From mboxrd@z Thu Jan  1 00:00:00 1970
From: "H. Peter Anvin" <hpa@zytor.com>
Subject: Re: [kernel-hardening] Re: [PATCH] x86: make IDT read-only
Date: Tue, 09 Apr 2013 11:26:55 -0700
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To: Kees Cook <keescook@chromium.org>
Cc: Alexander Duyck <alexander.h.duyck@intel.com>, Alex Shi <alex.shi@intel.com>, Jeremy Fitzhardinge <jeremy@goop.org>, Will Drewry <wad@chromium.org>, Julien Tinnes <jln@google.com>, Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>, Frederic Weisbecker <fweisbec@gmail.com>, Dan Rosenberg <drosenberg@vsecurity.com>, "x86@kernel.org" <x86@kernel.org>, LKML <linux-kernel@vger.kernel.org>, Steven Rostedt <rostedt@goodmis.org>, Borislav Petkov <borislav.petkov@amd.com>, Ingo Molnar <mingo@redhat.com>, "kernel-hardening@lists.openwall.com" <kernel-hardening@lists.openwall.com>, "Paul E. McKenney" <paulmck@linux.vnet.ibm.com>, "virtualization@lists.linux-foundation.org" <virtualization@lists.linux-foundation.org>, "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>
List-Id: virtualization@lists.linuxfoundation.org

On 04/09/2013 11:22 AM, Kees Cook wrote:
> 
> $ ./sgdt
> ffff88001fc04000
> # cat /sys/kernel/debug/kernel_page_tables
> ...
> ---[ Low Kernel Mapping ]---
> ...
> 0xffff880001e00000-0xffff88001fe00000         480M     RW         PSE GLB NX pmd
> 

That is the 1:1 memory map area...

	-hpa
-- 
H. Peter Anvin, Intel Open Source Technology Center
I work for Intel.  I don't speak on their behalf.