issue with reattaching nvme drives

[Oguz Bektas]

hi list,


while doing attach/detach followed by attach of an nvme device/drive,
qemu is complaining that the drive already exists (duplicate ID)

VM is running with this commandline on Proxmox VE 6.2:

------
/usr/bin/kvm \
  -id 105 \
  -name kali \
  -chardev 'socket,id=qmp,path=/var/run/qemu-server/105.qmp,server,nowait' \
  -mon 'chardev=qmp,mode=control' \
  -chardev 'socket,id=qmp-event,path=/var/run/qmeventd.sock,reconnect=5' \
  -mon 'chardev=qmp-event,mode=control' \
  -pidfile /var/run/qemu-server/105.pid \
  -daemonize \
  -smbios 'type=1,uuid=fee8e512-7465-4a1d-8361-6acbc423b897' \
  -smp '1,sockets=1,cores=1,maxcpus=1' \
  -nodefaults \
  -boot 
'menu=on,strict=on,reboot-timeout=1000,splash=/usr/share/qemu-server/bootsplash.jpg'
 \
  -vnc unix:/var/run/qemu-server/105.vnc,password \
  -cpu kvm64,enforce,+kvm_pv_eoi,+kvm_pv_unhalt,+lahf_lm,+sep \
  -m 2048 \
  -device 'pci-bridge,id=pci.1,chassis_nr=1,bus=pci.0,addr=0x1e' \
  -device 'pci-bridge,id=pci.2,chassis_nr=2,bus=pci.0,addr=0x1f' \
  -device 'vmgenid,guid=3dde676f-f7da-45d5-b344-66f094845c8a' \
  -device 'piix3-usb-uhci,id=uhci,bus=pci.0,addr=0x1.0x2' \
  -device 'usb-tablet,id=tablet,bus=uhci.0,port=1' \
  -device 'VGA,id=vga,bus=pci.0,addr=0x2' \
  -device 'virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3' \
  -iscsi 'initiator-name=iqn.1993-08.org.debian:01:c1255109cd2' \
  -drive 
'file=/mnt/pve/nasi/template/iso/kali-linux-2020.1a-installer-amd64.iso,if=none,id=drive-ide2,media=cdrom,aio=threads'
 \
  -device 'ide-cd,bus=ide.1,unit=0,drive=drive-ide2,id=ide2,bootindex=200' \
  -drive 
'file=/dev/pve/vm-105-disk-0,if=none,id=drive-nvme0,format=raw,cache=none,aio=native,detect-zeroes=on'
 \
  -device 'nvme,drive=drive-nvme0,id=nvme0,bootindex=100,serial=nvme0' \
  -netdev 
'type=tap,id=net0,ifname=tap105i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on'
 \
  -device 
'virtio-net-pci,mac=8E:87:65:F4:C6:4F,netdev=net0,bus=pci.0,addr=0x12,id=net0,bootindex=300'
 \
  -machine 'type=pc+pve0'
------

the relevant bits are the following lines:

------
  -drive 
'file=/dev/pve/vm-105-disk-0,if=none,id=drive-nvme0,format=raw,cache=none,aio=native,detect-zeroes=on'
 \
  -device 'nvme,drive=drive-nvme0,id=nvme0,bootindex=100,serial=nvme0' \
------

the nvme emulation is working fine, and hotplugging and hot-unplugging is also 
working. however when i try to detach an existing drive via hmp command, and 
attach it again with the same id (which doesn't exist according to qom-tree and 
qtree after detaching the drive), i'm getting this error:
----
Duplicate ID 'drive-nvme0' for drive
----

this is happening in qemu/util/qemu-option.c on qemu 4.2.0

adding it back with a different id works, so to me it seems like after 
detaching the drive and device from the VM, something stays remnant in the 
memory, making qemu think the drive is still there??

did anyone encounter this before? is this a bug?

can the maintainers give some insight?

if you need any more information please let me know.

regards,
oguz bektas