From: Dave Hansen Date: Thu, 18 Sep 2014 19:56:06 +0000 (-0700) Subject: x86/mm: Update memory map description to list hypervisor-reserved area X-Git-Tag: v3.18-rc1~59^2 X-Git-Url: https://asedeno.scripts.mit.edu/gitweb/?a=commitdiff_plain;h=beb9147e95a75f41c984d7235cf6d59f3ca2d5db;p=linux.git x86/mm: Update memory map description to list hypervisor-reserved area 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 Link: http://lkml.kernel.org/r/20140918195606.841389D2@viggo.jf.intel.com Signed-off-by: Ingo Molnar --- diff --git a/Documentation/x86/x86_64/mm.txt b/Documentation/x86/x86_64/mm.txt index afe68ddbe6a4..052ee643a32e 100644 --- a/Documentation/x86/x86_64/mm.txt +++ b/Documentation/x86/x86_64/mm.txt @@ -5,7 +5,7 @@ Virtual memory map with 4 level page tables: 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