ON(IS_ERR(map)))
216 return PTR_ERR(map);
217
218 timer->map = map;
219 return 0;
Anup Patel5ae7f872013-04-30 12:02:15 +0530220}
221
Marc Zyngier53e72402013-01-23 13:21:58 -0500222void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu)
223{
224 struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
225
226 INIT_WORK(&timer->expired, kvm_timer_inject_irq_work);
227 hrtimer_init(&timer->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
228 timer->timer.function = kvm_timer_expire;
Marc Zyngier53e72402013-01-23 13:21:58 -0500229}
230
231static void kvm_timer_init_interrupt(void *info)
232{
Anup Patel5ae7f872013-04-30 12:02:15 +0530233 enable_percpu_irq(host_vtimer_irq, 0);
Marc Zyngier53e72402013-01-23 13:21:58 -0500234}
235
Andre Przywara39735a32013-12-13 14:23:26 +0100236int kvm_arm_timer_set_reg(struct kvm_vcpu *vcpu, u64 regid, u64 value)
237{
238 struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
239
240 switch (regid) {
241 case KVM_REG_ARM_TIMER_CTL:
242 timer->cntv_ctl = value;
243 break;
244 case KVM_REG_ARM_TIMER_CNT:
245 vcpu->kvm->arch.timer.cntvoff = kvm_phys_timer_read() - value;
246 break;
247 case KVM_REG_ARM_TIMER_CVAL:
248 timer->cntv_cval = value;
249 break;
250 default:
251 return -1;
252 }
253 return 0;
254}
255
256u64 kvm_arm_timer_get_reg(struct kvm_vcpu *vcpu, u64 regid)
257{
258 struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
259
260 switch (regid) {
261 case KVM_REG_ARM_TIMER_CTL:
262 return timer->cntv_ctl;
263 case KVM_REG_ARM_TIMER_CNT:
264 return kvm_phys_timer_read() - vcpu->kvm->arch.timer.cntvoff;
265 case KVM_REG_ARM_TIMER_CVAL:
266 return timer->cntv_cval;
267 }
268 return (u64)-1;
269}
Marc Zyngier53e72402013-01-23 13:21:58 -0500270
271static int kvm_timer_cpu_notify(struct notifier_block *self,
272 unsigned long action, void *cpu)
273{
274 switch (action) {
275 case CPU_STARTING:
276 case CPU_STARTING_FROZEN:
277 kvm_timer_init_interrupt(NULL);
278 break;
279 case CPU_DYING:
280 case CPU_DYING_FROZEN:
Anup Patel5ae7f872013-04-30 12:02:15 +0530281 disable_percpu_irq(host_vtimer_irq);
Marc Zyngier53e72402013-01-23 13:21:58 -0500282 break;
283 }
284
285 return NOTIFY_OK;
286}
287
288static struct notifier_block kvm_timer_cpu_nb = {
289 .notifier_call = kvm_timer_cpu_notify,
290};
291
292static const struct of_device_id arch_timer_of_match[] = {
293 { .compatible = "arm,armv7-timer", },
Marc Zyngierf61701e2013-05-30 18:31:28 +0100294 { .compatible = "arm,armv8-timer", },
Marc Zyngier53e72402013-01-23 13:21:58 -0500295 {},
296};
297
298int kvm_timer_hyp_init(void)
299{
300 struct device_node *np;
301 unsigned int ppi;
302 int err;
303
304 timecounter = arch_timer_get_timecounter();
305 if (!timecounter)
306 return -ENODEV;
307
308 np = of_find_matching_node(NULL, arch_timer_of_match);
309 if (!np) {
310 kvm_err("kvm_arch_timer: can't find DT node\n");
311 return -ENODEV;
312 }
313
314 ppi = irq_of_parse_and_map(np, 2);
315 if (!ppi) {
316 kvm_err("kvm_arch_timer: no virtual timer interrupt\n");
317 err = -EINVAL;
318 goto out;
319 }
320
321 err = request_percpu_irq(ppi, kvm_arch_timer_handler,
322 "kvm guest timer", kvm_get_running_vcpus());
323 if (err) {
324 kvm_err("kvm_arch_timer: can't request interrupt %d (%d)\n",
325 ppi, err);
326 goto out;
327 }
328
Anup Patel5ae7f872013-04-30 12:02:15 +0530329 host_vtimer_irq = ppi;
Marc Zyngier53e72402013-01-23 13:21:58 -0500330
Ming Lei553f8092014-04-07 01:36:08 +0800331 err = __register_cpu_notifier(&kvm_timer_cpu_nb);
Marc Zyngier53e72402013-01-23 13:21:58 -0500332 if (err) {
333 kvm_err("Cannot register timer CPU notifier\n");
334 goto out_free;
335 }
336
337 wqueue = create_singlethread_workqueue("kvm_arch_timer");
338 if (!wqueue) {
339 err = -ENOMEM;
340 goto out_free;
341 }
342
343 kvm_info("%s IRQ%d\n", np->name, ppi);
344 on_each_cpu(kvm_timer_init_interrupt, NULL, 1);
345
346 goto out;
347out_free:
348 free_percpu_irq(ppi, kvm_get_running_vcpus());
349out:
350 of_node_put(np);
351 return err;
352}
353
354void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu)
355{
356 struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
357
358 timer_disarm(timer);
Marc Zyngierf120cd62014-06-23 13:59:13 +0100359 if (timer->map)
360 kvm_vgic_unmap_phys_irq(vcpu, timer->map);
Marc Zyngier53e72402013-01-23 13:21:58 -0500361}
362
Christoffer Dall05971122014-12-12 21:19:23 +0100363void kvm_timer_enable(struct kvm *kvm)
Marc Zyngier53e72402013-01-23 13:21:58 -0500364{
Christoffer Dall05971122014-12-12 21:19:23 +0100365 if (kvm->arch.timer.enabled)
366 return;
Marc Zyngier53e72402013-01-23 13:21:58 -0500367
Christoffer Dall05971122014-12-12 21:19:23 +0100368 /*
369 * There is a potential race here between VCPUs starting for the first
370 * time, which may be enabling the timer multiple times. That doesn't
371 * hurt though, because we're just setting a variable to the same
372 * variable that it already was. The important thing is that all
373 * VCPUs have the enabled variable set, before entering the guest, if
374 * the arch timers are enabled.
375 */
376 if (timecounter && wqueue)
377 kvm->arch.timer.enabled = 1;
378}
379
380void kvm_timer_init(struct kvm *kvm)
381{
382 kvm->arch.timer.cntvoff = kvm_phys_timer_read();
Marc Zyngier53e72402013-01-23 13:21:58 -0500383}