Problem Description:

A regression in the DPDK Vhost library was introduced in v24.07.

In rte_vhost_dequeue_burst(), if the Virtiqueue is not ready, it returns early without resetting the packet count to 0, creating a discrepency between the count value and the packets array. With OVS, it leads to a segmentation fault.

 Impact Assessment: Describe the severity and impact (e.g., network down,availability of a workaround, etc.).

 Software Versions: openvswitch3.5

  Issue Type: regression

 Reproducibility:

The issue might be reproducible with Vhost-user, when using vIOMMU and 2MB hugepages for the guest, but that is an unlikely case.

It was discovered with VDUSE + Vhost-vDPA, when not using hugepages for the guest.

 Reproduction Steps: Provide detailed steps or scripts to replicate the issue.

 Observed Behavior: ovs-vswitchd crashes with a segmentation fault.

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