Re: Disaggregated (Xoar) Dom0 Building

["Lonnie" <lonnie@xxxxxxxxxxx>]

Hi Teddy,

You are actually on track with what I was thinking in this area which initially 
gave me 2 main ideas:

1. Take the NOVA Microhypervisor (very small TCB at only 5K LOC) and try to get 
QEMU or Bhyve integrated as the VMM which would require a huge amount of 
development time.  The Genode framework has a configuration/compile approach 
that uses NOVA with a custom VirtualBox, but I did not want to go that route.

2. Take the Alpine XEN distro as the base and then update the dated Xoar 
patches which effectively breaks Dom0 into 9 Service and Driver Mini/Nano VMs 
for which I was thinking about further setting them up as ultra-thin Unikernels 
(MirageOS, IncludeOS, etc.) but still researching.

My effort is to make a purely Ultra-Thin RAM-Based Xen Hypervisor that boots 
UEFI for modern systems. Plus a number of other features if all goes well.

Your ideas of QEMU as a Unikernel would probably really work for both XEN and 
NOVA (with a bit of work on the NOVA side). I actually liked NOVA and 
experimented with it a while back being able to produce a very lightweight 
Microhypervisor ISO that would boot and do some simple things and even fire up 
lightweight Linux instances but with very limited capabilities, of course, just 
to see if it worked. Unfortunately, that direction although very interesting, 
would definitely take too much development to make a viable and more complete 
hypervisor.  I did like that you could easily start with no VM and easily start 
one or more and then use Hot-Keys to flip between consoles. That was pretty 
cool and is something that I would like to see about working into this XEN 
effort as well maybe some config file in the Xen.efi directory for that or 
something but am still thinking about it.

I think that perhaps the Alpine-XEN-Xoar approach could be benefitual but XEN, 
plus supporting libraries is still a bit larger than I would have hoped 
although you get more capabilities and more of a solid hypervisor as well, I 
think.  Maybe we can chat more about things if you like.

Best,
Lonnie
On Thursday, June 27, 2024 14:38 CEST, Teddy Astie <teddy.astie@xxxxxxxxxx> 
wrote:

> Hi Lonnie,
> 
> Le 27/06/2024 à 11:33, Lonnie Cumberland a écrit :
> > I am working towards is to have 
> > everything as a RAM-based ultra-lightweight thin hypervisor.   I looked 
> > over ACRN, the NOVA Microhypervisor (Headron, Beadrock Udo), 
> > Rust-Shyper, Bareflank-MicroV, and many other development efforts but it 
> > seems that Xen is the most advanced for my purposes here.
> > 
> 
> You can have a disk-less (or ramdisk based) distro supporting Xen with 
> Alpine Linux (with Xen flavour). It does still use Dom0 with all its 
> responsibilities though.
> 
> >>> Currently, I am investigating and researching the ideas of 
> >>> "Disaggregating" Dom0 and have the Xoar Xen patches ("Breaking Up is 
> >>> Hard to Do: Security and Functionality in a Commodity Hypervisor" 
> >>> 2011) available which were developed against version 22155 of 
> >>> xen-unstable. The Linux patches are against Linux with pvops 
> >>> 2.6.31.13 and developed on a standard Ubuntu 10.04 install. My effort 
> >>> would also be up update these patches.
> >>>
> >>> I have been able to locate the Xen "Dom0 Disaggregation" 
> >>> (https://wiki.xenproject.org/wiki/Dom0_Disaggregation) am reading up 
> >>> on things now but wanted to ask the developers list about any 
> >>> experience you may have had in this area since the research objective 
> >>> is to integrate Xoar with the latest Xen 4.20, if possible, and to 
> >>> take it further to basically eliminate Dom0 all together with 
> >>> individual Mini-OS or Unikernel "Service and Driver VM's" instead 
> >>> that are loaded at UEFI boot time.
> 
> The latest stuff going on I have in mind regarding this idea of moving 
> stuff out of Dom0 is QEMU as Unikernel (using Unikraft), there were some 
> discussions on this in Matrix and at Xen Summit, and it's currently work 
> in progress from Unikraft side.
> 
> Teddy
> 
> 
> Teddy Astie | Vates XCP-ng Intern
> 
> XCP-ng & Xen Orchestra - Vates solutions
> 
> web: https://vates.tech
>