Proxmox VE 8.4.14 and Virtualization-Based Security (VBS)

J

jul43257

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Oct 30, 2025
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Hello everyone,

has anyone managed to get a Windows VM (Windows 11, Windows Server 2022, or Windows Server 2025) running with Virtualization-Based Security (VBS) enabled?
I’ve tried various CPU versions and configuration combinations — as soon as VBS is enabled, the VM becomes practically unusable and constantly sits at around 100% CPU usage.
I’ve read through the forum but haven’t found any configuration that worked.
I’m aware of the “workaround” of using x86-64-v4 as the CPU type, but with that configuration, VBS cannot be enabled.
As far as I’m concerned, VBS is a standard security feature and should be enabled in a modern Windows setup.
 
Hello,

Try with the "host" CPU type, VBS is based on virtualisation so you need the virtualisation flags that are not included in classic CPU types.
 
apoyen said:
Hello,

Try with the "host" CPU type, VBS is based on virtualisation so you need the virtualisation flags that are not included in classic CPU types.
Click to expand...
Thanks for the suggestion - yes, I’m aware that VBS requires a CPU type with virtualization support. However, when I use such CPU type, for example, “host”, and enable VBS inside the VM, the VM becomes unusable, with CPU usage stuck at around 100%. I also tried a custom "host" CPU with various flags like "-md-clear", "-flush-l1d", and "+hv-tlbflush", but the behavior remained the same.

I mentioned classic CPU types like x86-64-v4 because, in other threads, people suggested using those. They reported that their VMs became usable again - which makes sense since VBS is disabled in that case.
 
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