Description of problem:
Mangedsave never finished if guest have net failover element

Version-Release number of selected component (if applicable):
libvirt-daemon-6.0.0-13.module+el8.2.0+6048+0fa476b4.x86_64
qemu-kvm-4.2.0-15.module+el8.2.0+6029+618ef2ec.x86_64

How reproducible:
100%

Steps to Reproduce:
1. prepare a guest have net failover xml:

1. virsh dumpxml vm1 --inactive

<interface type='network'>
<mac address='fe:54:00:18:0b:29'/>
<source network='default'/>
<model type='virtio'/>
<teaming type='persistent'/>
<alias name='ua-backup0'/>
<address type='pci' domain='0x0000' bus='0x08' slot='0x00' function='0x0'/>
</interface>
<interface type='network'>
<mac address='fe:54:00:18:0b:29'/>
<source network='hostdevnet'/>
<model type='virtio'/>
<teaming type='transient' persistent='ua-backup0'/>
<address type='pci' domain='0x0000' bus='0x07' slot='0x00' function='0x0'/>
</interface>

1. virsh net-dumpxml hostdevnet
   <network connections='2'>
   <name>hostdevnet</name>
   <uuid>d1d21152-ab38-4b66-9ddd-13d788b727fc</uuid>
   <forward mode='hostdev' managed='yes'>
   <address type='pci' domain='0x0000' bus='0x82' slot='0x10' function='0x1'/>
   <address type='pci' domain='0x0000' bus='0x82' slot='0x10' function='0x3'/>
   <address type='pci' domain='0x0000' bus='0x82' slot='0x10' function='0x5'/>
   <address type='pci' domain='0x0000' bus='0x82' slot='0x10' function='0x7'/>
   </forward>
   </network>

2. start guest and login check guest vnic:
IN guest:

1. ip addr
   1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
   link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
   inet 127.0.0.1/8 scope host lo
   valid_lft forever preferred_lft forever
   inet6 ::1/128 scope host
   valid_lft forever preferred_lft forever
   2: enp8s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
   link/ether fe:54:00:18:0b:29 brd ff:ff:ff:ff:ff:ff
   inet 10.73.33.191/23 brd 10.73.33.255 scope global dynamic noprefixroute enp8s0
   valid_lft 43087sec preferred_lft 43087sec
   inet6 2620:52:0:4920:a9a2:280c:adc8:5a1d/64 scope global dynamic noprefixroute
   valid_lft 2591889sec preferred_lft 604689sec
   inet6 fe80::cd32:c409:d931:34da/64 scope link noprefixroute
   valid_lft forever preferred_lft forever
   3: enp8s0nsby: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel master enp8s0 state UP group default qlen 1000
   link/ether fe:54:00:18:0b:29 brd ff:ff:ff:ff:ff:ff
   inet 192.168.122.96/24 brd 192.168.122.255 scope global dynamic noprefixroute enp8s0nsby
   valid_lft 3487sec preferred_lft 3487sec
   inet6 fe80::e25a:be03:b8ce:253/64 scope link noprefixroute
   valid_lft forever preferred_lft forever
   4: enp7s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc mq master enp8s0 state UP group default qlen 1000
   link/ether fe:54:00:18:0b:29 brd ff:ff:ff:ff:ff:ff
   inet 10.73.33.191/23 brd 10.73.33.255 scope global dynamic noprefixroute enp7s0
   valid_lft 43087sec preferred_lft 43087sec
   inet6 fe80::e709:c37e:f302:9b6d/64 scope link noprefixroute
   valid_lft forever preferred_lft forever

3. run managedsave command:

1. virsh managedsave vm1
   (never finish, have to cancel it by user)
   ^Cerror: Failed to save domain vm1 state
   error: operation aborted: domain save job: canceled by client

4. login guest and vf not reattach back:

]# ip addr
1: lo: <LOOPBACK,UP,LOWER_UP> mtu 65536 qdisc noqueue state UNKNOWN group default qlen 1000
link/loopback 00:00:00:00:00:00 brd 00:00:00:00:00:00
inet 127.0.0.1/8 scope host lo
valid_lft forever preferred_lft forever
inet6 ::1/128 scope host
valid_lft forever preferred_lft forever
2: enp8s0: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc noqueue state UP group default qlen 1000
link/ether fe:54:00:18:0b:29 brd ff:ff:ff:ff:ff:ff
inet 10.73.33.191/23 brd 10.73.33.255 scope global dynamic noprefixroute enp8s0
valid_lft 42880sec preferred_lft 42880sec
inet6 2620:52:0:4920:a9a2:280c:adc8:5a1d/64 scope global dynamic noprefixroute
valid_lft 2591682sec preferred_lft 604482sec
inet6 fe80::cd32:c409:d931:34da/64 scope link noprefixroute
valid_lft forever preferred_lft forever
3: enp8s0nsby: <BROADCAST,MULTICAST,UP,LOWER_UP> mtu 1500 qdisc fq_codel master enp8s0 state UP group default qlen 1000
link/ether fe:54:00:18:0b:29 brd ff:ff:ff:ff:ff:ff
inet 192.168.122.96/24 brd 192.168.122.255 scope global dynamic noprefixroute enp8s0nsby
valid_lft 3280sec preferred_lft 3280sec
inet6 fe80::e25a:be03:b8ce:253/64 scope link noprefixroute
valid_lft forever preferred_lft forever

