[dpdk-dev] Trouble with Tx on some i40 ports in KVM VM

[Zhou, Danny]

On your system, what is your iommu and intel_iommu kernel parameters? 

Could you try to use uio_pci_generic for both PF on host and VF in guest after configuring "iommu=pt" on your system?

> -----Original Message-----
> From: dev [mailto:dev-bounces at dpdk.org] On Behalf Of Andrew Theurer
> Sent: Wednesday, June 10, 2015 5:48 AM
> To: dev at dpdk.org
> Subject: [dpdk-dev] Trouble with Tx on some i40 ports in KVM VM
> 
> Hello.  I am having some trouble with getting various dpdk applications to work when using in a KVM VM.  This happens
> with the 2nd port on a dual port adapter.  What I have configured:
> 
> Haswell-ep host with KVM, 2 x i40e phys functions bound to vfio-pci, 2 functions assigned to KVM guest.  In the guest, the
> i40 functions bound to uio_pci_generic, running testpmd with these options: --nb-cores=2 --nb-ports=2 --portmask=3
> --interactive --auto-start.
> 
> On another host directly connected to these adapters, I run pktgen on the 2 i40e ports.  If I Tx on port1, I get packets back
> on port0.  If I Tx on port0, no packets come back on port0.  For some reason Tx simply does not happen on that second
> port.
> 
> I have tried this test where there is no KVM, just using host, and it works as expected.  I have also tried this test with ixgbe
> adapter in a KVM VM (I have both in same system), and it works as expected.  I have also tried just using a bridge in the VM
> with i40e ports, with i40e module in use, and that also works as expected.  So, I don't think this has anything to do with the
> adapters themselves, or cables, etc.  Something is not working when using the KVM VM, I just don't know what it is.
> 
> Here is xstats from testpmd:
> ###### NIC extended statistics for port 1
> rx_packets: 134615456
> tx_packets: 0
> rx_bytes: 8615389184
> tx_bytes: 0
> tx_errors: 0
> rx_missed_errors: 0
> rx_crc_errors: 0
> rx_bad_length_errors: 0
> rx_errors: 0
> alloc_rx_buff_failed: 0
> fdir_match: 0
> fdir_miss: 0
> tx_flow_control_xon: 0
> rx_flow_control_xon: 0
> tx_flow_control_xoff: 0
> rx_flow_control_xoff: 0
> rx_queue_0_rx_packets: 0
> rx_queue_0_rx_bytes: 0
> tx_queue_0_tx_packets: 0
> tx_queue_0_tx_bytes: 0
> tx_queue_0_tx_errors: 0
> 
> I can't find any evidence of errors anywhere.  It's just not doing Tx at all on that port.  I have also tried using ptkgen in the
> VM, to manually send packets on that port, and again, no packets sent, but no errors either.
> 
> Has anyone else tried 2 i40e ports in a KVM VM?  Any ideas what could be going on here?
> 
> Thanks,
> 
> -Andrew