Changes in Makefile

0349ff2887059112ce06831ab29aec47a2a7285a - kho: add support for linked-block serialization

Wed, 03 Jun 2026 17:43:56 +0200

kho: add support for linked-block serializationIntroduce a linked-block serialization mechanism for state handover.Previously, LUO used contiguous memory blocks for serializing sessionsand files, which imposed limits on the total number of items that couldbe preserved across a live update.This commit adds the infrastructure for a more flexible, block-basedapproach where serialized data is stored in a chain of linked blocks.This is a generic KHO serialization block infrastructure that can beused by multiple subsystems.Signed-off-by: Pasha Tatashin Link: https://patch.msgid.link/20260603154402.468928-8-pasha.tatashin@soleen.comSigned-off-by: Mike Rapoport (Microsoft) List of files: /linux/kernel/liveupdate/Makefile

cab056f2aae7250af50e503b81a80dfc567a1acd - liveupdate: luo_flb: introduce File-Lifecycle-Bound global state

Thu, 18 Dec 2025 16:57:51 +0100

liveupdate: luo_flb: introduce File-Lifecycle-Bound global stateIntroduce a mechanism for managing global kernel state whose lifecycle istied to the preservation of one or more files. This is necessary forsubsystems where multiple preserved file descriptors depend on a single,shared underlying resource.An example is HugeTLB, where multiple file descriptors such as memfd andguest_memfd may rely on the state of a single HugeTLB subsystem. Preserving this state for each individual file would be redundant andincorrect. The state should be preserved only once when the first file ispreserved, and restored/finished only once the last file is handled.This patch introduces File-Lifecycle-Bound (FLB) objects to solve thisproblem. An FLB is a global, reference-counted object with a defined setof 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 complexsubsystems like IOMMU, VFIO, and KVM to integrate with the Live UpdateOrchestrator.Link: https://lkml.kernel.org/r/20251218155752.3045808-5-pasha.tatashin@soleen.comSigned-off-by: Pasha Tatashin Cc: Alexander Graf Cc: David Gow Cc: David Matlack Cc: David Rientjes Cc: Jonathan Corbet Cc: Kees Cook Cc: Mike Rapoport Cc: Petr Mladek Cc: Pratyush Yadav Cc: Samiullah Khawaja Cc: Tamir Duberstein Signed-off-by: Andrew Morton List of files: /linux/kernel/liveupdate/Makefile

7c722a7f44e0c1f9714084152226bc7bd644b7e3 - liveupdate: luo_file: implement file systems callbacks

