Intel Alder Lake & Raptor Lake Face Linux PCID Disablement Over INVLPG Issue.
Originally Published 2 years ago — by Phoronix
Linux kernel developers are disabling Process Context Identifiers (PCID) for Intel Alder Lake and Raptor Lake processors due to an issue with incomplete global INVLPG flushes. A patch is set to be mainlined for Linux 6.4 development and back-ported to stable kernel versions. Intel is working on a microcode mitigation for the issue, but for now, PCID support will be disabled. PCID support helps offset some of the overhead in dealing with Kernel Page Table Isolation/mitigating Meltdown.