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: 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>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

diff --git a/virt/kvm/arm/vgic/vgic-mmio.c b/virt/kvm/arm/vgic/vgic-mmio.c
index 762f81900529eef4051d42517aa117875927d565..9d06a1f8e6c0ade065266f5c535eec304390a09c 100644 (file)
--- a/virt/kvm/arm/vgic/vgic-mmio.c
+++ b/virt/kvm/arm/vgic/vgic-mmio.c
@@ -381,7 +381,7 @@ 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);
 }
 
@@ -389,7 +389,7 @@ 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);
 }