Actual results:
managedsave cannot finish after set net failover elements in guest

Expected results:
managedsave command return success or report an error if this operation is not support

Additional info:

guest full xml:
<domain type='kvm'>
<name>vm1</name>
<uuid>f98741e7-ddad-4be1-82c0-0ae3655d1c25</uuid>
<memory unit='KiB'>1024000</memory>
<currentMemory unit='KiB'>1024000</currentMemory>
<vcpu placement='static' current='2'>4</vcpu>
<resource>
<partition>/machine</partition>
</resource>
<sysinfo type='smbios'/>
<os>
<type arch='x86_64' machine='pc-q35-rhel8.2.0'>hvm</type>
<boot dev='hd'/>
</os>
<features>
<acpi/>
<apic/>
<pae/>
</features>
<cpu mode='host-model' check='partial'>
<numa>
<cell id='0' cpus='0-1' memory='512000' unit='KiB'/>
<cell id='1' cpus='2-3' memory='512000' unit='KiB'/>
</numa>
</cpu>
<clock offset='utc'/>
<on_poweroff>destroy</on_poweroff>
<on_reboot>restart</on_reboot>
<on_crash>restart</on_crash>
<devices>
<emulator>/usr/libexec/qemu-kvm</emulator>
<disk type='file' device='disk'>
<driver name='qemu' type='qcow2'/>
<source file='/var/lib/libvirt/migrate/RHEL-8.2-lhuang.qcow2'/>
<target dev='vda' bus='virtio'/>
<address type='pci' domain='0x0000' bus='0x03' slot='0x00' function='0x0'/>
</disk>
<controller type='usb' index='0' model='qemu-xhci'>
<address type='pci' domain='0x0000' bus='0x04' slot='0x00' function='0x0'/>
</controller>
<controller type='sata' index='0'>
<address type='pci' domain='0x0000' bus='0x00' slot='0x1f' function='0x2'/>
</controller>
<controller type='pci' index='0' model='pcie-root'/>
<controller type='pci' index='1' model='pcie-root-port'>
<model name='pcie-root-port'/>
<target chassis='1' port='0x10'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x0' multifunction='on'/>
</controller>
<controller type='pci' index='2' model='pcie-to-pci-bridge'>
<model name='pcie-pci-bridge'/>
<address type='pci' domain='0x0000' bus='0x01' slot='0x00' function='0x0'/>
</controller>
<controller type='pci' index='3' model='pcie-root-port'>
<model name='pcie-root-port'/>
<target chassis='3' port='0x11'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x1'/>
</controller>
<controller type='pci' index='4' model='pcie-root-port'>
<model name='pcie-root-port'/>
<target chassis='4' port='0x12'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x2'/>
</controller>
<controller type='pci' index='5' model='pcie-root-port'>
<model name='pcie-root-port'/>
<target chassis='5' port='0x13'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x3'/>
</controller>
<controller type='pci' index='6' model='pcie-root-port'>
<model name='pcie-root-port'/>
<target chassis='6' port='0x14'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x4'/>
</controller>
<controller type='pci' index='7' model='pcie-root-port'>
<model name='pcie-root-port'/>
<target chassis='7' port='0x15'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x5'/>
</controller>
<controller type='pci' index='8' model='pcie-root-port'>
<model name='pcie-root-port'/>
<target chassis='8' port='0x16'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x02' function='0x6'/>
</controller>
<controller type='virtio-serial' index='0'>
<address type='pci' domain='0x0000' bus='0x05' slot='0x00' function='0x0'/>
</controller>
<interface type='network'>
<mac address='fe:54:00:18:0b:29'/>
<source network='default'/>
<model type='virtio'/>
<teaming type='persistent'/>
<alias name='ua-backup0'/>
<address type='pci' domain='0x0000' bus='0x08' slot='0x00' function='0x0'/>
</interface>
<interface type='network'>
<mac address='fe:54:00:18:0b:29'/>
<source network='hostdevnet'/>
<model type='virtio'/>
<teaming type='transient' persistent='ua-backup0'/>
<address type='pci' domain='0x0000' bus='0x07' slot='0x00' function='0x0'/>
</interface>
<serial type='pty'>
<target type='isa-serial' port='0'>
<model name='isa-serial'/>
</target>
</serial>
<console type='pty'>
<target type='serial' port='0'/>
</console>
<channel type='spicevmc'>
<target type='virtio' name='com.redhat.spice.0'/>
<address type='virtio-serial' controller='0' bus='0' port='9'/>
</channel>
<channel type='unix'>
<source mode='bind' path='/var/lib/libvirt/qemu/r6.agent'/>
<target type='virtio' name='org.qemu.guest_agent.0'/>
<address type='virtio-serial' controller='0' bus='0' port='1'/>
</channel>
<input type='tablet' bus='usb'>
<address type='usb' bus='0' port='2'/>
</input>
<input type='mouse' bus='ps2'/>
<input type='keyboard' bus='ps2'/>
<graphics type='spice' autoport='yes' listen='0.0.0.0' keymap='en-us'>
<listen type='address' address='0.0.0.0'/>
</graphics>
<video>
<model type='qxl' ram='131072' vram='65536' vgamem='16384' heads='1' primary='yes'/>
<address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x0'/>
</video>
<memballoon model='virtio'>
<stats period='2'/>
<address type='pci' domain='0x0000' bus='0x06' slot='0x00' function='0x0'/>
</memballoon>
</devices>
</domain>

qemu command line:

