x86/mm: Only check uniform after calling mtrr_type_lookup()

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Today pud_set_huge() and pmd_set_huge() test for the MTRR type to be
WB or INVALID after calling mtrr_type_lookup().

Those tests can be dropped as the only reason not to use a large mapping
would be uniform being 0.

Any MTRR type can be accepted as long as it applies to the whole memory
range covered by the mapping, as the alternative would only be to map
the same region with smaller pages instead, using the same PAT type as
for the large mapping.

  [ bp: Massage commit message. ]

Suggested-by: Linus Torvalds <torvalds@linux-foundation.org>
Signed-off-by: Juergen Gross <jgross@suse.com>
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>
Tested-by: Michael Kelley <mikelley@microsoft.com>
Link: https://lore.kernel.org/r/20230502120931.20719-16-jgross@suse.com
Signed-off-by: Borislav Petkov (AMD) <bp@alien8.de>

...

This commit is contained in:

Juergen Gross 2023-05-02 14:09:30 +02:00 • committed by Borislav Petkov (AMD)

parent 973df19420

commit 12f0dd8df1

1 changed files with 8 additions and 16 deletions

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arch/x86/mm/pgtable.c

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