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Commit 4fa6b9c5 authored by Avi Kivity's avatar Avi Kivity
Browse files

KVM: ioapic: fix lost interrupt when changing a device's irq 



The ioapic acknowledge path translates interrupt vectors to irqs.  It
currently uses a first match algorithm, stopping when it finds the first
redirection table entry containing the vector.  That fails however if the
guest changes the irq to a different line, leaving the old redirection table
entry in place (though masked).  Result is interrupts not making it to the
guest.

Fix by always scanning the entire redirection table.

Signed-off-by: default avatarAvi Kivity <avi@qumranet.com>
parent 6bf6a953

virt/kvm/ioapic.c

+11 −20
Original line number Diff line number Diff line
@@ -269,28 +269,9 @@ void kvm_ioapic_set_irq(struct kvm_ioapic *ioapic, int irq, int level) 
	}

}



static int get_eoi_gsi(struct kvm_ioapic *ioapic, int vector)

static void __kvm_ioapic_update_eoi(struct kvm_ioapic *ioapic, int gsi)

{

	int i;



	for (i = 0; i < IOAPIC_NUM_PINS; i++)

		if (ioapic->redirtbl[i].fields.vector == vector)

			return i;

	return -1;

}



void kvm_ioapic_update_eoi(struct kvm *kvm, int vector)

{

	struct kvm_ioapic *ioapic = kvm->arch.vioapic;

	union ioapic_redir_entry *ent;

	int gsi;



	gsi = get_eoi_gsi(ioapic, vector);

	if (gsi == -1) {

		printk(KERN_WARNING "Can't find redir item for %d EOI\n",

		       vector);

		return;

	}



	ent = &ioapic->redirtbl[gsi];

	ASSERT(ent->fields.trig_mode == IOAPIC_LEVEL_TRIG);
@@ -300,6 +281,16 @@ void kvm_ioapic_update_eoi(struct kvm *kvm, int vector) 
		ioapic_deliver(ioapic, gsi);

}



void kvm_ioapic_update_eoi(struct kvm *kvm, int vector)

{

	struct kvm_ioapic *ioapic = kvm->arch.vioapic;

	int i;



	for (i = 0; i < IOAPIC_NUM_PINS; i++)

		if (ioapic->redirtbl[i].fields.vector == vector)

			__kvm_ioapic_update_eoi(ioapic, i);

}



static int ioapic_in_range(struct kvm_io_device *this, gpa_t addr)

{

	struct kvm_ioapic *ioapic = (struct kvm_ioapic *)this->private;