Abstract: Input/output (I/O) operation requests from pageable storage mode guests are interpreted without host intervention. In a pageable mode virtual environment, requests issued by pageable storage mode guests are processed by one or more processors of the environment absent intervention from one or more hosts of the environment. Processing of the requests includes manipulating, by at least one processor on behalf of the guests, buffer state information stored in host storage. The manipulating is performed via instructions initiated by the guests and processed by one or more of the processors.

Abstract: A method, system and program product for managing assignment of virtual physical addresses. The method includes requesting, using a services function provided by a virtual machine operating system, a MAC address assignment for a real device and searching, in a MAC assignment table created and stored within a virtual memory space, to determine whether or not an explicit MAC address is assigned to the device. If an explicit MAC address is determined to be assigned to the device, retrieving the explicit MAC address upon verifying that the MAC address is not in use by another device and forwarding, using the services function, the explicit MAC address retrieved for assignment to the real device. If an explicit MAC address is not assigned to the device, retrieving an available MAC address from a MAC address pool table and forwarding the available MAC address retrieved for assignment to the real device.

Abstract: A data connection of a shared resource is placed in isolation mode to remove its ability to communicate with other data connections of the shared resource. This ability to isolate the data connection is dynamic in that it can be turned on/off at any time. This provides increased data security for the entities using the data connection.

Abstract: A method, system and program product for managing assignment of virtual physical addresses. The method includes requesting, using a services function provided by a virtual machine operating system, a MAC address assignment for a real device and searching, in a MAC assignment table created and stored within a virtual memory space, to determine whether or not an explicit MAC address is assigned to the device. If an explicit MAC address is determined to be assigned to the device, retrieving the explicit MAC address upon verifying that the MAC address is not in use by another device and forwarding, using the services function, the explicit MAC address retrieved for assignment to the real device. If an explicit MAC address is not assigned to the device, retrieving an available MAC address from a MAC address pool table and forwarding the available MAC address retrieved for assignment to the real device.

Abstract: Input/output interruptions are managed in computing environments that do not use dedicated per-guest interruption hardware to present interruptions. Dispatchable guest programs in the environment receive I/O interruptions directly without hypervisor intervention. This is facilitated by using one or more interruption controls stored in memory and associated with each guest program. For those guest programs that are not currently dispatchable, interruptions can be posted for the guests and notifications to the hypervisor can be aggregated. The hypervisor can then process a plurality of notifications for the plurality of guests in a single invocation.

Abstract: Input/output interruptions are managed in computing environments that do not use dedicated per-guest interruption hardware to present interruptions. Dispatchable guest programs in the environment receive I/O interruptions directly without hypervisor intervention. This is facilitated by using one or more interruption controls stored in memory and associated with each guest program. For those guest programs that are not currently dispatchable, interruptions can be posted for the guests and notifications to the hypervisor can be aggregated. The hypervisor can then process a plurality of notifications for the plurality of guests in a single invocation.

Abstract: Input/output interruptions are managed in computing environments that do not use dedicated per-guest interruption hardware to present interruptions. Dispatchable guest programs in the environment receive I/O interruptions directly without hypervisor intervention. This is facilitated by using one or more interruption controls stored in memory and associated with each guest program. For those guest programs that are not currently dispatchable, interruptions can be posted for the guests and notifications to the hypervisor can be aggregated. The hypervisor can then process a plurality of notifications for the plurality of guests in a single invocation.

Abstract: A method for communicating from a first virtual machine, defined by a virtual machine operating system, to an external device via a local area network (LAN). The virtual machine operating system also defines other virtual machines and a base portion common to all of the virtual machines. The first virtual machine writes an IP datagram to an output buffer allocated to the first virtual machine. The IP datagram comprises data and a destination IP address associated with the external device. The program functions in the base portion read the IP datagram from the output buffer to determine the destination IP address and then copy the IP datagram from the output buffer into storage allocated to the common base portion whereby the IP datagram passes from the first virtual machine into the common base portion storage without passing through any other virtual machines. Then, the program functions request a tangible adapter card for the network to send the IP datagram to the IP destination address.

Abstract: Input/output interruptions are managed in computing environments that do not use dedicated per-guest interruption hardware to present interruptions. Dispatchable guest programs in the environment receive I/O interruptions directly without hypervisor intervention. This is facilitated by using one or more interruption controls stored in memory and associated with each guest program. For those guest programs that are not currently dispatchable, interruptions can be posted for the guests and notifications to the hypervisor can be aggregated. The hypervisor can then process a plurality of notifications for the plurality of guests in a single invocation.

