Message-ID: <4731F6CE.6000205@us.ibm.com>
Date: Wed, 07 Nov 2007 11:33:02 -0600
From: Anthony Liguori <aliguori@us.ibm.com>
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To: Rusty Russell <rusty@rustcorp.com.au>
CC: Avi Kivity <avi@qumranet.com>,
       Gregory Haskins <gregory.haskins.ml@gmail.com>,
       Dor Laor <dor.laor@qumranet.com>,
       virtualization@lists.linux-foundation.org, linux-kernel@vger.kernel.org
Subject: Re: Use of virtio device IDs
References: <4730A15A.6070001@us.ibm.com> <4731334A.6090405@gmail.com> <47314FBD.1070505@qumranet.com> <200711071709.47192.rusty@rustcorp.com.au>
In-Reply-To: <200711071709.47192.rusty@rustcorp.com.au>
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Rusty Russell wrote:
> On Wednesday 07 November 2007 16:40:13 Avi Kivity wrote:
>   
>> Gregory Haskins wrote:
>>     
>>>  but FWIW: This is a major motivation for the reason that the
>>> IOQ stuff I posted a while back used strings for device identification
>>> instead of a fixed length, centrally managed namespace like PCI
>>> vendor/dev-id.  Then you can just name your device something reasonably
>>> unique (e.g. "qumranet::veth", or "ibm-pvirt-clock").
>>>       
>> I dislike strings.  They make it look as if you have a nice extensible
>> interface, where in reality you have a poorly documented interface which
>> leads to poor interoperability.
>>     
>
> Yes, you end up with exactly names like "qumranet::veth" 
> and "ibm-pvirt-clock".  I would recommend looking very hard at /proc, Open 
> Firmware on a modern system, or the Xen store, to see what a lack of 
> limitation can do to you :)
>   

FWIW, I've switched to using the PCI subsystem vendor/device IDs for 
virtio which Rusty suggested.  I think this makes even more sense than 
using the main vendor/device ID since I do think that we only should use 
a single vendor/device ID for all virtio PCI devices and then 
differentiate based on the subsystem IDs.

Regards,

Anthony Liguori

>> We will support non-pci for s390, but in order to support Windows and
>> older Linux PCI is necessary.
>>     
>
> The aim is that PCI support is clean, but that we're not really tied to PCI.  
> I think we're getting closer with the recent config changes.
>
> Cheers,
> Rusty.
>   

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