xen/arm: pfn_to_mfn and mfn_to_pfn return the argument if nothing is in the p2m
authorStefano Stabellini <stefano.stabellini@eu.citrix.com>
Mon, 11 Nov 2013 12:50:30 +0000 (12:50 +0000)
committerKonrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Mon, 11 Nov 2013 17:48:58 +0000 (12:48 -0500)
commit18c51e1a3fabb455ff1f5cd610097d89f577b8f7
tree5489d46bea7ecd8fc8713d8c59cde17372d96068
parentffc555be09bd2603abdbc6f8b64c6a7477facc48
xen/arm: pfn_to_mfn and mfn_to_pfn return the argument if nothing is in the p2m

Some common Xen drivers, like balloon.c, call pfn_to_mfn and mfn_to_pfn
even for autotranslate guests, expecting the argument back.
The following commit broke these drivers by changing the behavior of
pfn_to_mfn and mfn_to_pfn:

commit 4a19138c6505e224d9f4cc2fe9ada9188d7100ea
Author: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Date:   Thu Oct 17 16:22:27 2013 +0000

    arm/xen,arm64/xen: introduce p2m

They now return INVALID_P2M_ENTRY if Linux doesn't actually know what is
the mfn backing a pfn or what is the pfn corresponding to an mfn.
Fix the regression by switching to the old behavior.

Signed-off-by: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Acked-by: Ian Campbell <ian.campbell@citrix.com>
Tested-by: Ian Campbell <ian.campbell@citrix.com>
arch/arm/include/asm/xen/page.h