qemu-2.5.0

egrep '^flags.*(vmx|svm)' /proc/cpuinfo

[*] Virtualization:  --->                            [CONFIG_VIRTUALIZATION]
  <*/M>   Kernel-based Virtual Machine (KVM) support [CONFIG_KVM]
  <*/M>     KVM for Intel processors support         [CONFIG_KVM_INTEL]
  <*/M>     KVM for AMD processors support           [CONFIG_KVM_AMD]

[*] Networking support  --->                         [CONFIG_NET]
  Networking options  --->
    <*/M> 802.1d Ethernet Bridging                   [CONFIG_BRIDGE]
Device Drivers  --->
  [*] Network device support  --->                   [CONFIG_NETDEVICES]
    <*/M>    Universal TUN/TAP device driver support [CONFIG_TUN]

if [ $(uname -m) = i686 ]; then
   QEMU_ARCH=i386-softmmu
else
   QEMU_ARCH=x86_64-softmmu
fi

mkdir -vp build &&
cd        build &&

../configure --prefix=/usr               \
             --sysconfdir=/etc           \
             --target-list=$QEMU_ARCH    \
             --audio-drv-list=alsa       \
             --docdir=/usr/share/doc/qemu-2.5.0 &&

unset QEMU_ARCH &&

make

make install &&
[ -e  /usr/lib/libcacard.so ] &&
chmod -v 755 /usr/lib/libcacard.so

groupadd -g 61 kvm

usermod -a -G kvm <username>

cat > /lib/udev/rules.d/65-kvm.rules << "EOF"
KERNEL=="kvm", GROUP="kvm", MODE="0660"
EOF

ln -sv qemu-system-`uname -m` /usr/bin/qemu

Configuring qemu

To generate an image, run:

qemu-img create -f qcow2 vdisk.img 10G

Adjust the virtual disk size and image filename as desired. The actual size of the file will be less than specified, but will expand as it is used.

To install an operating system, download an iso of your choice or use a pre-installed cdrom device. For the purposes of this example, use Fedora 16 that is downloaded as Fedora-16-x86_64-Live-LXDE.iso in the current directory. Run the following:

qemu -enable-kvm -hda vdisk.img            \
     -cdrom Fedora-16-x86_64-Live-LXDE.iso \
     -boot d                               \
     -m 384

Follow the normal installation procedures for the chosen distribution. The -boot option specifies the boot order of drives as a string of drive letters. Valid drive letters are: a, b (floppy 1 and 2), c (first hard disk), d (first CD-ROM). The -m option is the amount of memory to use for the virtual machine. If you have sufficient memory (2G or more), 1G is a reasonable value. For computers with 512MB of RAM it's safe to use -m 192, or even -m 128 (the default). The -enable-kvm option allows for hardware acceleration. Without this switch, the emulation is relatively slow.

To run the newly installed operating system, run:

qemu -enable-kvm vdisk.img -m 384

You may have problem with -enable-kvm. Also, you may want to define audio and video drivers, number of cpu cores and threads. An alternative command to install the operating system is (see qemu man page for the parameters definitions):

qemu -enable-kvm             \
     -cdrom /home/fernando/ISO/linuxmint-17.1-mate-32bit.iso \
     -boot order=d           \
     -m 1G,slots=3,maxmem=4G \
     -machine smm=off        \
     -soundhw es1370         \
     -cpu host               \
     -smp cores=4,threads=2  \
     -vga std                \
     vdisk.img

One parameter not appearing in the qemu man page is -machine smm=off, and is used to allow -enable-kvm in some systems. In order to run the machine, you can alternatively issue:

qemu -enable-kvm             \
     -machine smm=off        \
     -boot order=d           \
     -m 1G,slots=3,maxmem=4G \
     -soundhw es1370         \
     -cpu host               \
     -smp cores=4,threads=2  \
     -vga vmware             \
     -hda vdisk.img

Sometimes, you want the machine to have different screen sizes than the ones natively offered by the virtual grahics card. The example below is for qemu vmware graphics card, which uses Xorg VMMouse Driver-13.1.0 and is set to give maximum screen size of 1600x900. As the root user, issue:

cat > /usr/share/X11/xorg.conf.d/20-vmware.conf << "EOF"
Section         "Monitor"
  Identifier    "Monitor0"
  # cvt 1600 900
  # 1600x900 59.95 Hz (CVT 1.44M9) hsync: 55.99 kHz; pclk: 118.25 MHz
  Modeline      "1600x900"  118.25  1600 1696 1856 2112  900 903 908 934 -hsync +vsync
  Option        "PreferredMode" "1600x900"
  HorizSync     1-200
  VertRefresh   1-200
EndSection

Section         "Device"
  Identifier    "VMware SVGA II Adapter"
  Option        "Monitor" "default"
  Driver        "vmware"
EndSection

Section         "Screen"
  Identifier    "Default Screen"
  Device        "VMware SVGA II Adapter"
  Monitor       "Monitor0"

  SubSection    "Display"
    Depth       24
    Modes       "1600x900" "1440x900" "1366x768" "1280x720" "800x480"
  EndSubSection

EndSection
EOF

New sizes will be available besides the native ones. You need to restart X in order to have the new sizes available.

qemu provides a DHCP server for the VM and, depending on the client system, sets up networking though the host.

One problem with the above networking solution is that it does not provide the ability to connect with the local network. To do that, there are several additional steps that need to be done, all as the root user: