Until recently, there have not been may seriously viable free/libre options for virtualization (running one operating system in a guest virtual machine on some other host system is the common setup/pattern for this). There was Bochs, which was an emulator, not a virtualization environment, and was thus highly slow. There was qemu, which (when coupled with kqemu) had reasonable speed, but still had some lag. There’s Xen, which is a heavyweight solution that seems to be primarily applicable to servers and also seems (unless coupled with Red Hat’s tools) to be rather poor for quick-and-easy VM creation and destruction.

There’s always the proprietary options such as VMware. This is feasible for the hobbyist now that VMware has made their server product free/gratis (I use it to run my mail/web server VM on our desktop), but it’s still proprietary. I’m not the biggest fan of proprietary things in my kernel (although VMware’s stuff does seem to be solid).

However, my laptop has one of those nifty new Core 2 Duo processors. Which means it has two interesting features: 64-bit support (which lets me run a blazingly-fast 64-bit version of Debian, but isn’t directly applicable to the virtualization situation), and Intel’s VT processor extensions, which allow for hardware virtualization support. This permits me to run the new kid on the block for Linux-based virtualization: KVM (Kernel Virtual Machine). I started playing with KVM this week, and it is quite nifty. It uses qemu for its interface and IO system, so it isn’t as fast as VMware in that regard, but it is still rather swift.

I’m currently running a Windows XP VM and a Red Hat 9 VM (lets me run my antiquated Maple 8). Combining KVM with VDE and dnsmasq gives me quite easy networking support (as easy as VMware’s, once I got it configured). Some small shell scripts give me quick access to running my VM’s, and I have a quick and easy system where I can arbitrarily create, destroy, and reallocate virtual machines at will. Works well. Granted, the graphics drivers could use some work (something like VMware’s paravirtualized stuff would be nice), but one can’t have everything.