[dpdk-dev] [dpdk-virtio] DPDK stopped working on virtio

[Clarylin L <clearasu@gmail.com>]

I am running DPDK application (testpmd) within a VM based on virtio. With
the same hypervisor and same DPDK code, it used to work well. But it
stopped working since last week. The VM's port could not receive anything.
I ran tcpdump on host's physical port, bridge interface as well as vnet
interface, and did see packets coming in. However on VM's port there was
nothing.

I ran gdb trying to debug, it hit function virtio_recv_mergeable_pkts(),
but nb_used=VIRTQUEUE_NUSED(rxvq) always gave 0. I guess it's because the
queue was empty.

I enabled the PMD debug logging and the only thing that might be an issue
was the following part. Other than this I could not see any thing that
could indicate potential issues.

Thu Feb 18 19:20:10 2016^@PMD: get_uio_dev(): Could not find uio resource
Thu Feb 18 19:20:10 2016^@PMD: virtio_resource_init_by_ioports(): PCI Port
IO found start=0xc040 with size=0x40

If someone can give any pointers that I should further look into, that'd be
very helpful. Appreciate your help!