Among the early pull requests submitted in advance of the Linux 6.14 stable release and in turn the Linux 6.15 merge window opening were the x86 FPU updates. Notable this round are faster x86/x86_64 encryption/decryption performance for both Intel and AMD processors as well as beginning to land the kernel-side changes needed to support Intel Advanced Performance Extensions (APX).

The x86/fpu updates for Linux 6.15 improve crypto performance by making the kernel-mode FPU reliably usable in soft IRQs. This improvement was talked about previously on Phoronix within [1]New Patches Would Make All Kernel Encryption/Decryption Faster On x86/x86_64 Hardware . The patches for this pull request range from a few percent up to a 23% improvement for AES-XTS for this very nice code improvement.

While Intel [2]Advanced Performance Extensions is geared just for user-space use, there are some kernel-side changes needed for supporting APX use with future Intel processors. Intel engineers recently began posting [3]the Linux kernel patches for APX and now with this x86/fpu pull that enablement work has begun to land. These are just the initial steps with more to come in follow on kernel cycles.

Those are the most exciting x86/fpu changes queued up ahead of the Linux 6.15 merge window. They'll be merged barring any last minute objections by Linus Torvalds. See [4]this pull request for all the details.



[1] https://www.phoronix.com/news/Linux-x86-Crypt-Drop-Fallback

[2] https://www.phoronix.com/search/Advanced+Performance+Extensions

[3] https://www.phoronix.com/news/Intel-APX-Linux-Kernel-Patches

[4] https://lore.kernel.org/lkml/Z96mVT2u3MMMbtN0@gmail.com/