KVM: arm64: vgic-v4: Only WARN for HW IRQ mismatch when unmapping vLPI

The VMM or guest can easily screw up GICv4 vLPI injection by
misconfiguring the MSI or the virtual ITS. Don't fuss over it; limit the
WARN in vgic_v4_unset_forwarding() to fire in the worrying case where an
unrelated HW IRQ was mapped to a vLPI.

Reported-by: Sudheer Dantuluri <dantuluris@google.com>
Tested-by: Sudheer Dantuluri <dantuluris@google.com>
Acked-by: Marc Zyngier <maz@kernel.org>
Link: https://lore.kernel.org/r/20250226183124.82094-3-oliver.upton@linux.dev
Signed-off-by: Oliver Upton <oliver.upton@linux.dev>

diff --git a/arch/arm64/kvm/vgic/vgic-v4.c b/arch/arm64/kvm/vgic/vgic-v4.c
index eedecbbbcf31bb746ecf839d1c0462f2dd9fea51..3e1de40720e0a7aab5b42ab813fea63b18e5de0e 100644 (file)
--- a/arch/arm64/kvm/vgic/vgic-v4.c
+++ b/arch/arm64/kvm/vgic/vgic-v4.c
@@ -512,7 +512,7 @@ int kvm_vgic_v4_unset_forwarding(struct kvm *kvm, int virq,
        if (ret)
                goto out;
 
-       WARN_ON(!(irq->hw && irq->host_irq == virq));
+       WARN_ON(irq->hw && irq->host_irq != virq);
        if (irq->hw) {
                atomic_dec(&irq->target_vcpu->arch.vgic_cpu.vgic_v3.its_vpe.vlpi_count);
                irq->hw = false;