Re: [PATCH 6/6] Documentation/x86: Update EFI memory region description

Matt Fleming
2015-11-13T09:29:12Z

On Fri, 13 Nov, at 10:22:10AM, Ingo Molnar wrote:
>
> * Matt Fleming <matt@codeblueprint.co.uk> wrote:
>
> > +We map EFI runtime services in the efi_pgd PGD in the virtual range of
> > +64Gb (arbitrarily set, can be raised if needed). The mappings are not
> > +part of any other kernel PGD and are only available during EFI runtime
> > +calls.
>
> Is that virtual address range 0-64Gb, i.e.:
>
> 0x00000000.00000000 - 0x00000010.00000000
>
> or is it somewhere else?

You've snipped the patch hunk that gives the address range used,

diff --git a/Documentation/x86/x86_64/mm.txt
b/Documentation/x86/x86_64/mm.txt
index 05712ac83e38..a9885bb1ac22 100644
--- a/Documentation/x86/x86_64/mm.txt
+++ b/Documentation/x86/x86_64/mm.txt
@@ -16,6 +16,8 @@ ffffec0000000000 - fffffc0000000000 (=44 bits) kasan
shadow memory (16TB)
... unused hole ...
ffffff0000000000 - ffffff7fffffffff (=39 bits) %esp fixup stacks
... unused hole ...
+ffffffef00000000 - ffffffff00000000 (=64 GB) EFI region mapping space
+... unused hole ...
ffffffff80000000 - ffffffffa0000000 (=512 MB) kernel text mapping,
from phys 0
ffffffffa0000000 - ffffffffff5fffff (=1525 MB) module mapping space
ffffffffff600000 - ffffffffffdfffff (=8 MB) vsyscalls