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.
NEW Original OEM 60W Power Adapter Charger A1344 for APPLE 13" MacBook Pro A1278
$22.25
85W OEM NEW Power Adapter Charger For Apple Macbook Pro 13 15" A1424 A1502 A1398
$24.25
Original OEM 87W USB-C Power Adapter Charger for Apple MacBook Pro 15" 13" A1719
$28.45
New Genuine OEM A1417 Battery For Apple Macbook Pro 15" Retina A1398 2012 2013
$42.98
Genuine Apple A1882 30W USB-C Power Adapter Apple OEM CHARGER
$18.99
Genuine OEM Apple 10w USB Wall Charger Adapter iPhone iPad with Lightning cable
$6.99
Genuine Apple A1718 61W USB-C Power Adapter Apple OEM CHARGER
$24.99
Apple OEM Original (A1374) 45W MagSafe Power Adapter with Fold Plug Only - White
$10.95
APPLE OEM Power Extension Cable 6ft for Macbook, Macbook Air, Pro 2.5A 125V-NEW
$19.99
Original OEM 45W Magsafe 2 Charger for APPLE MacBook Air 13" 11" A1466 2015 2013
$7.99