linux/kernel/user mode VM

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Revision as of 00:37, 17 October 2007 by Mazen (talk | contribs) (→‎Networking)
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Overview

This section is inteneded to help users interested in developping linux kernel modules to setup an UML VM to debug it during devlopmement phase.

Please note that this page will focus in configuring a VM running on a debian distribution based host.

Installation

First of all you need to install the package user-mode-linux 

apt-get install user-mode-linux

Then you need the package uml-utilities 

apt-get install uml-utilities

Configuration

File System Image

The easiest way to do that is to download an already build image 

wget ftp://ftp.freepascal.org/<some path>/fsroot.img.bz2

Then you need to decompress it 

bunzip2 fsroot.img.bz2

Please note that this is really a minimal installation, including the fp-compiler and aptitude packages. The lattest will allow you installing any package you want providing you setup your network correctly.

The provided root file system image has already VM part networking configured, so you need just to configure the host part as described in next section.

Networking

In order to setup networking you need to configure a tap interface 

cat - > /etc/network/interfaces 
# /etc/network/interfaces -- configuration file for ifup(8), ifdown(8)
# In this configuration example we will setup two physical networking
# cards eth0 and eth1. The first card, eth0, will be automatically
# configured at host starting up, while the second one will be configured
# on manual demand using "ifup eth1".
# We will also configure a virtual networking card tap0 which will be
# configured at system startup too.

auto lo eth0 tap0

# The loopback interface 
iface lo inet loopback

iface eth0 inet static
  address 192.168.1.2
  netmask 255.255.255.0
  network 192.168.1.0
  gateway 192.168.1.1

iface eth1 inet static
  address 192.168.2.1
  netmask 255.255.255.0
  network 192.168.2.0

iface tap0 inet static
  address 192.168.3.1
  netmask 255.255.255.0
  network 192.168.3.0
  tunctl_user uml-net
  uml_proxy_arp 192.168.3.2
  uml_proxy_ether eth0

In addition to this networking configuration, you need to instruct your kernel to forward IP packets 

cat - > /etc/sysctl.conf
#
# /etc/sysctl.conf - Configuration file for setting system variables
# See sysctl.conf (5) for information.
#

##############################################################3
# Functions previously found in netbase
#

# Uncomment the next line to enable packet forwarding for IPv4
net.ipv4.ip_forward=1

--Mazen 23:52, 16 October 2007 (CEST)

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