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Re: [RFC, PATCHv1 17/28] x86/mm: define virtual memory map for 5-level paging

From Randy Dunlap <rdunlap@infradead.org>
Newsgroups linux.kernel
Subject Re: [RFC, PATCHv1 17/28] x86/mm: define virtual memory map for 5-level paging
Date 2016-12-08 20:00 +0100
Message-ID <sMc5b-1bo-23@gated-at.bofh.it> (permalink)
References <sM9K2-8la-5@gated-at.bofh.it> <sM9K3-8la-67@gated-at.bofh.it>
Organization linux.* mail to news gateway

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On 12/08/16 08:21, Kirill A. Shutemov wrote:
> The first part of memory map (up to %esp fixup) simply scales existing
> map for 4-level paging by factor of 9 -- number of bits addressed by
> additional page table level.
> 
> The rest of the map is uncahnged.

                         unchanged.

(more fixes below)


> Signed-off-by: Kirill A. Shutemov <kirill.shutemov@linux.intel.com>
> ---
>  Documentation/x86/x86_64/mm.txt         | 23 ++++++++++++++++++++++-
>  arch/x86/Kconfig                        |  1 +
>  arch/x86/include/asm/kasan.h            |  9 ++++++---
>  arch/x86/include/asm/page_64_types.h    | 10 ++++++++++
>  arch/x86/include/asm/pgtable_64_types.h |  6 ++++++
>  arch/x86/include/asm/sparsemem.h        |  9 +++++++--
>  6 files changed, 52 insertions(+), 6 deletions(-)
> 
> diff --git a/Documentation/x86/x86_64/mm.txt b/Documentation/x86/x86_64/mm.txt
> index 8c7dd5957ae1..d33fb0799b3d 100644
> --- a/Documentation/x86/x86_64/mm.txt
> +++ b/Documentation/x86/x86_64/mm.txt
> @@ -12,7 +12,7 @@ ffffc90000000000 - ffffe8ffffffffff (=45 bits) vmalloc/ioremap space
>  ffffe90000000000 - ffffe9ffffffffff (=40 bits) hole
>  ffffea0000000000 - ffffeaffffffffff (=40 bits) virtual memory map (1TB)
>  ... unused hole ...
> -ffffec0000000000 - fffffc0000000000 (=44 bits) kasan shadow memory (16TB)
> +ffffec0000000000 - fffffbffffffffff (=44 bits) kasan shadow memory (16TB)
>  ... unused hole ...
>  ffffff0000000000 - ffffff7fffffffff (=39 bits) %esp fixup stacks
>  ... unused hole ...
> @@ -23,6 +23,27 @@ ffffffffa0000000 - ffffffffff5fffff (=1526 MB) module mapping space
>  ffffffffff600000 - ffffffffffdfffff (=8 MB) vsyscalls
>  ffffffffffe00000 - ffffffffffffffff (=2 MB) unused hole
>  
> +Virtual memory map with 5 level page tables:
> +
> +0000000000000000 - 00ffffffffffffff (=56 bits) user space, different per mm
> +hole caused by [57:63] sign extension

Can you briefly explain the sign extension?
Should that be [56:63]?

> +ff00000000000000 - ff0fffffffffffff (=52 bits) guard hole, reserved for hypervisor
> +ff10000000000000 - ff8fffffffffffff (=55 bits) direct mapping of all phys. memory
> +ff90000000000000 - ff91ffffffffffff (=49 bits) hole
> +ff92000000000000 - ffd1ffffffffffff (=54 bits) vmalloc/ioremap space
> +ffd2000000000000 - ff93ffffffffffff (=49 bits) virtual memory map (512TB)
> +... unused hole ...
> +ff96000000000000 - ffb5ffffffffffff (=53 bits) kasan shadow memory (8PB)
> +... unused hole ...
> +fffe000000000000 - fffeffffffffffff (=49 bits) %esp fixup stacks
> +... unused hole ...
> +ffffffef00000000 - ffffffff00000000 (=64 GB) EFI region mapping space

                    - fffffffeffffffff

> +... unused hole ...
> +ffffffff80000000 - ffffffffa0000000 (=512 MB)  kernel text mapping, from phys 0

                    - ffffffff9fffffff

> +ffffffffa0000000 - ffffffffff5fffff (=1526 MB) module mapping space
> +ffffffffff600000 - ffffffffffdfffff (=8 MB) vsyscalls
> +ffffffffffe00000 - ffffffffffffffff (=2 MB) unused hole
> +
>  The direct mapping covers all memory in the system up to the highest
>  memory address (this means in some cases it can also include PCI memory
>  holes).

