January 2026: Delivered a security-focused patch set in torvalds/linux to harden XenPV pagetables against the L1TF vulnerability (L1TF-PTE) and introduced TLB optimizations. The changes prevent activation of shadow paging by inverting PTEs when a page becomes non-present, avoid writing L1TF-vulnerable PTEs, and skip unnecessary PTE updates if the current state is correct, while optimizing TLB maintenance to reduce overhead. This work strengthens security posture against speculative execution attacks and improves memory-management efficiency in XenPV.

Monthly summary for 2025-10 focusing on linux-riscv/linux (Zen1/Naples microcode revision check fix) with emphasis on business value and technical achievements. Key deliverable: a bug fix improving microcode validation to prevent incorrect microcode revisions from being applied, aligned with AMD guidance, thereby enhancing system security and stability. This patch was applied to the x86/microcode path within the Linux kernel and tracked in the linux-riscv/linux repository.