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

jigsaw jigsaw at gmail.com
Tue Feb 4 12:14:10 CET 2014

Hi Mats,

I didn't have any deviation. What I did is just loading ixgbe (with
extra params for vf, as you mentioned in your first email),
and DPDK is up and running in guest. Of course I also followed section
8.10 of the DPDK release notes.

I can switch between DPDK and ixgebvf in guest at runtime and
everything works fine.

Sorry I can't help to debug coz I have only 82599EB at hand.


On Tue, Feb 4, 2014 at 12:45 PM, Mats Liljegren
<liljegren.mats2 at gmail.com> wrote:
> Hi Qinglai,
> Thanks for the response!
> My previous attempt was with ixgbe loaded in the host. I also needed
> to load ixgbevf, but this seems to be because of a short-coming in
> libvirt. Maybe loading ixgbevf and then unbind it when running the
> guest is what causes my problems. I could receive packets with this
> setup, but not transmit. I used extra debug to syslog, and it showed
> that packets was placed in the transmit queue, but these packets was
> never sent.
> I'll see if I can get this working without loading ixgbevf in the host.
> What instructions did you follow to get this working? Did you do any
> deviation from the instructions?
> Regards
> Mats
> On Tue, Feb 4, 2014 at 11:26 AM, jigsaw <jigsaw at gmail.com> wrote:
>> Hi Mats,
>> I've tried vf with 82599EB and it works fine. As long as the VF is
>> visible in guest, DPDK's VF driver should work just as ixgbevf, which
>> shares more or less the same code.
>> I don't understand why you would expect DPDK at guest to work as VF,
>> while the host has no ixgbe loaded.
>> To make further debug I'd suggest compile ixgbe driver with your own
>> syslogs. At least you will be able to see the signalling between vf
>> and ixgbe drivers.
>> -Qinglai
>> On Tue, Feb 4, 2014 at 12:08 PM, Mats Liljegren
>> <liljegren.mats2 at gmail.com> wrote:
>>> This is my fourth mail in my desperate attempt to get DPDK running in
>>> KVM and no comments so far, not even any "it works for me". Am I the
>>> only one crazy enough to believe that this can be done?
>>> Anyway, out of desperation I tried to get it running without having
>>> ixgbe or ixgbevf kernel modules loaded in host nor guest. I followed
>>> the instructions in the Programmer's Guide, chapter "Setting Up a KVM
>>> Virtual Machine Monitor", using the PMD version of the instructions.
>>> I get as far as being able to see my four virtual functions in the
>>> guest using "lspci". But starting the DPDK application gives me the
>>> following error:
>>> PMD:    The MAC address is not valid.
>>>         The most likely cause of this error is that the VM host
>>>         has not assigned a valid MAC address to this VF device.
>>>         Please consult the DPDK Release Notes (FAQ section) for
>>>         a possible solution to this problem.
>>> This may be true, but without any kernel modules loaded, how am I
>>> supposed to change any MAC addresses? Can this be done from within
>>> DPDK?
>>> As a side-note, I did try to load ixgbevf in the guest, but it
>>> produced no interfaces. There was no error messages in the syslog
>>> though.
>>> Is it possible to get X540 working in a guest or should I switch hardware?
>>> Since the instructions assumes I know the command line to KVM to start
>>> my guest (which I do not), I cannot followed them precisely. I use
>>> virsh and XML file, and maybe I've misunderstood how to translate the
>>> pci-assign parameter to XML code. I currently use a <hostdev> entry,
>>> but I've also tried <interface type='hostdev'>. Neither has been
>>> working for me so far, though the <interface> version got me as far as
>>> being able to receive packets at least, but not transmitting.
>>> Regards
>>> Mats
>>> On Mon, Feb 3, 2014 at 12:13 PM, Mats Liljegren
>>> <liljegren.mats2 at gmail.com> wrote:
>>>> 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?
>>>> Regards
>>>> Mats
>>>> 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

More information about the dev mailing list