From: Konrad Rzeszutek Wilk Date: Fri, 14 Jan 2011 22:55:44 +0000 (-0500) Subject: xen/m2p: No need to catch exceptions when we know that there is no RAM X-Git-Url: https://git.karo-electronics.de/?a=commitdiff_plain;h=146c4e511717e581065800938537b276173d8548;p=linux-beck.git xen/m2p: No need to catch exceptions when we know that there is no RAM .. 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. [v1: Added Review-by tag] Reviewed-by: Ian Campbell Signed-off-by: Konrad Rzeszutek Wilk --- diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h index 78ebbeb88d9c..195707060493 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