Messages in this thread Patch in this message | | | Date | Fri, 19 Sep 2014 04:48:37 -0700 | From | tip-bot for Dave Hansen <> | Subject | [tip:x86/mm] x86/mm: Update memory map description to list hypervisor-reserved area |
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Commit-ID: beb9147e95a75f41c984d7235cf6d59f3ca2d5db Gitweb: http://git.kernel.org/tip/beb9147e95a75f41c984d7235cf6d59f3ca2d5db Author: Dave Hansen <dave.hansen@linux.intel.com> AuthorDate: Thu, 18 Sep 2014 12:56:06 -0700 Committer: Ingo Molnar <mingo@kernel.org> CommitDate: Fri, 19 Sep 2014 12:48:02 +0200
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> --- Documentation/x86/x86_64/mm.txt | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/Documentation/x86/x86_64/mm.txt b/Documentation/x86/x86_64/mm.txt index afe68dd..052ee64 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
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