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Re: [Xen-devel] [PATCH] shared_info size and padding fixes

To: Jan Beulich <jbeulich@xxxxxxxxxx>
Subject: Re: [Xen-devel] [PATCH] shared_info size and padding fixes
From: John Levon <levon@xxxxxxxxxxxxxxxxx>
Date: Thu, 10 Aug 2006 13:13:48 +0100
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On Thu, Aug 10, 2006 at 10:33:01AM +0200, Jan Beulich wrote:

> >sizeof(shared_info_t) can change even in compatible hypervisor
> versions.
> >Add a clear warning about this, and fix the few places relying on it.
> >In addition, add some padding to arch_shared_info, to allow future
> >additions to the structure without breaking known offsets of members
> >following it in the shared info.
> Shouldn't you also bump the ABI version with these compatibility
> breaking
> changes to the shared info structure?

No, see the previous discussion with Keir - changing the size of the
shared info structure is apparently not part of the ABI (hence the
reason for the patch and the explanation above!)

Personally this seems unusual at best to me, but that's the way it is,
and furthermore has already happened with "nmi_reason".


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