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

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: stable@vger.kernel.org
Fixes: abd7229626b93 ("KVM: arm/arm64: Simplify active_change_prepare and plug race")
Reported-by: André Przywara <andre.przywara@arm.com>
Signed-off-by: Marc Zyngier <maz@kernel.org>

diff --git a/virt/kvm/arm/vgic/vgic-mmio.c b/virt/kvm/arm/vgic/vgic-mmio.c
index 2199302..d085e04 100644 (file)
--- a/virt/kvm/arm/vgic/vgic-mmio.c
+++ b/virt/kvm/arm/vgic/vgic-mmio.c
@@ -444,7 +444,7 @@ 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);
 }
 
@@ -452,7 +452,7 @@ static void vgic_change_active_prepare(struct kvm_vcpu *vcpu, u32 intid)
 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);
 }