arm/arm64: KVM: Don't allow creating VCPUs after vgic_initialized

When the vgic initializes its internal state it does so based on the number of VCPUs available at the time. If we allow KVM to create more VCPUs after the VGIC has been initialized, we are likely to error out in unfortunate ways later, perform buffer overflows etc. Acked-by: Marc Zyngier <[email protected]> Reviewed-by: Eric Auger <[email protected]> Signed-off-by: Christoffer Dall <[email protected]>
berg · Dec 13, 2014 · 716139d · 716139d
1 parent 1f57be2
commit 716139d
Showing 1 changed file with 5 additions and 0 deletions.
diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
@@ -213,6 +213,11 @@ struct kvm_vcpu *kvm_arch_vcpu_create(struct kvm *kvm, unsigned int id)
 	int err;
 	struct kvm_vcpu *vcpu;
 
+	if (irqchip_in_kernel(kvm) && vgic_initialized(kvm)) {
+		err = -EBUSY;
+		goto out;
+	}
+
 	vcpu = kmem_cache_zalloc(kvm_vcpu_cache, GFP_KERNEL);
 	if (!vcpu) {
 		err = -ENOMEM;