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Commit 4d82d12b authored by Paolo Bonzini's avatar Paolo Bonzini Committed by Radim Krčmář
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KVM: lapic: do not scan IRR when delivering an interrupt 



On interrupt delivery the PPR can only grow (except for auto-EOI),
so it is impossible that non-auto-EOI interrupt delivery results
in KVM_REQ_EVENT.  We can therefore use __apic_update_ppr.

Signed-off-by: default avatarPaolo Bonzini <pbonzini@redhat.com>
parent 26fbbee5

arch/x86/kvm/lapic.c

+15 −4
Original line number Diff line number Diff line
@@ -2115,6 +2115,7 @@ int kvm_get_apic_interrupt(struct kvm_vcpu *vcpu) 
{

	int vector = kvm_apic_has_interrupt(vcpu);

	struct kvm_lapic *apic = vcpu->arch.apic;

	u32 ppr;



	if (vector == -1)

		return -1;
@@ -2126,13 +2127,23 @@ int kvm_get_apic_interrupt(struct kvm_vcpu *vcpu) 
	 * because the process would deliver it through the IDT.

	 */



	apic_set_isr(vector, apic);

	apic_update_ppr(apic);

	apic_clear_irr(vector, apic);



	if (test_bit(vector, vcpu_to_synic(vcpu)->auto_eoi_bitmap)) {

		apic_clear_isr(vector, apic);

		/*

		 * For auto-EOI interrupts, there might be another pending

		 * interrupt above PPR, so check whether to raise another

		 * KVM_REQ_EVENT.

		 */

		apic_update_ppr(apic);

	} else {

		/*

		 * For normal interrupts, PPR has been raised and there cannot

		 * be a higher-priority pending interrupt---except if there was

		 * a concurrent interrupt injection, but that would have

		 * triggered KVM_REQ_EVENT already.

		 */

		apic_set_isr(vector, apic);

		__apic_update_ppr(apic, &ppr);

	}



	return vector;