Messages in this thread Patch in this message | | | Subject | [PATCH] x86: update memory map about hypervisor-reserved area | From | Dave Hansen <> | Date | Thu, 18 Sep 2014 08:46:21 -0700 |
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From: Dave Hansen <dave.hansen@linux.intel.com>
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> Cc: Andi Kleen <andi@firstfloor.org> Cc: x86@kernel.org Cc: linux-mm@kvack.org Cc: Thomas Gleixner <tglx@linutronix.de> Cc: Ingo Molnar <mingo@redhat.com> ---
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 _
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