From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1756877AbaIRT4X (ORCPT ); Thu, 18 Sep 2014 15:56:23 -0400 Received: from mga11.intel.com ([192.55.52.93]:26402 "EHLO mga11.intel.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1753741AbaIRT4W (ORCPT ); Thu, 18 Sep 2014 15:56:22 -0400 X-ExtLoop1: 1 X-IronPort-AV: E=Sophos;i="5.04,549,1406617200"; d="scan'208";a="601818153" Subject: [PATCH] [v2] x86: update memory map about hypervisor-reserved area To: linux-kernel@vger.kernel.org Cc: Dave Hansen , dave.hansen@linux.intel.com, ryabinin.a.a@gmail.com, dvyukov@google.com, andi@firstfloor.org, x86@kernel.org, linux-mm@kvack.org, tglx@linutronix.de, mingo@redhat.com From: Dave Hansen Date: Thu, 18 Sep 2014 12:56:06 -0700 Message-Id: <20140918195606.841389D2@viggo.jf.intel.com> Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org changes from v1: * fix the actual address since the reserved area is larger than the guard hole -- From: Dave Hansen Peter Anvin says: > 0xffff880000000000 is the lowest usable address because we have > agreed to leave 0xffff800000000000-0xffff880000000000 for the > hypervisor or other non-OS uses. Let's call this out in the documentation. This came up during the kernel address sanitizer discussions where it was proposed to use this area for other kernel things. Signed-off-by: Dave Hansen Cc: Andrey Ryabinin Cc: Dmitry Vyukov Cc: Andi Kleen Cc: x86@kernel.org Cc: linux-mm@kvack.org Cc: Thomas Gleixner Cc: Ingo Molnar --- b/Documentation/x86/x86_64/mm.txt | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-) diff -puN Documentation/x86/x86_64/mm.txt~update-x86-mm-doc Documentation/x86/x86_64/mm.txt --- a/Documentation/x86/x86_64/mm.txt~update-x86-mm-doc 2014-09-18 12:43:55.672230059 -0700 +++ b/Documentation/x86/x86_64/mm.txt 2014-09-18 12:55:17.642795338 -0700 @@ -5,7 +5,7 @@ Virtual memory map with 4 level page tab 0000000000000000 - 00007fffffffffff (=47 bits) user space, different per mm hole caused by [48:63] sign extension -ffff800000000000 - ffff80ffffffffff (=40 bits) guard hole +ffff800000000000 - ffff87ffffffffff (=43 bits) guard hole, reserved for hypervisor ffff880000000000 - ffffc7ffffffffff (=64 TB) direct mapping of all phys. memory ffffc80000000000 - ffffc8ffffffffff (=40 bits) hole ffffc90000000000 - ffffe8ffffffffff (=45 bits) vmalloc/ioremap space _