Quick VMs with QEMU

This is a simple article on how to make vms quickly with QEMU. This is what we use at work to host all our VMs. This quick reference shows you how to do this with Windows 7 64bit (and virtio drivers) but you can do the same with other OSs. One note is that I have not had much luck with the Windows XP block virtio drivers... not that I have much use for Windows these days anyway ;-).

Create the VM image

qemu-img create -f qcow2 win764vm.img 500G

Boot the system with the non-virtio block drivers

The following command is actually all on the same line, in bash (and some other shells) the \ means ignore the \n and assume that this is all one line. Don't put anything except a new line after the \ it is an escape caracter, just like in a C or Java string.

qemu-system-x86_64 -enable-kvm -m 2048 -k en-gb \
 -cdrom windows7_64bit.iso -hda win764vm.img \
 -boot d \
 -net nic,model=virtio,macaddr=00:00:D1:C0:54:39 \
 -net tap,ifname=tap5,script=no,downscript=no

I will leave you to install Windows... and even the network device drivers. Available from Fedora, if you have problems with that link look at KVM website. Don't worry about the block drivers, I will cover those in a moment.

Next, create a new drive and set the configuration to the below:

qemu-system-x86_64 -enable-kvm \
        -k en-gb \
        -m 2048 \
        -net nic,model=virtio,macaddr=52:54:00:12:34:56 \
        -net tap,ifname=tap5,script=no,downscript=no \
        -hda win764vm.img \
        -drive file=tempvio.img,if=none,id=drive-virtio0 \
        -device virtio-blk-pci,drive=drive-virtio0,id=virtio-blk-pci0 \
        -boot c \
        -monitor tcp:127.0.0.1:5925,server,nowait \
        -qmp tcp:127.0.0.1:5945,server,nowait \
        -cdrom virtio-win-0.1-30.iso

virtio-win-0.1-30.iso is the driver image you downloaded from Fedora/RedHat.

In windows you should now be able to see SCSI controller and Ethernet Controller in device manager... picture to follow.

More pictres

When you have finished, Shutdown the machine and change your script... again!

qemu-system-x86_64 -enable-kvm \
        -k en-gb \
        -m 2048 \
        -net nic,model=virtio,macaddr=52:54:00:12:34:56 \
        -net tap,ifname=tap5,script=no,downscript=no \
        -drive file=win764vm.img,if=none,id=drive-virtio0 \
        -device virtio-blk-pci,drive=drive-virtio0,id=virtio-blk-pci0 \
        -monitor tcp:127.0.0.1:5925,server,nowait \
        -qmp tcp:127.0.0.1:5945,server,nowait

Needs improving!

Replace a CDROM/DVD in QEMU Command Line (monitor)

(qemu) info block
info block
hd (#block136): root.raw (raw)
    Attached to:      /machine/peripheral-anon/device[0]
    Cache mode:       writeback

cd (#block315): ../ISOs/install-amd64-minimal-20180405T214502Z.iso (raw, read-only)
    Attached to:      /machine/peripheral-anon/device[1]
    Removable device: locked, tray closed
    Cache mode:       writeback

ide2-cd0 (#block576): ../ISOs/install-amd64-minimal-20180405T214502Z.iso (raw, read-only)
    Attached to:      /machine/unattached/device[20]
    Removable device: locked, tray closed
    Cache mode:       writeback

sd0: [not inserted]
    Removable device: not locked, tray closed

In the guest, eject the cdrom drive (eject /dev/sr0)

(qemu) info block
info block
hd (#block136): root.raw (raw)
    Attached to:      /machine/peripheral-anon/device[0]
    Cache mode:       writeback

cd (#block315): ../ISOs/install-amd64-minimal-20180405T214502Z.iso (raw, read-only)
    Attached to:      /machine/peripheral-anon/device[1]
    Removable device: not locked, tray open
    Cache mode:       writeback

ide2-cd0 (#block576): ../ISOs/install-amd64-minimal-20180405T214502Z.iso (raw, read-only)
    Attached to:      /machine/unattached/device[20]
    Removable device: not locked, tray open
    Cache mode:       writeback

sd0: [not inserted]
    Removable device: not locked, tray closed

Now eject the device from the qemu command line

(qemu) eject ide2-cd0

and/or

(qemu) eject cd

To insert a new disk:

(qemu) change ide2-cd0 ../ISOs/alpine-standard-3.9.4-x86_64.iso

...or use a full path.

linux-kvm.org | stackoverflow.com

Extending a QCOW2 Disk

To extend a qemu qcow2 disk, do this:

qemu-img resize virtualdisc.qcow2 300G

Installing Windows 10

Quick, Simple and No Cortana...

qemu-system-x86_64 -name Win10Dev \
	-accel kvm \
	-k en-gb \
	-m 4096 \
	-cpu host,hv_relaxed,hv_vapic,hv_time,hv_spinlocks=0x1fff \
	-machine pc-q35-2.11 \
	-smp 2 \
	-rtc base=localtime \
	-vnc :40 \
	-net nic,model=virtio,macaddr=02:9a:e5:66:ea:70 \
	-net tap,ifname=tap40,script=no,downscript=no \
	-drive file=root.qcow2,format=qcow2,if=none,id=drive-virtio0 \
	-device virtio-blk-pci,drive=drive=virtio0,id=virtio-blk-pci0 \
	-drive file=../ISOs/windows10-x68_64.iso,media=cdrom \
	drive file=../ISOs/virtio-win-0.1.164-r2.iso,media=cdrom

Bridge the VM to the ethernet network. This assumes that br0 is correctly set-up to forward ethernet frames to eth0 (or whatever interface is relevent):

ip tuntap add tap40 mode tap
ip link set down dev tap40
brctl addif br0 tap40
ip link set up dev tap40

Once the clean install is ready there are a number of steps to be performed:

Turn off "Enhance pointer percision"
Remove Cortana
Remove OneDrive
Remove Tiles

Turn off "Enhance pointer precision"

Install Network Adapter Drivers

Remove Cortana

There are many suggestions of how to remove Cortana in Windows 10 the best I found is a combination of a little programme and a batch file from winaero.com (copy locally).

Removing Cortana does "break" Windows 10 Search feature, perhaps you would rather just disable Cortana. A Registry hack that will not remove Cortana is available here: postintrend uninstall Cortana on Windows 10.

Extract the files from Uninistall_Cortana.zip then run Uninstall_Cortana.cmd as Administrator. It will take a little time but once done Cortana will be gone.

Console window after uninstall cortana has finished

Type here to search does not work anymore and you may not type to find your programmes on the start menu. Also, all the tiles have been removed by right clicking and clicking unpin from start or uninstall if available.

Remove OneDrive

A simple command file in the Windows10Mods.zip package will remove the package and some DLLs... run as Administrator!

Hide 3D Objects Icon

The other simple script in the Windows10Mods.zip file will help with removing that annoying ICON

Remove Tiles

Right Click on all the tiles in the start menu and click "Unpin from Start" or "Uninstall" if available.

Quick Reference