Linked by Thom Holwerda on Wed 3rd Jan 2018 00:42 UTC
Intel

A fundamental design flaw in Intel's processor chips has forced a significant redesign of the Linux and Windows kernels to defang the chip-level security bug.

Programmers are scrambling to overhaul the open-source Linux kernel's virtual memory system. Meanwhile, Microsoft is expected to publicly introduce the necessary changes to its Windows operating system in an upcoming Patch Tuesday: these changes were seeded to beta testers running fast-ring Windows Insider builds in November and December.

Crucially, these updates to both Linux and Windows will incur a performance hit on Intel products. The effects are still being benchmarked, however we're looking at a ballpark figure of five to 30 per cent slow down, depending on the task and the processor model. More recent Intel chips have features - such as PCID - to reduce the performance hit.

That's one hell of a bug.

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RE[2]: Microcode
by kwan_e on Wed 3rd Jan 2018 21:15 UTC in reply to "RE: Microcode"
kwan_e
Member since:
2007-02-18

but features like branch prediction are still hardwired and require new silicon designs.


That is surprising to me. I'd have thought you'd want to make something like branch prediction modifiable (well, just like other instructions/features) so fixes can be applied.

So my question is, why is the lack of security check hardwired, or why it was designed in such a way that not even a microcode update could fix it?

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