[colug-432] KVM management

Joshua Kramer joskra42.list at gmail.com
Wed Aug 8 12:31:19 EDT 2012

One thing to consider when using KVM with Windows guests is the
drivers.  KVM has hardware support for virtualized VGA and IDE
interfaces; however, those are slow.  In their place are "hardware"
components called QXL and VIRTIO.  There are kernel drivers for most
modern Linux distributions for these devices, so when you set up a VM
you can select those right off the bat.

I was able to install Windows 7 Home by creating a VM from scratch
with VIRTIO.  However, the first time I did this, I didn't know about
VIRTIO so I used the IDE driver.  If you want to switch from IDE to
VIRTIO on an OS that is already installed, using KVM, there are some
acrobatics involved:

1. Download the ISO of a KVM driver disk from RedHat;
2. Mount the ISO in the CDROM drive of the VM in question;
3. Create a small hard disk image (this can be any size, even 10MB);
4. Attach the disk image to the VM in question, using the VIRTIO interface;
5. Boot the VM.

Windows will detect the new disk on the unknown interface, and prompt
you for drivers.  You then direct it to the ISO, and the drivers are
installed.  At this time, other drivers are also installed (for mouse,
sound, qxl, etc).  After this is done, you can shut down the machine,
change the main hard disk to VIRTIO from IDE, and disconnect your
secondary image.

The VirtualBox and VMWare Windows drivers have always come with an
installation program on CD.  I think KVM should do the same.

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