Meltdown: Reading Kernel Memory from User Space

Memory isolation is a cornerstone security feature in the construction of every modern computer system. Allowing the simultaneous execution of multiple mutually distrusting applications at the same time on the same hardware, it is the basis of enabling secure execution of multiple processes on the same machine or in the cloud. The operating system is in charge of enforcing this isolation, as well as isolating its own kernel memory regions from other users. Given its central role on modern processors, the isolation between the kernel and user processes is backed by the hardware, in the form of a supervisor bit that determines whether code in the current.