32-Bit Linux Prepares For Performance Hit Due To KPTI For Meltdown Mitigation

32-Bit Linux Prepares For Performance Hit Due To KPTI For Meltdown Mitigation: Since January there has been KPTI in the x86_64 Linux kernel as Kernel-based Page Table Isolation for mitigating the Meltdown CPU vulnerability. On the back-burner since then has been KPTI support for the Linux x86 32-bit kernel to protect those using older 32-bit-only processors. With the upcoming Linux 4.19 kernel, KPTI is landing for Linux x86 32-bit. Here are sone benchmarks showing the performance penalty when upgrading to this new kernel on an Ubuntu i686 laptop.