| Age | Commit message (Collapse) | Author | |
|---|---|---|---|
| 2025-11-27 | liveupdate: luo_session: add ioctls for file preservation | Pasha Tatashin | |
| Introducing the userspace interface and internal logic required to manage the lifecycle of file descriptors within a session. Previously, a session was merely a container; this change makes it a functional management unit. The following capabilities are added: A new set of ioctl commands are added, which operate on the file descriptor returned by CREATE_SESSION. This allows userspace to: - LIVEUPDATE_SESSION_PRESERVE_FD: Add a file descriptor to a session to be preserved across the live update. - LIVEUPDATE_SESSION_RETRIEVE_FD: Retrieve a preserved file in the new kernel using its unique token. - LIVEUPDATE_SESSION_FINISH: finish session The session's .release handler is enhanced to be state-aware. When a session's file descriptor is closed, it correctly unpreserves the session based on its current state before freeing all associated file resources. Link: https://lkml.kernel.org/r/20251125165850.3389713-8-pasha.tatashin@soleen.com Signed-off-by: Pasha Tatashin <pasha.tatashin@soleen.com> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> 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 <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> | |||
| 2025-11-27 | liveupdate: luo_core: add user interface | Pasha Tatashin | |
| Introduce the user-space interface for the Live Update Orchestrator via ioctl commands, enabling external control over the live update process and management of preserved resources. The idea is that there is going to be a single userspace agent driving the live update, therefore, only a single process can ever hold this device opened at a time. The following ioctl commands are introduced: LIVEUPDATE_IOCTL_CREATE_SESSION Provides a way for userspace to create a named session for grouping file descriptors that need to be preserved. It returns a new file descriptor representing the session. LIVEUPDATE_IOCTL_RETRIEVE_SESSION Allows the userspace agent in the new kernel to reclaim a preserved session by its name, receiving a new file descriptor to manage the restored resources. Link: https://lkml.kernel.org/r/20251125165850.3389713-6-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> | |||
| 2025-11-27 | liveupdate: luo_session: add sessions support | Pasha 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> | |||
| 2025-11-27 | liveupdate: luo_core: Live Update Orchestrator | Pasha Tatashin | |
| Patch series "Live Update Orchestrator", v8. This series introduces the Live Update Orchestrator, a kernel subsystem designed to facilitate live kernel updates using a kexec-based reboot. This capability is critical for cloud environments, allowing hypervisors to be updated with minimal downtime for running virtual machines. LUO achieves this by preserving the state of selected resources, such as memory, devices and their dependencies, across the kernel transition. As a key feature, this series includes support for preserving memfd file descriptors, which allows critical in-memory data, such as guest RAM or any other large memory region, to be maintained in RAM across the kexec reboot. 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 preserved resources 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 while keeping designated devices operational across the transition (e.g., via kexec). The primary use case is updating hypervisors with minimal disruption to running virtual machines. For userspace side of hypervisor update 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 transition logic, integration with KHO, and hooks for subsystems and file descriptors, will be added in subsequent patches. Create a character device at /dev/liveupdate. A new uAPI header, <uapi/linux/liveupdate.h>, will define the necessary structures. The magic number for IOCTL is registered in Documentation/userspace-api/ioctl/ioctl-number.rst. Link: https://lkml.kernel.org/r/20251125165850.3389713-1-pasha.tatashin@soleen.com Link: https://lkml.kernel.org/r/20251125165850.3389713-2-pasha.tatashin@soleen.com Link: 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 <pasha.tatashin@soleen.com> Reviewed-by: Pratyush Yadav <pratyush@kernel.org> 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: 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: Zijun Hu <quic_zijuhu@quicinc.com> Cc: Pratyush Yadav <ptyadav@amazon.de> Cc: Zhu Yanjun <yanjun.zhu@linux.dev> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> | |||
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index : git.armlinux.org.uk/linux-arm.git | |
| Russell King's ARM Linux kernel tree | Russell King |
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