summaryrefslogtreecommitdiff
path: root/include/linux/kho
AgeCommit message (Collapse)Author
7 daystests/liveupdate: add in-kernel liveupdate testPasha Tatashin
Introduce an in-kernel test module to validate the core logic of the Live Update Orchestrator's File-Lifecycle-Bound feature. This provides a low-level, controlled environment to test FLB registration and callback invocation without requiring userspace interaction or actual kexec reboots. The test is enabled by the CONFIG_LIVEUPDATE_TEST Kconfig option. Link: https://lkml.kernel.org/r/20251218155752.3045808-6-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Alexander Graf <graf@amazon.com> Cc: David Gow <davidgow@google.com> Cc: David Matlack <dmatlack@google.com> Cc: David Rientjes <rientjes@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kees Cook <kees@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Pratyush Yadav <pratyush@kernel.org> Cc: Samiullah Khawaja <skhawaja@google.com> Cc: Tamir Duberstein <tamird@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
7 daysliveupdate: luo_flb: introduce File-Lifecycle-Bound global statePasha Tatashin
Introduce a mechanism for managing global kernel state whose lifecycle is tied to the preservation of one or more files. This is necessary for subsystems where multiple preserved file descriptors depend on a single, shared underlying resource. An example is HugeTLB, where multiple file descriptors such as memfd and guest_memfd may rely on the state of a single HugeTLB subsystem. Preserving this state for each individual file would be redundant and incorrect. The state should be preserved only once when the first file is preserved, and restored/finished only once the last file is handled. This patch introduces File-Lifecycle-Bound (FLB) objects to solve this problem. An FLB is a global, reference-counted object with a defined set of operations: - A file handler (struct liveupdate_file_handler) declares a dependency on one or more FLBs via a new registration function, liveupdate_register_flb(). - When the first file depending on an FLB is preserved, the FLB's .preserve() callback is invoked to save the shared global state. The reference count is then incremented for each subsequent file. - Conversely, when the last file is unpreserved (before reboot) or finished (after reboot), the FLB's .unpreserve() or .finish() callback is invoked to clean up the global resource. The implementation includes: - A new set of ABI definitions (luo_flb_ser, luo_flb_head_ser) and a corresponding FDT node (luo-flb) to serialize the state of all active FLBs and pass them via Kexec Handover. - Core logic in luo_flb.c to manage FLB registration, reference counting, and the invocation of lifecycle callbacks. - An API (liveupdate_flb_get/_incoming/_outgoing) for other kernel subsystems to safely access the live object managed by an FLB, both before and after the live update. This framework provides the necessary infrastructure for more complex subsystems like IOMMU, VFIO, and KVM to integrate with the Live Update Orchestrator. Link: https://lkml.kernel.org/r/20251218155752.3045808-5-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Alexander Graf <graf@amazon.com> Cc: David Gow <davidgow@google.com> Cc: David Matlack <dmatlack@google.com> Cc: David Rientjes <rientjes@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Kees Cook <kees@kernel.org> Cc: Mike Rapoport <rppt@kernel.org> Cc: Petr Mladek <pmladek@suse.com> Cc: Pratyush Yadav <pratyush@kernel.org> Cc: Samiullah Khawaja <skhawaja@google.com> Cc: Tamir Duberstein <tamird@gmail.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26kho/abi: add memblock ABI headerMike Rapoport (Microsoft)
Introduce KHO ABI header describing preservation ABI for memblock's reserve_mem regions and link the relevant documentation to KHO docs. [lukas.bulwahn@redhat.com: MAINTAINERS: adjust file entry in MEMBLOCK AND MEMORY MANAGEMENT INITIALIZATION] Link: https://lkml.kernel.org/r/20260107090438.22901-1-lukas.bulwahn@redhat.com [rppt@kernel.org: update reserved_mem node description, per Pratyush] Link: https://lkml.kernel.org/r/aW_M-HYZzx5SkbnZ@kernel.org Link: https://lkml.kernel.org/r/20260105165839.285270-7-rppt@kernel.org Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Cc: Alexander Graf <graf@amazon.com> Cc: Jason Miu <jasonmiu@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26kho: relocate vmalloc preservation structure to KHO ABI headerJason Miu
