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| author | Jeremy Fitzhardinge <jeremy@goop.org> | 2007-11-29 03:21:20 +0300 |
|---|---|---|
| committer | Linus Torvalds <torvalds@woody.linux-foundation.org> | 2007-11-29 20:24:52 +0300 |
| commit | 2c80b01beae3db9f99a161ec216405dd694bc4c2 (patch) | |
| tree | aea1b56634dad1467eca5a53a81b6a08d7b619b5 /arch/x86/xen/mmu.c | |
| parent | c06869d660ceffec7dc0fca19ed9646ed5845c7f (diff) | |
| download | linux-2c80b01beae3db9f99a161ec216405dd694bc4c2.tar.xz | |
xen: mask _PAGE_PCD from ptes
_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>
Diffstat (limited to 'arch/x86/xen/mmu.c')
| -rw-r--r-- | arch/x86/xen/mmu.c | 4 |
1 files changed, 4 insertions, 0 deletions
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c index b2e32f9d0071..0ac6c5dc49ba 100644 --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -244,6 +244,8 @@ pte_t xen_make_pte(unsigned long long pte) if (pte & 1) pte = phys_to_machine(XPADDR(pte)).maddr; + pte &= ~_PAGE_PCD; + return (pte_t){ pte, pte >> 32 }; } @@ -291,6 +293,8 @@ pte_t xen_make_pte(unsigned long pte) if (pte & _PAGE_PRESENT) pte = phys_to_machine(XPADDR(pte)).maddr; + pte &= ~_PAGE_PCD; + return (pte_t){ pte }; } |