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Subject[PATCH 10/11] xen/m2p: No need to catch exceptions when we know that there is no RAM
Date
. beyound what we think is the end of memory. However there might
be more System RAM - but assigned to a guest. Hence jump to the
M2P override check and consult.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
---
arch/x86/include/asm/xen/page.h | 6 +++++-
1 files changed, 5 insertions(+), 1 deletions(-)

diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h
index 7b17fc5..ed46ec2 100644
--- a/arch/x86/include/asm/xen/page.h
+++ b/arch/x86/include/asm/xen/page.h
@@ -85,6 +85,10 @@ static inline unsigned long mfn_to_pfn(unsigned long mfn)
if (xen_feature(XENFEAT_auto_translated_physmap))
return mfn;

+ if (unlikely((mfn >> machine_to_phys_order) != 0)) {
+ pfn = ~0;
+ goto try_override;
+ }
pfn = 0;
/*
* The array access can fail (e.g., device space beyond end of RAM).
@@ -92,7 +96,7 @@ static inline unsigned long mfn_to_pfn(unsigned long mfn)
* but we must handle the fault without crashing!
*/
__get_user(pfn, &machine_to_phys_mapping[mfn]);
-
+try_override:
/*
* If this appears to be a foreign mfn (because the pfn
* doesn't map back to the mfn), then check the local override
--
1.7.1


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