Windows 11 frequent, temporary freezes with Virtual Machine platform enabled

L

Lombra

New Member
Feb 2, 2025
18
3
3
Hi,

I'm having issues with a Windows 11 VM freezing when the Virtual Machine platform optional Windows feature is enabled. It's rather inconsistent, but usually occurs within a few minutes of logging in. (or booting?) It freezes for a few minutes, disconnecting the Remote Desktop session. The Proxmox console is completely frozen, including mouse cursor. Guest agent does not respond. The behaviour repeats every few minutes or so. I've seen similar issues mentioned, but no real solution.

Using an Intel Core 125H.

Code: 
agent: 1
bios: ovmf
boot: order=scsi0;ide0;net0
cores: 4
cpu: host,flags=+nested-virt
efidisk0: local-lvm:vm-201-disk-0,efitype=4m,ms-cert=2023k,pre-enrolled-keys=1,size=4M
ide0: local:iso/virtio-win-0.1.271.iso,media=cdrom,size=709474K
machine: pc-q35-11.0
memory: 8192
meta: creation-qemu=11.0.0,ctime=1787174629
name: verk
net0: virtio=BC:24:11:79:D7:4A,bridge=INTERNAL,firewall=1
numa: 0
onboot: 1
ostype: win11
scsi0: local-lvm:vm-201-disk-1,aio=native,discard=on,iothread=1,size=100G,ssd=1
scsihw: virtio-scsi-single
smbios1: uuid=91db5eca-9617-49c3-9b18-de9e60d3d0b6
sockets: 1
tpmstate0: local-lvm:vm-201-disk-2,size=4M,version=v2.0
vga: virtio
vmgenid: 647a81cf-deb7-45ae-b9b5-1bf22e5cb0b8

Code: 
proxmox-ve: 9.2.0 (running kernel: 7.0.6-2-pve)
pve-manager: 9.2.3 (running version: 9.2.3/d0fde103346cf89a)
proxmox-kernel-helper: 9.2.0
proxmox-kernel-7.0: 7.0.6-2
proxmox-kernel-7.0.6-2-pve-signed: 7.0.6-2
proxmox-kernel-6.17: 6.17.13-13
proxmox-kernel-6.17.13-13-pve-signed: 6.17.13-13
proxmox-kernel-6.17.2-1-pve-signed: 6.17.2-1
proxmox-kernel-6.14: 6.14.11-9
proxmox-kernel-6.14.11-9-pve-signed: 6.14.11-9
proxmox-kernel-6.14.11-4-pve-signed: 6.14.11-4
proxmox-kernel-6.14.11-1-pve-signed: 6.14.11-1
proxmox-kernel-6.14.8-2-pve-signed: 6.14.8-2
ceph-fuse: 19.2.3-pve1
corosync: 3.1.10-pve2
criu: 4.1.1-1
frr-pythontools: 10.6.1-1+pve2
ifupdown2: 3.3.0-1+pmx12
intel-microcode: 3.20251111.1~deb13u1
ksm-control-daemon: 1.5-1
libjs-extjs: 7.0.0-5
libproxmox-acme-perl: 1.7.1
libproxmox-backup-qemu0: 2.0.2
libproxmox-rs-perl: 0.4.1
libpve-access-control: 9.1.1
libpve-apiclient-perl: 3.4.2
libpve-cluster-api-perl: 9.1.6
libpve-cluster-perl: 9.1.6
libpve-common-perl: 9.1.13
libpve-guest-common-perl: 6.0.3
libpve-http-server-perl: 6.0.5
libpve-network-perl: 1.6.6
libpve-notify-perl: 9.1.6
libpve-rs-perl: 0.15.3
libpve-storage-perl: 9.1.5
libspice-server1: 0.15.2-1+b1
lvm2: 2.03.31-2+pmx1
lxc-pve: 7.0.0-2
lxcfs: 7.0.0-pve1
novnc-pve: 1.7.0-1
proxmox-backup-client: 4.2.1-1
proxmox-backup-file-restore: 4.2.1-1
proxmox-backup-restore-image: 1.0.0
proxmox-firewall: 1.2.3
proxmox-kernel-helper: 9.2.0
proxmox-mail-forward: 1.0.3
proxmox-mini-journalreader: 1.6
proxmox-offline-mirror-helper: 0.7.4
proxmox-widget-toolkit: 5.2.3
pve-cluster: 9.1.6
pve-container: 6.1.10
pve-docs: 9.2.2
pve-edk2-firmware: 4.2025.05-2
pve-esxi-import-tools: 1.0.1
pve-firewall: 6.0.4
pve-firmware: 3.18-4
pve-ha-manager: 5.2.4
pve-i18n: 3.7.5
pve-qemu-kvm: 11.0.0-4
pve-xtermjs: 6.0.0-1
qemu-server: 9.1.16
smartmontools: 7.5-pve2
spiceterm: 3.4.2
swtpm: 0.8.0+pve3
vncterm: 1.9.2
zfsutils-linux: 2.4.2-pve1
 
There are several threads about CPU usage using Host with VBS etc enabled. But it sounds like you want the virtualization?

C

Post in thread 'High VM-EXIT and Host CPU usage on idle with Windows Server 2025'

uberarchiver said:
https://www.phoronix.com/news/Linux-6.18-KVM

View attachment 94043

And google : "kvm enable avic disable nested virtualization"

Might help. Might not help. Got some VMEXITs eliminated myself
Click to expand...
Do you know if there is a way to confirm if AVIC is working in the guest?

This is something I was trying to figure out over recent days, I can only find ways to confirm its loaded in amd_kvm module and if its present on host CPU, but not ways to confirm its active in the guest.
 
Maybe this in the above thread?
R

Post in thread 'High VM-EXIT and Host CPU usage on idle with Windows Server 2025'

My write up about issues with Windows 11, high CPU used, VBS, WSL2, nested virt.

https://opensourcetechblog.hashnode...ce-on-proxmox-and-keep-live-migration-working

My main takeaway is, that with "older" hardware, in my case 3rd generation Xeon CPUs(dual socket), CPU frequency needs to be manually defined, while for newer hardware the kernel trusts the clock and it does not have to be.

As @ltctech mentioned, it would be great if CPU frequency could be defined as part of the custom cpu. Maybe by using some "I know what I am...

fwiw from searching
 
It's clear that there exists a number of issues, but these don't seem to exactly match mine. I don't have issues with the VM not booting, and I wouldn't say that it's slow; I would say it works as expected between the freezing. The CPU model is a modern one, too. I tried a few different CPU types, but the VM wouldn't work, due to missing CPU flags or something. I also tried using QEMU 10 and i440fx, but that didn't help.

I did apply the registry edit from the cited thread, however, and it works so far, but I've not yet tested for long enough to consider it stable.

Code: 
[HKEY_LOCAL_MACHINE\SYSTEM\CurrentControlSet\Control\Session Manager\kernel]
"EnablePerCpuClockTickScheduling"=dword:00000002
 
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