Bug 1799017

+++ This bug was initially created as a clone of Bug #1798996 +++

Description of problem:
Boot guest over ovs with vhost-user ports. In guest, keep vhost-user NIC using virtio-pci driver. Then migrate guest from src to des host. Both qemu and guest will hang on src host.

Version-Release number of selected component (if applicable):
4.18.0-176.el8.x86_64
qemu-kvm-4.2.0-8.module+el8.2.0+5607+dc756904.x86_64
openvswitch2.12-2.12.0-21.el8fdp.x86_64

How reproducible:
100%

Steps to Reproduce:
1. Boot ovs with 1 vhost-user NIC on both src and des host. Refer to [1]

2. Boot qemu with vhost-user. Refer to [2]

3. Check vhost-user driver in guest. Keep it's default virtio-pci.

4. Migrate guest from src to des. Both src qemu and guest hang.

(qemu) migrate -d tcp:10.73.72.196:5555
(qemu) 

Actual results:
Both qemu and guest hang when do migration.

Expected results:
Both qemu and guest should keep working well and can migrate successfully.

Additional info:
1. This is a regression bug.
openvswitch2.12-2.12.0-12.el8fdp.x86_64   works well.

2. If binding vhost-user NIC from virtio-pci to vfio-pci in guest, this issue is gone.

3. openvswitch2.13-2.13.0-0.20200121git2a4f006.el8fdp.x86_64 works well.

4. This was testing with FDP 20.B. As there is no version "FDP 20.B" in bugzilla now, so I chose 20.A. I would highlight 20.A version works well.

5. Though qemu hang, I don't think it's qemu issue. 

As below versions (1) and (2) work well.

(1)qemu-kvm-4.2.0-8.module+el8.2.0+5607+dc756904.x86_64 & openvswitch2.13-2.13.0-0.20200121git2a4f006.el8fdp.x86_64 works well

(2)qemu-kvm-4.2.0-8.module+el8.2.0+5607+dc756904.x86_64 & openvswitch2.12-2.12.0-12.el8fdp.x86_64                   works well

(3)qemu-kvm-4.2.0-8.module+el8.2.0+5607+dc756904.x86_64 & openvswitch2.12-2.12.0-21.el8fdp.x86_64(bug version)      fail

Reference:
[1]
#!/bin/bash

set -e

echo "killing old ovs process"
pkill -f ovs-vswitchd || true
sleep 5
pkill -f ovsdb-server || true

echo "probing ovs kernel module"
modprobe -r openvswitch || true
modprobe openvswitch

echo "clean env"
DB_FILE=/etc/openvswitch/conf.db
rm -rf /var/run/openvswitch
mkdir /var/run/openvswitch
rm -f $DB_FILE

echo "init ovs db and boot db server"
export DB_SOCK=/var/run/openvswitch/db.sock
ovsdb-tool create /etc/openvswitch/conf.db /usr/share/openvswitch/vswitch.ovsschema
ovsdb-server --remote=punix:$DB_SOCK --remote=db:Open_vSwitch,Open_vSwitch,manager_options --pidfile --detach --log-file
ovs-vsctl --no-wait init

echo "start ovs vswitch daemon"
ovs-vsctl --no-wait set Open_vSwitch . other_config:dpdk-init=true
ovs-vsctl --no-wait set Open_vSwitch . other_config:dpdk-socket-mem="1024,1024"
ovs-vsctl --no-wait set Open_vSwitch . other_config:dpdk-lcore-mask="0x1"
ovs-vsctl --no-wait set Open_vSwitch . other_config:vhost-iommu-support=true
ovs-vswitchd unix:$DB_SOCK --pidfile --detach --log-file=/var/log/openvswitch/ovs-vswitchd.log

echo "creating bridge and ports"

ovs-vsctl --if-exists del-br ovsbr0
ovs-vsctl add-br ovsbr0 -- set bridge ovsbr0 datapath_type=netdev
ovs-vsctl add-port ovsbr0 dpdk0 -- set Interface dpdk0 type=dpdk options:dpdk-devargs=0000:5e:00.0 
ovs-vsctl add-port ovsbr0 vhost-user0 -- set Interface vhost-user0 type=dpdkvhostuserclient options:vhost-server-path=/tmp/vhostuser0.sock
ovs-ofctl del-flows ovsbr0
ovs-ofctl add-flow ovsbr0 "in_port=1,idle_timeout=0 actions=output:2"
ovs-ofctl add-flow ovsbr0 "in_port=2,idle_timeout=0 actions=output:1"

ovs-vsctl set Open_vSwitch . other_config={}
ovs-vsctl set Open_vSwitch . other_config:dpdk-lcore-mask=0x1
ovs-vsctl set Open_vSwitch . other_config:pmd-cpu-mask=0x14
ovs-vsctl set Interface dpdk0 options:n_rxq=1


echo "all done"

[2]
/usr/libexec/qemu-kvm \
-name guest=rhel8.2 \
-machine pc-q35-rhel8.2.0,kernel_irqchip=split \
-cpu host \
-m 8192 \
-overcommit mem-lock=on \
-smp 6,sockets=6,cores=1,threads=1 \
-object memory-backend-file,id=ram-node0,prealloc=yes,mem-path=/dev/hugepages/libvirt/qemu/1-rhel8.2,share=yes,size=8589934592,host-nodes=0,policy=bind \
-numa node,nodeid=0,cpus=0-5,memdev=ram-node0 \
-device intel-iommu,intremap=on,caching-mode=on,device-iotlb=on \
-device pcie-root-port,port=0x10,chassis=1,id=pci.1,bus=pcie.0,multifunction=on,addr=0x2 \
-device pcie-root-port,port=0x11,chassis=2,id=pci.2,bus=pcie.0,addr=0x2.0x1 \
-device pcie-root-port,port=0x12,chassis=3,id=pci.3,bus=pcie.0,addr=0x2.0x2 \
-blockdev driver=file,cache.direct=off,cache.no-flush=on,filename=/mnt/nfv/rhel8.2.qcow2,node-name=my_file \
-blockdev driver=qcow2,node-name=my,file=my_file \
-device virtio-blk-pci,scsi=off,iommu_platform=on,ats=on,bus=pci.2,addr=0x0,drive=my,id=virtio-disk0,bootindex=1,write-cache=on \
-chardev socket,id=charnet1,path=/tmp/vhostuser0.sock,server \
-netdev vhost-user,chardev=charnet1,id=hostnet1 \
-device virtio-net-pci,rx_queue_size=1024,netdev=hostnet1,id=net1,mac=18:66:da:5f:dd:02,bus=pci.3,addr=0x0,iommu_platform=on,ats=on \
-monitor stdio \
-vnc 0:1 \