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

[Anthony Liguori <anthony@codemonkey.ws>]

On 06/07/2010 08:39 AM, Avi Kivity wrote:
> 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 }

We need a query-netdev and then info qdm already provides the guest nic 
properties.  Just filter out devices that have a netdev property.

Regards,

Anthony Liguori

>> $ 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.
>