static int ram_block_enable_notify(const char *block_name, void *host_addr, ram_addr_t offset, ram_addr_t length, void *opaque) { MigrationIncomingState *mis = opaque; struct uffdio_register reg_struct; reg_struct.range.start = (uintptr_t)host_addr; reg_struct.range.len = length; reg_struct.mode = UFFDIO_REGISTER_MODE_MISSING; /* Now tell our userfault_fd that it's responsible for this area */ if (ioctl(mis->userfault_fd, UFFDIO_REGISTER, &reg_struct)) { error_report("%s userfault register: %s", __func__, strerror(errno)); return 0;