TLDR;Copying from the thread on 4chanThere is evidence of a massive Intel CPU hardware bug (currently under embargo) that directly affects big cloud providers like Amazon and Google. The fix will introduce notable performance penalties on Intel machines (30-35%).People have noticed a recent development in the Linux kernel: a rather massive, important redesign (page table isolation) is being introduced very fast for kernel standards... and being backported! The "official" reason is to incorporate a mitigation called KASLR... which most security experts consider almost useless. There's also some unusual, suspicious stuff going on: the documentation is missing, some of the comments are redacted ( https://twitter.com/grsecurity/status/947147105684123649 ) and people with Intel, Amazon and Google emails are CC'd.According to one of the people working on it, PTI is only needed for Intel CPUs, AMD is not affected by whatever it protects against ( https://lkml.org/lkml/2017/12/27/2 ). PTI affects a core low-level feature (virtual memory) and has severe performance penalties: 29% for an i7-6700 and 34% for an i7-3770S, according to Brad Spengler from grsecurity. PTI is simply not active for AMD CPUs. The kernel flag is named X86_BUG_CPU_INSECURE and its description is "CPU is insecure and needs kernel page table isolation".Microsoft has been silently working on a similar feature since November: https://twitter.com/aionescu/status/930412525111296000 People are speculating on a possible massive Intel CPU hardware bug that directly opens up serious vulnerabilities on big cloud providers which offer shared hosting (several VMs on a single host), for example by letting a VM read from or write to another one.