Messages in this thread Patch in this message |  | | | From | Konrad Rzeszutek Wilk <> | | Subject | [PATCH 11/11] xen/m2p: Check whether the MFN has IDENTITY_FRAME bit set.. | | Date | Mon, 31 Jan 2011 17:44:36 -0500 |
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From: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
If we have the IDENTITY_FRAME bit set from the P2M, there is no point in looking up MFN in the M2P override. This is b/c the MFN is a physical MFN.
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> --- arch/x86/include/asm/xen/page.h | 8 +++++++- 1 files changed, 7 insertions(+), 1 deletions(-) diff --git a/arch/x86/include/asm/xen/page.h b/arch/x86/include/asm/xen/page.h index ed46ec2..e6f7f37 100644 --- a/arch/x86/include/asm/xen/page.h +++ b/arch/x86/include/asm/xen/page.h @@ -81,6 +81,7 @@ static inline int phys_to_machine_mapping_valid(unsigned long pfn) static inline unsigned long mfn_to_pfn(unsigned long mfn) { unsigned long pfn; + unsigned long p2m_mfn; if (xen_feature(XENFEAT_auto_translated_physmap)) return mfn; @@ -102,7 +103,12 @@ try_override: * doesn't map back to the mfn), then check the local override * table to see if there's a better pfn to use. */ - if (get_phys_to_machine(pfn) != mfn) + p2m_mfn = get_phys_to_machine(pfn); + + if (p2m_mfn == IDENTITY_FRAME(mfn)) + return pfn; + + if (p2m_mfn != mfn) pfn = m2p_find_override_pfn(mfn, pfn); return pfn; -- 1.7.1
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