xen: mask _PAGE_PCD from ptes

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_PAGE_PCD maps a page with caching disabled, which is typically used for
mapping harware registers.  Xen never allows it to be set on a mapping, and
unprivileged guests never need it since they can't see the real underlying
hardware.  However, some uncached mappings are made early when probing the
(non-existent) APIC, and its OK to mask off the PCD flag in these cases.

This became necessary because Xen started checking for this bit, rather
than silently masking it off.

Signed-off-by: Jeremy Fitzhardinge <jeremy@xensource.com>
Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

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Jeremy Fitzhardinge 2007-11-28 16:21:20 -08:00 • committed by Linus Torvalds

parent c06869d660

commit 2c80b01bea

1 changed files with 4 additions and 0 deletions

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arch/x86/xen/mmu.c

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