KVM: arm/arm64: Fix spinlock acquisition in vgic_set_owner (7465894e) · Commits · 戴 / test

vgic_set_owner acquires the irq lock without disabling interrupts, resulting in a lockdep splat (an interrupt could fire and result in the same lock being taken if the same virtual irq is to be injected). In practice, it is almost impossible to trigger this bug, but better safe than sorry. Convert the lock acquisition to a spin_lock_irqsave() and keep lockdep happy. Reported-by:

James Morse <james.morse@arm.com> Signed-off-by:

Marc Zyngier <marc.zyngier@arm.com> Signed-off-by:

Christoffer Dall <christoffer.dall@linaro.org>

virt/kvm/arm/vgic/vgic.c

+3 −2

Original line number	Diff line number	Diff line
		@@ -492,6 +492,7 @@ int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int vintid)
		int kvm_vgic_set_owner(struct kvm_vcpu vcpu, unsigned int intid, void owner)
		{
		struct vgic_irq *irq;
		unsigned long flags;
		int ret = 0;

		if (!vgic_initialized(vcpu->kvm))
		@@ -502,12 +503,12 @@ int kvm_vgic_set_owner(struct kvm_vcpu vcpu, unsigned int intid, void owner)
		return -EINVAL;

		irq = vgic_get_irq(vcpu->kvm, vcpu, intid);
		spin_lock(&irq->irq_lock);
		spin_lock_irqsave(&irq->irq_lock, flags);
		if (irq->owner && irq->owner != owner)
		ret = -EEXIST;
		else
		irq->owner = owner;
		spin_unlock(&irq->irq_lock);
		spin_unlock_irqrestore(&irq->irq_lock, flags);

		return ret;
		}

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