State persistence over kexec

This talk is about Kernel HandOver (KHO) mechanism that allows preserving memory contents across kexec. We will describe how KHO enables preservation of memory accross kexec, what metadata it uses to pass between old and new kernels and the mechanism that ensures that new kernel can bootstrap itself without stepping over the preserved memory. The combination of serialization, preservation of arbitrary memory ranges and guaranteed availability of memory for bootstrap of the new kernel makes KHO a solid foundation for solutions that aim to preserve both kernel and userspace memory across kexec.