In addition to Intel software engineers this week being busy doing a late restructuring of AVX10 support in moving away from possible 256-bit maximum vector register size (a great move and still so excited to see this materialize!), there are also Intel engineers continuing work on enabling Advanced Performance Extensions (APX) on the Linux kernel side.
Intel APX is another exciting innovation happening for their future processors. While the compiler-side support for Advanced Performance Extensions has been coming together, necessary Linux kernel infrastructure has yet to be settled. Last month saw initial Linux kernel patches for handling APX while today they were revised. As noted then, APX isn’t intended to be used in kernel-mode but rather just user-space applications, but that the kernel needs to make accommodates with the new APX register state and other differences that need to be properly handled.
That first round of Intel APX patches for the Linux kernel had also included a patch to drop Intel Memory Protection Extensions (MPX) support as it clashed with the initial APX code and MPX itself has been deprecated for a while. But in today’s updated patches the MPX removal patch itself was dropped since the APX code has been reworked to jive together nicely.
The updated Intel APX code also has various other Intel APX code alterations as it undergoes review and upstream kernel mailing list discussion. Those interested can find today’s Intel APX kernel patches via this patch series that is still under a “request for comments” marking.
With the APX patches not settled yet, this code isn’t yet in a position for merging in the upcoming Linux v6.15 merge window. Thus we’re now looking at a H2’2025 Linux kernel release at the earliest before the Intel APX kernel support will be ready. Thus it’s still looking like it won’t be until Intel’s next-next-generation of processors before APX is likely to debut.
