In the last few hours, several specialized outlets have reported the release of new security patches for Windows, macOS, and Linux in response to a serious vulnerability present in all Intel processors from the last ten years. The good news is that these new hotfixes solve the most critical aspects of the bug. The bad news is that affected chips could lose performance depending on the application, with numbers reaching 30 to 40 percent...
If 2017 was the year Intel felt the pressure of legitimate competition, then 2018 is shaping up to be something much worse. Hardware bugs are inevitable, and to tell the truth no silicon generation has managed to escape them completely. In the best case, a new microcode update or additional BIOS functions can fix the problem or isolate its negative effects, but this time it's something more complex and delicate: a flaw considered 'fundamental' in the processors Intel launched during the last ten years has forced developers to create emergency patches, which at the same time represent a structural change for the way operating systems work.
Inside the Meltdown vulnerability
The bug, appropriately identified as Meltdown, allows processes in user space (the memory area reserved for running programs and some drivers) to distinguish or recognize to a certain extent the format or content of protected areas assigned to the kernel (which equates to a data leak), when that shouldn't happen. The kernel is 'invisible' to programs, and under normal conditions that would be enough, but the bug in Intel's silicon demands going one step further: instead of staying invisible to a running process, the solution is that it's not there directly. This absolute separation is known as KPTI or 'Kernel Page Table Isolation', although the Linux kernel team used the term 'Forcefully Unmap Complete Kernel With Interrupt Trampolines', that is, FUCKWIT.
The bug seems to be contained, but like many medications, the patches also have fine print. The fact of switching from one space to another for each system call implies that the processor has to discard data from its cache and read it back from memory, causing considerable overhead. In other words, affected processors will run slower. How hard is the hit? The final number depends both on the work environment and the chips' natural capabilities, but the most optimistic number is 5 percent, while at the other extreme it could reach 40 percent. Now, what about AMD processors? According to engineer Tom Lendacky, the Sunnyvale hardware does not suffer this vulnerability nor requires the use of KPTI, however we must wait. Everything will depend on how good the patch implementation is, and the storm of benchmarks will be brutal. To be continued...
Intel's response and the CEO's stock sale
Update 1: Here is Intel's official statement. The company indicated that it is working with AMD and ARM to resolve the problem 'constructively' because it is not exclusive to its hardware, and that the performance impact on the average user 'will not be significant'. On the other hand, it added that the plan was to reveal the existence of the bug within a week, but they decided to advance it due to 'inaccurate reports' from the press.
Update 2: Intel CEO Brian Krzanich sold $24 million in company shares at the end of November, months after having received information about the vulnerability.
