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Date: Wed, 1 Aug 2012 16:50:59 +0100
From: Stefano Stabellini <stefano.stabellini@eu.citrix.com>
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To: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
CC: Stefano Stabellini <Stefano.Stabellini@eu.citrix.com>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>,
        "xen-devel@lists.xensource.com" <xen-devel@lists.xensource.com>,
        Ian Campbell <Ian.Campbell@citrix.com>, "Tim (Xen.org)" <tim@xen.org>,
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        "catalin.marinas@arm.com" <catalin.marinas@arm.com>,
        "arnd@arndb.de" <arnd@arndb.de>
Subject: Re: [PATCH 08/24] xen/arm: Introduce xen_pfn_t for pfn and mfn
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On Wed, 1 Aug 2012, Konrad Rzeszutek Wilk wrote:
> On Thu, Jul 26, 2012 at 04:33:50PM +0100, Stefano Stabellini wrote:
> > All the original Xen headers have xen_pfn_t as mfn and pfn type, however
> > when they have been imported in Linux, xen_pfn_t has been replaced with
> > unsigned long. That might work for x86 and ia64 but it does not for arm.
> 
> How come?

see below

> > Bring back xen_pfn_t and let each architecture define xen_pfn_t as they
> > see fit.
> 
> I am OK with this as long as your include a comment in both of the
> interface.h saying why this is needed. I am curious why 'unsinged long'
> won't work? Is it b/c on ARM you always want a 64-bit type?

Yes, we would like to make the same interface work for 32 and 64
bit guests, without any need for a "compat layer" as we currently have
on x86.
In fact I am going to add another patch to explicitly size all the
other unsigned long that we have in the public interface.