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i386: use pte_update_defer in ptep_test_and_clear_{dirty,young}
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If you actually clear the bit, you need to:

+         pte_update_defer(vma->vm_mm, addr, ptep);

The reason is, when updating PTEs, the hypervisor must be notified.  Using
atomic operations to do this is fine for all hypervisors I am aware of.
However, for hypervisors which shadow page tables, if these PTE
modifications are not trapped, you need a post-modification call to fulfill
the update of the shadow page table.

Acked-by: Zachary Amsden <[email protected]>
Cc: Hugh Dickins <[email protected]>
Signed-off-by: David Rientjes <[email protected]>
Signed-off-by: Andrew Morton <[email protected]>
Signed-off-by: Linus Torvalds <[email protected]>
Zachary Amsden authored and Linus Torvalds committed May 7, 2007
1 parent 10a8d6a commit 0013572
Showing 1 changed file with 18 additions and 20 deletions.
38 changes: 18 additions & 20 deletions include/asm-i386/pgtable.h
Original file line number Diff line number Diff line change
@@ -297,22 +297,24 @@ do { \
} while (0)

#define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_DIRTY
static inline int ptep_test_and_clear_dirty(struct vm_area_struct *vma,
unsigned long addr, pte_t *ptep)
{
if (!pte_dirty(*ptep))
return 0;
return test_and_clear_bit(_PAGE_BIT_DIRTY, &ptep->pte_low);
}
#define ptep_test_and_clear_dirty(vma, addr, ptep) ({ \
int ret = 0; \
if (pte_dirty(*ptep)) \
ret = test_and_clear_bit(_PAGE_BIT_DIRTY, &ptep->pte_low); \
if (ret) \
pte_update_defer(vma->vm_mm, addr, ptep); \
ret; \
})

#define __HAVE_ARCH_PTEP_TEST_AND_CLEAR_YOUNG
static inline int ptep_test_and_clear_young(struct vm_area_struct *vma,
unsigned long addr, pte_t *ptep)
{
if (!pte_young(*ptep))
return 0;
return test_and_clear_bit(_PAGE_BIT_ACCESSED, &ptep->pte_low);
}
#define ptep_test_and_clear_young(vma, addr, ptep) ({ \
int ret = 0; \
if (pte_young(*ptep)) \
ret = test_and_clear_bit(_PAGE_BIT_ACCESSED, &ptep->pte_low); \
if (ret) \
pte_update_defer(vma->vm_mm, addr, ptep); \
ret; \
})

/*
* Rules for using ptep_establish: the pte MUST be a user pte, and
@@ -330,10 +332,8 @@ do { \
({ \
int __dirty; \
__dirty = ptep_test_and_clear_dirty((vma), (address), (ptep)); \
if (__dirty) { \
pte_update_defer((vma)->vm_mm, (address), (ptep)); \
if (__dirty) \
flush_tlb_page(vma, address); \
} \
__dirty; \
})

@@ -342,10 +342,8 @@ do { \
({ \
int __young; \
__young = ptep_test_and_clear_young((vma), (address), (ptep)); \
if (__young) { \
pte_update_defer((vma)->vm_mm, (address), (ptep)); \
if (__young) \
flush_tlb_page(vma, address); \
} \
__young; \
})

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