Re: [dpdk-users] [dpdk-dev] seg fault in InterVM communication using virtio

[Yuanhan Liu <yuanhan.liu@linux.intel.com>]

On Thu, Mar 02, 2017 at 06:02:28PM +0530, mitali wrote:
> Hi,
> 
> Ok. But with other PMDs like igb, when we are providing sriov vf to VM and
> running our client/server dpdk application then there is no issue in
> communication between VMs.
> As soon as we use virtio setup for VMs and running same dpdk application, it
> stops after sending 127 packet and seg fault comes while executing
> rte_eth_tx_burst(). We are still not clear why with virtio its creating this
> issue but not with any other PMD.

No idea. You don't provide any further details. Please, would you just
enable the debug info, rebuild, run it with gdb and then dump the call
stack after crash?

	--yliu
> 
> Mitali
> 
> On Thursday 02 March 2017 05:53 PM, Yuanhan Liu wrote:
> >On Wed, Mar 01, 2017 at 07:20:37PM +0530, mitali wrote:
> >>Hi,
> >>
> >>We have some doubt regarding virtio front end. As we are running dpdk
> >>application inside VM with virtio setup, do we need to use virtio specific
> >>functions like virtio_recv_pkts() and virtio_xmit_pkts() to receive and
> >>transmit packets, functions for port initialization like
> >>virtio_dev_queue_setup()? If yes, we are unable to find any application
> >>which uses these functions. Can you provide us some pointers on examples
> >>which uses these functions.
> >If you are running DPDK inside guest (with virtio), then the virtio is
> >yet another PMD, meaning you should program it with the normal DPDK
> >ethdev APIs, something like rte_eth_dev_configure, rte_eth_rx/tx_queue_setup,
> >etc.
> >
> >	--yliu
> >>Thanks,
> >>Mitali
> >>
> >>On Thursday 23 February 2017 11:57 AM, Yuanhan Liu wrote:
> >>>On Wed, Feb 22, 2017 at 02:25:29PM +0530, mitali wrote:
> >>>>Hi Yuanhan,
> >>>>
> >>>>We are using virt-manager to start the VMs. We are attaching the image which
> >>>>shows the vNIC setup for the VMs.
> >>>>
> >>>>We have written our own dpdk application to send and receive UDP packets. The
> >>>>command we are using is
> >>>>
> >>>>./build/app/dpdkapi -c 1 -- -p 1 where dpdkapi is our application.
> >>>>
> >>>>Inside the application we are sending and receiving packets from vNIC using
> >>>>rte_eth_tx_burst() and rte_eth_rx_burst().
> >>>>
> >>>>At the sender side after 127 packets the application stops and we observe a seg
> >>>>fault in dmesg. Using the print statements we observed that it faults in
> >>>>rte_eth_tx_burst(). All the 127 were received at the receiving VM.
> >>>Would you recompile dpdk with debug info enaled, which could be done by:
> >>>
> >>>	make ... EXTRA_CFLAGS='-g3 -O0'
> >>>
> >>>And run it with gdb then dump the call stack?
> >>>
> >>>	--yliu