Abstract: A method for communicating from a first virtual machine, defined by a virtual machine operating system, to an external device via a local area network (LAN). The virtual machine operating system also defines other virtual machines and a base portion common to all of the virtual machines. The first virtual machine writes an IP datagram to an output buffer allocated to the first virtual machine. The IP datagram comprises data and a destination IP address associated with the external device. The program functions in the base portion read the IP datagram from the output buffer to determine the destination IP address and then copy the IP datagram from the output buffer into storage allocated to the common base portion whereby the IP datagram passes from the first virtual machine into the common base portion storage without passing through any other virtual machines. Then, the program functions request a tangible adapter card for the network to send the IP datagram to the IP destination address.

Abstract: Input/output interruptions are managed in computing environments that do not use dedicated per-guest interruption hardware to present interruptions. Dispatchable guest programs in the environment receive I/O interruptions directly without hypervisor intervention. This is facilitated by using one or more interruption controls stored in memory and associated with each guest program. For those guest programs that are not currently dispatchable, interruptions can be posted for the guests and notifications to the hypervisor can be aggregated. The hypervisor can then process a plurality of notifications for the plurality of guests in a single invocation.

Abstract: A method for communicating from a first virtual machine, defined by a virtual machine operating system, to an external device via a local area network (LAN). The virtual machine operating system also defines other virtual machines and a base portion common to all of the virtual machines. The first virtual machine writes an IP datagram to an output buffer allocated to the first virtual machine. The IP datagram comprises data and a destination IP address associated with the external device. The program functions in the base portion read the IP datagram from the output buffer to determine the destination IP address and then copy the IP datagram from the output buffer into storage allocated to the common base portion whereby the IP datagram passes from the first virtual machine into the common base portion storage without passing through any other virtual machines. Then, the program functions request a tangible adapter card for the network to send the IP datagram to the IP destination address.

Abstract: Input/output interruptions are managed in computing environments that do not use dedicated per-guest interruption hardware to present interruptions. Dispatchable guest programs in the environment receive I/O interruptions directly without hypervisor intervention. This is facilitated by using one or more interruption controls stored in memory and associated with each guest program. For those guest programs that are not currently dispatchable, interruptions can be posted for the guests and notifications to the hypervisor can be aggregated. The hypervisor can then process a plurality of notifications for the plurality of guests in a single invocation.

Abstract: Method and means to provide a mechanism by which a hypervisor can permit a real machine to interpretively execute certain I/O instructions independently of the value of an I-bit in the subchannel. This is necessary as the I-bit covers all I/O instructions that can be interpretively executed; however, there can be instances where the hypervisor cannot allow the interpretive execution of other I/O instructions but can permit the interpretive execution of the SIGA instruction.

Abstract: This invention describes a method and system for virtualizing an internal capability of a computing system; specifically, the invention describes a method and system for establishing a virtual machine containing a programmed hardware-machine function that is normally executed natively as proprietary internal code in its own hardware environment, a Central Electronics Complex (CEC) or logical partition of a CEC. The code resides in a separate hardware domain of the CEC called the Service Element (SE). The IBM VM/ESA (VM) operating system requests the SE to transfer a copy of the code into a virtual machine that VM has initialized, where the machine function is provided (in the current embodiment) as an isolated and encapsulated part of a virtual Parallel Sysplex system comprising multiple virtual CECs in a testing environment.

Abstract: A method and an apparatus for simulation of data in a computing system environment having a controlling program, a main memory, a plurality of hosts, at least one adapter and a queued-direct input/output device using a queued-direct input/output protocol. A pageable virtual machine is provided under control of a virtual-machine hypervisor in processing communication with one or more hosts. Simulation is then provided by strictly separating a set of protocol control blocks between those that contain main-memory addresses and those that do not. Copies of those control blocks that contain main-memory addresses is created and their addresses converted by the hypervisor from addresses used by the program in its virtual machine to real-memory addresses usable by the adapter.

Abstract: A method and an apparatus for controlling movement of data between any host and any network including a set of devices in a computing system environment having a main memory with a queuing mechanism having a plurality of queues capable of being shared between a plurality of independent processes running on at least one host and at least one I/O adapter. A finite-state machine (FSM) is provided in the main memory and the FSM is divided into two disjoint sets of states, one of which represents state-values processed by the host and set by the adapter, and said other set represents state-values processed by the adapter and set by said host. Using each of these set of states free-running, non-deadlocking processes are provided within the host and the adapter so that the processes sequence circularly and continuously through a vector related to the FSMs.

Abstract: This invention describes a method and system for virtualizing an internal capability of a computing system; specifically, the invention describes a method and system for establishing a virtual machine containing a programmed hardware-machine function that is normally executed natively as proprietary internal code in its own hardware environment, a Central Electronics Complex (CEC) or logical partition of a CEC. The code resides in a separate hardware domain of the CEC called the Service Element (SE). The IBM VM/ESA (VM) operating system requests the SE to transfer a copy of the code into a virtual machine that VM has initialized, where the machine function is provided (in the current embodiment) as an isolated and encapsulated part of a virtual Parallel Sysplex system comprising multiple virtual CECs in a testing environment.