Tue, 25 Nov 2025 17:58:36 +0100

liveupdate: luo_file: implement file systems callbacksThis patch implements the core mechanism for managing preserved filesthroughout the live update lifecycle. It provides the logic to invoke thefile handler callbacks (preserve, unpreserve, freeze, unfreeze, retrieve,and finish) at the appropriate stages.During the reboot phase, luo_file_freeze() serializes the final metadatafor each file (handler compatible string, token, and data handle) into amemory region preserved by KHO. In the new kernel, luo_file_deserialize()reconstructs the in-memory file list from this data, preparing the sessionfor retrieval.Link: https://lkml.kernel.org/r/20251125165850.3389713-7-pasha.tatashin@soleen.comSigned-off-by: Pasha Tatashin Reviewed-by: Mike Rapoport (Microsoft) Reviewed-by: Pratyush Yadav Tested-by: David Matlack Cc: Aleksander Lobakin Cc: Alexander Graf Cc: Alice Ryhl Cc: Andriy Shevchenko Cc: anish kumar Cc: Anna Schumaker Cc: Bartosz Golaszewski Cc: Bjorn Helgaas Cc: Borislav Betkov Cc: Chanwoo Choi Cc: Chen Ridong Cc: Chris Li Cc: Christian Brauner Cc: Daniel Wagner Cc: Danilo Krummrich Cc: Dan Williams Cc: David Hildenbrand Cc: David Jeffery Cc: David Rientjes Cc: Greg Kroah-Hartman Cc: Guixin Liu Cc: "H. Peter Anvin" Cc: Hugh Dickins Cc: Ilpo Järvinen Cc: Ingo Molnar Cc: Ira Weiny Cc: Jann Horn Cc: Jason Gunthorpe Cc: Jens Axboe Cc: Joanthan Cameron Cc: Joel Granados Cc: Johannes Weiner Cc: Jonathan Corbet Cc: Lennart Poettering Cc: Leon Romanovsky Cc: Leon Romanovsky Cc: Lukas Wunner Cc: Marc Rutland Cc: Masahiro Yamada Cc: Matthew Maurer Cc: Miguel Ojeda Cc: Myugnjoo Ham Cc: Parav Pandit Cc: Pratyush Yadav Cc: Randy Dunlap Cc: Roman Gushchin Cc: Saeed Mahameed Cc: Samiullah Khawaja Cc: Song Liu Cc: Steven Rostedt Cc: Stuart Hayes Cc: Tejun Heo Cc: Thomas Gleinxer Cc: Thomas Weißschuh Cc: Vincent Guittot Cc: William Tu Cc: Yoann Congal Cc: Zhu Yanjun Cc: Zijun Hu Signed-off-by: Andrew Morton List of files: /linux/kernel/liveupdate/Makefile

0153094d03df5a2e834a19c59b255649a258ae46 - liveupdate: luo_session: add sessions support

Tue, 25 Nov 2025 17:58:34 +0100

liveupdate: luo_session: add sessions supportIntroduce concept of "Live Update Sessions" within the LUO framework. LUOsessions provide a mechanism to group and manage `struct file *` instances(representing file descriptors) that need to be preserved across akexec-based live update.Each session is identified by a unique name and acts as a container forfile objects whose state is critical to a userspace workload, such as avirtual machine or a high-performance database, aiming to maintain theirfunctionality across a kernel transition.This groundwork establishes the framework for preserving file-backed stateacross kernel updates, with the actual file data preservation mechanismsto 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.orgLink: https://lkml.kernel.org/r/20251125165850.3389713-5-pasha.tatashin@soleen.comSigned-off-by: Pasha Tatashin Signed-off-by: Dan Carpenter Reviewed-by: Mike Rapoport (Microsoft) Reviewed-by: Pratyush Yadav Tested-by: David Matlack Cc: Aleksander Lobakin Cc: Alexander Graf Cc: Alice Ryhl Cc: Andriy Shevchenko Cc: anish kumar Cc: Anna Schumaker Cc: Bartosz Golaszewski Cc: Bjorn Helgaas Cc: Borislav Betkov Cc: Chanwoo Choi Cc: Chen Ridong Cc: Chris Li Cc: Christian Brauner Cc: Daniel Wagner Cc: Danilo Krummrich Cc: Dan Williams Cc: David Hildenbrand Cc: David Jeffery Cc: David Rientjes Cc: Greg Kroah-Hartman Cc: Guixin Liu Cc: "H. Peter Anvin" Cc: Hugh Dickins Cc: Ilpo Järvinen Cc: Ingo Molnar Cc: Ira Weiny Cc: Jann Horn Cc: Jason Gunthorpe Cc: Jens Axboe Cc: Joanthan Cameron Cc: Joel Granados Cc: Johannes Weiner Cc: Jonathan Corbet Cc: Lennart Poettering Cc: Leon Romanovsky Cc: Leon Romanovsky Cc: Lukas Wunner Cc: Marc Rutland Cc: Masahiro Yamada Cc: Matthew Maurer Cc: Miguel Ojeda Cc: Myugnjoo Ham Cc: Parav Pandit Cc: Pratyush Yadav Cc: Randy Dunlap Cc: Roman Gushchin Cc: Saeed Mahameed Cc: Samiullah Khawaja Cc: Song Liu Cc: Steven Rostedt Cc: Stuart Hayes Cc: Tejun Heo Cc: Thomas Gleinxer Cc: Thomas Weißschuh Cc: Vincent Guittot Cc: William Tu Cc: Yoann Congal Cc: Zhu Yanjun Cc: Zijun Hu Signed-off-by: Andrew Morton List of files: /linux/kernel/liveupdate/Makefile

