Live updating a virtual machine virtualizing physical resources

A computer program product for live updating a virtual machine, the computer program product comprising:

• one or more computer readable storage media, and program instructions collectively stored on the one or more computer readable storage media, the stored program instructions comprising:
• program instructions to instantiate, for a first virtual machine (VM) executing in a physical machine, a second VM in the physical machine, the first VM using a physical adapter installed in the physical machine, the first VM virtualizing a portion of physical memory of the physical machine, the second VM virtualizing the physical adapter;
• program instructions to deploy, using a memory mapping virtualizing the portion of physical memory, the second VM;
• program instructions to checkpoint an application executing in the first VM, the checkpointing generating application state data of the application, the application state data including data necessary to restart the application from a point at which the application was checkpointed;
• program instructions to execute the application in the second VM using the application state data, wherein using the application state data avoids starting the application from an initial configuration state in the second VM;
• program instructions to update, in the second VM, the applications process data reference associated with the memory mapping, wherein the application process data references data stored in the portion of physical memory and the updating instructing the application to use the memory mapping;
• program instructions to intercept, by a page fault handler in the second VM, and responsive to the application in the second VM making an outdated reference to the first VM's virtualization of the portion of the physical memory prior to a completion of the updating the applications process data reference to the memory mapping;
• and
• program instructions to access, by the page fault handler, the portion of the physical memory using a corresponding reference from the second VM's memory mapping without moving data from the portion of the physical memory.

A computer system comprising one or more processors, one or more computer-readable memories, and one or more computer-readable storage devices, and program instructions stored on at least one of the one or more storage devices for execution by at least one of the one or more processors via at least one of the one or more memories, the stored program instructions comprising:

• program instructions to instantiate, for a first virtual machine (VM) executing in a physical machine, a second VM in the physical machine, the first VM using a physical adapter installed in the physical machine, the first VM virtualizing a portion of physical memory of the physical machine, the second VM virtualizing the physical adapter;
• program instructions to deploy, using a memory mapping virtualizing the portion of physical memory, the second VM;
• program instructions to checkpoint an application executing in the first VM, the checkpointing generating application state data of the application, the application state data including data necessary to restart the application from a point at which the application was checkpointed;
• program instructions to execute the application in the second VM using the application state data, wherein using the application state data avoids starting the application from an initial configuration state in the second VM;
• program instructions to update, in the second VM, the applications process data reference associated with the memory mapping, wherein the application process data references data stored in the portion of physical memory and the updating instructing the application to use the memory mapping;
• program instructions to intercept, by a page fault handler in the second VM, and responsive to the application in the second VM making an outdated reference to the first VM's virtualization of the portion of the physical memory prior to a completion of the updating, the applications process data reference to the memory mapping;
• and
• program instructions to access, by the page fault handler, the portion of the physical memory using a corresponding reference from the second VM's memory mapping without moving data from the portion of the physical memory.