[Qemu-devel] Re: [RFC] QMP: Introduce query-netdevices documentation

[Avi Kivity <avi@redhat.com>]

On 06/07/2010 03:57 PM, Miguel Di Ciurcio Filho wrote:
> On Sun, Jun 6, 2010 at 12:50 PM, Avi Kivity<avi@redhat.com>  wrote:
>    
>>> +Each json-object contain the following:
>>> +
>>> +- "device": device name (json-string)
>>> +- "vlan": only present if the device is attached to a VLAN (json-int)
>>> +- "info": json-object containing the following:
>>> +          - "model": type of the device (json-string)
>>> +              - Possible values: "tap", "socket", "xen", "slirp", "dump",
>>> +                                 "vde", "ne2k_pci", "i82551", "i82557b",
>>> +                                 "i82559er", "rtl8139", "e1000", "pcnet",
>>> +                                 "virtio", "dp83932", "lan9118",
>>> "mcf_fec",
>>> +                                 "xilinx-ethlite", "lance", "stellaris",
>>> +                                 "smc91c111", "ne2k_isa", "mv88w8618",
>>> +                                 "mipsnet", "fseth", "dp83932", "usb"
>>>
>>>        
>> This casts the vlan model into concrete.  I thought we wanted to move away
>> from it?  Instead have separate entries for host and guest devices.
>>      
> The vlan attribute is optional. In this case, it is a vlan inside the
> context of the VM. I've searched the archives and I've found some
> references about the confusion about real VLANs (802.1Q) and QEMU's
> vlans. Correct me if I'm wrong, but I suppose they are completely
> different animals.
>    

Right.  I'm talking about the qemu internal vlans.

> When you say separate entries for host and guest devices, you mean
> something like this:
>
> $ qemu -netdev tap,id=tap0 -device e1000,netdev=tap0
>
> This makes a 1:1 relation. So clearly tap0 is a host device, e1000.0
> will be a guest device, and they are connected.
>    

Yes.  I'd want separate queries for each, or perhaps a single query that 
returns

{ 'hostdev': some-object-with-host-device-properties-only, 'nic': 
some-object-that-describes-the-guest-nic }

> $ qemu -net tap,ifname=tap0 -net nic,model=e1000
>
> This glues the two devices into a vlan inside the VM.
>
> Do you mean that this second model should be deprecated?
>    

I think it is.  It doesn't play well with acceleration technologies like 
vhost that want a 1:1 relationship.

-- 
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