linux-kernel - [PATCH v3 02/62] KVM: arm64: WARN if unmapping vLPI fails

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Message-ID: <20250611224604.313496-4-seanjc@google.com>
Date: Wed, 11 Jun 2025 15:45:05 -0700
From: Sean Christopherson <seanjc@...gle.com>
To: Marc Zyngier <maz@...nel.org>, Oliver Upton <oliver.upton@...ux.dev>, 
	Sean Christopherson <seanjc@...gle.com>, Paolo Bonzini <pbonzini@...hat.com>, Joerg Roedel <joro@...tes.org>, 
	David Woodhouse <dwmw2@...radead.org>, Lu Baolu <baolu.lu@...ux.intel.com>
Cc: linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.linux.dev, 
	kvm@...r.kernel.org, iommu@...ts.linux.dev, linux-kernel@...r.kernel.org, 
	Sairaj Kodilkar <sarunkod@....com>, Vasant Hegde <vasant.hegde@....com>, 
	Maxim Levitsky <mlevitsk@...hat.com>, Joao Martins <joao.m.martins@...cle.com>, 
	Francesco Lavra <francescolavra.fl@...il.com>, David Matlack <dmatlack@...gle.com>
Subject: [PATCH v3 02/62] KVM: arm64: WARN if unmapping vLPI fails

WARN if unmapping a vLPI in kvm_vgic_v4_unset_forwarding() fails, as
failure means an IRTE has likely been left in a bad state, i.e. IRQs
won't go where they should.  WARNing in arch code will eventually allow
dropping all the plumbing a similar WARN in kvm_irq_routing_update(),
and thus avoid having to plumb back a return code just to WARN.

Signed-off-by: Sean Christopherson <seanjc@...gle.com>
---
 arch/arm64/kvm/vgic/vgic-v4.c | 1 +
 1 file changed, 1 insertion(+)

diff --git a/arch/arm64/kvm/vgic/vgic-v4.c b/arch/arm64/kvm/vgic/vgic-v4.c
index 193946108192..86e54cefc237 100644
--- a/arch/arm64/kvm/vgic/vgic-v4.c
+++ b/arch/arm64/kvm/vgic/vgic-v4.c
@@ -546,6 +546,7 @@ int kvm_vgic_v4_unset_forwarding(struct kvm *kvm, int host_irq)
 		atomic_dec(&irq->target_vcpu->arch.vgic_cpu.vgic_v3.its_vpe.vlpi_count);
 		irq->hw = false;
 		ret = its_unmap_vlpi(host_irq);
+		WARN_ON_ONCE(ret);
 	}
 
 	raw_spin_unlock_irqrestore(&irq->irq_lock, flags);
-- 
2.50.0.rc1.591.g9c95f17f64-goog