/usr/libexec/qemu-kvm -name guest=vm1,debug-threads=on -S -object secret,id=masterKey0,format=raw,file=/var/lib/libvirt/qemu/domain-10-vm1/master-key.aes -machine pc-q35-rhel8.2.0,accel=kvm,usb=off,dump-guest-core=off -cpu Haswell-noTSX-IBRS,vme=on,ss=on,vmx=on,f16c=on,rdrand=on,hypervisor=on,arat=on,tsc-adjust=on,umip=on,md-clear=on,stibp=on,arch-capabilities=on,ssbd=on,xsaveopt=on,pdpe1gb=on,abm=on,ibpb=on,amd-ssbd=on,skip-l1dfl-vmentry=on -m 1000 -overcommit mem-lock=off -smp 2,maxcpus=4,sockets=4,cores=1,threads=1 -numa node,nodeid=0,cpus=0-1,mem=500 -numa node,nodeid=1,cpus=2-3,mem=500 -uuid f98741e7-ddad-4be1-82c0-0ae3655d1c25 -no-user-config -nodefaults -chardev socket,id=charmonitor,fd=41,server,nowait -mon chardev=charmonitor,id=monitor,mode=control -rtc base=utc -no-shutdown -boot strict=on -device pcie-root-port,port=0x10,chassis=1,id=pci.1,bus=pcie.0,multifunction=on,addr=0x2 -device pcie-pci-bridge,id=pci.2,bus=pci.1,addr=0x0 -device pcie-root-port,port=0x11,chassis=3,id=pci.3,bus=pcie.0,addr=0x2.0x1 -device pcie-root-port,port=0x12,chassis=4,id=pci.4,bus=pcie.0,addr=0x2.0x2 -device pcie-root-port,port=0x13,chassis=5,id=pci.5,bus=pcie.0,addr=0x2.0x3 -device pcie-root-port,port=0x14,chassis=6,id=pci.6,bus=pcie.0,addr=0x2.0x4 -device pcie-root-port,port=0x15,chassis=7,id=pci.7,bus=pcie.0,addr=0x2.0x5 -device pcie-root-port,port=0x16,chassis=8,id=pci.8,bus=pcie.0,addr=0x2.0x6 -device qemu-xhci,id=usb,bus=pci.4,addr=0x0 -device virtio-serial-pci,id=virtio-serial0,bus=pci.5,addr=0x0 -blockdev

{"driver":"file","filename":"/var/lib/libvirt/migrate/RHEL-8.2-lhuang.qcow2","node-name":"libvirt-1-storage","auto-read-only":true,"discard":"unmap"}

-blockdev

{"node-name":"libvirt-1-format","read-only":false,"driver":"qcow2","file":"libvirt-1-storage","backing":null}

-device virtio-blk-pci,scsi=off,bus=pci.3,addr=0x0,drive=libvirt-1-format,id=virtio-disk0,bootindex=1 -netdev tap,fd=43,id=hostua-backup0,vhost=on,vhostfd=44 -device virtio-net-pci,failover=on,netdev=hostua-backup0,id=ua-backup0,mac=fe:54:00:18:0b:29,bus=pci.8,addr=0x0 -chardev pty,id=charserial0 -device isa-serial,chardev=charserial0,id=serial0 -chardev spicevmc,id=charchannel0,name=vdagent -device virtserialport,bus=virtio-serial0.0,nr=9,chardev=charchannel0,id=channel0,name=com.redhat.spice.0 -chardev socket,id=charchannel1,fd=45,server,nowait -device virtserialport,bus=virtio-serial0.0,nr=1,chardev=charchannel1,id=channel1,name=org.qemu.guest_agent.0 -device usb-tablet,id=input0,bus=usb.0,port=2 -spice port=5901,addr=0.0.0.0,disable-ticketing,seamless-migration=on -k en-us -device qxl-vga,id=video0,ram_size=134217728,vram_size=67108864,vram64_size_mb=0,vgamem_mb=16,max_outputs=1,bus=pcie.0,addr=0x1 -device vfio-pci,host=0000:82:10.3,id=hostdev0,bus=pci.7,addr=0x0,failover_pair_id=ua-backup0 -device virtio-balloon-pci,id=balloon0,bus=pci.6,addr=0x0 -sandbox on,obsolete=deny,elevateprivileges=deny,spawn=deny,resourcecontrol=deny -msg timestamp=on