The `struct kho_vmalloc` defines the in-memory layout for preserving vmalloc regions across kexec. This layout is a contract between kernels and part of the KHO ABI. To reflect this relationship, the related structs and helper macros are relocated to the ABI header, `include/linux/kho/abi/kexec_handover.h`. This move places the structure's definition under the protection of the KHO_FDT_COMPATIBLE version string. The structure and its components are now also documented within the ABI header to describe the contract and prevent ABI breaks. [rppt@kernel.org: update comment, per Pratyush] Link: https://lkml.kernel.org/r/aW_Mqp6HcqLwQImS@kernel.org Link: https://lkml.kernel.org/r/20260105165839.285270-6-rppt@kernel.org Signed-off-by: Jason Miu <jasonmiu@google.com> Co-developed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Cc: Alexander Graf <graf@amazon.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Pratyush Yadav <pratyush@kernel.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26kho: introduce KHO FDT ABI headerJason Miu
Introduce the `include/linux/kho/abi/kexec_handover.h` header file, which defines the stable ABI for the KHO mechanism. This header specifies how preserved data is passed between kernels using an FDT. The ABI contract includes the FDT structure, node properties, and the "kho-v1" compatible string. By centralizing these definitions, this header serves as the foundational agreement for inter-kernel communication of preserved states, ensuring forward compatibility and preventing misinterpretation of data across kexec transitions. Since the ABI definitions are now centralized in the header files, the YAML files that previously described the FDT interfaces are redundant. These redundant files have therefore been removed. Link: https://lkml.kernel.org/r/20260105165839.285270-5-rppt@kernel.org Signed-off-by: Jason Miu <jasonmiu@google.com> Co-developed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Cc: Alexander Graf <graf@amazon.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26kho/abi: memfd: make generated documentation more coherentMike Rapoport (Microsoft)
memfd preservation ABI description starts with "This header defines" which is fine in the header but reads weird in the generated html documentation. Update it to make the generated documentation coherent. Link: https://lkml.kernel.org/r/20260105165839.285270-3-rppt@kernel.org Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Cc: Alexander Graf <graf@amazon.com> Cc: Jason Miu <jasonmiu@google.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2026-01-26kho/abi: luo: make generated documentation more coherentMike Rapoport (Microsoft)
Patch series "kho: ABI headers and Documentation updates". LUO started adding KHO ABI headers to include/linux/kho/abi, but the core parts of KHO and memblock are still using the old way for descriptions on their ABIs. Let's consolidate all things KHO in include/linux/kho/abi. And while on that, make some documentation updates to have more coherent KHO docs. This patch (of 6): LUO ABI description starts with "This header defines" which is fine in the header but reads weird in the generated html documentation. Update it to make the generated documentation coherent. Link: https://lkml.kernel.org/r/20260105165839.285270-1-rppt@kernel.org Link: https://lkml.kernel.org/r/20260105165839.285270-2-rppt@kernel.org Signed-off-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Cc: Alexander Graf <graf@amazon.com> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Pasha Tatashin <pasha.tatashin@soleen.com> Cc: Jason Miu <jasonmiu@google.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27mm: memfd_luo: allow preserving memfdPratyush Yadav
