Comment 11 for bug 1883009

There is a single virtio port:

# ls -la /dev/virtio-ports/
lrwxrwxrwx 1 root root 11 May 25 19:07 org.qemu.guest_agent.0 -> ../vport2p1
# ls -la /dev/vport*
crw------- 1 root root 243, 1 May 25 19:07 /dev/vport2p1

As you can notice, there is 1 single deivce, but it starts from vport2p1.

It can be confirmed with the the proxmox's qemu command line (there is no virsh/libvirt):
/usr/bin/kvm -id 100 -name XYZ
  -chardev socket,id=qmp,path=/var/run/qemu-server/100.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/100.pid
  -daemonize
  -smbios type=1,uuid=xyz-2b19-4f25-xyz-xyz
  -smp 4,sockets=1,cores=4,maxcpus=4
  -nodefaults
  -boot menu=on,strict=on,reboot-timeout=1000,splash=/usr/share/qemu-server/bootsplash.jpg
  -vnc unix:/var/run/qemu-server/100.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=6a11a495-xyz-4773-xyz-xyz
  -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
  -chardev socket,path=/var/run/qemu-server/100.qga,server,nowait,id=qga0
  -device virtio-serial,id=qga0,bus=pci.0,addr=0x8
  -device virtserialport,chardev=qga0,name=org.qemu.guest_agent.0
  -device virtio-balloon-pci,id=balloon0,bus=pci.0,addr=0x3
  -iscsi initiator-name=iqn.1993-08.org.debian:01:xyz
  -drive file=/var/lib/vz/template/iso/ubuntu-20.04-live-server-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
  -device virtio-scsi-pci,id=scsihw0,bus=pci.0,addr=0x5
  -drive file=/var/lib/vz/images/100/vm-100-disk-0.qcow2,if=none,id=drive-scsi0,format=qcow2,cache=none,aio=native,detect-zeroes=on
  -device scsi-hd,bus=scsihw0.0,channel=0,scsi-id=0,lun=0,drive=drive-scsi0,id=scsi0,bootindex=100
  -netdev type=tap,id=net0,ifname=tap100i0,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on
  -device virtio-net-pci,mac=00:ca:fe:00:20:13,netdev=net0,bus=pci.0,addr=0x12,id=net0,bootindex=300
  -netdev type=tap,id=net1,ifname=tap100i1,script=/var/lib/qemu-server/pve-bridge,downscript=/var/lib/qemu-server/pve-bridgedown,vhost=on
  -device virtio-net-pci,mac=00:ca:fe:00:20:12,netdev=net1,bus=pci.0,addr=0x13,id=net1,bootindex=301
  -machine type=pc+pve0