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 <asm/arch_timer.h>
27 #include <asm/kvm_vgic.h>
28 #include <asm/kvm_arch_timer.h>
30 static struct timecounter
*timecounter
;
31 static struct workqueue_struct
*wqueue
;
32 static struct kvm_irq_level timer_irq
= {
36 static cycle_t
kvm_phys_timer_read(void)
38 return timecounter
->cc
->read(timecounter
->cc
);
41 static bool timer_is_armed(struct arch_timer_cpu
*timer
)
46 /* timer_arm: as in "arm the timer", not as in ARM the company */
47 static void timer_arm(struct arch_timer_cpu
*timer
, u64 ns
)
50 hrtimer_start(&timer
->timer
, ktime_add_ns(ktime_get(), ns
),
54 static void timer_disarm(struct arch_timer_cpu
*timer
)
56 if (timer_is_armed(timer
)) {
57 hrtimer_cancel(&timer
->timer
);
58 cancel_work_sync(&timer
->expired
);
63 static void kvm_timer_inject_irq(struct kvm_vcpu
*vcpu
)
65 struct arch_timer_cpu
*timer
= &vcpu
->arch
.timer_cpu
;
67 timer
->cntv_ctl
|= 1 << 1; /* Mask the interrupt in the guest */
68 kvm_vgic_inject_irq(vcpu
->kvm
, vcpu
->vcpu_id
,
69 vcpu
->arch
.timer_cpu
.irq
->irq
,
70 vcpu
->arch
.timer_cpu
.irq
->level
);
73 static irqreturn_t
kvm_arch_timer_handler(int irq
, void *dev_id
)
75 struct kvm_vcpu
*vcpu
= *(struct kvm_vcpu
**)dev_id
;
78 * We disable the timer in the world switch and let it be
79 * handled by kvm_timer_sync_hwstate(). Getting a timer
80 * interrupt at this point is a sure sign of some major
83 pr_warn("Unexpected interrupt %d on vcpu %p\n", irq
, vcpu
);
87 static void kvm_timer_inject_irq_work(struct work_struct
*work
)
89 struct kvm_vcpu
*vcpu
;
91 vcpu
= container_of(work
, struct kvm_vcpu
, arch
.timer_cpu
.expired
);
92 vcpu
->arch
.timer_cpu
.armed
= false;
93 kvm_timer_inject_irq(vcpu
);
96 static enum hrtimer_restart
kvm_timer_expire(struct hrtimer
*hrt
)
98 struct arch_timer_cpu
*timer
;
99 timer
= container_of(hrt
, struct arch_timer_cpu
, timer
);
100 queue_work(wqueue
, &timer
->expired
);
101 return HRTIMER_NORESTART
;
105 * kvm_timer_flush_hwstate - prepare to move the virt timer to the cpu
106 * @vcpu: The vcpu pointer
108 * Disarm any pending soft timers, since the world-switch code will write the
109 * virtual timer state back to the physical CPU.
111 void kvm_timer_flush_hwstate(struct kvm_vcpu
*vcpu
)
113 struct arch_timer_cpu
*timer
= &vcpu
->arch
.timer_cpu
;
116 * We're about to run this vcpu again, so there is no need to
117 * keep the background timer running, as we're about to
118 * populate the CPU timer again.
124 * kvm_timer_sync_hwstate - sync timer state from cpu
125 * @vcpu: The vcpu pointer
127 * Check if the virtual timer was armed and either schedule a corresponding
128 * soft timer or inject directly if already expired.
130 void kvm_timer_sync_hwstate(struct kvm_vcpu
*vcpu
)
132 struct arch_timer_cpu
*timer
= &vcpu
->arch
.timer_cpu
;
136 /* Check if the timer is enabled and unmasked first */
137 if ((timer
->cntv_ctl
& 3) != 1)
140 cval
= timer
->cntv_cval
;
141 now
= kvm_phys_timer_read() - vcpu
->kvm
->arch
.timer
.cntvoff
;
143 BUG_ON(timer_is_armed(timer
));
147 * Timer has already expired while we were not
148 * looking. Inject the interrupt and carry on.
150 kvm_timer_inject_irq(vcpu
);
154 ns
= cyclecounter_cyc2ns(timecounter
->cc
, cval
- now
);
155 timer_arm(timer
, ns
);
158 void kvm_timer_vcpu_init(struct kvm_vcpu
*vcpu
)
160 struct arch_timer_cpu
*timer
= &vcpu
->arch
.timer_cpu
;
162 INIT_WORK(&timer
->expired
, kvm_timer_inject_irq_work
);
163 hrtimer_init(&timer
->timer
, CLOCK_MONOTONIC
, HRTIMER_MODE_ABS
);
164 timer
->timer
.function
= kvm_timer_expire
;
165 timer
->irq
= &timer_irq
;
168 static void kvm_timer_init_interrupt(void *info
)
170 enable_percpu_irq(timer_irq
.irq
, 0);
174 static int kvm_timer_cpu_notify(struct notifier_block
*self
,
175 unsigned long action
, void *cpu
)
179 case CPU_STARTING_FROZEN
:
180 kvm_timer_init_interrupt(NULL
);
183 case CPU_DYING_FROZEN
:
184 disable_percpu_irq(timer_irq
.irq
);
191 static struct notifier_block kvm_timer_cpu_nb
= {
192 .notifier_call
= kvm_timer_cpu_notify
,
195 static const struct of_device_id arch_timer_of_match
[] = {
196 { .compatible
= "arm,armv7-timer", },
200 int kvm_timer_hyp_init(void)
202 struct device_node
*np
;
206 timecounter
= arch_timer_get_timecounter();
210 np
= of_find_matching_node(NULL
, arch_timer_of_match
);
212 kvm_err("kvm_arch_timer: can't find DT node\n");
216 ppi
= irq_of_parse_and_map(np
, 2);
218 kvm_err("kvm_arch_timer: no virtual timer interrupt\n");
223 err
= request_percpu_irq(ppi
, kvm_arch_timer_handler
,
224 "kvm guest timer", kvm_get_running_vcpus());
226 kvm_err("kvm_arch_timer: can't request interrupt %d (%d)\n",
233 err
= register_cpu_notifier(&kvm_timer_cpu_nb
);
235 kvm_err("Cannot register timer CPU notifier\n");
239 wqueue
= create_singlethread_workqueue("kvm_arch_timer");
245 kvm_info("%s IRQ%d\n", np
->name
, ppi
);
246 on_each_cpu(kvm_timer_init_interrupt
, NULL
, 1);
250 free_percpu_irq(ppi
, kvm_get_running_vcpus());
256 void kvm_timer_vcpu_terminate(struct kvm_vcpu
*vcpu
)
258 struct arch_timer_cpu
*timer
= &vcpu
->arch
.timer_cpu
;
263 int kvm_timer_init(struct kvm
*kvm
)
265 if (timecounter
&& wqueue
) {
266 kvm
->arch
.timer
.cntvoff
= kvm_phys_timer_read();
267 kvm
->arch
.timer
.enabled
= 1;