Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime

From	"H. Peter Anvin" <hpa@zytor.com>
Newsgroups	linux.kernel
Subject	Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime
Date	2015-09-26 22:30 +0200
Message-ID	<qd4gx-28W-3@gated-at.bofh.it> (permalink)
References	(4 earlier) <qd1sl-6zC-15@gated-at.bofh.it> <qd2eK-7JC-25@gated-at.bofh.it> <qd3Nw-1lI-21@gated-at.bofh.it> <qd3Nw-1lI-27@gated-at.bofh.it> <qd3Xb-1Ms-3@gated-at.bofh.it>
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Sadly a lot of firmware is known to fail in that configuration :(  That was very much our guest choice.

I don't actually think it is all that infeasible to keep relative offsets consistent for the regions we have to map. PMD_SIZE is not a very large chunk so it could be a problem.

On September 26, 2015 1:09:17 PM PDT, Ard Biesheuvel <ard.biesheuvel@linaro.org> wrote:
>
>> On 26 sep. 2015, at 12:57, Matt Fleming <matt@codeblueprint.co.uk>
>wrote:
>> 
>>> On Sat, 26 Sep, at 12:49:26PM, H. Peter Anvin wrote:
>>> 
>>> It is still a hack unless all relative offsets are preserved.  That
>>> is actually simpler, even: no sorting necessary.
>> 
>> Unless I'm missing something, preserving relative offsets is exactly
>> what we do today, modulo PMD_SIZE gaps.
>> 
>
>I think what Peter means is preserving the relative offsets inside the
>entire 1:1 space.
>
>This is not at all what we do currently, and i don't think it is
>generally feasible on 32-bit (since the physical range may conflict
>with the virtual kernel mappings)
>
>However, on 64 bit (both arm and x86), this boils down to not calling
>setVA() in the first place, which i'm all in favor of.

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Thread

[PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime Matt Fleming <matt@codeblueprint.co.uk> - 2015-09-26 00:10 +0200
  Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime Ingo Molnar <mingo@kernel.org> - 2015-09-26 08:00 +0200
    Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2015-09-26 08:50 +0200
    Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime Matt Fleming <matt@codeblueprint.co.uk> - 2015-09-26 15:50 +0200
      Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime Ingo Molnar <mingo@kernel.org> - 2015-09-27 09:10 +0200
        Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2015-09-28 08:50 +0200
          Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime Ingo Molnar <mingo@kernel.org> - 2015-09-28 10:30 +0200
            Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2015-09-28 12:00 +0200
              Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime Ingo Molnar <mingo@kernel.org> - 2015-09-29 11:20 +0200
                Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2015-09-29 12:50 +0200
                Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime Matt Fleming <matt@codeblueprint.co.uk> - 2015-09-29 16:20 +0200
                Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime Matt Fleming <matt@codeblueprint.co.uk> - 2015-09-29 16:00 +0200
    Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime Andy Lutomirski <luto@amacapital.net> - 2015-09-26 19:10 +0200
      Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime "H. Peter Anvin" <hpa@zytor.com> - 2015-09-26 19:30 +0200
        Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2015-09-26 20:20 +0200
          Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime Matt Fleming <matt@codeblueprint.co.uk> - 2015-09-26 22:00 +0200
            Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2015-09-26 22:10 +0200
              Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime "H. Peter Anvin" <hpa@zytor.com> - 2015-09-26 22:30 +0200
                Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime Andy Lutomirski <luto@amacapital.net> - 2015-09-27 18:40 +0200
                Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime Matthew Garrett <mjg59@srcf.ucam.org> - 2015-09-27 20:40 +0200
                Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime Ingo Molnar <mingo@kernel.org> - 2015-09-28 08:20 +0200
                Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime Matthew Garrett <mjg59@srcf.ucam.org> - 2015-09-28 09:10 +0200
                Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime Laszlo Ersek <lersek@redhat.com> - 2015-09-30 00:00 +0200
                Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2015-09-30 11:40 +0200
                Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime Andy Lutomirski <luto@amacapital.net> - 2015-09-30 18:50 +0200
                Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime James Bottomley <jbottomley@odin.com> - 2015-09-30 19:30 +0200
                Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime "H. Peter Anvin" <hpa@zytor.com> - 2015-09-30 03:00 +0200
          Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime "H. Peter Anvin" <hpa@zytor.com> - 2015-09-26 22:00 +0200
        Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime Matt Fleming <matt@codeblueprint.co.uk> - 2015-09-26 22:00 +0200
      Re: [PATCH 1/2] x86/efi: Map EFI memmap entries in-order at runtime Ingo Molnar <mingo@kernel.org> - 2015-09-27 09:00 +0200
  [tip:core/urgent] x86/efi:   Fix boot crash by mapping EFI memmap entries bottom-up at runtime,   instead of top-down tip-bot for Matt Fleming <tipbot@zytor.com> - 2015-10-01 15:00 +0200
    Re: [tip:core/urgent] x86/efi: Fix boot crash by mapping EFI memmap  entries bottom-up at runtime, instead of top-down Matt Fleming <matt@codeblueprint.co.uk> - 2015-10-02 11:50 +0200

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