Re: [PATCH 1/4] efi/x86: make efi_memmap_reserve only insert into boot mem areas

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From	Matt Fleming <matt@codeblueprint.co.uk>
Newsgroups	linux.kernel
Subject	Re: [PATCH 1/4] efi/x86: make efi_memmap_reserve only insert into boot mem areas
Date	Fri, 27 Jan 2017 16:00:02 +0100
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On Fri, 13 Jan, at 05:29:52AM, Dave Young wrote:
> 
> It sounds reasonable though I'm still not sure about EFI_LOADER*.
> 
> The main purpose of this patch is to address the invalid mem ranges
> case. As Ard mentioned I will test with Peter's patch first, if it works
> fine I would like to either drop this patch as a future improvement or add
> it at the end of the next post.
> 
> Matt, what's your opinion about the boot_only check and the EFI_LOADERS*
> question?

The main reason that efi_mem_reserve() isn't used for EFI_LOADER
regions today is because we already have a mechanism for reserving it
via memblock_reserve(), which we do during a very early stage of boot
when parsing all the different types of SETUP_* objects.

It's questionable whether it would make sense to switch to
efi_mem_reserve() for EFI_LOADER regions because then you'd
potentially have different APIs for different SETUP_* objects.

As things stand today, I would suggest triggering a WARN_ON() if
someone tries to efi_mem_reserve() an EFI_LOADER region, until/unless
the day comes when a user exists in the kernel.

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Re: [PATCH 1/4] efi/x86: make efi_memmap_reserve only insert into  boot mem areas Matt Fleming <matt@codeblueprint.co.uk> - 2017-01-27 16:00 +0100
  Re: [PATCH 1/4] efi/x86: make efi_memmap_reserve only insert into  boot mem areas Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2017-01-27 18:40 +0100
    Re: [PATCH 1/4] efi/x86: make efi_memmap_reserve only insert into  boot mem areas Matt Fleming <matt@codeblueprint.co.uk> - 2017-01-27 23:20 +0100
      Re: [PATCH 1/4] efi/x86: make efi_memmap_reserve only insert into  boot mem areas Ard Biesheuvel <ard.biesheuvel@linaro.org> - 2017-01-27 23:30 +0100

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