arch/x86/kvm/timer.c

   1 #include <linux/kvm_host.h>
   2 #include <linux/kvm.h>
   3 #include <linux/hrtimer.h>
   4 #include <asm/atomic.h>
   5 #include "kvm_timer.h"
   6
   7 static int __kvm_timer_fn(struct kvm_vcpu *vcpu, struct kvm_timer *ktimer)
   8 {
   9         int restart_timer = 0;
  10         wait_queue_head_t *q = &vcpu->wq;
  11
  12         /*
  13          * There is a race window between reading and incrementing, but we do
  14          * not care about potentially loosing timer events in the !reinject
  15          * case anyway.
  16          */
  17         if (ktimer->reinject || !atomic_read(&ktimer->pending)) {
  18                 atomic_inc(&ktimer->pending);
  19                 /* FIXME: this code should not know anything about vcpus */
  20                 set_bit(KVM_REQ_PENDING_TIMER, &vcpu->requests);
  21         }
  22
  23         if (waitqueue_active(q))
  24                 wake_up_interruptible(q);
  25
  26         if (ktimer->t_ops->is_periodic(ktimer)) {
  27                 hrtimer_add_expires_ns(&ktimer->timer, ktimer->period);
  28                 restart_timer = 1;
  29         }
  30
  31         return restart_timer;
  32 }
  33
  34 enum hrtimer_restart kvm_timer_fn(struct hrtimer *data)
  35 {
  36         int restart_timer;
  37         struct kvm_vcpu *vcpu;
  38         struct kvm_timer *ktimer = container_of(data, struct kvm_timer, timer);
  39
  40         vcpu = ktimer->vcpu;
  41         if (!vcpu)
  42                 return HRTIMER_NORESTART;
  43
  44         restart_timer = __kvm_timer_fn(vcpu, ktimer);
  45         if (restart_timer)
  46                 return HRTIMER_RESTART;
  47         else
  48                 return HRTIMER_NORESTART;
  49 }
  50