KVM: arm: vgic: Fix limit condition when writing to GICD_I[CS]ACTIVER

commit 1c32ca5dc6d00012f0c964e5fdd7042fcc71efb1 upstream.

When deciding whether a guest has to be stopped we check whether this
is a private interrupt or not. Unfortunately, there's an off-by-one bug
here, and we fail to recognize a whole range of interrupts as being
global (GICv2 SPIs 32-63).

Fix the condition from > to be >=.

Cc: [email protected]
Fixes: abd7229 ("KVM: arm/arm64: Simplify active_change_prepare and plug race")
Reported-by: André Przywara <[email protected]>
Signed-off-by: Marc Zyngier <[email protected]>
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: Marc Zyngier

virt/kvm/arm/vgic/vgic-mmio.c

@@ -260,15 +260,15 @@ static void vgic_mmio_change_active(struct kvm_vcpu *vcpu, struct vgic_irq *irq,
 static void vgic_change_active_prepare(struct kvm_vcpu *vcpu, u32 intid)
 {
 	if (vcpu->kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3 ||
-	    intid > VGIC_NR_PRIVATE_IRQS)
+	    intid >= VGIC_NR_PRIVATE_IRQS)
 		kvm_arm_halt_guest(vcpu->kvm);
 }
 
 /* See vgic_change_active_prepare */
 static void vgic_change_active_finish(struct kvm_vcpu *vcpu, u32 intid)
 {
 	if (vcpu->kvm->arch.vgic.vgic_model == KVM_DEV_TYPE_ARM_VGIC_V3 ||
-	    intid > VGIC_NR_PRIVATE_IRQS)
+	    intid >= VGIC_NR_PRIVATE_IRQS)
 		kvm_arm_resume_guest(vcpu->kvm);
 }