Commit 44847dea authored by Paolo Bonzini's avatar Paolo Bonzini
Browse files

KVM: ioapic: extract body of kvm_ioapic_set_irq 



We will reuse it to process a nonzero IRR that is passed to KVM_SET_IRQCHIP.

Reviewed-by: default avatarAlex Williamson <alex.williamson@redhat.com>
Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 0bc830b0

virt/kvm/ioapic.c

+50 −24
Original line number Diff line number Diff line
@@ -163,6 +163,55 @@ static bool rtc_irq_check_coalesced(struct kvm_ioapic *ioapic) 
	return false;

}



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 && 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;

}



static void update_handled_vectors(struct kvm_ioapic *ioapic)

{

	DECLARE_BITMAP(handled_vectors, 256);
@@ -308,38 +357,15 @@ static int ioapic_service(struct kvm_ioapic *ioapic, int irq, bool line_status) 
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];

	if (!irq_level) {

		ioapic->irr &= ~mask;

		ret = 1;

	} else {

		int edge = (entry.fields.trig_mode == IOAPIC_EDGE_TRIG);

	ret = ioapic_set_irq(ioapic, irq, irq_level, line_status);



		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;