The ability to preserve a memfd allows userspace to use KHO and LUO to transfer its memory contents to the next kernel. This is useful in many ways. For one, it can be used with IOMMUFD as the backing store for IOMMU page tables. Preserving IOMMUFD is essential for performing a hypervisor live update with passthrough devices. memfd support provides the first building block for making that possible. For another, applications with a large amount of memory that takes time to reconstruct, reboots to consume kernel upgrades can be very expensive. memfd with LUO gives those applications reboot-persistent memory that they can use to quickly save and reconstruct that state. While memfd is backed by either hugetlbfs or shmem, currently only support on shmem is added. To be more precise, support for anonymous shmem files is added. The handover to the next kernel is not transparent. All the properties of the file are not preserved; only its memory contents, position, and size. The recreated file gets the UID and GID of the task doing the restore, and the task's cgroup gets charged with the memory. Once preserved, the file cannot grow or shrink, and all its pages are pinned to avoid migrations and swapping. The file can still be read from or written to. Use vmalloc to get the buffer to hold the folios, and preserve it using kho_preserve_vmalloc(). This doesn't have the size limit. Link: https://lkml.kernel.org/r/20251125165850.3389713-15-pasha.tatashin@soleen.com Signed-off-by: Pratyush Yadav <ptyadav@amazon.de> Co-developed-by: Pasha Tatashin <pasha.tatashin@soleen.com> Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Tested-by: David Matlack <dmatlack@google.com> Cc: Aleksander Lobakin <aleksander.lobakin@intel.com> Cc: Alexander Graf <graf@amazon.com> Cc: Alice Ryhl <aliceryhl@google.com> Cc: Andriy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: anish kumar <yesanishhere@gmail.com> Cc: Anna Schumaker <anna.schumaker@oracle.com> Cc: Bartosz Golaszewski <bartosz.golaszewski@linaro.org> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Borislav Betkov <bp@alien8.de> Cc: Chanwoo Choi <cw00.choi@samsung.com> Cc: Chen Ridong <chenridong@huawei.com> Cc: Chris Li <chrisl@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Cc: Daniel Wagner <wagi@kernel.org> Cc: Danilo Krummrich <dakr@kernel.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Jeffery <djeffery@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Guixin Liu <kanie@linux.alibaba.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jann Horn <jannh@google.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Joanthan Cameron <Jonathan.Cameron@huawei.com> Cc: Joel Granados <joel.granados@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Lennart Poettering <lennart@poettering.net> Cc: Leon Romanovsky <leon@kernel.org> Cc: Leon Romanovsky <leonro@nvidia.com> Cc: Lukas Wunner <lukas@wunner.de> Cc: Marc Rutland <mark.rutland@arm.com> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Matthew Maurer <mmaurer@google.com> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Myugnjoo Ham <myungjoo.ham@samsung.com> Cc: Parav Pandit <parav@nvidia.com> Cc: Pratyush Yadav <pratyush@kernel.org> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Saeed Mahameed <saeedm@nvidia.com> Cc: Samiullah Khawaja <skhawaja@google.com> Cc: Song Liu <song@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Stuart Hayes <stuart.w.hayes@gmail.com> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleinxer <tglx@linutronix.de> Cc: Thomas Weißschuh <linux@weissschuh.net> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: William Tu <witu@nvidia.com> Cc: Yoann Congal <yoann.congal@smile.fr> Cc: Zhu Yanjun <yanjun.zhu@linux.dev> Cc: Zijun Hu <quic_zijuhu@quicinc.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27liveupdate: luo_file: implement file systems callbacksPasha Tatashin
This patch implements the core mechanism for managing preserved files throughout the live update lifecycle. It provides the logic to invoke the file handler callbacks (preserve, unpreserve, freeze, unfreeze, retrieve, and finish) at the appropriate stages. During the reboot phase, luo_file_freeze() serializes the final metadata for each file (handler compatible string, token, and data handle) into a memory region preserved by KHO. In the new kernel, luo_file_deserialize() reconstructs the in-memory file list from this data, preparing the session for retrieval. Link: https://lkml.kernel.org/r/20251125165850.3389713-7-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Tested-by: David Matlack <dmatlack@google.com> Cc: Aleksander Lobakin <aleksander.lobakin@intel.com> Cc: Alexander Graf <graf@amazon.com> Cc: Alice Ryhl <aliceryhl@google.com> Cc: Andriy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: anish kumar <yesanishhere@gmail.com> Cc: Anna Schumaker <anna.schumaker@oracle.com> Cc: Bartosz Golaszewski <bartosz.golaszewski@linaro.org> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Borislav Betkov <bp@alien8.de> Cc: Chanwoo Choi <cw00.choi@samsung.com> Cc: Chen Ridong <chenridong@huawei.com> Cc: Chris Li <chrisl@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Cc: Daniel Wagner <wagi@kernel.org> Cc: Danilo Krummrich <dakr@kernel.