Intel's "redundant prefix issue"

Posted Nov 15, 2023 21:55 UTC (Wed) by mfuzzey (subscriber, #57966)
In reply to: Intel's "redundant prefix issue" by pizza
Parent article: Intel's "redundant prefix issue"

If they were non encrypted but signed that would still prevent malicious microcode update (unless done by Intel) whilst keeping the microcode readable for those interested.

People who want to experiment with microcode could then enable their own keys on their own system (at their own risk).

Intel's "redundant prefix issue"

Posted Nov 16, 2023 9:43 UTC (Thu) by Sesse (subscriber, #53779) [Link] (5 responses)

There are (old) AMD CPUs with non-encrypted and non-signed microcode. Some researchers have even managed to make small changes to them. Knock yourself out.

Intel's "redundant prefix issue"

Posted Nov 16, 2023 13:25 UTC (Thu) by geert (subscriber, #98403) [Link] (4 responses)

So we can convert these AMD CPUs to e.g. RISC-V or m68k CPUs? ;-)

Intel's "redundant prefix issue"

Posted Nov 17, 2023 0:13 UTC (Fri) by p2mate (guest, #51563) [Link] (2 responses)

Can we then finally have a 64bit version of the m68k architecture? :)

Intel's "redundant prefix issue"

Posted Nov 17, 2023 8:03 UTC (Fri) by geert (subscriber, #98403) [Link]

Apparently the Apollo Core 68080 does have 64-bit (quad-word) support.
Unfortunately it's proprietary.
http://www.apollo-core.com/index.htm?page=coding&tl=1

Intel's "redundant prefix issue"

Posted Nov 17, 2023 8:17 UTC (Fri) by Sesse (subscriber, #53779) [Link]

I don't really know what people think the microcode is capable of doing, but it's not like the CPU decoder is purely software, just in a funny language.

Intel's "redundant prefix issue"

Posted Nov 27, 2023 14:16 UTC (Mon) by immibis (subscriber, #105511) [Link]

No. 99% of the CPU is hard-wired, and the microcode file controls some of the more obscure features, edge cases and rarely executed or very complex instructions.