From: Rusty Russell <rusty@rustcorp.com.au>
To: Anthony Liguori <aliguori@us.ibm.com>
Subject: Re: virtio config_ops refactoring
Date: Wed, 7 Nov 2007 09:57:43 +1100
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       linux-kernel@vger.kernel.org, Dor Laor <dor.laor@qumranet.com>
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On Wednesday 07 November 2007 04:48:35 Anthony Liguori wrote:
> Semantically, find requires that a field have both a type and a length.
> With the exception of the VIRTQUEUE field used internally by lguest,
> type is always a unique identifier.  Since virtqueue information is not
> a required part of the config space, it seems to me that type really
> should be treated as a unique identifier.

Hi Anthony,

	Not sure I get this.  It is a unique identifier.  You need the length
to handle unknown fields.

> find_vq also is curious in that it is stateful in it's enumeration.

Well, they're *all* stateful.  This gives a simple method of knowing what 
fields the guest understands: it marks the fields as it finds them.  Then it 
sets the status, which allows the host to know when it's completed 
configuration reads.

I like enumerating the virtqueues: it's not necessary but it's clearer.

> This adds seemingly unnecessary complexity.

I'd be happy for a simpler mechanism...

Cheers,
Rusty.
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