Re: [PATCH 2/2] x86/xen: Disable DMI parsing in Xen kernel.

From: Ian Campbell
Date: Thu Feb 28 2008 - 05:35:51 EST



On Thu, 2008-02-28 at 10:46 +0100, Ingo Molnar wrote:
> * Ian Campbell <ijc@xxxxxxxxxxxxxx> wrote:
>
> > Actually scratch this patchset -- its not sufficient. For example
> > ddcprobe in userspace causes the exact same issue vs 0xa0000.
> >
> > Looks like the only sane solution will be to mark regions between
> > 640K-1M reserved early on in boot.
>
> and as luck has it, such a patch from Alexander van Heukelum has been
> put into x86.git#testing just yesterday.
>
> So ... could you try x86.git#testing - does it work out of box? Is the
> reservation early enough to prevent pagetables be allocated in weird
> places?

That patch is 64 bit only and also I'm not sure what EBDA looks like to
a Xen domU (I expect it doesn't exist). I'll give it a go but I'm not
hopeful.

> [or am i missing something - this is about the guest kernel
> reserving th 640k..1M area, not the host kernel - right?]

Correct, the area between 640k and 1M is just normal memory for a Xen
guest and the memory map reflects that so page tables and other stuff
get allocated in regions which would be magic data structures on native.

Ian.
--
Ian Campbell

The woman you buy -- and she is the least expensive -- takes a great
deal of money. The woman who gives herself takes all your time.
-- Balzac

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