Comment 15 for bug 1823458

On a Xenial DPDK setup with the proposed qemu version (1:2.5+dfsg-5ubuntu10.37), I created a VM and attached a vhost-user interface to it using this xml:

$ cat vm3-iface2.xml
  <interface type='vhostuser'>
    <mac address='52:54:00:c3:37:7e'/>
    <source type='unix' path='/run/openvswitch/vhu2' mode='client'/>
    <model type='virtio'/>
    <driver name='vhost'/>
    <address type='pci' domain='0x0000' bus='0x00' slot='0x08' function='0x0'/>
  </interface>

the OVS interface was created with:
# ovs-vsctl add-port br1 vhu2 -- set Interface vhu2 type=dpdkvhostuser

The interface was added to the vm with:
$ virsh attach-device vm3 vm3-iface2.xml --live

and detached with:
$ virsh detach-device vm3 vm3-iface2.xml --live

Inside the guest, the vhost-user interface was configured with DHCP, and a ping started to the DHCP server, 10.0.2.2:

ubuntu@vm3:~$ ping 10.0.2.2
PING 10.0.2.2 (10.0.2.2) 56(84) bytes of data.
64 bytes from 10.0.2.2: icmp_seq=1 ttl=255 time=0.122 ms
64 bytes from 10.0.2.2: icmp_seq=2 ttl=255 time=0.107 ms
64 bytes from 10.0.2.2: icmp_seq=3 ttl=255 time=0.112 ms
64 bytes from 10.0.2.2: icmp_seq=4 ttl=255 time=0.110 ms
From 10.198.200.1 icmp_seq=5 Destination Port Unreachable
From 10.198.200.1 icmp_seq=6 Destination Port Unreachable
From 10.198.200.1 icmp_seq=7 Destination Port Unreachable
From 10.198.200.1 icmp_seq=8 Destination Port Unreachable
64 bytes from 10.0.2.2: icmp_seq=9 ttl=255 time=0.255 ms
From 10.198.200.1 icmp_seq=10 Destination Port Unreachable
From 10.198.200.1 icmp_seq=11 Destination Port Unreachable
From 10.198.200.1 icmp_seq=12 Destination Port Unreachable
From 10.198.200.1 icmp_seq=13 Destination Port Unreachable
From 10.198.200.1 icmp_seq=14 Destination Port Unreachable
From 10.198.200.1 icmp_seq=15 Destination Port Unreachable
64 bytes from 10.0.2.2: icmp_seq=16 ttl=255 time=0.277 ms
64 bytes from 10.0.2.2: icmp_seq=17 ttl=255 time=0.127 ms
64 bytes from 10.0.2.2: icmp_seq=18 ttl=255 time=0.104 ms

each change in ping (working, not working) corresponded to attaching or detaching the vhost-user interface; repeated attaches/detaches were made with no problems, and ping correctly working or not working based on if the interface was attached or not.

The guest was suspended, I waited for 5 seconds, and then resumed the guest, with no problems.

The guest was shutdown with the interface attached with no problem or crash; the guest was also shutdown with the interface detached (after attaching and detaching several times) with no problem.

All this was repeated several times with no problems seen.

I believe this covers regression testing for the area of code the patch touches, so marking this as fix committed again; this should be ready for release.