Description of problem:
After unplug the disk, then re-hotplug it again, qmp and hmp could detect this disk, but it could not be found in guest.

Version-Release number of selected component (if applicable):
Host:
kernel-4.18.0-67.el8.x86_64
qemu-kvm-3.1.0-15.module+el8+2792+e33e01a0.x86_64
seabios-bin-1.11.1-3.module+el8+2529+a9686a4d.noarch
sgabios-bin-0.20170427git-2.module+el8+2529+a9686a4d.noarch

Guest:
Win2019
virtio-win-prewhql-0.1-163.iso

How reproducible:
3/10

Steps to Reproduce:
1.Boot the guest with the following cli:
/usr/libexec/qemu-kvm \
        -S \
        -name 'avocado-vt-vm1' \
        -machine q35 \
        -nodefaults \
        -device VGA,bus=pcie.0,addr=0x1 \
        -object iothread,id=iothread0 \
        -drive id=drive_image1,if=none,snapshot=off,aio=threads,cache=none,format=qcow2,file=/home/kvm_autotest_root/images/win2019-64-virtio.qcow2 \
        -device pcie-root-port,id=pcie.0-root-port-3,slot=3,chassis=3,addr=0x3,bus=pcie.0 \
        -device virtio-blk-pci,id=image1,drive=drive_image1,bootindex=0,iothread=iothread0,bus=pcie.0-root-port-3,addr=0x0 \
        -m 15360 \
        -smp 12,maxcpus=12,cores=6,threads=1,sockets=2 \
        -cpu 'Opteron_G5',+kvm_pv_unhalt,hv_relaxed,hv_spinlocks=0x1fff,hv_vapic,hv_time \
        -device pcie-root-port,id=pcie.0-root-port-4,slot=4,chassis=4,addr=0x4,bus=pcie.0 \
        -device virtio-net-pci,mac=9a:31:32:33:34:35,id=idYxHDLn,vectors=4,netdev=idoOknQC,bus=pcie.0-root-port-4,addr=0x0 \
        -netdev tap,id=idoOknQC,vhost=on \
        -device pcie-root-port,id=pcie.0-root-port-5,slot=5,chassis=5,addr=0x5,bus=pcie.0 \
        -device virtio-scsi-pci,id=virtio_scsi_pci0,bus=pcie.0-root-port-5,addr=0x0 \
        -drive id=drive_cd1,if=none,snapshot=off,aio=threads,cache=none,media=cdrom,file=/home/kvm_autotest_root/iso/windows/winutils.iso \
        -device scsi-cd,id=cd1,drive=drive_cd1,bootindex=1 \
        -device pcie-root-port,id=pcie.0-root-port-2,slot=2,chassis=2,addr=0x2,bus=pcie.0 \
        -device qemu-xhci,id=usb1,bus=pcie.0-root-port-2,addr=0x0 \
        -device usb-tablet,id=usb-tablet1,bus=usb1.0,port=1 \
        -device pcie-root-port,id=pcie_extra_root_port_0,slot=6,chassis=6,addr=0x6,bus=pcie.0 \
        -vnc :1 \
        -rtc base=localtime,clock=host,driftfix=slew \
        -enable-kvm \
        -qmp tcp:0:4446,server,nowait \
        -monitor stdio

2. Prepare a data disk, and hotplug it by qmp;
# qemu-img create -f qcow2 storage0.qcow2 1G
# telnet localhost 4446
{"execute": "qmp_capabilities"}
{"return": {}}

{"execute": "human-monitor-command", "arguments": {"command-line": "drive_add auto id=drive_stg0,if=none,snapshot=off,aio=threads,cache=none,format=qcow2,file=/home/kvm_autotest_root/images/storage0.qcow2"}, "id": "Yu6Mfcom"}
{"return": "OK\r\n", "id": "Yu6Mfcom"}

{"execute": "device_add", "arguments": {"driver": "virtio-blk-pci", "id": "stg0", "drive": "drive_stg0", "iothread": "iothread0", "bus": "pcie_extra_root_port_0"}, "id": "t07OBwFH"}
{"return": {}, "id": "t07OBwFH"}

