KVM_S390_VCPU_FAULT
case KVM_S390_VCPU_FAULT: {
r = ioctl(vcpu->fd, KVM_S390_VCPU_FAULT, BUF_START_ADDR + i * PAGE_SIZE);
rc = ioctl(self->vcpu_fd, KVM_S390_VCPU_FAULT, self->base_gpa);