[PATCH 3/3] KVM: arm64: vgic: Gracefully handle resetting an unallocated interrupt

[Marc Zyngier <maz@kernel.org>]

Playing with racing vcpu reset and vgic teardown makes it relatively
easy to trigger a case where, by the time we try to reset a mapped
interrupt such as a timer's, the vgic is gone and there is no
interrupt to play with.

Check for NULL upfront to avoid further embarassement.

Reported-by: Alexander Potapenko <glider@google.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>
---
 arch/arm64/kvm/vgic/vgic.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/arch/arm64/kvm/vgic/vgic.c b/arch/arm64/kvm/vgic/vgic.c
index f454cef59e24b..2ea6d1d1d3091 100644
--- a/arch/arm64/kvm/vgic/vgic.c
+++ b/arch/arm64/kvm/vgic/vgic.c
@@ -542,6 +542,9 @@ void kvm_vgic_reset_mapped_irq(struct kvm_vcpu *vcpu, u32 vintid)
 	struct vgic_irq *irq = vgic_get_vcpu_irq(vcpu, vintid);
 	unsigned long flags;
 
+	if (!irq)
+		return;
+
 	if (!irq->hw)
 		goto out;
 
-- 
2.39.2