blob: c2e1ef4604e8784a1556954e047fbcec2480ad60 [file] [log] [blame]
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{
64 struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
65
Mark Rutland372b7c12013-03-27 15:56:11 +000066 timer->cntv_ctl |= ARCH_TIMER_CTRL_IT_MASK;
Marc Zyngier53e72402013-01-23 13:21:58 -050067 kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id,
Anup Patel5ae7f872013-04-30 12:02:15 +053068 timer->irq->irq,
69 timer->irq->level);
Marc Zyngier53e72402013-01-23 13:21:58 -050070}
71
72static irqreturn_t kvm_arch_timer_handler(int irq, void *dev_id)
73{
74 struct kvm_vcpu *vcpu = *(struct kvm_vcpu **)dev_id;
75
76 /*
77 * We disable the timer in the world switch and let it be
78 * handled by kvm_timer_sync_hwstate(). Getting a timer
79 * interrupt at this point is a sure sign of some major
80 * breakage.
81 */
82 pr_warn("Unexpected interrupt %d on vcpu %p\n", irq, vcpu);
83 return IRQ_HANDLED;
84}
85
86static void kvm_timer_inject_irq_work(struct work_struct *work)
87{
88 struct kvm_vcpu *vcpu;
89
90 vcpu = container_of(work, struct kvm_vcpu, arch.timer_cpu.expired);
91 vcpu->arch.timer_cpu.armed = false;
92 kvm_timer_inject_irq(vcpu);
93}
94
95static enum hrtimer_restart kvm_timer_expire(struct hrtimer *hrt)
96{
97 struct arch_timer_cpu *timer;
98 timer = container_of(hrt, struct arch_timer_cpu, timer);
99 queue_work(wqueue, &timer->expired);
100 return HRTIMER_NORESTART;
101}
102
103/**
104 * kvm_timer_flush_hwstate - prepare to move the virt timer to the cpu
105 * @vcpu: The vcpu pointer
106 *
107 * Disarm any pending soft timers, since the world-switch code will write the
108 * virtual timer state back to the physical CPU.
109 */
110void kvm_timer_flush_hwstate(struct kvm_vcpu *vcpu)
111{
112 struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
113
114 /*
115 * We're about to run this vcpu again, so there is no need to
116 * keep the background timer running, as we're about to
117 * populate the CPU timer again.
118 */
119 timer_disarm(timer);
120}
121
122/**
123 * kvm_timer_sync_hwstate - sync timer state from cpu
124 * @vcpu: The vcpu pointer
125 *
126 * Check if the virtual timer was armed and either schedule a corresponding
127 * soft timer or inject directly if already expired.
128 */
129void kvm_timer_sync_hwstate(struct kvm_vcpu *vcpu)
130{
131 struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
132 cycle_t cval, now;
133 u64 ns;
134
Mark Rutland372b7c12013-03-27 15:56:11 +0000135 if ((timer->cntv_ctl & ARCH_TIMER_CTRL_IT_MASK) ||
136 !(timer->cntv_ctl & ARCH_TIMER_CTRL_ENABLE))
Marc Zyngier53e72402013-01-23 13:21:58 -0500137 return;
138
139 cval = timer->cntv_cval;
140 now = kvm_phys_timer_read() - vcpu->kvm->arch.timer.cntvoff;
141
142 BUG_ON(timer_is_armed(timer));
143
144 if (cval <= now) {
145 /*
146 * Timer has already expired while we were not
147 * looking. Inject the interrupt and carry on.
148 */
149 kvm_timer_inject_irq(vcpu);
150 return;
151 }
152
153 ns = cyclecounter_cyc2ns(timecounter->cc, cval - now);
154 timer_arm(timer, ns);
155}
156
Anup Patel5ae7f872013-04-30 12:02:15 +0530157void kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu,
158 const struct kvm_irq_level *irq)
159{
160 struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
161
162 /*
163 * The vcpu timer irq number cannot be determined in
164 * kvm_timer_vcpu_init() because it is called much before
165 * kvm_vcpu_set_target(). To handle this, we determine
166 * vcpu timer irq number when the vcpu is reset.
