2 * Copyright (C) 2012 ARM Ltd.
3 * Author: Marc Zyngier <marc.zyngier@arm.com>
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.
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.
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
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>
25 #include <clocksource/arm_arch_timer.h>
26 #include <asm/arch_timer.h>
28 #include <kvm/arm_vgic.h>
29 #include <kvm/arm_arch_timer.h>
31 static struct timecounter *timecounter;
32 static struct workqueue_struct *wqueue;
33 static unsigned int host_vtimer_irq;
35 static cycle_t kvm_phys_timer_read(void)
37 return timecounter->cc->read(timecounter->cc);
40 static bool timer_is_armed(struct arch_timer_cpu *timer)
45 /* timer_arm: as in "arm the timer", not as in ARM the company */
46 static void timer_arm(struct arch_timer_cpu *timer, u64 ns)
49 hrtimer_start(&timer->timer, ktime_add_ns(ktime_get(), ns),
53 static void timer_disarm(struct arch_timer_cpu *timer)
55 if (timer_is_armed(timer)) {
56 hrtimer_cancel(&timer->timer);
57 cancel_work_sync(&timer->expired);
62 static void kvm_timer_inject_irq(struct kvm_vcpu *vcpu)
64 struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
66 timer->cntv_ctl |= ARCH_TIMER_CTRL_IT_MASK;
67 kvm_vgic_inject_irq(vcpu->kvm, vcpu->vcpu_id,
72 static irqreturn_t kvm_arch_timer_handler(int irq, void *dev_id)
74 struct kvm_vcpu *vcpu = *(struct kvm_vcpu **)dev_id;
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
82 pr_warn("Unexpected interrupt %d on vcpu %p\n", irq, vcpu);
86 static void kvm_timer_inject_irq_work(struct work_struct *work)
88 struct kvm_vcpu *vcpu;
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);
95 static enum hrtimer_restart kvm_timer_expire(struct hrtimer *hrt)
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;
104 * kvm_timer_flush_hwstate - prepare to move the virt timer to the cpu
105 * @vcpu: The vcpu pointer
107 * Disarm any pending soft timers, since the world-switch code will write the
108 * virtual timer state back to the physical CPU.
110 void kvm_timer_flush_hwstate(struct kvm_vcpu *vcpu)
112 struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
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.
123 * kvm_timer_sync_hwstate - sync timer state from cpu
124 * @vcpu: The vcpu pointer
126 * Check if the virtual timer was armed and either schedule a corresponding
127 * soft timer or inject directly if already expired.
129 void kvm_timer_sync_hwstate(struct kvm_vcpu *vcpu)
131 struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
135 if ((timer->cntv_ctl & ARCH_TIMER_CTRL_IT_MASK) ||
136 !(timer->cntv_ctl & ARCH_TIMER_CTRL_ENABLE))
139 cval = timer->cntv_cval;
140 now = kvm_phys_timer_read() - vcpu->kvm->arch.timer.cntvoff;
142 BUG_ON(timer_is_armed(timer));
146 * Timer has already expired while we were not
147 * looking. Inject the interrupt and carry on.
149 kvm_timer_inject_irq(vcpu);
153 ns = cyclecounter_cyc2ns(timecounter->cc, cval - now);
154 timer_arm(timer, ns);
157 void kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu,
158 const struct kvm_irq_level *irq)
160 struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
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.
171 void kvm_timer_vcpu_init(struct kvm_vcpu *vcpu)
173 struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
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;
180 static void kvm_timer_init_interrupt(void *info)
182 enable_percpu_irq(host_vtimer_irq, 0);
186 static int kvm_timer_cpu_notify(struct notifier_block *self,
187 unsigned long action, void *cpu)
191 case CPU_STARTING_FROZEN:
192 kvm_timer_init_interrupt(NULL);
195 case CPU_DYING_FROZEN:
196 disable_percpu_irq(host_vtimer_irq);
203 static struct notifier_block kvm_timer_cpu_nb = {
204 .notifier_call = kvm_timer_cpu_notify,
207 static const struct of_device_id arch_timer_of_match[] = {
208 { .compatible = "arm,armv7-timer", },
209 { .compatible = "arm,armv8-timer", },
213 int kvm_timer_hyp_init(void)
215 struct device_node *np;
219 timecounter = arch_timer_get_timecounter();
223 np = of_find_matching_node(NULL, arch_timer_of_match);
225 kvm_err("kvm_arch_timer: can't find DT node\n");
229 ppi = irq_of_parse_and_map(np, 2);
231 kvm_err("kvm_arch_timer: no virtual timer interrupt\n");
236 err = request_percpu_irq(ppi, kvm_arch_timer_handler,
237 "kvm guest timer", kvm_get_running_vcpus());
239 kvm_err("kvm_arch_timer: can't request interrupt %d (%d)\n",
244 host_vtimer_irq = ppi;
246 err = register_cpu_notifier(&kvm_timer_cpu_nb);
248 kvm_err("Cannot register timer CPU notifier\n");
252 wqueue = create_singlethread_workqueue("kvm_arch_timer");
258 kvm_info("%s IRQ%d\n", np->name, ppi);
259 on_each_cpu(kvm_timer_init_interrupt, NULL, 1);
263 free_percpu_irq(ppi, kvm_get_running_vcpus());
269 void kvm_timer_vcpu_terminate(struct kvm_vcpu *vcpu)
271 struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
276 int kvm_timer_init(struct kvm *kvm)
278 if (timecounter && wqueue) {
279 kvm->arch.timer.cntvoff = kvm_phys_timer_read();
280 kvm->arch.timer.enabled = 1;