linux/tools/testing/selftests/kho, branch master

kho: remove finalize state and clients

2026-04-05T20:53:04Z

Eliminate the `kho_finalize()` function and its associated state from the KHO subsystem. The transition to a radix tree for memory tracking makes the explicit "finalize" state and its serialization step obsolete. Remove the `kho_finalize()` and `kho_finalized()` APIs and their stub implementations. Update KHO client code and the debugfs interface to no longer call or depend on the `kho_finalize()` mechanism. Complete the move towards a stateless KHO, simplifying the overall design by removing unnecessary state management. Link: https://lkml.kernel.org/r/20260206021428.3386442-3-jasonmiu@google.com Signed-off-by: Jason Miu Reviewed-by: Pasha Tatashin Reviewed-by: Mike Rapoport (Microsoft) Cc: Alexander Graf Cc: Baoquan He Cc: Changyuan Lyu Cc: David Matlack Cc: David Rientjes Cc: Jason Gunthorpe Cc: Pratyush Yadav Cc: Ran Xiaokai Signed-off-by: Andrew Morton

kho: make debugfs interface optional

2025-11-27T22:24:31Z

Patch series "liveupdate: Rework KHO for in-kernel users", v9. This series refactors the KHO framework to better support in-kernel users like the upcoming LUO. The current design, which relies on a notifier chain and debugfs for control, is too restrictive for direct programmatic use. The core of this rework is the removal of the notifier chain in favor of a direct registration API. This decouples clients from the shutdown-time finalization sequence, allowing them to manage their preserved state more flexibly and at any time. In support of this new model, this series also: - Makes the debugfs interface optional. - Introduces APIs to unpreserve memory and fixes a bug in the abort path where client state was being incorrectly discarded. Note that this is an interim step, as a more comprehensive fix is planned as part of the stateless KHO work [1]. - Moves all KHO code into a new kernel/liveupdate/ directory to consolidate live update components. This patch (of 9): Currently, KHO is controlled via debugfs interface, but once LUO is introduced, it can control KHO, and the debug interface becomes optional. Add a separate config CONFIG_KEXEC_HANDOVER_DEBUGFS that enables the debugfs interface, and allows to inspect the tree. Move all debugfs related code to a new file to keep the .c files clear of ifdefs. Link: https://lkml.kernel.org/r/20251101142325.1326536-1-pasha.tatashin@soleen.com Link: https://lkml.kernel.org/r/20251101142325.1326536-2-pasha.tatashin@soleen.com Link: https://lore.kernel.org/all/20251020100306.2709352-1-jasonmiu@google.com [1] Co-developed-by: Mike Rapoport (Microsoft) Signed-off-by: Mike Rapoport (Microsoft) Signed-off-by: Pasha Tatashin Reviewed-by: Pratyush Yadav Cc: Alexander Graf Cc: Christian Brauner Cc: Jason Gunthorpe Cc: Jonathan Corbet Cc: Masahiro Yamada Cc: Miguel Ojeda Cc: Randy Dunlap Cc: Tejun Heo Cc: Changyuan Lyu Cc: Jason Gunthorpe Cc: Simon Horman Cc: Zhu Yanjun Signed-off-by: Andrew Morton

selftest/kho: update generation of initrd

2025-09-13T23:54:55Z

Use nolibc include directory rather than include a cumulative nolibc.h on the compiler command line and replace use of 'sudo cpio' with usr/gen_init_cpio. While on it fix spelling of KHO_FINALIZE Link: https://lkml.kernel.org/r/20250811082510.4154080-4-rppt@kernel.org Signed-off-by: Mike Rapoport (Microsoft) Suggested-by: Thomas Weißschuh Cc: Alexander Graf Cc: Baoquan He Cc: Changyuan Lyu Cc: Pasha Tatashin Cc: Pratyush Yadav Cc: Shuah Khan Signed-off-by: Andrew Morton

kho: add test for kexec handover

2025-08-02T19:01:41Z

Testing kexec handover requires a kernel driver that will generate some data and preserve it with KHO on the first boot and then restore that data and verify it was preserved properly after kexec. To facilitate such test, along with the kernel driver responsible for data generation, preservation and restoration add a script that runs a kernel in a VM with a minimal /init. The /init enables KHO, loads a kernel image for kexec and runs kexec reboot. After the boot of the kexeced kernel, the driver verifies that the data was properly preserved. [rppt@kernel.org: fix section mismatch] Link: https://lkml.kernel.org/r/aIiRC8fXiOXKbPM_@kernel.org Link: https://lkml.kernel.org/r/20250727083733.2590139-1-rppt@kernel.org Signed-off-by: Mike Rapoport (Microsoft) Cc: Alexander Graf Cc: Changyuan Lyu Cc: Pasha Tatashin Cc: Pratyush Yadav Cc: Shuah Khan Signed-off-by: Andrew Morton