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Date: Mon, 30 Aug 2010 10:38:45 -0500
From: Anthony Liguori <anthony@codemonkey.ws>
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Subject: [Qemu-devel] Re: Should QMP be RPC to internal C interfaces?
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To: Markus Armbruster <armbru@redhat.com>
Cc: qemu list <qemu-devel@nongnu.org>, Luiz Capitulino <lcapitulino@redhat.com>, agl@us.ibm.com, Amit Shah <amit.shah@redhat.com>, Paolo Bonzini <pbonzini@redhat.com>

On 08/30/2010 10:28 AM, Anthony Liguori wrote:
> Having two interfaces guarantees failure.  What's the separation 
> between internal and external?  Is qdev internal or external?

Let me put it another way, compatibility cannot be an after thought.

We need to think deeply about compatibility when we design our 
interfaces and we're going to have to redesign interfaces with 
compatibility in mind.  It's a hard problem but it's solvable.  Just 
defaulting arguments in QMP doesn't do anything to improve compatibility.

We cannot radically change our internal implementations and expect to 
bridge it all in some special sauce code somewhere.

This also suggests that we're going to have to practice deprecation to 
evolve our APIs in a reasonable fashion.

Regards,

Anthony Liguori

> Regards,
>
> Anthony Liguori