successfully booting arm vm (but not with cpu arg cortex-a72)

[Elleni]

Hello forum,

I successfully can start a vm with the following config:

arch: aarch64
balloon: 0
bios: ovmf
boot: order=scsi1;net0;scsi0
cores: 2
memory: 2048
meta: creation-qemu=9.2.0,ctime=1749821246
name: arm64-test
net0: virtio=BC:24:11:46:EF:D0,bridge=vmbr0
numa: 0
ostype: l26
scsi0: MyVMs:100/vm-100-disk-0.qcow2,size=100G
scsi1: MyVMs:iso/debian-12.11.0-arm64-DVD-1.iso,media=cdrom,size=3899692K
scsihw: virtio-scsi-pci
smbios1: uuid=a963d10e-4c94-4618-be03-2c21e0d49ed3
sockets: 1

I installed pve-edk2-firmware-aarch64

and qemu-system-arm -cpu help gives the following list:

Available CPUs:
  a64fx
  arm1026
  arm1136
  arm1136-r2
  arm1176
  arm11mpcore
  arm926
  arm946
  cortex-a15
  cortex-a35
  cortex-a53
  cortex-a55
  cortex-a57
  cortex-a7
  cortex-a710
  cortex-a72
  cortex-a76
  cortex-a8
  cortex-a9
  cortex-m0
  cortex-m3
  cortex-m33
  cortex-m4
  cortex-m55
  cortex-m7
  cortex-r5
  cortex-r52
  cortex-r5f
  max
  neoverse-n1
  neoverse-n2
  neoverse-v1
  pxa250
  pxa255
  pxa260
  pxa261
  pxa262
  pxa270-a0
  pxa270-a1
  pxa270
  pxa270-b0
  pxa270-b1
  pxa270-c0
  pxa270-c5
  sa1100
  sa1110
  ti925t

Trying to start the vm after issuing:

qm set 100 --args "cpu cortex-a72"
update VM 100: -args cpu cortex-a72

gives error:

WARN: no efidisk configured! Using temporary efivars disk.
qemu-system-aarch64: cpu: Could not open 'cpu': No such file or directory
TASK ERROR: start failed: QEMU exited with code 1

What am I missing - do I need some additional package to install or config to adapt?