> diff --git a/arch/x86/include/asm/kasan.h b/arch/x86/include/asm/kasan.h
> index 1410b567ecde..2587c6bd89be 100644
> --- a/arch/x86/include/asm/kasan.h
> +++ b/arch/x86/include/asm/kasan.h
> @@ -11,9 +11,12 @@
>   * 'kernel address space start' >> KASAN_SHADOW_SCALE_SHIFT
>   */
>  #define KASAN_SHADOW_START      (KASAN_SHADOW_OFFSET + \
> -					(0xffff800000000000ULL >> 3))
> -/* 47 bits for kernel address -> (47 - 3) bits for shadow */
> -#define KASAN_SHADOW_END        (KASAN_SHADOW_START + (1ULL << (47 - 3)))
> +					((-1UL << __VIRTUAL_MASK_SHIFT) >> 3))
> +/*
> + * 47 bits for kernel address -> (47 - 3) bits for shadow
> + * 56 bits for kernel address -> (56 - 3) bits fro shadow

typo: s/fro/for/

> + */
> +#define KASAN_SHADOW_END        (KASAN_SHADOW_START + (1ULL << (__VIRTUAL_MASK_SHIFT - 3)))
>  
>  #ifndef __ASSEMBLY__
>  


-- 
~Randy

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Thread

[RFC, PATCHv1 00/28] 5-level paging "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-12-08 17:30 +0100
  [RFC, PATCHv1 24/28] x86/mm: add sync_global_pgds() for configuration with 5-level paging "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-12-08 17:30 +0100
    Re: [RFC, PATCHv1 24/28] x86/mm: add sync_global_pgds() for  configuration with 5-level paging Andy Lutomirski <luto@amacapital.net> - 2016-12-08 19:50 +0100
      Re: [RFC, PATCHv1 24/28] x86/mm: add sync_global_pgds() for  configuration with 5-level paging "Kirill A. Shutemov" <kirill@shutemov.name> - 2016-12-08 20:40 +0100
  [RFC, PATCHv1 19/28] x86/mm: basic defines/helpers for CONFIG_X86_5LEVEL "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-12-08 17:30 +0100
  [RFC, PATCHv1 04/28] asm-generic: introduce <asm-generic/pgtable-nop4d.h> "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-12-08 17:30 +0100
  [RFC, PATCHv1 17/28] x86/mm: define virtual memory map for 5-level paging "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-12-08 17:30 +0100
    Re: [RFC, PATCHv1 17/28] x86/mm: define virtual memory map for  5-level paging Randy Dunlap <rdunlap@infradead.org> - 2016-12-08 20:00 +0100
      Re: [RFC, PATCHv1 17/28] x86/mm: define virtual memory map for  5-level paging "Kirill A. Shutemov" <kirill@shutemov.name> - 2016-12-08 20:30 +0100
  [RFC, PATCHv1 27/28] x86: enable la57 support "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-12-08 17:30 +0100
  [QEMU, PATCH] x86: implement la57 paging mode "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-12-08 17:30 +0100
    Re: [Qemu-devel] [QEMU, PATCH] x86: implement la57 paging mode no-reply@patchew.org - 2016-12-08 17:50 +0100
  [RFC, PATCHv1 28/28] TESTING-ONLY: bump TASK_SIZE_MAX "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-12-08 17:30 +0100
  [RFC, PATCHv1 03/28] arch, mm: convert all architectures to use 5level-fixup.h "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-12-08 17:30 +0100
  [RFC, PATCHv1 18/28] x86/paravirt: make paravirt code support 5-level paging "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-12-08 17:30 +0100
  [RFC, PATCHv1 07/28] x86: trivial portion of 5-level paging conversion "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-12-08 17:30 +0100
  [RFC, PATCHv1 01/28] asm-generic: introduce 5level-fixup.h "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-12-08 17:30 +0100
  [RFC, PATCHv1 26/28] x86/mm: add support for 5-level paging for KASLR "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-12-08 17:30 +0100
  [RFC, PATCHv1 06/28] x86: basic changes into headers for 5-level paging "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-12-08 17:40 +0100
  [RFC, PATCHv1 02/28] asm-generic: introduce __ARCH_USE_5LEVEL_HACK "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2016-12-08 17:40 +0100
  Re: [RFC, PATCHv1 00/28] 5-level paging Linus Torvalds <torvalds@linux-foundation.org> - 2016-12-08 19:20 +0100
    Re: [RFC, PATCHv1 00/28] 5-level paging hpa@zytor.com - 2016-12-08 19:30 +0100
    Re: [RFC, PATCHv1 00/28] 5-level paging "Kirill A. Shutemov" <kirill@shutemov.name> - 2016-12-08 20:30 +0100
  Re: [RFC, PATCHv1 00/28] 5-level paging Ingo Molnar <mingo@kernel.org> - 2016-12-09 06:10 +0100
    Re: [RFC, PATCHv1 00/28] 5-level paging Arnd Bergmann <arnd@arndb.de> - 2016-12-09 11:30 +0100
      Re: [RFC, PATCHv1 00/28] 5-level paging Catalin Marinas <catalin.marinas@arm.com> - 2016-12-09 12:00 +0100
    Re: [RFC, PATCHv1 00/28] 5-level paging "Kirill A. Shutemov" <kirill@shutemov.name> - 2016-12-09 11:40 +0100
      Re: [RFC, PATCHv1 00/28] 5-level paging Andi Kleen <ak@linux.intel.com> - 2016-12-09 17:50 +0100
        Re: [RFC, PATCHv1 00/28] 5-level paging "Kirill A. Shutemov" <kirill@shutemov.name> - 2016-12-09 18:30 +0100
      Re: [RFC, PATCHv1 00/28] 5-level paging Dave Hansen <dave.hansen@intel.com> - 2016-12-09 17:50 +0100

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