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

[Jason Wang <jasowang@redhat.com>]

On 10/16/2015 08:24 PM, sai pavan 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
>> >
>> > in your cli.
> Cool, This worked. Thanks !!
>
> Another question, is a way we can connect a particular device to hub,
> not connecting all ?

You can use "vlan" parameter in this case.

> Thanks,
> Sai Pavan