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 w/ Green Hologram SFP-10/25G-LR-S 10/25GBASE-LR SFP28 Transceiver Module
$79.99
Cisco Meraki MA-SFP-1GB-SX 1000BASE-SX SFP Transceiver Module
$24.99
Cisco GLC-FE-100LX 100BASE-LX SFP Transceiver Module
$15.59
Cisco SFP-25G-SR-S 25GBASE-SR SFP28, 850nm, 100m, LC, MMF
$54.00
Genuine Cisco SFP-10G-SR V03 10GBASE-SR SFP+ Transceiver Module 10-2415-03
$8.00
SFP-10G-SR Original Cisco 10GBASE-SR SFP+ V02 Multi mode Transceiver 10-2415-02
$5.00
Brand New Cisco GLC-LH-SMD 1000BASE-LX/LH SFP Module 1310nm 10km SMF LC
$13.89
Lot of 10 SFP-GB-GE-T Copper RJ45 10/100/1000Base-T 100m Transceiver Modules
$29.94
LOT OF 20 Genuine Cisco SFP-10G-SR V03 10GBASE-SR SFP+ Transceiver Module
$89.00
New Cisco SFP-10G-LRM 10G SFP+ LRM 1310nm 220m SMF/MMF LC Module
$34.99