From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mail-vc0-f170.google.com (mail-vc0-f170.google.com [209.85.220.170]) by kanga.kvack.org (Postfix) with ESMTP id 49CAE6B00A1 for ; Thu, 18 Sep 2014 12:42:12 -0400 (EDT) Received: by mail-vc0-f170.google.com with SMTP id hy4so974048vcb.29 for ; Thu, 18 Sep 2014 09:42:12 -0700 (PDT) Received: from mail-vc0-x22d.google.com (mail-vc0-x22d.google.com [2607:f8b0:400c:c03::22d]) by mx.google.com with ESMTPS id wl13si10322754vcb.9.2014.09.18.09.42.11 for (version=TLSv1 cipher=ECDHE-RSA-RC4-SHA bits=128/128); Thu, 18 Sep 2014 09:42:11 -0700 (PDT) Received: by mail-vc0-f173.google.com with SMTP id le20so954966vcb.4 for ; Thu, 18 Sep 2014 09:42:11 -0700 (PDT) MIME-Version: 1.0 In-Reply-To: <20140918154621.F16A2C86@viggo.jf.intel.com> References: <20140918154621.F16A2C86@viggo.jf.intel.com> Date: Thu, 18 Sep 2014 20:42:10 +0400 Message-ID: Subject: Re: [PATCH] x86: update memory map about hypervisor-reserved area From: Andrey Ryabinin Content-Type: text/plain; charset=UTF-8 Sender: owner-linux-mm@kvack.org List-ID: To: Dave Hansen Cc: LKML , dave.hansen@linux.intel.com, Dmitry Vyukov , Andi Kleen , x86@kernel.org, "linux-mm@kvack.org" , Thomas Gleixner , Ingo Molnar 2014-09-18 19:46 GMT+04:00 Dave Hansen : > > 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 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 > _ -- Best regards, Andrey Ryabinin -- 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