Ok I think I understand the subtleties of these attacks now. But: can anyone tell me why the accessibility check for protected memory doesn't happen before the cache loads the contents of RAM? If that happened then none of these attacks would be possible.
I got my computer engineering degree in 1999 and ended up going the computer science route making CRUD apps all day. I feel in my gut that some engineer, somewhere, MUST have asked this question at one of the big chip manufacturers.
Am I missing something fundamental? Is the access check too expensive? If it isn't, then can the microcode be updated to do this, or is caching/accessibility checking happening at a level above microcode? If that's the case then it would seem that pretty much all processors everywhere that do speculation without protected memory access checks are now obsolete.
I got my computer engineering degree in 1999 and ended up going the computer science route making CRUD apps all day. I feel in my gut that some engineer, somewhere, MUST have asked this question at one of the big chip manufacturers.
Am I missing something fundamental? Is the access check too expensive? If it isn't, then can the microcode be updated to do this, or is caching/accessibility checking happening at a level above microcode? If that's the case then it would seem that pretty much all processors everywhere that do speculation without protected memory access checks are now obsolete.