For several years I have run both the Knoppix ISO-image and disk-based versions under kvm for installs, maintenance etc. The basic method works for 8.3 too, but only as far as the first flash install.
Klaus K has made Knoppix more "fool-proof" to run under kvm by restricting it to read-only mode. For many users, that is clearly a feature: You may run your ordinary Knoppix install under kvm so it functions as both host and guest at once, but if persistent store is involved, and the host and the guest instances perform different updates to that, then what?
It is only a question of time until the file system is corrupted - it is easy to imagine that prof. Knopper has introduced this restriction from experiences with broken systems.
The bug is that it doesn't stop there. If you run different copies of Knoppix on different partitions, or run Knoppix under another OS variety, even another version of Knoppix, the only thing to be careful about is that the partition where the persistent store of the VM resides is not writable by other OS'es. But don't try to explain that to Knoppix 8.3. It only checks whether it is run under kvm, and in that case, the system is mounted read-only. Which kind of blocks many important uses of Knoppix images.
While the default behaviour is "correct", there must be a cheatcode for disabling it, e.g. VIRTWRITE. I guess specialists on minirt.gz should not have too much problems rolling their own, but this is a general issue, so for me it belongs in Knopper-land proper.
Lenovo ThinkPad T480s Laptop Computer 14" Core i5 8GB RAM 128GB SSD Windows 11
$208.99
Lenovo ThinkPad T450s 14" Intel i5 5th Gen 8GB RAM 250GB SSD Win 10 Wifi Laptop
$129.00
Lenovo Laptop ThinkPad Light Gaming AMD Ryzen 7 PRO 16GB 256GB SSD Windows 11
$269.67
Lenovo - Legion Slim 5 16" Gaming Laptop WUXGA - Ryzen 5 7640HS with 16GB Mem...
$1349.99
Lenovo - Yoga 7 2-in-1 14" 2K Touchscreen Laptop - AMD Ryzen 5 8640HS with 8G...
$749.99
Lenovo Yoga 2-in-1 Touch Laptop PC 11.6" Windows 10 4GB RAM 250GB SSD HDMI WiFi
$89.99
Lenovo Ideapad 1i 15.6" FHD Touch Laptop - Intel Core i3-1215U with 8GB Memor...
$499.99
Lenovo IdeaPad 5 Intel Core i7-1065G7 1.3Ghz 12GB Ram 512GB SSD 15.6" Laptop
$99.95
lenovo legion gaming laptop pro
$750.00
Lenovo ThinkPad L13 Yoga Gen 2 i5-1145G7 @ 2.60GHz 16GB/256GB Win 10 Pro - W/Pen
$263.19