VMs do no start until the CPU configuration is set to “Copy host CPU configuration”

[Patrick]

When Whonix Host starts in a VM… To make developer builds more easy…
I could write a systemd unit file that does “something” only when detecting virtualization. Even only if some forms of virtualization are detected. Perhaps (not) do something when detected running inside VirtualBox / Xen (Qubes) but (not) do something when running inside KVM.
“something” could be such as switching from KVM to QEMU.
At that stage the VMs are already imported so probably another command is needed to change from KVM to QEMU?
I just need to know the conditions (which virtualization or any virtualization) and which command to run.

Or better… Does Nested KVM Virtualization work for you? I see it documented here:
Whonix for KVM

Can you enable Nested KVM Virtualization on the physical host as well as inside Whonix Host (running in VM)?

It it sane to enable Nested KVM Virtualization on Whonix Host by default?

Otherwise we get minimal QEMU support for developer testing purposes? @HulaHoop

QEMU

That is only if we cannot get Nested KVM Virtualization functional?

@onion_knight

First, at least one of the kernel hardening boot parameters somehow messes with the CPU detection on the host (in my case, a quadcore showing only two physical cores, the virtual cores being ignored), which heavily decreases performances. I need to further investigate this issue to find out which specific boot parameter(s) causes that.

Copied here: Kernel Hardening - security-misc - #15 by HulaHoop