/*
* Schedule the background timer before calling kvm_vcpu_block, so that this
* thread is removed from its waitqueue and made runnable when there's a timer
* interrupt to handle.
*/
void kvm_timer_schedule(struct kvm_vcpu *vcpu)
{
struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
u64 ns;
cycle_t cval, now;
BUG_ON(timer_is_armed(timer));
/*
* No need to schedule a background timer if the guest timer has
* already expired, because kvm_vcpu_block will return before putting
* the thread to sleep.
*/
if (kvm_timer_should_fire(vcpu))
return;
/*
* If the timer is not capable of raising interrupts (disabled or
* masked), then there's no more work for us to do.
*/
if (!kvm_timer_irq_can_fire(vcpu))
return;
/* The timer has not yet expired, schedule a background timer */
cval = timer->cntv_cval;
now = kvm_phys_timer_read() - vcpu->kvm->arch.timer.cntvoff;
ns = cyclecounter_cyc2ns(timecounter->cc,
cval - now,
timecounter->mask,
&timecounter->frac);
timer_arm(timer, ns);
}
/*
* Check if there was a change in the timer state (should we raise or lower
* the line level to the GIC).
*/
static void kvm_timer_update_state(struct kvm_vcpu *vcpu)
{
struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
/*
* If userspace modified the timer registers via SET_ONE_REG before
* the vgic was initialized, we mustn't set the timer->irq.level value
* because the guest would never see the interrupt. Instead wait
* until we call this function from kvm_timer_flush_hwstate.
*/
if (!vgic_initialized(vcpu->kvm))
return;
if (kvm_timer_should_fire(vcpu) != timer->irq.level)
kvm_timer_update_irq(vcpu, !timer->irq.level);
}
int kvm_cpu_has_pending_timer(struct kvm_vcpu *vcpu)
{
return kvm_timer_should_fire(vcpu);
}