3.In guest, check the disk status, create partition & format this disk, and run iozone test on it;
wmic diskdrive get index
Index
0
1

diskpart>
list disk
select disk 1
create partition primary
select partition 1
assign letter=I
format fs=ntfs
exit

D:\Iozone\iozone.exe -azR -r 64k -n 125M -g 512M -M -i 0 -i 1 -b I:\iozone_test -f I:\testfile

4. After inzone test finished, unplug this disk in qmp, and check the device status in guest;
{"execute": "device_del", "arguments": {"id": "stg0"}, "id": "XVosfhHr"}
{"return": {}, "id": "XVosfhHr"}
{"timestamp": {"seconds": 1551251295, "microseconds": 687533}, "event": "DEVICE_DELETED", "data": {"path": "/machine/peripheral/stg0/virtio-backend"}}
{"timestamp": {"seconds": 1551251295, "microseconds": 740903}, "event": "DEVICE_DELETED", "data": {"device": "stg0", "path": "/machine/peripheral/stg0"}}

guest:
wmic diskdrive get index
Index
0

5. Re-plug this disk, and check its status in qmp/hmp;
{"execute": "human-monitor-command", "arguments": {"command-line": "drive_add auto id=drive_stg0,if=none,snapshot=off,aio=threads,cache=none,format=qcow2,file=/home/kvm_autotest_root/images/storage0.qcow2"}, "id": "vbXJbRsZ"}
{"return": "OK\r\n", "id": "vbXJbRsZ"}
{"execute": "device_add", "arguments": {"driver": "virtio-blk-pci", "id": "stg0", "drive": "drive_stg0", "iothread": "iothread0", "bus": "pcie_extra_root_port_0"}, "id": "ovGz8Gdx"}
{"return": {}, "id": "ovGz8Gdx"}

(qemu) info block
drive_stg0 (#block1118): /home/kvm_autotest_root/images/storage0.qcow2 (qcow2)
    Attached to:      /machine/peripheral/stg0/virtio-backend
    Cache mode:       writeback, direct


6. Check the disk index in guest;
wmic diskdrive get index

Actual results:
Index
0
No data disk could be found in guest.


Expected results:
Index
0
1
The data disk could be detected in guest successfully.

Additional info:
1)3/10, the disk could not be re-hotpluged successfully. And the Disk Management tool would hang when this issue happened. 

2)From the automation log, this issue also happened on virtio-scsi disk.

3)Host cpu info:
Architecture:        x86_64
CPU op-mode(s):      32-bit, 64-bit
Byte Order:          Little Endian
CPU(s):              24
On-line CPU(s) list: 0-23
Thread(s) per core:  2
Core(s) per socket:  6
Socket(s):           2
NUMA node(s):        4
Vendor ID:           AuthenticAMD
CPU family:          21
Model:               2
Model name:          AMD Opteron(tm) Processor 6344
Stepping:            0
CPU MHz:             1192.857
BogoMIPS:            5186.97
Virtualization:      AMD-V
L1d cache:           16K
L1i cache:           64K
L2 cache:            2048K
L3 cache:            6144K
NUMA node0 CPU(s):   0,2,4,6,8,10
NUMA node1 CPU(s):   12,14,16,18,20,22
NUMA node2 CPU(s):   1,3,5,7,9,11
NUMA node3 CPU(s):   13,15,17,19,21,23
Flags:               fpu vme de pse tsc msr pae mce cx8 apic sep mtrr pge mca cmov pat pse36 clflush mmx fxsr sse sse2 ht syscall nx mmxext fxsr_opt pdpe1gb rdtscp lm constant_tsc rep_good nopl nonstop_tsc cpuid extd_apicid amd_dcm aperfmperf pni pclmulqdq monitor ssse3 fma cx16 sse4_1 sse4_2 popcnt aes xsave avx f16c lahf_lm cmp_legacy svm extapic cr8_legacy abm sse4a misalignsse 3dnowprefetch osvw ibs xop skinit wdt fma4 tce nodeid_msr tbm topoext perfctr_core perfctr_nb cpb hw_pstate ssbd ibpb vmmcall bmi1 arat npt lbrv svm_lock nrip_save tsc_scale vmcb_clean flushbyasid decodeassists pausefilter pfthreshold