Re: [PATCH, v2] x86: use the right protections for split-uppagetables

[Ingo Molnar]

* Ingo Molnar <mingo@xxxxxxx> wrote:

> [ Huang Ying also experienced problems in this area when writing
>   the EFI code, but the real bug in split_large_page() was not
>   realized back then. ]

> -	 * On Intel the NX bit of all levels must be cleared to make a
> -	 * page executable. See section 4.13.2 of Intel 64 and IA-32
> -	 * Architectures Software Developer's Manual).

Hm, in hindsight, we should have noticed this bug sooner - when 
the NX comment above was added. There's never any good reason to 
play protection games with higher-level pagetable entries. We 
dont do it to user-space pagetables either - we just populate 
them to _PAGE_TABLE and that's it.

	Ingo
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