1. qemu installation

   There are many ways to install. For ubuntu/debian users, you can directly install apt

   Official website: https://www.qemu.org/download/

   sudo apt-get install zlib1g-dev
   sudo apt-get install libglib2.0-0
   sudo apt-get install libglib2.0-dev
   sudo apt-get install libtool
   sudo apt-get install libsdl1.2-dev
   sudo apt-get install libpixman-1-dev
   sudo apt-get install autoconf
   sudo apt-get install qemu 
   sudo apt-get install qemu-user-static
   sudo apt-get install qemu-system
   

   Or use the source installation method

   https://github.com/qemu/qemu

2. Configuration of build root cross compiling environment

Download builderoot

Configure builderoot

In the interface that appears, "Target Architecture" is changed to "MIPS", and the big end and the small end can choose by themselves. In addition, in "Toolschain", the version of "Kernel Headers" should be changed to the version of their own system

You can use {uname -r} to query

My kernel version is 4.13.0-36-generic

The sad thing is that there is no 4.13 in the Kernel Headers option x……

At this time, select "Manually specified Linux version" and manually specify it as 4.13 in the "Custom kernel headers series" below x

Execute the following command after exiting

During compilation... It will be slow Wait patiently ==

One thing to note is that I encountered a problem when compiling

Some of these files should have been linux-4.13 when downloaded tar. XZ but there seems to be something wrong with Makefile. The access becomes Linux - tar. xz

My approach to this issue is:

3. Continue compiling

After compilation, the elf file under mips architecture can be compiled by using the mipsel Linux GNU GCC instruction

At the same time, the dependency libraries required for mips program execution are also saved in / usr / mipsel Linux GNU / lib

1. Network environment configuration of qemu virtual machine

   Install dependencies first

   sudo apt-get install bridge-utils uml-utilities

   Here, I choose to use the bridge method to interconnect the host computer with the virtual machine, and then link the virtual machine with the external network through NAT

   Note that if NAT is not set, the virtual machine cannot access the Internet, which is also a problem not mentioned in many articles (I stayed in the pit for a long time)

   sudo brctl addbr br0
   sudo ifconfig br0 192.168.122.1/24 up
   sudo tunctl -t tap0
   sudo ifconfig tap0 192.168.122.11/24 up
   sudo brctl addif br0 tap0
   

   Download the image of qemu virtual machine

   https://people.debian.org/~aurel32/qemu/mips/
   

   The kernel and image I chose were vmlinux-3.2.0-4-4kc-malta and debian_wheezy_mips_standard.qcow2

   The default user name and password are root/root

   Then configure DHCP and DNS services locally

   sudo dnsmasq --strict-order --except-interface=lo --interface=br0 --listen-address=192.168.122.1 --bind-interfaces --dhcp-range=192.168.122.2,192.168.122.254 --conf-file="" --pid-file=/var/run/qemu-dhcp-virbr0.pid --dhcp-leasefile=/var/run/qemu-dhcp-virbr0.leases --dhcp-no-override

   Now use

   sudo qemu-system-mips64 -M malta -kernel vmlinux-3.2.0-4-4kc-malta -hda debian_wheezy_mips_standard.qcow2 -append "root=/dev/sda1 console=tty0" -netdev tap,id=tapnet,ifname=tap0,script=no -device rtl8139,netdev=tapnet -nographic

   Command to start the virtual machine, so that the virtual machine can communicate with the host computer

   Next, configure the Internet connection

   Turn on port forwarding

   sudo sysctl -w net.ipv4.ip_forward=1
   sudo sysctl -p /etc/sysctl.conf
   

   Configure iptables

   sudo iptables -t nat -A POSTROUTING -s "192.168.122.0/255.255.255.0" ! -d "192.168.122.0/255.255.255.0" -j MASQUERADE
   sudo iptables -N vm-service
   sudo iptables -A vm-service -j ACCEPT
   sudo iptables -A FORWARD -s 192.168.122.0/24 -j   vm-service
   

   Then use the above command to start the virtual machine, and you can communicate with the external network

    

2. QEMU mipsel runs dynamically compiled programs

   QEMU mipsel usually runs programs. When encountering dynamically compiled programs, it will prompt that the dependent library is missing

   The methods given in the book and on the Internet are chroot, but there are several holes when using this command

   First copy the lib library compiled by builderoot to the program folder

   Then execute the chroot command

      cp $(which qemu-mipsel) .
      sudo chroot . ./qemu-mipsel hello
   

   The lib library has been copied to the directory, but the dependent library is still missing during execution

   At this time, the high probability is that qemu mipsel lacks a dependency Library One solution is to view and copy the qemu dependency library through the ldd instruction. The other method I recommend is to directly use the statically compiled qemu mipsel static

      cp $(which qemu-mipsel-static) .
      sudo chroot . ./qemu-mipsel-static hello
   

So far My qemu installation and pit climbing are over. If there is any problem, please forgive me (tell me)