diff options
| author | Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> | 2010-08-31 23:06:22 +0200 |
|---|---|---|
| committer | Jeremy Fitzhardinge <jeremy.fitzhardinge@citrix.com> | 2010-10-22 21:57:26 +0200 |
| commit | cfd8951e082a589637f9de3c33efd3218fdb3c03 (patch) | |
| tree | e4b55dc7c0aa6dce4e022d1162abfd2633758720 | |
| parent | xen: defer building p2m mfn structures until kernel is mapped (diff) | |
| download | linux-cfd8951e082a589637f9de3c33efd3218fdb3c03.tar.xz linux-cfd8951e082a589637f9de3c33efd3218fdb3c03.zip | |
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>
| -rw-r--r-- | arch/x86/include/asm/xen/page.h | 9 | ||||
| -rw-r--r-- | arch/x86/xen/mmu.c | 15 |
2 files changed, 22 insertions, 2 deletions
diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h index e40ca6e67bb5..875f5a08a6c7 100644 --- a/arch/x86/include/asm/xen/page.h +++ b/arch/x86/include/asm/xen/page.h @@ -41,10 +41,17 @@ extern bool set_phys_to_machine(unsigned long pfn, unsigned long mfn); static inline unsigned long pfn_to_mfn(unsigned long pfn) { + unsigned long mfn; + if (xen_feature(XENFEAT_auto_translated_physmap)) return pfn; - return get_phys_to_machine(pfn) & ~FOREIGN_FRAME_BIT; + mfn = get_phys_to_machine(pfn); + + if (mfn != INVALID_P2M_ENTRY) + mfn &= ~FOREIGN_FRAME_BIT; + + return mfn; } static inline int phys_to_machine_mapping_valid(unsigned long pfn) diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c index 9b43bb398d37..4c63b7f452dd 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; |