International Business Machines Corporation

Arm Limited

Adam James McNeeney

Paul Knowles

Henry Paul Nash

Matthew Lucien Evans

Gareth James Evans

Bruce Gerard Mealey

Geraint M North

Brian Chase Twichell

Andrew John Turner

Anthony Jebson

David James Oliver Rigby

James Mulcajy

A method and apparatus for simulating target program code on a host data processing apparatus, the simulation mapping load-exclusive instructions in the target program code to load instructions, and mapping store-exclusive instructions in the target program code to compare-and-swap instructions.

Simulation of exclusive instructions

A method is provided for controlling processing of target program code on a host data processing apparatus to simulate processing of the target program code on a target data processing apparatus. In response to a target memory access instruction of the target program code specifying a target address within a simulated address space having a larger size than a host address space supported by a memory management unit of the host data processing apparatus, an address space resizing table is looked up to map the target address to a transformed address within said host address space, and information is generated for triggering a memory access based on translation of the transformed address by the memory management unit of the host data processing apparatus.

Address space resizing table for simulation of processing of target program code on a target data processing apparatus

Provided are a computer program product, system, and method for transferring a virtual machine from a first server to a second server. A first enhanced system translator executing on the first server includes a first virtual machine interface to interface with a first instance of the virtual machine on the first server and a first convert state component. A second enhanced system translator executing on the second server includes a second virtual machine interface to interface with a second instance of the virtual machine and a second convert state component. The first convert state component converts a state of the first instance of the virtual machine to a first instruction set architecture and the second convert state component converts the first instructions set architecture to a second instruction set architecture for use by the second instance of the virtual machine to run on the second server.

Cross architecture virtual machine migration

A technique for operating a group of virtual machines (VMs) includes utilizing a checkpoint procedure to maintain secondary VMs to assume tasks of primary VMs within a cluster in the event of failover. On failover of a first one of the primary VMs, a first one of the secondary VMs assumes the tasks from the checkpoint immediately preceding a failover event. Each of the primary VMs is connected to receive data from remaining ones of the primary VMs via an internal bus and process the data on receipt. Checkpoints for the primary VMs are synchronized. For each of the primary VMs, release to the external bus of data generated on the basis of received internal bus data is prevented until a subsequent checkpoint has occurred. On failover of one of the primary VMs, all of the primary VMs are directed to initiate failover to an associated one of the secondary VMs.

Techniques for virtual machine management

An interrupt controller for controlling the routing and handling of interrupts received at a data processing apparatus including at least one physical processing unit configured to run at least one of a plurality of virtual processors and a memory. The interrupt controller includes redistribution circuitry with at least one data store corresponding to the unit, the data store storing a pointer to a virtual pending table storing currently pending virtual interrupts for a virtual processor currently running on the corresponding unit and a pointer to a pending table configured to store currently pending physical interrupts for the corresponding unit and an input configured to receive a virtual interrupt for interrupting a virtual processor. Control circuitry is configured to add the virtual interrupt to the virtual pending table and to store the virtual interrupt in the virtual pending table for the virtual processor that is stored in the memory.

Handling and routing interrupts to virtual processors

A system, method and computer program for transferring a running virtual machine from a first to a second physical machine, where each of the physical machines has a different instruction set architecture. The system may comprise a receiver for receiving a transfer request. In response to receiving the transfer request, the virtual machine is paused and a state of the virtual machine is collected. A first interface component operable on the first physical machine stopped and a second interface component operable on the second physical machine is started. The state is transferred to the second interface component. The virtual machine is started on the second physical machine in response to the state transfer.

A system, method and computer program for transferring a running virtual machine from a first to a second physical machine, where each of the physical machines has a different instruction set architecture. The system may comprise a receiver for receiving a transfer request; responsive to receiving the transfer request, pausing the virtual machine and collecting a state of the virtual machine. A first interface component operable on the first physical machine is stopped and a second interface component operable on the second physical machine is started. The state is transferred to the second interface component. The the virtual machine on the second physical machine is started in response to the state transfer.

A computer-implemented method of debugging computer code includes: obtaining state information corresponding to a first machine at a checkpoint initiated during execution of the computer code on the first machine; and configuring the second machine to a same operating state as the first machine at the checkpoint to create a mirrored version of the first machine. The method also includes receiving a notification that execution of the program on a first machine has failed, and in response to receiving the notification: triggering a processor of the second machine to initiate execution of a copy of the code from a specific code execution point at which the checkpoint was; activating a debugger module to run concurrently with the execution of the program on the second machine and collect and store the debug data as corresponding to execution failure of the computer code at the first machine.

Checkpoint debugging using mirrored virtual machines

Performing storage writes in a mirrored virtual machine system by receiving a state of a primary virtual machine during execution of an application, wherein the primary virtual machine runs on a first physical machine and a secondary virtual machine runs on a second physical machine, wherein the state is captured by checkpointing, and the primary virtual machine is configured to write data to a first block and concurrently write the data to a write buffer on the secondary virtual machine. The method also includes storing a copy of data within a second block to a rollback buffer for the secondary virtual machine, in response to identifying a checkpoint in the application, merging the rollback buffer with the write buffer, in response to detecting a failover, writing a copy of the rollback buffer to the disk storage, and continuing execution on the secondary virtual machine from the last checkpoint.

Storage writes in a mirrored virtual machine system

A method achieves data consistency in a shared storage accessible by a first and second machine. The method includes, in response to receiving state information of the first machine, configuring the second machine to a mirrored operating state corresponding to an operating state of the first machine, receiving a notification that the first machine will overwrite existing data stored in the shared storage, and, in response to the notification, reading the existing data, storing a copy of existing data in a local storage of the second machine, and sending an acknowledgment to the first machine that the copy has been stored in the local storage, to enable the first machine to overwrite the existing data with newly written data. The method also includes, in response to receiving a failure notification, retrieving the copy of the existing data, overwriting the newly written data with the copy of the existing data.

Maintaining consistency of storage in a mirrored virtual environment

A system of debugging computer code includes a processor: obtaining state information corresponding to a first machine at a checkpoint initiated during execution of the computer code on the first machine; and configuring the second machine to a same operating state as the first machine at the checkpoint to create a mirrored version of the first machine. The system also includes receiving a notification that execution of the program on a first machine has failed, and in response to receiving the notification: triggering a processor of the second machine to initiate execution of a copy of the code from a specific code execution point at which the checkpoint was; activating a debugger module to run concurrently with the execution of the program on the second machine and collect and store the debug data as corresponding to execution failure of the computer code at the first machine.

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Cambridge, United Kingdom

Adam James McNeeney