unsafe { core::ptr::read_volatile(big_addr as *mut u64) };
```
Finally, this triggers our exception code, because we try to read from a virtual address for which no address translations have been installed. Remember, we only installed identity-mapped page tables for the first 1 GiB of address space in lesson `0C`.
Finally, this triggers our exception code, because we try to read from a virtual address for which no address translations have been installed. Remember, we only installed identity-mapped page tables for the first 1 GiB of address space in lesson `0D`.
After the exception handler is finished, it returns to the first instruction