Hi Jay,
Thanks a lot for your reply and support in understanding and addressing the
issue.
We are running *VPP + DPDK IAVF*.
Attached the *startup.conf *and *setup.txt* we are using while running vpp.
Below is the host *VF *details. Let me know incase you need any other
information.
*0000:01:01.0 *Ethernet controller [0200]: Intel Corporation Ethernet
Adaptive Virtual Function [8086:1889] (rev 02)
Subsystem: Super Micro Computer Inc Device [15d9:0000]
Kernel driver in use: vfio-pci
Kernel modules: iavf
Thanks and regards,
Jyotsna
On Wed, Nov 26, 2025 at 8:00 PM Jay Wang via lists.fd.io <jay.wang2=
[email protected]> wrote:
> Hi Jyotsna,
>
>
>
> Just to confirm --- are you running VPP + DPDK IAVF, or VPP + the AVF
> plugin with the quick workaround?
>
> I’m asking because the patch is only applicable to VPP + DPDK IAVF.
>
> If you are using that setup, could you please share your startup.conf and
> the VPP CLI commands you used to configure VPP?
>
> That will help me look into the issue in more detail.
>
>
>
> Cheers,
>
> Jay Wang
>
> *From:* [email protected] <[email protected]> *On Behalf Of *Jyotsna
> Dhumale via lists.fd.io
> *Sent:* Tuesday, November 25, 2025 10:21 AM
> *To:* [email protected]
> *Cc:* [email protected]; Paul Szczepanek <[email protected]>;
> Vinod Krishna <[email protected]>; Dhruv Tripathi <
> [email protected]>; Wathsala Vithanage <[email protected]>
> *Subject:* Re: [vpp-dev] [VPP 25.02 | ARM64 | E810-C | IAVF] Packets
> showing length 65535 in DPDK input node (works fine on VPP 22.02)
>
>
>
> Hi Jay Wang,
> Thanks a lot for the patch. Even I am facing the same problem[pkt_len
> 65535] with *VPP25.02* and *ARM64*
>
> *Board : Ampere(R) Altra(R) Processor Q64-30 CPU @ 3.0GHz NIC : E810-C 4
> ports*
> I tested with the patch you provided, but I am still running into same
> problem of pkt_len coming as 65535.
> Attached the build log for your reference, which shows patch is applied
> correctly and build is successful.
> Later VPP is built using the new vpp-ext-dep package generated with the
> patch.
>
> Anything that I am missing or missing in the patch?
>
> Let me know if you need any other information from my side.
>
> Thanks and regards,
>
> Jyotsna
>
>
>
> On Thu, Nov 20, 2025 at 3:15 AM Jay Wang via lists.fd.io <jay.wang2=
> [email protected]> wrote:
>
> Hi Nousi,
>
>
>
> I can confirm that I was able to reproduce your issue in my local test
> environment(*Ampere Altra Max 96 Cores* with *the Intel E810-C 2x ports
> NIC*).
>
> The issue also persists in the latest VPP codebase, so I spent some time
> investigating it.
>
> From what I observed, commit[1] appears to be the root cause. This commit
> introduces NEON intrinsics to add support for the IAVF Rx vector path on
> Arm platforms in DPDK.
>
> I don’t want to bother you with the implementation details of the Rx
> vector function[2]. But in short, the issue occurs because the function
> writes the *pkt_len* field to the wrong location in the *rte_mbuf* when
> copying from the hardware descriptor.
>
> I’ve created a quick workaround for VPP 25.02(see attached patch) and
> tested it with 64B/1024B packets. It seems to work fine. Please give it a
> try and let me know if it resolves the issue on your side.
>
>
>
> VPP 25.02 works fine on X86 systems because it uses a different Rx vector
> code path.
>
> Interestingly, I observed a similar packet length issue when testing the
> X86 counterpart of Rx vector code path[3].
>
>
>
> Thanks,
>
> Jay Wang
>
>
>
> [1] https://gerrit.fd.io/r/c/vpp/+/37017
>
> [2]
> https://github.com/DPDK/dpdk/blob/main/drivers/net/intel/iavf/iavf_rxtx_vec_neon.c#L144
>
> [3]
> https://github.com/DPDK/dpdk/blob/main/drivers/net/intel/iavf/iavf_rxtx_vec_sse.c#L391
>
> *From:* [email protected] <[email protected]> *On Behalf Of *nousi
> via lists.fd.io
> *Sent:* Tuesday, November 11, 2025 2:22 PM
> *To:* [email protected]
> *Subject:* [vpp-dev] [VPP 25.02 | ARM64 | E810-C | IAVF] Packets showing
> length 65535 in DPDK input node (works fine on VPP 22.02)
>
>
>
> Hi everyone,
>
> I’m seeing a packet length issue after upgrading to *VPP 25.02* on *ARM64
> (Ampere® Altra® Q64-30 @ 3.0GHz)* with an *Intel E810-C (4x ports)* NIC
> using the *IAVF driver*.
>
> All packets received in the *dpdk-input node* show a *length of 65535
> bytes*, which is clearly incorrect. This is visible in both *trace* and *
> pcap* captures.
>
> Here’s what I’ve observed so far:
>
> - The issue only appears with *VPP 25.02* on *ARM64*.
> - The *same platform (hardware + NIC)* works perfectly with *VPP 22.02*
> — packet lengths are reported correctly.
> - On *X86 *systems, *VPP 25.02* also works fine (no packet length
> issue).
> - So it seems specific to *VPP 25.02 + ARM64 + IAVF driver*
> combination.
>
> *Setup details:*
>
> - *CPU:* Ampere® Altra® Q64-30 (ARM64)
> - *NIC:* Intel E810-C (4 ports)
> - *Driver:* IAVF (DPDK)
> - *VPP version:* 25.02
> - *Symptom:* All packets show length = 65535 in dpdk-input node
>
> Has anyone else seen this behavior or is aware of any related changes in *
> VPP 25.02* or the * IAVF/DPDK layer* for ARM64?
> Would appreciate any pointers, patches, or debug hints — especially if
> someone has tested E810/IAVF on ARM with newer VPP versions.
>
> Thanks a lot in advance!
>
> *Nousi.*
>
> IMPORTANT NOTICE: The contents of this email and any attachments are
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> IMPORTANT NOTICE: The contents of this email and any attachments are
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>
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