Kernel Soft Reset Preserving User Context
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Solution Overview
Problem
Current computing systems face challenges in updating kernels without losing user context, as traditional reboot methods destroy user context and are time-consuming, involving power on self-tests and platform reinitialization, which affects uptime and availability.
Innovation Solution
The implementation of a kernel soft reset (KSR) technology, which allows updating the kernel without losing user context by loading a new kernel image into volatile memory, initializing its data structures, and passing control to it while preserving the user context, thus avoiding full reboot operations and power on self-tests.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Reliability
If a traditional reboot is performed to update the kernel, then the kernel is updated to a new version, but the user context is lost and system downtime increases
Solution Approach 1:
The patent segments the reboot process into distinct phases: saving user context to non-volatile memory, resetting the kernel, and restoring user context. This allows the kernel to be updated while preserving user applications and data, eliminating the need for a complete system reboot and reducing downtime.
Solution Approach 2:
The patent performs preliminary actions by saving user context to non-volatile memory before the kernel reset occurs. This preparatory step ensures that user context is preserved and can be quickly restored after the kernel update, avoiding the time-consuming process of reloading user applications from scratch.
2Reliability
If a cold reset is performed to update firmware, then firmware is updated, but memory contents are cleared and platform hardware must be fully re-initialized
Solution Approach 1:
The patent extracts user context from volatile memory and stores it in non-volatile memory before the firmware update process. This separation allows the kernel to be reset and firmware to be updated while user context remains preserved in non-volatile storage, enabling faster recovery and maintaining system availability.
3Reliability
If power on self-tests and platform initialization are performed during kernel update, then system stability is ensured, but update time increases significantly
Solution Approach 1:
The patent applies partial action by performing only the necessary kernel reset operations without executing the complete power on self-test and platform initialization sequence. Since user context is preserved in non-volatile memory, full system re-initialization is unnecessary, allowing the update to proceed faster while maintaining adequate system stability through selective re-initialization of only critical components.
Data Source
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AI summary
Technologies are described which permit kernel updates or firmware fixes, and include re-initialization of kernel data structures, without losing user context information that has been created by services, virtual machines, or user applications. Tailored code in a server or other computing system sets a kernel soft reset (KSR) indicator and saves the user context to non-volatile storage. When a KSR is underway, boot code skips the power on self-test and similar initializations (thereby reducing downtime), loads a kernel image, initializes kernel data structures, restores the user context, and passes control to the initialized kernel to continue computing system operation with the same user context. Device drivers may also be re-initialized. The loaded kernel may use newly fixed firmware, or may have a security patch installed, for instance. The non-volatile storage may operate at RAM speed, e.g., it may include NVDIMM memory. The kernel may be validated before receiving control.