On Fri, Jan 27, 2023 at 11:29:10AM +0000, Steven Price wrote: > +static int kvm_rme_config_realm(struct kvm *kvm, struct kvm_enable_cap *cap) > +{ > + struct kvm_cap_arm_rme_config_item cfg; > + struct realm *realm = &kvm->arch.realm; > + int r = 0; > + > + if (kvm_realm_state(kvm) != REALM_STATE_NONE) > + return -EBUSY; This should also check kvm_is_realm() (otherwise we dereference a NULL realm). I was wondering about fuzzing the API to find more of this kind of issue, but don't know anything about it. Is there a recommended way to fuzz KVM? Thanks, Jean