9e2fd062fa1713a33380cc97ef324d086dd45ba5 - liveupdate: luo_core: Live Update Orchestrator

Tue, 25 Nov 2025 17:58:31 +0100

liveupdate: luo_core: Live Update OrchestratorPatch series "Live Update Orchestrator", v8.This series introduces the Live Update Orchestrator, a kernel subsystemdesigned to facilitate live kernel updates using a kexec-based reboot. This capability is critical for cloud environments, allowing hypervisorsto be updated with minimal downtime for running virtual machines. LUOachieves this by preserving the state of selected resources, such asmemory, devices and their dependencies, across the kernel transition.As a key feature, this series includes support for preserving memfd filedescriptors, which allows critical in-memory data, such as guest RAM orany other large memory region, to be maintained in RAM across the kexecreboot.The other series that use LUO, are VFIO [1], IOMMU [2], and PCI [3]preservations.Github repo of this series [4].The core of LUO is a framework for managing the lifecycle of preservedresources through a userspace-driven interface. Key features include:- Session Management Userspace agent (i.e. luod [5]) creates named sessions, each represented by a file descriptor (via centralized agent that controls /dev/liveupdate). The lifecycle of all preserved resources within a session is tied to this FD, ensuring automatic kernel cleanup if the controlling userspace agent crashes or exits unexpectedly.- File Preservation A handler-based framework allows specific file types (demonstrated here with memfd) to be preserved. Handlers manage the serialization, restoration, and lifecycle of their specific file types.- File-Lifecycle-Bound State A new mechanism for managing shared global state whose lifecycle is tied to the preservation of one or more files. This is crucial for subsystems like IOMMU or HugeTLB, where multiple file descriptors may depend on a single, shared underlying resource that must be preserved only once.- KHO Integration LUO drives the Kexec Handover framework programmatically to pass its serialized metadata to the next kernel. The LUO state is finalized and added to the kexec image just before the reboot is triggered. In the future this step will also be removed once stateless KHO is merged [6].- Userspace Interface Control is provided via ioctl commands on /dev/liveupdate for creating and retrieving sessions, as well as on session file descriptors for managing individual files.- Testing The series includes a set of selftests, including userspace API validation, kexec-based lifecycle tests for various session and file scenarios, and a new in-kernel test module to validate the FLB logic.Introduce LUO, a mechanism intended to facilitate kernel updates whilekeeping designated devices operational across the transition (e.g., viakexec). The primary use case is updating hypervisors with minimaldisruption to running virtual machines. For userspace side of hypervisorupdate we have copyless migration. LUO is for updating the kernel.This initial patch lays the groundwork for the LUO subsystem.Further functionality, including the implementation of state transitionlogic, integration with KHO, and hooks for subsystems and filedescriptors, will be added in subsequent patches.Create a character device at /dev/liveupdate.A new uAPI header, , will define the necessarystructures. The magic number for IOCTL is registered inDocumentation/userspace-api/ioctl/ioctl-number.rst.Link: https://lkml.kernel.org/r/20251125165850.3389713-1-pasha.tatashin@soleen.comLink: https://lkml.kernel.org/r/20251125165850.3389713-2-pasha.tatashin@soleen.comLink: https://lore.kernel.org/all/20251018000713.677779-1-vipinsh@google.com/ [1]Link: https://lore.kernel.org/linux-iommu/20250928190624.3735830-1-skhawaja@google.com [2]Link: https://lore.kernel.org/linux-pci/20250916-luo-pci-v2-0-c494053c3c08@kernel.org [3]Link: https://github.com/googleprodkernel/linux-liveupdate/tree/luo/v8 [4]Link: https://tinyurl.com/luoddesign [5]Link: https://lore.kernel.org/all/20251020100306.2709352-1-jasonmiu@google.com [6]Link: https://lore.kernel.org/all/20251115233409.768044-1-pasha.tatashin@soleen.com [7]Link: https://github.com/soleen/linux/blob/luo/v8b03/diff.v7.v8 [8]Signed-off-by: Pasha Tatashin Reviewed-by: Pratyush Yadav Reviewed-by: Mike Rapoport (Microsoft) Tested-by: David Matlack Cc: Aleksander Lobakin Cc: Alexander Graf Cc: Alice Ryhl Cc: Andriy Shevchenko Cc: anish kumar Cc: Anna Schumaker Cc: Bartosz Golaszewski Cc: Bjorn Helgaas Cc: Borislav Betkov Cc: Chanwoo Choi Cc: Chen Ridong Cc: Chris Li Cc: Christian Brauner Cc: Daniel Wagner Cc: Danilo Krummrich Cc: Dan Williams Cc: David Hildenbrand Cc: David Jeffery Cc: David Rientjes Cc: Greg Kroah-Hartman Cc: Guixin Liu Cc: "H. Peter Anvin" Cc: Hugh Dickins Cc: Ilpo Järvinen Cc: Ingo Molnar Cc: Ira Weiny Cc: Jann Horn Cc: Jason Gunthorpe Cc: Jens Axboe Cc: Joanthan Cameron Cc: Joel Granados Cc: Johannes Weiner Cc: Jonathan Corbet Cc: Lennart Poettering Cc: Leon Romanovsky Cc: Leon Romanovsky Cc: Lukas Wunner Cc: Marc Rutland Cc: Masahiro Yamada Cc: Matthew Maurer Cc: Miguel Ojeda Cc: Myugnjoo Ham Cc: Parav Pandit Cc: Randy Dunlap Cc: Roman Gushchin Cc: Saeed Mahameed Cc: Samiullah Khawaja Cc: Song Liu Cc: Steven Rostedt Cc: Stuart Hayes Cc: Tejun Heo Cc: Thomas Gleinxer Cc: Thomas Weißschuh Cc: Vincent Guittot Cc: William Tu Cc: Yoann Congal Cc: Zijun Hu Cc: Pratyush Yadav Cc: Zhu Yanjun Signed-off-by: Andrew Morton List of files: /linux/kernel/liveupdate/Makefile

