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

From: H. Peter Anvin
Date: Sat Sep 26 2015 - 16:20:04 EST

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@xxxxxxxxxx> wrote:
>> On 26 sep. 2015, at 12:57, Matt Fleming <matt@xxxxxxxxxxxxxxxxxxx>
>>> 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.

Sent from my Android device with K-9 Mail. Please excuse my brevity.
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