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| author | Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> | 2010-08-31 14:06:22 -0700 |
|---|---|---|
| committer | Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> | 2010-10-22 12:57:26 -0700 |
| commit | cfd8951e082a589637f9de3c33efd3218fdb3c03 (patch) | |
| tree | e4b55dc7c0aa6dce4e022d1162abfd2633758720 /arch/x86/xen | |
| parent | 33a847502b0338351cebd8fc0c68ac796cfadbbd (diff) | |
xen: don't map missing memory
When setting up a pte for a missing pfn (no matching mfn), just create
an empty pte rather than a junk mapping.
Signed-off-by: Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com>
Diffstat (limited to 'arch/x86/xen')
| -rw-r--r-- | arch/x86/xen/mmu.c | 15 |
1 files changed, 14 insertions, 1 deletions
diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c index 9b43bb398d3..4c63b7f452d 100644 --- a/arch/x86/xen/mmu.c +++ b/arch/x86/xen/mmu.c @@ -745,7 +745,20 @@ static pteval_t pte_pfn_to_mfn(pteval_t val) if (val & _PAGE_PRESENT) { unsigned long pfn = (val & PTE_PFN_MASK) >> PAGE_SHIFT; pteval_t flags = val & PTE_FLAGS_MASK; - val = ((pteval_t)pfn_to_mfn(pfn) << PAGE_SHIFT) | flags; + unsigned long mfn = pfn_to_mfn(pfn); + + /* + * If there's no mfn for the pfn, then just create an + * empty non-present pte. Unfortunately this loses + * information about the original pfn, so + * pte_mfn_to_pfn is asymmetric. + */ + if (unlikely(mfn == INVALID_P2M_ENTRY)) { + mfn = 0; + flags = 0; + } + + val = ((pteval_t)mfn << PAGE_SHIFT) | flags; } return val; |