Re: [Qemu-devel] Problems on vlan-based vnics!

[Jason Wang <jasowang@redhat.com>]

On 09/28/2015 07:52 PM, cauchy-love wrote:
> hi stefan.
>    I have setup a VM on a server with two NICs (eth0 and eth1).  eth0 is connected with vlan22 and eth1 is connected with vlan33. I then added eth0.22 to br2  and eth1.33 to br3. after that tap2 and tap3 were added to br2 and br3 respectively. When i start up the vm,  the network connection is failed if tap2 and tap3 are allocated to this VM while it is ok if i only allocate one tap to this VM. It is shown that the packets were all routed to one NIC. So what is the problem?
> yi
>

Need more information. You qemu command line or libvirt xml. Versions of
qemu, host kernel and guest kernel. Is the issue only reproduced with
e1000 or others? Does it work if there's no vlan? And maybe you can try
qemu.git to see if it could be reproduced.

Thanks

>
>
> --
> 发自我的网易邮箱手机智能版
>
>
> 在 2015-06-22 20:13:20，"Stefan Hajnoczi" <stefanha@gmail.com> 写道：
>> On Sat, Jun 20, 2015 at 02:26:29PM +0300, Shmulik Ladkani wrote:
>>> Currently, MAX_NICS is hardcoded as 8.
>>>
>>> Add a configuration option '--net-max-nics' so one can override the
>>> default.
>>> Unless specified, default value is kept as 8.
>>>
>>> Signed-off-by: Shmulik Ladkani <shmulik.ladkani@ravellosystems.com>
>>> ---
>>>  configure         | 7 +++++++
>>>  include/net/net.h | 2 +-
>>>  2 files changed, 8 insertions(+), 1 deletion(-)
>> The -device e1000,netdev=tap0,id=e1000-nic0 syntax is preferred to -net
>> nic syntax and does not have the 8 NIC limit.
>>
>> Please use the -device syntax instead of -net.  Emulated NICs that
>> support virtio_net_hdr offload also perform better with the -device
>> syntax because -net nic does not allow virtio_net_hdr offloads.
>>
>> If you think this patch should be merged, please explain the use case.