Re: using segmentation in the kernel

From: Arjan van de Ven
Date: Wed Oct 12 2005 - 10:45:15 EST

> > and I don't believe this one yota. THe only way to do this is to run
> > modules in ring 1, at which point you are in deep shit anyway.
> Not neccessarily. Its how Xen works on x86-32 for example. It keeps
> itself protected from the entire Linux instance by using segmentation on

it only works if you make a very small syscall-like area which you use
to talk to the "real" kernel. Which is entirely not how linux modules
work right now.... at which point you're just about a userspace
application anyway. Might be an interesting research project of

> 32bit processors (not 64bit however as x86-64 has no segments in 64bit)

afaik x86-64 grew segments recently for 64 bit mode for an unnamed other
virtualization vendor

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