PCIe Virtual Device Runtime Reconfiguration via Simulated Bus Reset
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Solution Overview
Problem
Current PCIe compliant systems lack the ability to dynamically reconfigure virtual devices at runtime without rebooting the server, limiting flexibility and causing downtime, especially in environments requiring zero downtime or rapid repurposing of servers.
Innovation Solution
The method involves a simulated secondary bus reset mechanism, where a PCIe compliant virtual device is reconfigured by issuing a simulated secondary bus reset, allowing changes to device attributes and configurations without rebooting the server, using a VIC adapter and driver software to manage the reconfiguration process.
Engineering Contradictions & Design Principles
Engineering Contradiction Analysis
1Adaptability or versatility
If a traditional PCIe system is used, then system stability is maintained, but the ability to dynamically reconfigure virtual devices at runtime is lost, causing server downtime
Solution Approach 1:
The patent changes the state parameters of PCIe virtual devices by issuing simulated secondary bus resets, allowing configuration parameters to be modified at runtime without physical device changes or server reboots, thus achieving dynamic reconfiguration while maintaining system availability
Solution Approach 2:
The patent introduces an intermediary mechanism that traps simulated secondary bus reset signals and intercepts configuration space reads/writes, acting as a mediator between the PCIe system and virtual devices to enable runtime reconfiguration without disrupting system operation
2Ease of operation
If the server is rebooted to reconfigure virtual devices, then complete reconfiguration is achieved, but service downtime increases
Solution Approach 1:
The patent performs preliminary actions by trapping the simulated secondary bus reset signal and preparing the configuration space before actually reconfiguring the virtual device, allowing the reconfiguration to proceed smoothly without requiring server reboot and minimizing service interruption
Solution Approach 2:
The patent maintains continuity of useful action by enabling configuration changes to take effect immediately during runtime without interrupting server operation, allowing the system to continue providing services while virtual devices are being reconfigured
3Adaptability or versatility
If virtual device configuration is changed at runtime, then flexibility is improved, but PCIe topology consistency may be compromised
Solution Approach 1:
The patent implements feedback mechanisms where configuration space reads are intercepted and validated, ensuring that any configuration changes maintain PCIe topology consistency and that the reconfigured virtual devices remain properly integrated into the system architecture
Data Source
AI summary
An example method for transformation of Peripheral Component Interconnect Express (PCIe) compliant virtual devices in a server in a network environment is provided and includes receiving, during runtime of the server, a request to change a first configuration of a PCIe compliant virtual device to a different second configuration, identifying a bridge on a PCIe topology below which the virtual device is located, issuing a simulated secondary bus reset to the bridge, the virtual device being reconfigured according to the change in configuration after the simulated secondary bus reset is issued, re-enumerating below the bridge after the change in configuration completes without rebooting the server, and updating the PCI topology with the virtual device in the second configuration. A virtual interface card adapter traps the simulated secondary bus reset, removes the virtual device from the PCI topology, and reconfigures the virtual device from the first configuration to the second configuration.