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.
Oracle 7085209 LSI MegaRAID SAS 9361-8i 1GB Cache 12Gbps SAS/SATA PCIe RAID Card
$28.20
Cisco UCS LSI MegaRAID 9271CV-8I SAS2308 PCIe SAS Internal RAID Controller
$28.00
LSI 9207-8i 8-Port SAS Non-RAID 6GBPS PCIe Host Bus Adapter
$34.95
LSI 9305-16i SATA SAS 12Gbs RAID Controller PCIe 3.0 x8 IT-Mode 4* 8643 SATA
$229.99
Inspur LSI 9300-8i Raid Card 12Gbps HBA HDD Controller High Profile IT MODE
$15.98
LSI MegaRAID 9361-8i 12Gb PCIe 8-Port SAS/SATA RAID 1Gb w/BBU/CacheVault/License
$39.95
LSI MegaRAID 9361-8i 12Gbps PCIe 3 x8 SATA SAS 3 8 Port RAID + BBU & CacheVault
$39.00
ORICO Multi Bay RAID Hard Drive Enclosure USB 3.0/ Type-C For 2.5/3.5'' HDD SSDs
$82.49
ACASIS 2.5/3.5 inch 2 Bay SATA USB 3.0 Hard Drive Disk HDD SSD Enclosure 4 RAID
$58.99
G-Technology G-SPEED eS PRO 4-Bay Mini-SAS RAID Array 0G02057
$99.99