diff options
| author | Jeremy Fitzhardinge <jeremy@goop.org> | 2010-10-14 01:02:24 +0200 |
|---|---|---|
| committer | H. Peter Anvin <hpa@linux.intel.com> | 2010-10-14 01:07:13 +0200 |
| commit | fef5ba797991f9335bcfc295942b684f9bf613a1 (patch) | |
| tree | 25aa49f656def959f5380d1320ebbf1f469e3c07 /arch/x86/include/asm/io.h | |
| parent | memblock, bootmem: Round pfn properly for memory and reserved regions (diff) | |
| download | linux-fef5ba797991f9335bcfc295942b684f9bf613a1.tar.xz linux-fef5ba797991f9335bcfc295942b684f9bf613a1.zip | |
xen: Cope with unmapped pages when initializing kernel pagetable
Xen requires that all pages containing pagetable entries to be mapped
read-only. If pages used for the initial pagetable are already mapped
then we can change the mapping to RO. However, if they are initially
unmapped, we need to make sure that when they are later mapped, they
are also mapped RO.
We do this by knowing that the kernel pagetable memory is pre-allocated
in the range e820_table_start - e820_table_end, so any pfn within this
range should be mapped read-only. However, the pagetable setup code
early_ioremaps the pages to write their entries, so we must make sure
that mappings created in the early_ioremap fixmap area are mapped RW.
(Those mappings are removed before the pages are presented to Xen
as pagetable pages.)
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
LKML-Reference: <4CB63A80.8060702@goop.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
Diffstat (limited to 'arch/x86/include/asm/io.h')
| -rw-r--r-- | arch/x86/include/asm/io.h | 1 |
1 files changed, 1 insertions, 0 deletions
diff --git a/arch/x86/include/asm/io.h b/arch/x86/include/asm/io.h index 30a3e9776123..66aee6c4123b 100644 --- a/arch/x86/include/asm/io.h +++ b/arch/x86/include/asm/io.h @@ -348,6 +348,7 @@ extern void __iomem *early_memremap(resource_size_t phys_addr, unsigned long size); extern void early_iounmap(void __iomem *addr, unsigned long size); extern void fixup_early_ioremap(void); +extern bool is_early_ioremap_ptep(pte_t *ptep); #define IO_SPACE_LIMIT 0xffff |