PROXMXO 8.1: vCLS VM's inside Nested ESXI are not seeing CPU FLAG "cpuid.mwait"


New Member
Oct 14, 2023
Hi All,

Just deployed some ESXI hosts nested within proxmox and I have an issue with clustering vm's which fail to start inside ESXI as they dont see cpu flag "cpu.mwait":

VM Conf:

root@pve1:/etc/pve/qemu-server# cat 701.conf
balloon: 0
bios: ovmf
boot: order=sata0;ide2;net0
cores: 4
cpu: host
efidisk0: SNAIL:vm-701-disk-0,efitype=4m,pre-enrolled-keys=1,size=1M
ide2: none,media=cdrom
memory: 8192
meta: creation-qemu=8.1.2,ctime=1700944776
name: ESXI-1
net0: vmxnet3=BC:24:11:19:02:D1,bridge=vmbr0
net1: vmxnet3=BC:24:11:B9:DE:37,bridge=vmbr3
net2: vmxnet3=BC:24:11:43:E0:39,bridge=vmbr4
numa: 0
ostype: l26
sata0: SNAIL:vm-701-disk-1,size=128G
sata1: CHEETAH:vm-701-disk-0,backup=0,size=80G,ssd=1
scsihw: virtio-scsi-single
smbios1: uuid=1421e68a-5a5a-4bf0-b500-786762360b8f
sockets: 1
vmgenid: c45ffe30-92a9-46e2-8425-2d322fe4088c

Error in Vcenter:


Here is the KB on VMWare mentiong the cause if the error I see: Link


I do see an aticle on phronix from last year mentioning kernel patch to Use MWAIT Instead Of HALT for AMD CPU's: Link


I applied the workaround on the VMWare KB linked above and all seems to be running fine now, but as I need to do more and more VMWare clustering just wondering if this is a known issue on Proxmox side ?

On Proxmox side we are running 8.1 with of the shelf consumer components:

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