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Jeffery <djeffery@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Guixin Liu <kanie@linux.alibaba.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jann Horn <jannh@google.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Joanthan Cameron <Jonathan.Cameron@huawei.com> Cc: Joel Granados <joel.granados@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Lennart Poettering <lennart@poettering.net> Cc: Leon Romanovsky <leon@kernel.org> Cc: Leon Romanovsky <leonro@nvidia.com> Cc: Lukas Wunner <lukas@wunner.de> Cc: Marc Rutland <mark.rutland@arm.com> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Matthew Maurer <mmaurer@google.com> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Myugnjoo Ham <myungjoo.ham@samsung.com> Cc: Parav Pandit <parav@nvidia.com> Cc: Pratyush Yadav <ptyadav@amazon.de> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Saeed Mahameed <saeedm@nvidia.com> Cc: Samiullah Khawaja <skhawaja@google.com> Cc: Song Liu <song@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Stuart Hayes <stuart.w.hayes@gmail.com> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleinxer <tglx@linutronix.de> Cc: Thomas Weißschuh <linux@weissschuh.net> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: William Tu <witu@nvidia.com> Cc: Yoann Congal <yoann.congal@smile.fr> Cc: Zhu Yanjun <yanjun.zhu@linux.dev> Cc: Zijun Hu <quic_zijuhu@quicinc.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27liveupdate: luo_session: add sessions supportPasha Tatashin
Introduce concept of "Live Update Sessions" within the LUO framework. LUO sessions provide a mechanism to group and manage `struct file *` instances (representing file descriptors) that need to be preserved across a kexec-based live update. Each session is identified by a unique name and acts as a container for file objects whose state is critical to a userspace workload, such as a virtual machine or a high-performance database, aiming to maintain their functionality across a kernel transition. This groundwork establishes the framework for preserving file-backed state across kernel updates, with the actual file data preservation mechanisms to be implemented in subsequent patches. [dan.carpenter@linaro.org: fix use after free in luo_session_deserialize()] Link: https://lkml.kernel.org/r/c5dd637d7eed3a3be48c5e9fedb881596a3b1f5a.1764163896.git.dan.carpenter@linaro.org Link: https://lkml.kernel.org/r/20251125165850.3389713-5-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Signed-off-by: Dan Carpenter <dan.carpenter@linaro.org> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Tested-by: David Matlack <dmatlack@google.com> Cc: Aleksander Lobakin <aleksander.lobakin@intel.com> Cc: Alexander Graf <graf@amazon.com> Cc: Alice Ryhl <aliceryhl@google.com> Cc: Andriy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: anish kumar <yesanishhere@gmail.com> Cc: Anna Schumaker <anna.schumaker@oracle.com> Cc: Bartosz Golaszewski <bartosz.golaszewski@linaro.org> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Borislav Betkov <bp@alien8.de> Cc: Chanwoo Choi <cw00.choi@samsung.com> Cc: Chen Ridong <chenridong@huawei.com> Cc: Chris Li <chrisl@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Cc: Daniel Wagner <wagi@kernel.org> Cc: Danilo Krummrich <dakr@kernel.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Jeffery <djeffery@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Guixin Liu <kanie@linux.alibaba.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jann Horn <jannh@google.