[libvirt] RFC: setting mac address on network devices being assigned to a guest via PCI passthrough (<hostdev>)

[Laine Stump]

On 01/23/2012 01:06 PM, Paolo Bonzini wrote:
> On 01/23/2012 05:12 PM, Laine Stump wrote:
>>>
>>> In view of the discussion on SCSI passthrough, it seems to me that
>>> this should be attached to an <interface> element:
>>>
>>> <devices>
>>> <interface type='hostdev'>
>>> <source>
>>> <address type='pci' bus='0x06' slot='0x02' function='0x0'/>
>>> </source>
>>> <mac address='00:16:3e:5d:c7:9e'/>
>>> <address type='pci' .../>
>>> </interface>
>>> </devices>
>>
>> Nice! I should have thought of this in my original proposal - it's the
>> logical extension of having networks of type='hostdev'. I would prefer
>> this as well, but it hits one of Dan's criticism's of the original
>> proposal (from
>> https://www.redhat.com/archives/libvir-list/2011-August/msg01033.html ),
>> so I didn't further consider using a change to <interface>:
>
> I didn't have time now to read the whole original discussion, however...
>
>> On 08/22/2011 at 05:17 AM, Dan Berrange wrote:
>>>  The issue I see is that if an application wants to know what
>>>  PCI devices have been assigned to a guest, they can no longer
>>>  just look at<hostdev>  elements. They also need to look at
>>> <interface>  elements. If we follow this proposed model in other
>>>  areas, we could end up with PCI devices appearing as<disks>
>>> <controllers>  and who knows what else.
>
> ... this is exactly what we're doing for <controller>.  In that case, 
> the <source> syntax is roughly the same that you use in a SCSI pool.
>
> See here for how it arose:
>
> http://www.redhat.com/archives/libvir-list/2011-October/msg01298.html
>
>> Since originally proposing the <hostdev> examples for network
>> cards, I've switched to the opinion that this was in fact the
>> wrong thing todo at all. The network devices should be in the
>> <interface> element, so we have access to all the properties
>> that this element allows for.
>>
>> My general view is that <hostdev> should be kept for "opaque"
>> device assignment where we're not caring about what capabilities
>> the device has. Just "blind" assignment of the PCI/USB/ISA
>> hardware device based on their hardware addresses.
>
> (That's Dan speaking, not me :)).

Oh, I missed that! Thanks for pointing it out! (I try to at least pick 
out and read Dan's responses on all topics, even those unrelated to what 
I'm working on, but I managed to overlook that one :-( )

So, I will proceed using the syntax you proposed.