From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-pa0-f48.google.com (mail-pa0-f48.google.com [209.85.220.48]) by kanga.kvack.org (Postfix) with ESMTP id DB49A6B0096 for ; Thu, 18 Sep 2014 11:46:54 -0400 (EDT) Received: by mail-pa0-f48.google.com with SMTP id fb1so868655pad.35 for ; Thu, 18 Sep 2014 08:46:54 -0700 (PDT) Received: from mga09.intel.com (mga09.intel.com. [134.134.136.24]) by mx.google.com with ESMTP id gx11si7174017pbd.145.2014.09.18.08.46.48 for ; Thu, 18 Sep 2014 08:46:48 -0700 (PDT) Subject: [PATCH] x86: update memory map about hypervisor-reserved area From: Dave Hansen Date: Thu, 18 Sep 2014 08:46:21 -0700 Message-Id: <20140918154621.F16A2C86@viggo.jf.intel.com> Sender: owner-linux-mm@kvack.org List-ID: 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 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 2014-09-17 21:44:10.499781092 -0700 +++ b/Documentation/x86/x86_64/mm.txt 2014-09-17 21:44:31.852740822 -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 - ffff80ffffffffff (=40 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 _ -- To unsubscribe, send a message with 'unsubscribe linux-mm' in the body to majordomo@kvack.org. For more info on Linux MM, see: http://www.linux-mm.org/ . Don't email: email@kvack.org