[Xen-devel] [PATCH 04/10] xen/mmu: For 1-1 mapping, automatically set _PAGE_IOMAP.

[Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>]

This means that for PFNs (specifically: those in any E820 gaps
or non-RAM E820 regions) that have 1-1 mapping we set the
_PAGE_IOMAP flag.

Later on we could remove the _PAGE_IOMAP code handling, but
for right now lets keep this in to not introduce any bisection
failures across this patchset.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@xxxxxxxxxx>
---
 arch/x86/xen/mmu.c |    3 +++
 1 files changed, 3 insertions(+), 0 deletions(-)

diff --git a/arch/x86/xen/mmu.c b/arch/x86/xen/mmu.c
index 4ba7e4e..bd02e7d 100644
--- a/arch/x86/xen/mmu.c
+++ b/arch/x86/xen/mmu.c
@@ -832,6 +832,9 @@ static pteval_t pte_pfn_to_mfn(pteval_t val)
                pteval_t flags = val & PTE_FLAGS_MASK;
                unsigned long mfn = pfn_to_mfn(pfn);
 
+               if (mfn == pfn)
+                       flags |= _PAGE_IOMAP;
+
                /*
                 * If there's no mfn for the pfn, then just create an
                 * empty non-present pte.  Unfortunately this loses
-- 
1.7.1


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