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

[sai pavan]

Hi Jason,

On Fri, Oct 16, 2015 at 1:07 PM, Jason Wang <address@hidden> 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 <address@hidden> 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
>
> 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
>