3 ms·
Can opcodes be diverted to enter SMM instead of what they were supposed to be doing?
by rzzzt 4y ago
Can opcodes be diverted to enter SMM instead of what they were supposed to be doing?
- monocasa 4y agoI don't see why not assuming that the opcode decoded to a ucode fetch in the first place, but I don't have that exact information in front of me to say 100% sure. I'd be shocked though if that wasn't possible. Around your question though, on modernish Intel another mode exists that executes "XuCode" out of relatively normal RAM that kind of ends up looking like a restricted x86 subset to implement very complex x86 instructions. My understanding is that SGX enclave enter/exit is mainly implemented in XuCode. https://www.intel.com/content/www/us/en/developer/articles/technical/software-security-guidance/secure-coding/xucode-implementing-complex-instruction-flows.html https://www.intel.com/content/www/us/en/developer/articles/t...