From mboxrd@z Thu Jan  1 00:00:00 1970
From: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Subject: Re: [PATCH] xen/x86: Force removal of memory range when
 not covered by MTRRs
Date: Fri, 15 Feb 2013 11:40:10 -0500
Message-ID: <20130215164010.GE13775@phenom.dumpdata.com>
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To: Jan Beulich <JBeulich@suse.com>
Cc: Stefan Bader <stefan.bader@canonical.com>, xen-devel@lists.xen.org
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On Fri, Feb 15, 2013 at 02:52:41PM +0000, Jan Beulich wrote:
> >>> On 15.02.13 at 14:47, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> wrote:
> >> >> Since when is E820_UNUSABLE memory being used as guest
> >> >> memory? If that's indeed the case, that's the bug to fix. The
> >> >> above data to me shows, however, that the range above
> >> >> 228000000 is considered invalid. So then the question is why the
> >> >> kernel tries to map that memory in the first place (the hypervisor
> >> >> rejecting the attempt, despite Dom0 being privileged, seems
> >> >> correct to me, as the range is also known not to be MMIO).
> > 
> > B/c it gets the E820 from the hypervisor, which shows that area as
> > E820_UNUSABLE. And dom0 (or rather, the generic memory code) ends up
> > creating pagetables for it.
> 
> That would be wrong even on native, and I don't see how that
> would happen: memblock_add() gets called from
> memblock_x86_fill() only for E820_RAM and E820_RESERVED_KERN
> ranges.

Hm, the bug report shows that the ranges (which are E820_UNUSABLE)
do get called with init_memory_mapping.