Commit 5bda6eed authored by Wincy Van's avatar Wincy Van Committed by Marcelo Tosatti
Browse files

KVM: ioapic: Record edge-triggered interrupts delivery status 

This patch fixes the bug discussed in
https://www.mail-archive.com/kvm@vger.kernel.org/msg109813.html



This patch uses a new field named irr_delivered to record the
delivery status of edge-triggered interrupts, and clears the
delivered interrupts in kvm_get_ioapic. So it has the same effect
of commit 0bc830b0
("KVM: ioapic: clear IRR for edge-triggered interrupts at delivery")
while avoids the bug of Windows guests.

Signed-off-by: default avatarWincy Van <fanwenyi0529@gmail.com>
Signed-off-by: default avatarMarcelo Tosatti <mtosatti@redhat.com>
parent ae548c5c

arch/x86/kvm/ioapic.c

+6 −1
Original line number Diff line number Diff line
@@ -206,6 +206,8 @@ static int ioapic_set_irq(struct kvm_ioapic *ioapic, unsigned int irq, 


	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;
@@ -349,7 +351,7 @@ static int ioapic_service(struct kvm_ioapic *ioapic, int irq, bool line_status) 
	irqe.shorthand = 0;



	if (irqe.trig_mode == IOAPIC_EDGE_TRIG)

		ioapic->irr &= ~(1 << irq);

		ioapic->irr_delivered |= 1 << irq;



	if (irq == RTC_GSI && line_status) {

		/*
@@ -597,6 +599,7 @@ static void kvm_ioapic_reset(struct kvm_ioapic *ioapic) 
	ioapic->base_address = IOAPIC_DEFAULT_BASE_ADDRESS;

	ioapic->ioregsel = 0;

	ioapic->irr = 0;

	ioapic->irr_delivered = 0;

	ioapic->id = 0;

	memset(ioapic->irq_eoi, 0x00, IOAPIC_NUM_PINS);

	rtc_irq_eoi_tracking_reset(ioapic);
@@ -654,6 +657,7 @@ int kvm_get_ioapic(struct kvm *kvm, struct kvm_ioapic_state *state) 


	spin_lock(&ioapic->lock);

	memcpy(state, ioapic, sizeof(struct kvm_ioapic_state));

	state->irr &= ~ioapic->irr_delivered;

	spin_unlock(&ioapic->lock);

	return 0;

}
@@ -667,6 +671,7 @@ int kvm_set_ioapic(struct kvm *kvm, struct kvm_ioapic_state *state) 
	spin_lock(&ioapic->lock);

	memcpy(ioapic, state, sizeof(struct kvm_ioapic_state));

	ioapic->irr = 0;

	ioapic->irr_delivered = 0;

	update_handled_vectors(ioapic);

	kvm_vcpu_request_scan_ioapic(kvm);

	kvm_ioapic_inject_all(ioapic, state->irr);

arch/x86/kvm/ioapic.h

+1 −0
Original line number Diff line number Diff line
@@ -77,6 +77,7 @@ struct kvm_ioapic { 
	struct rtc_status rtc_status;

	struct delayed_work eoi_inject;

	u32 irq_eoi[IOAPIC_NUM_PINS];

	u32 irr_delivered;

};



#ifdef DEBUG

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