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Joanthan Cameron <Jonathan.Cameron@huawei.com> Cc: Joel Granados <joel.granados@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Lennart Poettering <lennart@poettering.net> Cc: Leon Romanovsky <leon@kernel.org> Cc: Leon Romanovsky <leonro@nvidia.com> Cc: Lukas Wunner <lukas@wunner.de> Cc: Marc Rutland <mark.rutland@arm.com> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Matthew Maurer <mmaurer@google.com> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Myugnjoo Ham <myungjoo.ham@samsung.com> Cc: Parav Pandit <parav@nvidia.com> Cc: Pratyush Yadav <ptyadav@amazon.de> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Saeed Mahameed <saeedm@nvidia.com> Cc: Samiullah Khawaja <skhawaja@google.com> Cc: Song Liu <song@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Stuart Hayes <stuart.w.hayes@gmail.com> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleinxer <tglx@linutronix.de> Cc: Thomas Weißschuh <linux@weissschuh.net> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: William Tu <witu@nvidia.com> Cc: Yoann Congal <yoann.congal@smile.fr> Cc: Zhu Yanjun <yanjun.zhu@linux.dev> Cc: Zijun Hu <quic_zijuhu@quicinc.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>
2025-11-27liveupdate: luo_core: integrate with KHOPasha Tatashin
Integrate the LUO with the KHO framework to enable passing LUO state across a kexec reboot. This patch implements the lifecycle integration with KHO: 1. Incoming State: During early boot (`early_initcall`), LUO checks if KHO is active. If so, it retrieves the "LUO" subtree, verifies the "luo-v1" compatibility string, and reads the `liveupdate-number` to track the update count. 2. Outgoing State: During late initialization (`late_initcall`), LUO allocates a new FDT for the next kernel, populates it with the basic header (compatible string and incremented update number), and registers it with KHO (`kho_add_subtree`). 3. Finalization: The `liveupdate_reboot()` notifier is updated to invoke `kho_finalize()`. This ensures that all memory segments marked for preservation are properly serialized before the kexec jump. Link: https://lkml.kernel.org/r/20251125165850.3389713-3-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> Tested-by: David Matlack <dmatlack@google.com> Reviewed-by: Mike Rapoport (Microsoft) <rppt@kernel.org> Cc: Aleksander Lobakin <aleksander.lobakin@intel.com> Cc: Alexander Graf <graf@amazon.com> Cc: Alice Ryhl <aliceryhl@google.com> Cc: Andriy Shevchenko <andriy.shevchenko@linux.intel.com> Cc: anish kumar <yesanishhere@gmail.com> Cc: Anna Schumaker <anna.schumaker@oracle.com> Cc: Bartosz Golaszewski <bartosz.golaszewski@linaro.org> Cc: Bjorn Helgaas <bhelgaas@google.com> Cc: Borislav Betkov <bp@alien8.de> Cc: Chanwoo Choi <cw00.choi@samsung.com> Cc: Chen Ridong <chenridong@huawei.com> Cc: Chris Li <chrisl@kernel.org> Cc: Christian Brauner <brauner@kernel.org> Cc: Daniel Wagner <wagi@kernel.org> Cc: Danilo Krummrich <dakr@kernel.org> Cc: Dan Williams <dan.j.williams@intel.com> Cc: David Hildenbrand <david@redhat.com> Cc: David Jeffery <djeffery@redhat.com> Cc: David Rientjes <rientjes@google.com> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Guixin Liu <kanie@linux.alibaba.com> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Hugh Dickins <hughd@google.com> Cc: Ilpo Järvinen <ilpo.jarvinen@linux.intel.com> Cc: Ingo Molnar <mingo@redhat.com> Cc: Ira Weiny <ira.weiny@intel.com> Cc: Jann Horn <jannh@google.com> Cc: Jason Gunthorpe <jgg@nvidia.com> Cc: Jens Axboe <axboe@kernel.dk> Cc: Joanthan Cameron <Jonathan.Cameron@huawei.com> Cc: Joel Granados <joel.granados@kernel.org> Cc: Johannes Weiner <hannes@cmpxchg.org> Cc: Jonathan Corbet <corbet@lwn.net> Cc: Lennart Poettering <lennart@poettering.net> Cc: Leon Romanovsky <leon@kernel.org> Cc: Leon Romanovsky <leonro@nvidia.com> Cc: Lukas Wunner <lukas@wunner.de> Cc: Marc Rutland <mark.rutland@arm.com> Cc: Masahiro Yamada <masahiroy@kernel.org> Cc: Matthew Maurer <mmaurer@google.com> Cc: Miguel Ojeda <ojeda@kernel.org> Cc: Myugnjoo Ham <myungjoo.ham@samsung.com> Cc: Parav Pandit <parav@nvidia.com> Cc: Pratyush Yadav <ptyadav@amazon.de> Cc: Randy Dunlap <rdunlap@infradead.org> Cc: Roman Gushchin <roman.gushchin@linux.dev> Cc: Saeed Mahameed <saeedm@nvidia.com> Cc: Samiullah Khawaja <skhawaja@google.com> Cc: Song Liu <song@kernel.org> Cc: Steven Rostedt <rostedt@goodmis.org> Cc: Stuart Hayes <stuart.w.hayes@gmail.com> Cc: Tejun Heo <tj@kernel.org> Cc: Thomas Gleinxer <tglx@linutronix.de> Cc: Thomas Weißschuh <linux@weissschuh.net> Cc: Vincent Guittot <vincent.guittot@linaro.org> Cc: William Tu <witu@nvidia.com> Cc: Yoann Congal <yoann.congal@smile.fr> Cc: Zhu Yanjun <yanjun.zhu@linux.dev> Cc: Zijun Hu <quic_zijuhu@quicinc.com> Signed-off-by: Andrew Morton <akpm@linux-foundation.org>