static int ioapic_set_irq(struct kvm_ioapic *ioapic, unsigned int irq,
int irq_level, bool line_status)
{
union kvm_ioapic_redirect_entry entry;
u32 mask = 1 << irq;
u32 old_irr;
int edge, ret;
entry = ioapic->redirtbl[irq];
edge = (entry.fields.trig_mode == IOAPIC_EDGE_TRIG);
if (!irq_level) {
ioapic->irr &= ~mask;
ret = 1;
goto out;
}
/*
* Return 0 for coalesced interrupts; for edge-triggered interrupts,
* this only happens if a previous edge has not been delivered due
* do masking. For level interrupts, the remote_irr field tells
* us if the interrupt is waiting for an EOI.
*
* RTC is special: it is edge-triggered, but userspace likes to know
* if it has been already ack-ed via EOI because coalesced RTC
* interrupts lead to time drift in Windows guests. So we track
* EOI manually for the RTC interrupt.
*/
if (irq == RTC_GSI && line_status &&
rtc_irq_check_coalesced(ioapic)) {
ret = 0;
goto out;
}
old_irr = ioapic->irr;
ioapic->irr |= mask;
if (edge)
ioapic->irr_delivered &= ~mask;
if ((edge && old_irr == ioapic->irr) ||
(!edge && entry.fields.remote_irr)) {
ret = 0;
goto out;
}
ret = ioapic_service(ioapic, irq, line_status);
out:
trace_kvm_ioapic_set_irq(entry.bits, irq, ret == 0);
return ret;
}
int kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int irq_source_id,
int level, bool line_status)
{
u32 old_irr;
u32 mask = 1 << irq;
union kvm_ioapic_redirect_entry entry;
int ret, irq_level;
BUG_ON(irq < 0 || irq >= IOAPIC_NUM_PINS);
spin_lock(&ioapic->lock);
old_irr = ioapic->irr;
irq_level = __kvm_irq_line_state(&ioapic->irq_states[irq],
irq_source_id, level);
entry = ioapic->redirtbl[irq];
irq_level ^= entry.fields.polarity;
if (!irq_level) {
ioapic->irr &= ~mask;
ret = 1;
} else {
int edge = (entry.fields.trig_mode == IOAPIC_EDGE_TRIG);
if (irq == RTC_GSI && line_status &&
rtc_irq_check_coalesced(ioapic)) {
ret = 0; /* coalesced */
goto out;
}
ioapic->irr |= mask;
if ((edge && old_irr != ioapic->irr) ||
(!edge && !entry.fields.remote_irr))
ret = ioapic_service(ioapic, irq, line_status);
else
ret = 0; /* report coalesced interrupt */
}
out:
trace_kvm_ioapic_set_irq(entry.bits, irq, ret == 0);
spin_unlock(&ioapic->lock);
return ret;
}
