>+/* Set debug control for trapped instruction exiting to userspace */
>+static void vcpu_set_debug_exit_userspace(struct kvm_vm *vm, int vcpuid,
>+ struct kvm_guest_debug *debug) {
The debug argument looks pointless. Probably you can remove it.
>+ memset(debug, 0, sizeof(*debug));
>+ debug->control = KVM_GUESTDBG_ENABLE | KVM_GUESTDBG_EXIT_USERSPACE;
>+ vcpu_set_guest_debug(vm, VCPU_ID_1, debug);
>+}
