[RFC PATCH v2 14/32] x86: mm: Provide support to use memblock when spliting large pages

[Borislav Petkov]

Hi Brijesh,

On Thu, Apr 06, 2017 at 09:05:03AM -0500, Brijesh Singh wrote:
> I looked into arch/x86/mm/init_{32,64}.c and as you pointed the file contains
> routines to do basic page splitting. I think it sufficient for our usage.

Good :)

> I should be able to drop the memblock patch from the series and update the
> Patch 15 [1] to use the kernel_physical_mapping_init().
> 
> The kernel_physical_mapping_init() creates the page table mapping using
> default KERNEL_PAGE attributes, I tried to extend the function by passing
> 'bool enc' flags to hint whether to clr or set _PAGE_ENC when splitting the
> pages. The code did not looked clean hence I dropped that idea.

Or, you could have a

__kernel_physical_mapping_init_prot(..., prot)

helper which gets a protection argument and hands it down. The lower
levels already hand down prot which is good.

The interface kernel_physical_mapping_init() will then itself call:

	__kernel_physical_mapping_init_prot(..., PAGE_KERNEL);

for the normal cases.

That in a pre-patch of course.

How does that sound?

-- 
Regards/Gruss,
    Boris.

SUSE Linux GmbH, GF: Felix Imendörffer, Jane Smithard, Graham Norton, HRB 21284 (AG Nürnberg)
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