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.
Cisco 2901/K9-V06 Integrated Services Gigabit Voice Router
$69.99
Cisco Catalyst 3650 48-Port Managed PoE+ Gigabit Switch WS-C3650-48FS-E
$55.99
Cisco WS-C3850-48P-L 48-Port Gigabit 3850 PoE Switch w/ 715W+ C3850-NM-4-1G Mod
$83.00
Cisco Catalyst 3850 48 PoE+ 48-Port Gigabit Managed Switch WS-C3850-48F-E
$150.00
Cisco C3850-NM-2-10G 2 Port Network Exp.Module for 3850
$38.99
Cisco Catalyst WS-C2960-48TT-L V02 48 Port Fast Ethernet Switch
$34.00
Cisco WS-C4948-10GE-S 4948-10GE 48 Port Gigabit +10GB Switch w single AC 15.0 OS
$99.99
Cisco CBS350-24FP-4G 28 Port PoE Managed Ethernet Switch
$319.99
Cisco C9300-48 48 Port Switch Dual PSU W/C9300-NM-8X P/N: C9300-48U-A Tested
$799.99
UNCLAIMED Cisco Meraki MS120-24P-HW - 24Ports Ethernet PoE Switch Same Day Ship
$315.00