[dpdk-dev] How to debug packet sends to virtual functions

Mats Liljegren liljegren.mats2 at gmail.com
Mon Feb 3 12:13:35 CET 2014

Never mind, I was hit by the infamous MAC spoofing... I got it working
on both the host and the guest using ixgbevf driver, so apparently the
cables are correctly attached.

Using DPDK is still no-go. It can receive packets, but when sending
the packets the function returns success, but the driver reports
nothing (i.e. no errors, no sent packets, no nothing, except for
received packets of course).

What could cause this behavior?


On Fri, Jan 31, 2014 at 7:30 PM, Mats Liljegren
<liljegren.mats2 at gmail.com> wrote:
> I have a follow-up on this:
> ixgbe version 3.13.10-k
> ixgbevf version 2.7.12-k
> (These are what was provided by Ubuntu 13.10)
> I tried the following sequence on the host, before starting the guest:
> 1) sudo rmmod ixgbe
> 2) sudo modprobe ixgbe max_vfs=2
> 3) sudo ifconfig em1 up  # This is the physical function
> 4) sudo ifconfig em1_0  # This is the virtual function
> 5) ping
> I can see that the ping request reaches its target, and a reply is
> sent back. But this reply is not received by the ping shell command.
> Why?
> Regards,
> Mats
> On Wed, Jan 29, 2014 at 6:56 PM, Mats Liljegren
> <liljegren.mats2 at gmail.com> wrote:
>> I'm trying to get a modified version of the l2fwd example running, and
>> have problems with packets being silently thrown away. I can receive
>> packets, and my printf's indicates that the packets are being sent to
>> the correct port, using correct MAC address as source address. And
>> still, the packets are lost.
>> Since the port is a virtual function, it seems like I cannot use
>> tcpdump on it to see the network traffic. There is nothing coming out
>> of the cable (activity light not flashing, the receiving end running
>> tcpdump does not see any traffic).
>> I'm using two X540 with two virtual functions each. The application
>> runs in a KVM/Qemu environmen.
>> Any suggestions how to debug this?
>> Regards,
>> Mats

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