Re: [Xen-devel] What's allocated on head 1M region of domU?

[Mark Williamson <mark.williamson@xxxxxxxxxxxx>]

> > What error code do you get?  Are you trying to map the first meg all at
> > once and it's failing, or does it fail if you map any page in the first
> > meg?  What exactly is the call that's failing?
> >
> > I guess if you were trying to map the guest's shared_info page then you
> > might be disallowed...?
>
> I try to map no all at once.
> I've figured out that top xen kernel is sitting on top 1M region :-|

Xen takes the top 64MB or a guest's virtual address space.  But I thought you 
were trying to map the other end?

> > See the comments starting around line 476 of xen/include/public/xen.h,
> > which describes the start of day memory layout and defines some of the
> > structures involved.  This will not be the same once the guest is up and
> > running because the guest will allocate its own full pagetables and make
> > its own decisions about where it wants to put stuff.  However, it'll at
> > least give you some clues about how the guest is built initially...  I
> > hope this helps you some.
>
> I read the parts you suggested to me.
> It helps me great :-)

Good - those comments are some of the most useful anywhere in the codebase ;-)

Cheers,
Mark


-- 
Dave: Just a question. What use is a unicyle with no seat?  And no pedals!
Mark: To answer a question with a question: What use is a skateboard?
Dave: Skateboards have wheels.
Mark: My wheel has a wheel!

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