Re: [PATCHv1, RFC 0/8] Boot-time switching between 4- and 5-level paging

From	hpa@zytor.com
Newsgroups	linux.kernel
Subject	Re: [PATCHv1, RFC 0/8] Boot-time switching between 4- and 5-level paging
Date	2017-05-26 21:50 +0200
Message-ID	<tLtpf-1zn-11@gated-at.bofh.it> (permalink)
References	(1 earlier) <tLamB-6m2-1@gated-at.bofh.it> <tLna9-6jc-11@gated-at.bofh.it> <tLpOG-7Ks-17@gated-at.bofh.it> <tLt5T-1sR-5@gated-at.bofh.it> <tLt5T-1sR-3@gated-at.bofh.it>
Organization	linux.* mail to news gateway

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On May 26, 2017 12:23:18 PM PDT, Dave Hansen <dave.hansen@intel.com> wrote:
>On 05/26/2017 11:24 AM, hpa@zytor.com wrote:
>> The only case where that even has any utility is for an application
>> to want more than 128 TiB address space on a machine with no more
>> than 64 TiB of RAM.  It is kind of a narrow use case, I think.
>
>Doesn't more address space increase the effectiveness of ASLR?  I
>thought KASLR, especially, was limited in its effectiveness because of
>a
>lack of address space.

The shortage of address space for KASLR is not addressable by LA57; rather, it would have to be addressed by compiling the kernel using a different (less efficient) memory model, presumably the "medium" memory model.
-- 
Sent from my Android device with K-9 Mail. Please excuse my brevity.

Thread

[PATCHv1, RFC 0/8] Boot-time switching between 4- and 5-level paging "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-05-25 22:40 +0200
  [PATCHv1, RFC 2/8] x86/mm: Make virtual memory layout movable for CONFIG_X86_5LEVEL "Kirill A. Shutemov" <kirill.shutemov@linux.intel.com> - 2017-05-25 22:40 +0200
  Re: [PATCHv1, RFC 0/8] Boot-time switching between 4- and 5-level paging Linus Torvalds <torvalds@linux-foundation.org> - 2017-05-26 01:30 +0200
    Re: [PATCHv1, RFC 0/8] Boot-time switching between 4- and 5-level paging Andy Lutomirski <luto@kernel.org> - 2017-05-26 02:50 +0200
      Re: [PATCHv1, RFC 0/8] Boot-time switching between 4- and 5-level  paging Kevin Easton <kevin@guarana.org> - 2017-05-26 06:30 +0200
        Re: [PATCHv1, RFC 0/8] Boot-time switching between 4- and 5-level paging Andy Lutomirski <luto@kernel.org> - 2017-05-26 09:30 +0200
    Re: [PATCHv1, RFC 0/8] Boot-time switching between 4- and 5-level  paging "Kirill A. Shutemov" <kirill@shutemov.name> - 2017-05-26 15:10 +0200
      Re: [PATCHv1, RFC 0/8] Boot-time switching between 4- and 5-level  paging Andi Kleen <ak@linux.intel.com> - 2017-05-26 15:40 +0200
      Re: [PATCHv1, RFC 0/8] Boot-time switching between 4- and 5-level paging Linus Torvalds <torvalds@linux-foundation.org> - 2017-05-26 18:00 +0200
        Re: [PATCHv1, RFC 0/8] Boot-time switching between 4- and 5-level  paging "Kirill A. Shutemov" <kirill@shutemov.name> - 2017-05-26 18:00 +0200
          Re: [PATCHv1, RFC 0/8] Boot-time switching between 4- and 5-level paging Linus Torvalds <torvalds@linux-foundation.org> - 2017-05-26 18:20 +0200
        Re: [PATCHv1, RFC 0/8] Boot-time switching between 4- and 5-level  paging Dave Hansen <dave.hansen@intel.com> - 2017-05-26 21:30 +0200
          Re: [PATCHv1, RFC 0/8] Boot-time switching between 4- and 5-level paging hpa@zytor.com - 2017-05-26 21:50 +0200
        Re: [PATCHv1, RFC 0/8] Boot-time switching between 4- and 5-level paging hpa@zytor.com - 2017-05-26 21:30 +0200
      Re: [PATCHv1, RFC 0/8] Boot-time switching between 4- and 5-level paging hpa@zytor.com - 2017-05-26 22:20 +0200

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