KVM: Route irq 0 to vcpu 0 exclusively (8c35f237) · Commits · 戴 / test

Some Linux versions allow the timer interrupt to be processed by more than one cpu, leading to hangs due to tsc instability. Work around the issue by only disaptching the interrupt to vcpu 0. Problem analyzed (and patch tested) by Sheng Yang. Signed-off-by:

Avi Kivity <avi@qumranet.com>

virt/kvm/ioapic.c

+8 −0

Original line number	Diff line number	Diff line
		@@ -211,6 +211,10 @@ static void ioapic_deliver(struct kvm_ioapic *ioapic, int irq)
		case IOAPIC_LOWEST_PRIORITY:
		vcpu = kvm_get_lowest_prio_vcpu(ioapic->kvm, vector,
		deliver_bitmask);
		#ifdef CONFIG_X86
		if (irq == 0)
		vcpu = ioapic->kvm->vcpus[0];
		#endif
		if (vcpu != NULL)
		ioapic_inj_irq(ioapic, vcpu, vector,
		trig_mode, delivery_mode);
		@@ -220,6 +224,10 @@ static void ioapic_deliver(struct kvm_ioapic *ioapic, int irq)
		deliver_bitmask, vector, IOAPIC_LOWEST_PRIORITY);
		break;
		case IOAPIC_FIXED:
		#ifdef CONFIG_X86
		if (irq == 0)
		deliver_bitmask = 1;
		#endif
		for (vcpu_id = 0; deliver_bitmask != 0; vcpu_id++) {
		if (!(deliver_bitmask & (1 << vcpu_id)))
		continue;

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