Windows 7 Virtualization with KVM

This page describes how to set up Funtoo Linux to run Windows 7 Professional 32-bit within a KVM virtual machine. KVM is suitable for running Windows 7 for general desktop application use. It does not provide 3D support, but offers a nice, high-performance virtualization solution for day-to-day productivity applications. It is also very easy to set up.

Introduction

KVM is a hardware-accelerated full-machine hypervisor and virtualization solution included as part of kernel 2.6.20 and later. It allows you to create and start hardware-accelerated virtual machines under Linux using the QEMU tools.

Windows 7 Professional 32-bit running within qemu-kvm

KVM Setup

You will need KVM to be set up on the machine that will be running the virtual machine. This can be a local Linux system, or if you are using SPICE (see SPICE), a local or remote system. See the SPICE section for tweaks that you will need to make to these instructions if you plan to run Windows 7 on a Funtoo Linux system that you will connect to remotely.

Follow these steps for the system that will be running the virtual machine.

If you are using an automatically-built kernel, it is likely that kernel support for KVM is already available.

If you build your kernel from scratch, please see the KVM page for detailed instructions on how to enable KVM. These instructions also cover the process of emerging qemu, which is also necessary. Do this first, as described on the KVM page -- then come back here.

Important

Before using KVM, be sure that your user account is in the kvm group so that qemu can access /dev/kvm. You will need to use a command such as vigr as root to do this, and then log out and log back in for this to take effect.

Prior to using KVM, modprobe the appropriate accelerated driver for Intel or AMD, as root:

# modprobe kvm_intel

Windows 7 ISO Images

In this tutorial, we are going to install Windows 7 Professional, 32-bit Edition. Microsoft provides a free download of the ISO DVD image, but this does require a valid license key for installation. You can download Windows 7 Professional, 32 bit at the following location:

http://msft-dnl.digitalrivercontent.net/msvista/pub/X15-65804/X15-65804.iso

Note

Windows 7 Professional, 32-bit Edition is a free download but requires a valid license key for installation.

In addition, it's highly recommended that you download "VirtIO" drivers produced by Red Hat. These drivers are installed under Windows and significantly improve Windows 7 network and disk performance. You want to download the ISO file (not the ZIP file) at the following location:

http://alt.fedoraproject.org/pub/alt/virtio-win/latest/images/

Create Raw Disk

In this tutorial, we are going to create a 30GB raw disk image for Windows 7. Raw disk images offer better performance than the commonly-used QCOW2 format. Do this as a regular user:

$ cd
$ qemu-img create -f raw win7.img 30G

We now have an empty virtual disk image called win7.img in our home directory.

QEMU script

Now, we'll create the following script to start our virtual machine and begin Windows 7 installation. Note that this script assumes that the two ISO files downloaded earlier were placed in the user's Downloads directory. Adjust paths as necessary if that is not the case. Also be sure to adjust the following parts of the script:

  • Adjust the name of VIRTIMG to match the exact name of the VirtIO ISO image you downloaded earlier
  • Adjust the smp option to use the number of CPU cores and threads (if your system has hyperthreading) of your Linux system's CPU.

Use your favorite text editor to create the following script. Name it something like vm.sh:

#!/bin/sh
export QEMU_AUDIO_DRV=alsa 
DISKIMG=~/win7.img
WIN7IMG=~/Downloads/X15-65804.iso
VIRTIMG=~/Downloads/virtio-win-0.1-74.iso
qemu-system-x86_64 --enable-kvm -drive file=${DISKIMG},if=virtio -m 2048 \
-net nic,model=virtio -net user -cdrom ${WIN7IMG} \
-drive file=${VIRTIMG},index=3,media=cdrom \
-rtc base=localtime,clock=host -smp cores=2,threads=4 \
-usbdevice tablet -soundhw ac97 -cpu host -vga vmware

Now, make the script executable:

$ chmod +x vm.sh

Here is a brief summary of what the script does. It starts the qemu-kvm program and instructs it to use KVM to accelerate virtualization. The display will be shown locally, in a window. If you are using the SPICE method, described later in this document, no window will appear, and you will be able to connect remotely to your running virtual machine.

The system disk is the 30GB raw image you created, and we tell QEMU to use "virtio" mode for this disk, as well as "virtio" for network access. This will require that we install special drivers during installation to access the disk and enable networking, but will give us better performance.

To assist us in installing the VirtIO drivers, we have configured the system with two DVD drives -- the first holds the Windows 7 installation media, and the second contains the VirtIO driver ISO that we will need to access during Windows 7 installation.

The -usbdevice tablet option will cause our mouse and keyboard interaction with our virtual environment to be intuitive and easy to use.

Important

For optimal performance, adjust the script so that the -smp option specifies the exact number of cores and threads on your system -- on non-HyperThreading systems (AMD and some Intel), simply remove the ,threads=X option entirely and just specify cores. Also ensure that the -m option provides enough RAM for Windows 7, without eating up all your system's RAM. On a 4GB Linux system, use 1536. For an 8GB system, 2048 is safe.

SPICE (Accelerated Remote Connection)

SPICE is a new technology that has been incorporated into QEMU, which allows the virtual machine to run on one system, and allows you to use spicec, the SPICE client, to connect to your remote virtual machine. In real-world use, you can run a SPICE server (via QEMU) and client on the same machine if you like, or have them on the same local area network, or have server and client connect over an Internet connection. Here are some important facts about SPICE:

  • SPICE provides accelerated, optimized video updates over the network, similar to VNC
  • QEMU can be configured to run a SPICE server, which you can connect to via spicec, the SPICE client. The SPICE client renders to a local window on your system.
  • SPICE allows easy copying and pasting across operating systems -- for example, you can copy something in GNOME, paste it into the spicec window and have it appear on your Windows 7 system.

SPICE Setup

To set up SPICE, you need to perform the following changes to the "standard" steps described in this document:

  1. Emerge QEMU with the spice USE variable on the system that will be running the Windows 7 virtual machine.
  2. Emerge spice on the system that you will be using to connect to your remote Windows 7 virtual machine.
  3. In the vm.sh script, remove the existing -vga vmware qemu-kvm option, and add these options: -vga qxl -device virtio-serial-pci -spice port=5900,password=mypass -device virtserialport,chardev=spicechannel0,name=com.redhat.spice.0 -chardev spicevmc,id=spicechannel0,name=vdagent
  4. Run vm.sh as described in the next section on your remote server (your Windows 7 system will now boot, but you can't see the virtual machine display) and then connect to it by running the following command on your local system:
# spicec -h remotehost -p 5900 -w mypass

The SPICE client window will appear locally and allow you to interact with your Windows 7 system.

Starting Windows 7 Installation

Now, it's time to start Windows 7 installation. Run vm.sh as follows:

$ ./vm.sh

Windows 7 installation will begin. During the installation process, you will need to enter a valid license key, and also load both VirtIO drivers from Red Hat when prompted (Browse to the second DVD, then win7 directory, then x86).

After some time, Windows 7 installation will complete. You will be able to perform Windows Update, as by default, you will have network access if your host Linux system has network access.

Enjoy your virtualized Windows 7 system!