Intel Gives Up On Making Some Spectre Microcode Fixes
Samuel Wan / 3 weeks ago
Intel Gives Up On Spectre Microcode For Older CPUs
At the start of the year, Intel got caught unprepared when Spectre and Meltdown were revealed. Since then, Intel has been in firefighting mode from the start. So far, Intel is using software-based mitigations only. For post-Haswell based CPUs, Intel has already released new microcode updates for Spectre. Unfortunately for some older CPUs, it looks like Intel is giving up on providing any real fix at all.
The Spectre attack works by exploiting the CPU branch predictor. By making a specific bad prediction, flaw exposes other data in memory. This exposes data held by other programs which can be sensitive like passwords. Microsoft was the first to issue an fix by modifying the OS behaviour. This software fix led to heavy performance degradation with specific workloads. To remedy the issue, Intel released a microcode update, changing the CPU behaviour and restoring performance.
Decision Cuts Out Core 2 and Gulftown
So far, Intel has released new microcode fixes for all CPUs Haswell and later. Due to various bugs, Intel has to make a new patch for each specific architecture. Earlier documentation from Intel suggested that Core 2 Penryn and Wolfdale CPUs would get the fix. Unfortunately, that is not the case as Intel has given up on their beta builds. Even more troubling is that 1st Generation Core processors such as Gulftown, Bloomfield and Clarksfield will not be getting the fix either. Since these CPUs aren’t getting the fix, it means they will continue to suffer performance losses.
It is unclear why Intel has decided not to issue a fix for these chips. Perhaps it is harder due to missing features, or there aren’t enough users to make it worthwhile. Honestly, it is hard to expect a fix for such old processors. However, it is sad that Intel raised out hopes only to dash them. It would have been nice to see Intel own up to their mistake and step up with a fix for all users. Afterall, there are still many systems running Core 2 and 1st Gen Core CPUs out in the wild and vulnerable. It would have been a sign of good faith to rebuild user trust after this debacle.