Description of problem:
RHOSP16 features SR-IOV Instance warm migration, which suggest that SR-IOV neutron ports which are type 'direct' needs to be detached , migrated and then attached back.
https://docs.google.com/presentation/d/1nvnqhVw0v142JbQwLq04lVq2HYUC9rPLlzNXuboChkE/edit#slide=id.g6d9f1cce05_51_3103

But the instance/qemu-kvm fails with segfault and crashes the instace when the SR-IOV port is detached.

Version-Release number of selected component (if applicable):
RHOSP16.0 z1

How reproducible:
Always

Steps to Reproduce:
1. Create SR-IOV instance
2. Detach the SR-IOV port from instance.
3.

Actual results:
Warm migration of SR-IOV instance with suggested method of detaching fails.

Expected results:
Warm migration works as suggested.

Additional info:

Mar  6 17:26:44 overcloud-computesriov-0 kernel: igb 0000:19:00.2: VF 4 attempted to override administratively set MAC address#012Reload the VF driver to resume operations
Mar  6 17:26:44 overcloud-computesriov-0 kernel: CPU 2/KVM[523965]: segfault at 0 ip 00005641072d52bd sp 00007ffbb7ffe308 error 6 in qemu-kvm[564106c5d000+a31000]
Mar  6 17:26:44 overcloud-computesriov-0 kernel: Code: 08 48 89 50 10 48 89 37 48 89 7e 10 c3 f3 0f 1e fa 48 8b 47 08 48 8b 57 10 48 85 c0 74 0c 48 89 50 10 48 8b 57 10 48 8b 47 08 <48> 89 02 c3 0f 1f 44 00 00 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e
Mar  6 17:26:44 overcloud-computesriov-0 abrt-hook-ccpp[524509]: Process 523945 (qemu-kvm) of user 107 killed by SIGSEGV - dumping core
Mar  6 17:26:44 overcloud-computesriov-0 kernel: IN=eno1 OUT= MAC=ff:ff:ff:ff:ff:ff:18:66:da:5a:ef:d1:08:00 SRC=10.74.128.80 DST=255.255.255.255 LEN=77 TOS=0x00 PREC=0x00 TTL=64 ID=51630 DF PROTO=UDP SPT=42444 DPT=8009 LEN=57 
Mar  6 17:26:45 overcloud-computesriov-0 abrt-hook-ccpp[524510]: Can't generate core backtrace: dwfl_getthread_frames failed: Callback returned failure