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| author | Dave Hansen <dave.hansen@linux.intel.com> | 2014-09-18 21:56:06 +0200 |
|---|---|---|
| committer | Ingo Molnar <mingo@kernel.org> | 2014-09-19 12:48:02 +0200 |
| commit | beb9147e95a75f41c984d7235cf6d59f3ca2d5db (patch) | |
| tree | d1cc1f24978e29bb2c51149cfe8cc6a6df854971 /Documentation/x86 | |
| parent | x86/mm, hibernate: Do not assume the first e820 area to be RAM (diff) | |
| download | linux-beb9147e95a75f41c984d7235cf6d59f3ca2d5db.tar.xz linux-beb9147e95a75f41c984d7235cf6d59f3ca2d5db.zip | |
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 <dave.hansen@linux.intel.com>
Cc: Andrey Ryabinin <ryabinin.a.a@gmail.com>
Cc: Dmitry Vyukov <dvyukov@google.com>
Link: http://lkml.kernel.org/r/20140918195606.841389D2@viggo.jf.intel.com
Signed-off-by: Ingo Molnar <mingo@kernel.org>
Diffstat (limited to 'Documentation/x86')
| -rw-r--r-- | Documentation/x86/x86_64/mm.txt | 2 |
1 files changed, 1 insertions, 1 deletions
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 |