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

["Zhang, Helin" <helin.zhang@intel.com>]

Hi Andrew

So you are using PF pass-through?
What version of DPDK were you using? You need to use try the latest DPDK on
dpdk.org master branch, as there is a bug fix recently which might be helpful
for using PF pass-through.
Please try the latest and see if the issue is still there or not!

Regards,
Helin

> -----Original Message-----
> From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Andrew Theurer
> Sent: Wednesday, June 10, 2015 8:47 AM
> To: Zhou, Danny
> Cc: dev@dpdk.org
> Subject: Re: [dpdk-dev] Trouble with Tx on some i40 ports in KVM VM
> 
> 
> 
> ----- Original Message -----
> > From: "Danny Zhou" <danny.zhou@intel.com>
> > To: "Andrew Theurer" <atheurer@redhat.com>
> > Cc: dev@dpdk.org
> > Sent: Tuesday, June 9, 2015 6:38:49 PM
> > Subject: RE: Trouble with Tx on some i40 ports in KVM VM
> >
> > 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?
> 
> I use iommu=pt intel_iommu=on
> 
> To clarify, I am not using a VF in the VM.  I am only using PF's, assigning them to
> the VM.  The host needs vfio module for kvm to assign these to the VM.
> I don't see how uio_pci_generic can be used in the host if the PF is being passed
> to the VM.
> 
> Thanks,
> 
> -Andrew
> >
> > > -----Original Message-----
> > > From: dev [mailto:dev-bounces@dpdk.org] On Behalf Of Andrew Theurer
> > > Sent: Wednesday, June 10, 2015 5:48 AM
> > > To: dev@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
> >