Re: [PATCH] KVM: Validate irqchip index for LoongArch and PowerPC

Sashiko reported that irqchip index is not validated for LoongArch and
PowerPC. Add validation and reject out-of-range irqchip indexes to avoid
indexing past the routing table's chip array.

Fixes: de9ba2f36368 ("KVM: PPC: Support irq routing and irqfd for in-kernel MPIC")
Fixes: 1928254c5ccb ("LoongArch: KVM: Add irqfd support")
Reported-by: Sashiko <sashiko-bot@kernel.org>
Closes: https://lore.kernel.org/kvm/20260525051714.485D51F000E9@smtp.kernel.org/ (local)
Signed-off-by: Yanfei Xu <redacted>
---
  arch/loongarch/kvm/irqfd.c | 3 ++-
  arch/powerpc/kvm/mpic.c    | 3 ++-
  2 files changed, 4 insertions(+), 2 deletions(-)

diff --git a/arch/loongarch/kvm/irqfd.c b/arch/loongarch/kvm/irqfd.c
index f4f953b22419..40ed1081c4b6 100644
--- a/arch/loongarch/kvm/irqfd.c
+++ b/arch/loongarch/kvm/irqfd.c

@@ -51,7 +51,8 @@ int kvm_set_routing_entry(struct kvm *kvm,
  		e->irqchip.irqchip = ue->u.irqchip.irqchip;
  		e->irqchip.pin = ue->u.irqchip.pin;
  
-		if (e->irqchip.pin >= KVM_IRQCHIP_NUM_PINS)
+		if (e->irqchip.pin >= KVM_IRQCHIP_NUM_PINS ||
+		    e->irqchip.irqchip >= KVM_NR_IRQCHIPS)
  			return -EINVAL;
  
  		return 0;

diff --git a/arch/powerpc/kvm/mpic.c b/arch/powerpc/kvm/mpic.c
index 3070f36d9fb8..fb5f9e65e02e 100644
--- a/arch/powerpc/kvm/mpic.c
+++ b/arch/powerpc/kvm/mpic.c

@@ -1833,7 +1833,8 @@ int kvm_set_routing_entry(struct kvm *kvm,
  		e->set = mpic_set_irq;
  		e->irqchip.irqchip = ue->u.irqchip.irqchip;
  		e->irqchip.pin = ue->u.irqchip.pin;
-		if (e->irqchip.pin >= KVM_IRQCHIP_NUM_PINS)
+		if (e->irqchip.pin >= KVM_IRQCHIP_NUM_PINS ||
+		    e->irqchip.irqchip >= KVM_NR_IRQCHIPS)