48a1b2321d763b5edeaf20bd4576d8c4b5df772b - liveupdate: kho: move to kernel/liveupdate

Sat, 01 Nov 2025 15:23:23 +0100

liveupdate: kho: move to kernel/liveupdateMove KHO to kernel/liveupdate/ in preparation of placing all Live Updatecore kernel related files to the same place.[pasha.tatashin@soleen.com: disable the menu when DEFERRED_STRUCT_PAGE_INIT] Link: https://lkml.kernel.org/r/CA+CK2bAvh9Oa2SLfsbJ8zztpEjrgr_hr-uGgF1coy8yoibT39A@mail.gmail.comLink: https://lkml.kernel.org/r/20251101142325.1326536-8-pasha.tatashin@soleen.comSigned-off-by: Pasha Tatashin Reviewed-by: Jason Gunthorpe Reviewed-by: Mike Rapoport (Microsoft) Cc: Alexander Graf Cc: Changyuan Lyu Cc: Christian Brauner Cc: Jason Gunthorpe Cc: Jonathan Corbet Cc: Masahiro Yamada Cc: Miguel Ojeda Cc: Pratyush Yadav Cc: Randy Dunlap Cc: Simon Horman Cc: Tejun Heo Cc: Zhu Yanjun Signed-off-by: Andrew Morton List of files: /linux/kernel/liveupdate/Makefile