167 */
168 timer->irq = irq;
169}
170
Marc Zyngier53e72402013-01-23 13:21:58 -0500171void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu)
172{
173 struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
174
175 INIT_WORK(&timer->expired, kvm_timer_inject_irq_work);
176 hrtimer_init(&timer->timer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
177 timer->timer.function = kvm_timer_expire;
Marc Zyngier53e72402013-01-23 13:21:58 -0500178}
179
180static void kvm_timer_init_interrupt(void *info)
181{
Anup Patel5ae7f872013-04-30 12:02:15 +0530182 enable_percpu_irq(host_vtimer_irq, 0);
Marc Zyngier53e72402013-01-23 13:21:58 -0500183}
184
185
186static int kvm_timer_cpu_notify(struct notifier_block *self,
187 unsigned long action, void *cpu)
188{
189 switch (action) {
190 case CPU_STARTING:
191 case CPU_STARTING_FROZEN:
192 kvm_timer_init_interrupt(NULL);
193 break;
194 case CPU_DYING:
195 case CPU_DYING_FROZEN:
Anup Patel5ae7f872013-04-30 12:02:15 +0530196 disable_percpu_irq(host_vtimer_irq);
Marc Zyngier53e72402013-01-23 13:21:58 -0500197 break;
198 }
199
200 return NOTIFY_OK;
201}
202
203static struct notifier_block kvm_timer_cpu_nb = {
204 .notifier_call = kvm_timer_cpu_notify,
205};
206
207static const struct of_device_id arch_timer_of_match[] = {
208 { .compatible = "arm,armv7-timer", },
Marc Zyngierf61701e2013-05-30 18:31:28 +0100209 { .compatible = "arm,armv8-timer", },
Marc Zyngier53e72402013-01-23 13:21:58 -0500210 {},
211};
212
213int kvm_timer_hyp_init(void)
214{
215 struct device_node *np;
216 unsigned int ppi;
217 int err;
218
219 timecounter = arch_timer_get_timecounter();
220 if (!timecounter)
221 return -ENODEV;
222
223 np = of_find_matching_node(NULL, arch_timer_of_match);
224 if (!np) {
225 kvm_err("kvm_arch_timer: can't find DT node\n");
226 return -ENODEV;
227 }
228
229 ppi = irq_of_parse_and_map(np, 2);
230 if (!ppi) {
231 kvm_err("kvm_arch_timer: no virtual timer interrupt\n");
232 err = -EINVAL;
233 goto out;
234 }
235
236 err = request_percpu_irq(ppi, kvm_arch_timer_handler,
237 "kvm guest timer", kvm_get_running_vcpus());
238 if (err) {
239 kvm_err("kvm_arch_timer: can't request interrupt %d (%d)\n",
240 ppi, err);
241 goto out;
242 }
243
Anup Patel5ae7f872013-04-30 12:02:15 +0530244 host_vtimer_irq = ppi;
Marc Zyngier53e72402013-01-23 13:21:58 -0500245
246 err = register_cpu_notifier(&kvm_timer_cpu_nb);
247 if (err) {
248 kvm_err("Cannot register timer CPU notifier\n");
249 goto out_free;
250 }
251
252 wqueue = create_singlethread_workqueue("kvm_arch_timer");
253 if (!wqueue) {
254 err = -ENOMEM;
255 goto out_free;
256 }
257
258 kvm_info("%s IRQ%d\n", np->name, ppi);
259 on_each_cpu(kvm_timer_init_interrupt, NULL, 1);
260
261 goto out;
262out_free:
263 free_percpu_irq(ppi, kvm_get_running_vcpus());
264out:
265 of_node_put(np);
266 return err;
267}
268
269void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu)
270{
271 struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
272
273 timer_disarm(timer);
274}
275
276int kvm_timer_init(struct kvm *kvm)
277{
278 if (timecounter && wqueue) {
279 kvm->arch.timer.cntvoff = kvm_phys_timer_read();
280 kvm->arch.timer.enabled = 1;
281 }
282
283 return 0;
284}