Re: GNU Mach: in user-mode?

[Samuel Thibault]

Ivan Shmakov, le Fri 05 Jun 2009 22:26:46 +0700, a écrit :
> >>>>> Samuel Thibault <samuel.thibault@gnu.org> writes:
> 
>  >>>> * The time and qualification necessary to deploy one or more
>  >>>> GNU/Linux systems on a single host using User-Mode Linux is (to my
>  >>>> experience) significantly lower than for the other solutions (KVM,
>  >>>> Xen)
> 
>  >>> For Xen I agree.  For KVM, I don't.  Building a UML image is not
>  >>> particularly easier than building a KVM image.
> 
>  >> I've implied using rootstrap to build an image.
> 
>  > And you can use debootstrap to build a debian image.  There is no
>  > fundamental difference here.
> 
>       There is: debootstrap only runs privileged.

Gah, damn silly OSes that don't permit mounting images as
non-priviledged user :)

>  > Oh, I thought it was given to any user.
> 
>       There's the `kvm' group in Debian GNU/Linux.

Yes, I've seen that, but I meant that I had completely forgotten that I
had added myself to it long time ago.

>  > So they still fear security breaches...
> 
>       A completely bug-free version of Linux is yet to be released.

Sure, but they still allow anybody to open a TCP/IP socket by default.

>       With the latter being said, I wonder, wouldn't the changes
>       necessary to run GNU Mach in user-mode be similar to those
>       already done to make it suitable for Xen?

The thing is: Xen provides you with pagetable-like operations so it's
quite easy to do it. Linux doesn't provide you with that and so you'll
have to reimplement memory management tricks.

Samuel