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Originally Posted by meynaf
While a 68060 can probably prefetch data for filling its DCache, it doesn't do speculative memory accesses ('xcept maybe for fetching code).
And even if it did, I/O areas are marked by the MMU as non-cacheable (or at least they should !).
x86 are immune to this - they have IN/OUT instructions for I/O.
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The majority of I/O is memory mapped. The I/O instructions are legacy only and _extremely_ slow.
I could do some hw hacking faster with a Pentium than with my current system. So a 90MHz in-order processor can push out more bytes than a modern 2.5+GHz 4 core out of order processor. Slow!
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For ARM, I don't know.
The tricks are :
- Current operating systems map the supervisor area, or at least part of it, in the user's memory (for the sake of quick OS calling).
- Current cpus (again for the sake of speed) do the memory access in the cache before checking the access rights (which takes more time).
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Intel do. AMD say they don't.
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Now wondering if this kind of attack can be done from within WinUAE in JIT mode...
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Spectre should work but what should be attacked?
Meltdown I think not as the "68k" should only be able to access the memory of the emulated Amiga anyway. Or?