Re: [Qemu-devel] Connecting netdev to emulated nics.

[Jason Wang <jasowang@redhat.com>]

On 10/16/2015 11:18 PM, Peter Crosthwaite wrote:
> On Fri, Oct 16, 2015 at 5:24 AM, sai pavan <saipavanboddu@gmail.com> wrote:
>> Hi Jason,
>>
>> On Fri, Oct 16, 2015 at 1:07 PM, Jason Wang <jasowang@redhat.com> wrote:
>>>
>>> On 10/16/2015 01:15 PM, sai pavan wrote:
>>>> +Peter
>>>>
>>>> Hi Jason,
>>>>
>>>> On Thu, Oct 15, 2015 at 2:44 PM, Jason Wang <jasowang@redhat.com> wrote:
>>>>> On 10/15/2015 02:36 PM, sai pavan wrote:
>>>>>> Hi,
>>>>>>
>>>>>> I am debugging an issue, where through one of the nics I am not able
>>>>>> to connect to dtcp.
>>>>>> So to dig in deep, i was going thought net.c files, and ended-up
>>>>>> understanding little.
>>>>>>
>>>>>> So can i know how does a netdev connects to nic.
>>>>>>
>>>>>> nd_table[] has some pointers for netdev devices. Where are this
>>>>>> actually instantiated ? I am missing that part of the code.
>>>>>>
>>>>>> How do the netdevs and nic's have 1-1 connections.
>>>>> You may want to have a look at set_netdev().
>>>> Thanks this helped to see more regarding netdev.
>>>>
>>>> one more question, there are 4 Ethernet Controllers in the soc im working on
>>>> https://github.com/qemu/qemu/blob/master/hw/arm/xlnx-zynqmp.c#L223
>>>>
>>>> Each having configure nic and netdev internally. But only one can
>>>> automatically connect to dhcp. Each one is assigned default mac
>>>> address, Do each of the mac needs to be pre-registered with internal
>>>> dhcp.?
>>> I think this is because if you don't specify any net clients on cli,
>>> qemu will use default network configuration that has a hub with two
>>> ports, first ports is connected to a nic and second port were connected
>>> to userspace network
>>> (http://wiki.qemu.org/Documentation/Networking#User_Networking_.28SLIRP.29)
>>> which implements dhcp. You can see the network topology through "info
>>> networks" commands.
>>>
>>> E.g if you want to let all nics to be connected to the user networking,
>>> you may want to use:
>>>
>>> -net nic -net nic -net nic -net nic -net user
>>>
> Is there a long form of this CLI that does not rely on positional arguments?
>
> Regards,
> Peter

I'm not sure I get the question. The reason looks like xlnx-zynqmp.c
relies on the first 4 nics of nd_table[].

>>> in your cli.
>> Cool, This worked. Thanks !!
>>
>> Another question, is a way we can connect a particular device to hub,
>> not connecting all ?
>>
>> Thanks,
>> Sai Pavan
>>>> Regards,
>>>> Sai Pavan
>>>>
>>>>>> And if my SOC has more than 1 sysbus type ethernet chips. How can i
>>>>>> connect each one of them from command line ?
>>>>> You can do this by using hubport as nic's peer e.g:
>>>>>
>>>>> -netdev hubport,id=port0,hubid=hubid -device e1000,netdev=port0
>>>>>
>>>>>> Regards,
>>>>>> Sai Pavan