Arch Linux

Isola

Member

Registered: 2010-02-02

Posts: 99

Advice on how to setup my systems (xen, gpu passthrough, X)

Hello Archers

I'll try to keep it as short as possible

What I want:
I want to run different operating systems at the same time.
I want to be able to switch between them fast.
I want all keys to work in the guest systems (I've had trouble getting along with VNC regarding this)
I would prefer if the host system is as stable, lightweight, and as unmodified as possible

Why:
To learn about different systems and how to set them up.
I want to compare services/daemons of the same type, such as e-mail, ftp, http.
I also believe in using the right tool(OS) for the right job

How:
I've read about Xen's GPU passthrough feature which interest me quite a bit, but I'm a little unsure how it works, from boot of the host to X in a guest.

I know you "hide" PCI/GPU interfaces at the bootloader stage. But if you for example hide the main GPU because you want this in your guest, what happens on the screen while the host system is booting? Is the monitor just saying "No signal" until the guest starts booting and takes over it?

If I disregard the GPU passthrough feature, I think I would need X on my host system. I read Xen either uses VNC or SDL to serve a screen of a guest. However, VNC isn't perfect with mod keys and mouse acceleration, and SDL requires X to be running at all times (host X crashes = all guest with SDL crashes).

So I was thinking if it's possible to connect to a running X within a guest, from my X running on the host, and use Ctrl+Alt+F1...F12 to change between the different guests running X.

I'm familiar with starting applications on remote X servers by changing the DISPLAY variable, but is it also possible to do something like

DISPLAY=xenguest1:0 xinit /path/to/wm -- :1

And then have the guest X on, say, Ctrl+alt+F4, while the host X is on Ctrl+alt+F3?

Previous experiences:
I've used VirtualBox and QEMU, but in both cases I felt the quest OSes were more temporary and targeted towards development on different platforms. The mouse pointer was also a bit laggy in QEMU, which I didn't like while testing graphical systems.