You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: bios.rs
    path of file: ./repos/Theseus/kernel/nano_core/src
    
    the code of the file until where you have to start completion: //! The main entry point into Rust code from a legacy BIOS (multiboot2) bootloader.

use crate::{nano_core, shutdown};
use boot_info::BootInformation;
use memory::VirtualAddress;

#[no_mangle]
pub extern "C" fn rust_entry(boot_info_vaddr: usize, double_fault_stack_top: usize) {
    match inner(boot_info_vaddr, double_fault_stack_top) {
        Ok(_) => shutdown(format_args!("BUG: nano_core() unexpectedly returned!")),
        Err(e) => shutdown(format_args!("{e}")),
    }
}

fn inner(boot_info_vaddr: usize, double_fault_stack_top: usize) -> Result<(), &'static str> {
    VirtualA
    
fn inner(boot_info_vaddr: usize, double_fault_stack_top: usize) -> Result<(), &'static str> {
    VirtualAddress::new(boot_info_vaddr)
        .ok_or("BUG: multiboot2 info virtual address is invalid")?;
    let boot_info = unsafe { multiboot2::load(boot_info_vaddr) }
        .ok()
        .ok_or("BUG: failed to load multiboot 2 info")?;
    let kernel_stack_start = VirtualAddress::new(double_fault_stack_top - boot_info.stack_size()?)
        .ok_or("BUG: kernel_stack_start virtual address is invalid")?;
    let double_fault_stack_top = VirtualAddress::new(double_fault_stack_top)
        .ok_or("BUG: double_fault_stack_top virtual address is invalid")?;

    nano_core(boot_info, double_fault_stack_top, kernel_stack_start)
}