What were you trying to do that didn't work?
After migration, check the guest network, found the network is not available:
1. fail to ssh the guest through IP on dst host
2. Ping fail on dst host:
[root@s390x-kvm-016 ~]# ping 192.168.122.180
PING 192.168.122.180 (192.168.122.180) 56(84) bytes of data.
From 192.168.122.1 icmp_seq=1 Destination Host Unreachable
From 192.168.122.1 icmp_seq=2 Destination Host Unreachable
From 192.168.122.1 icmp_seq=3 Destination Host Unreachable
From 192.168.122.1 icmp_seq=4 Destination Host Unreachable

You can visit below log for details:

http://10.0.160.15:8000/VIRT_299455_s390x_blockdev-2024-06-17-04%3A44%3A04/VIRT_299496-2024-06-17-04%3A44%3A04_logs/long_debug.log

Please provide the package NVR for which bug is seen:
hosts info: kernel-6.9.0-7.el10.s390x && qemu-kvm-9.0.0-2.el10.s390x
guest info: kernel-6.9.0-7.el10.s390x

How reproducible:
50%

Steps to reproduce
1. Boot a VM on the source host
2. Boot a VM on the destination host with appending '-incoming defer'
3. Check the sshd service in VM, it runs well, get valid ip in guest
4. Enable postcopy and postcopy-preempt on the src and dst host
5. Migrate VM from src to dst, during migration is active, switch to postcopy phase
6. After migration, check sshd and firewalld services(sshd is running, firewalld is inactive) in VM, try to connect guest through ssh + guest ip, try to ping the guest on dst host

Expected results
In step 6, the network of guest is good, can ping the guest, ssh connection succeeds

Actual results
[root@s390x-kvm-016 ~]# ssh -o UserKnownHostsFile=/dev/null -o PreferredAuthentications=password -p 22 root@192.168.122.180
ssh: connect to host 192.168.122.180 port 22: No route to host
[root@s390x-kvm-016 ~]# ping 192.168.122.180
PING 192.168.122.180 (192.168.122.180) 56(84) bytes of data.
From 192.168.122.1 icmp_seq=1 Destination Host Unreachable
From 192.168.122.1 icmp_seq=2 Destination Host Unreachable
From 192.168.122.1 icmp_seq=3 Destination Host Unreachable
From 192.168.122.1 icmp_seq=4 Destination Host Unreachable