Re: [Xen-devel] [RFC] Xen Virtual Framebuffer

[Jon Smirl <jonsmirl@xxxxxxxxx>]

On 12/9/05, Tracy R Reed <treed@xxxxxxxxxxxxxxxxxxxxx> wrote:
> Jon Smirl wrote:
> > I haven't tried playing with X and Xen, but why doesn't it work to
> > just treat the multiple domains like a network? You run X in dom0 and
>
> I currently have one big machine (dual core AMD64, 2G RAM, etc) which I
> use for my desktop, my webserver, my mailserver, and I may add other
> domains eventually. Dom0 very special in terms of security and system
> maintainability. Ideally I would like to be able to put a mimimal
> install of a long-term stable distro like CentOS4 or RHEL4 in dom0 and
> use that domain only for managing my domU's. In fact I can see someone
> someday creating a special little distro just for running in dom0. I
> would like to be able to run my desktop/workstation environment in a
> domU with X and everything. I currently have to run X in dom0 for
> reasons already mentioned in this thread which means I clutter up my
> dom0 with a zillion files and do unsafe things in it like read email and
> browse the web. When I upgrade my desktop install it dramatically
> affects dom0 which potentially destabilizes everything.
>
> Ideally I would install a dom0 when I get a new piece of hardware (or
> better yet, manufacturers ship it with dom0 preconfigured standard on
> all of their machines and then optionally the OS of your choice in a
> domU and you never know dom0 is there unless you care about such
> things!) and then never touch it for the life of the hardware.
>
> The beauty of Xen is that your hardware becomes a shared resource to run
> whatever combination of OS's you want on allowing you to get better
> utilization of all that precious CPU/RAM and you get good security
> separation as a bonus. Aside from being able to run X in a domU there is
> only one other thing I can think of asking for out of Xen which is the
> subject of my next email...

You don't have to run the X server in dom0. You can run it in any
domain that has sole control of the graphics hardware.  The core
problem is that only one domain can have control of the video
hardware, there is no realistic way to virtualize a 3D engine.

My knowledge of Xen is limited, is there currently a way to assign
control of a specific PCI device to a domain other than zero? If so,
assign the graphics card to that domain and run X there. Then use the
remote X protocol to access the other domains.

Linux implements unix domain sockets for high performance on a local
machine, does Xen provide an equivalent for interdomain communication?
If so X will perform better over this kind of connection instead of a
full TCP stack.

If you have assigned control of the video device to a domain other
that zero that implies that dom0 does not have a display anymore. It
there a way to use a network connection to talk to dom0 and control
the user domains? If so use xterm from the user domain running X to
connect to the network interface of dom0 and run the control program.

--
Jon Smirl
jonsmirl@xxxxxxxxx

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