[PATCH 8/8] xen/mmu: Set _PAGE_IOMAP if PFN is in identity P2M.

Konrad Rzeszutek Wilk
2010-12-30T19:50:20Z

If we find that the PFN is within the P2M as an identity
make sure to tack on the _PAGE_IOMAP flag.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
arch/x86/xen/mmu.c | 19 +++++++++++++++----
1 files changed, 15 insertions(+), 4 deletions(-)

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index d470435..158d07a 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -828,7 +828,7 @@ 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;
- unsigned long mfn = pfn_to_mfn(pfn);
+ unsigned long mfn = get_phys_to_machine(pfn);

/*
* If there's no mfn for the pfn, then just create an
@@ -839,8 +839,18 @@ static pteval_t pte_pfn_to_mfn(pteval_t val)
if (unlikely(mfn == INVALID_P2M_ENTRY)) {
mfn = 0;
flags = 0;
+ } else {
+ /*
+ * Paramount to do this test _after_ the
+ * INVALID_P2M_ENTRY as INVALID_P2M_ENTRY &
+ * IDENTITY_FRAME_BIT resolves to true.
+ */
+ mfn &= ~FOREIGN_FRAME_BIT;
+ if (mfn & IDENTITY_FRAME_BIT) {
+ mfn &= ~IDENTITY_FRAME_BIT;
+ flags |= _PAGE_IOMAP;
+ }
}
-
val = ((pteval_t)mfn << PAGE_SHIFT) | flags;
}

@@ -968,8 +978,9 @@ pte_t xen_make_pte_debug(pteval_t pte)
(unsigned long)addr, (unsigned long)other_addr);
} else {
other_addr = (_pte.pte & PTE_PFN_MASK);
- WARN((addr == other_addr) && (!io_page),
- "0x%lx is missing VM_IO!\n",
+ pteval_t iomap_set = (_pte.pte & PTE_FLAGS_MASK) & _PAGE_IOMAP;
+ WARN((addr == other_addr) && (!io_page) && (!iomap_set),
+ "0x%lx is missing VM_IO (and wasn't fixed)!\n",
(unsigned long)addr);
}

--
1.7.1