Intel engineers are working to improve the microcode update process for X86_64 CPU in Linux systems, with a focus on optimizing the late microcode bootloader. These changes are primarily aimed at servers and corporate users of Intel.
Through branch X86/Microcode at the Tip.git repository, the first batch of improvements for the X86 microcode in the Linux nucleus has been presented. These changes remove unnecessary mittexes, old debug code, and enable constant loading of the CPU microcode for systems based on X86. Now this option is always turned on.
At least these improvements are included in TIP and should become part of the upcoming Linux 6.6 cycle.
In addition, Thomas Glakesner is leading the work on improving the late loading of microcode on Intel Linux systems. In his series of patches, he explained that late loading of microcode is desirable for corporate users but is problematic because it requires detailed knowledge of changes and analyzing their influence on the already used components of the nucleus.
Intel recently added a new field to the microcode header, which contains the minimum version of the microcode for safe loading. Late microcode loading allows for updating the CPU microcode when the system is already loaded and launched, which is especially useful for large organizations and cloud providers who want to introduce updates quickly without system downtime.
It is still unclear whether the improved function of the late loading of Intel microcode will be included in the release of the nucleus version V6.6, but work on this improvement is already underway.