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Date: Tue, 6 Mar 2007 22:11:05 +0100
From: Ingo Molnar <mingo@elte.hu>
To: Jeremy Fitzhardinge <jeremy@goop.org>
Cc: "Nakajima, Jun" <jun.nakajima@intel.com>,
       virtualization <virtualization@lists.osdl.org>,
       Roland McGrath <roland@redhat.com>,
       Anthony Liguori <anthony@codemonkey.ws>,
       Andrew Morton <akpm@linux-foundation.org>,
       Linus Torvalds <torvalds@linux-foundation.org>,
       linux-kernel@vger.kernel.org, Jan Beulich <jbeulich@novell.com>
Subject: Re: Xen & VMI?
Message-ID: <20070306211105.GD26348@elte.hu>
References: <45ED82D9.6050204@codemonkey.ws> <8FFF7E42E93CC646B632AB40643802A80229779B@scsmsx412.amr.corp.intel.com> <20070306203712.GC21736@elte.hu> <45EDD6F1.7080100@goop.org>
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* Jeremy Fitzhardinge <jeremy@goop.org> wrote:

> If you're seriously talking about an ABI, [...]

HELLO, this isnt a hypothetical!! The moment there's a xen_paravirt_ops, 
Linux has DE FACTO committed itself to the Xen ABI: whatever 
functionality the hypercall_page call table plus the int $0x82 interface 
offers.

THE MOMENT any of that goes upstream and ships in a distro it's going to 
be there forever! Try to change paravirt_ops or any core bit of Linux so 
that this ABI cannot be sanely supported: 'fix it, you broke Xen!'. It 
wont matter that paravirt_ops is 'internal' to Linux.

so trying to argue as if there was no ABI imposed on Linux by hiding the 
Xen ABI behind paravirt_ops, and whistling into the air as if nothing 
happened is misguided at best.

	Ingo