boyter (npub1fzq…qpus) sorry, no.
X86 CPUs have a mode where you can use L3 cache as RAM, it is used during early initialisation when RAM isn't yet available. But it's all or nothing. You can't just use a part of your cache for main memory, leaving the rest of it operating as cache.
The way I saw it used (other than the above) was in some paranoidly secure system fortified against cold boot attacks, since you can't easily freeze the CPU, put it onto another board, and read the cache contents. The system supported regular RAM as well, but it was encrypted, with keys never physically leaving the CPU.
Curator of Mastodon.art fediblock :newt: /
npub1wc…t4sk7
2023-06-15 19:39:45
in reply to nevent1q…arcf
Author Public Key
npub1wc2kznjw6kldwzz8eedr9pf208waa8ww3fjsqk0nz4rdv8q663qswt4sk7Published at
2023-06-15 19:39:45Event JSON
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"content": "nostr:npub1fzqzdc3szm09rpcfy5l8eva4nfc5ht8x5qa0wvc6egk9dzhucekswxqpus sorry, no.\n\nX86 CPUs have a mode where you can use L3 cache as RAM, it is used during early initialisation when RAM isn't yet available. But it's all or nothing. You can't just use a part of your cache for main memory, leaving the rest of it operating as cache.\n\nThe way I saw it used (other than the above) was in some paranoidly secure system fortified against cold boot attacks, since you can't easily freeze the CPU, put it onto another board, and read the cache contents. The system supported regular RAM as well, but it was encrypted, with keys never physically leaving the CPU.",
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