Abstract: A system, a method, and a computer program product for secure memory implementation for secure execution of virtual machines. Data is processed in a first mode and a second mode, and commands are sent to a chip interconnect bus using real addresses, wherein the chip interconnect bus transports a number of bits for the real addresses. A memory controller is operatively coupled to a memory component. A secure memory range is specified by using range registers. If the real address is detected to be in the secure memory range to match a memory component address, a real address bit is set. If the real address is in the memory address hole, a security access violation is detected. If the real address is not in the secure address range and the real address bit is set, the security access violation is detected.

Abstract: An integrated circuit includes a first communication interface for communicatively coupling the integrated circuit with a coherent data processing system, a second communication interface for communicatively coupling the integrated circuit with an accelerator unit including an accelerator functional unit and an effective address-based accelerator cache for buffering copies of data from the system memory of the coherent data processing system, and a real address-based directory inclusive of contents of the accelerator cache. The real address-based directory assigns entries based on real addresses utilized to identify storage locations in the system memory.

Abstract: An integrated circuit for a coherent data processing system includes a first communication interface for communicatively coupling the integrated circuit with the coherent data processing system, a second communication interface for communicatively coupling the integrated circuit with an accelerator unit including an effective address-based accelerator cache for buffering copies of data from a system memory of the coherent data processing system, and a real address-based directory inclusive of contents of the accelerator cache. The real address-based directory assigns entries based on real addresses utilized to identify storage locations in the system memory. The integrated circuit further includes request logic that communicates memory access requests and request responses with the accelerator unit via the second communication interface.

Abstract: An integrated circuit includes a first communication interface for communicatively coupling the integrated circuit with a coherent data processing system, a second communication interface for communicatively coupling the integrated circuit with an accelerator unit including an effective address-based accelerator cache for buffering copies of data from a system memory, and a real address-based directory inclusive of contents of the accelerator cache. The real address-based directory assigns entries based on real addresses utilized to identify storage locations in the system memory. The integrated circuit further includes request logic that communicates memory access requests and request responses with the accelerator unit.

Abstract: An integrated circuit includes a first communication interface for communicatively coupling the integrated circuit with a coherent data processing system, a second communication interface for communicatively coupling the integrated circuit with an accelerator unit including an effective address-based accelerator cache for buffering copies of data from a system memory, and a real address-based directory inclusive of contents of the accelerator cache. The real address-based directory assigns entries based on real addresses utilized to identify storage locations in the system memory. The integrated circuit further includes directory control logic that configures at least a number of congruence classes utilized in the real address-based directory based on configuration parameters specified on behalf of or by the accelerator unit.

Abstract: A technique for operating a data processing system includes transitioning, by a cache, to a highest point of coherency (HPC) for a cache line in a required state without receiving data for one or more segments of the cache line that are needed. The cache issues a command to a lowest point of coherency (LPC) that requests data for the one or more segments of the cache line that were not received and are needed. The cache receives the data for the one or more segments of the cache line from the LPC that were not previously received and were needed.

Abstract: Managing lowest point of coherency (LPC) memory using a service layer adapter, the adapter coupled to a processor and an accelerator on a host computing system, the processor configured for symmetric multi-processing, including receiving, by the adapter, a memory access instruction from the accelerator; retrieving, by the adapter, a real address for the memory access instruction; determining, using base address registers on the adapter, that the real address targets the LPC memory, wherein the base address registers direct memory access requests between the LPC memory and other memory locations on the host computing system; and sending, by the adapter, the memory access instruction and the real address to a media controller for the LPC memory, wherein the media controller for the LPC memory is attached to the adapter via a memory interface.

Abstract: A data processing system includes first and second coherency domains and employs a snoop-based coherence protocol. In response to receipt by the first coherency domain of a memory access request originating from a master in the second coherency domain, a plurality of coherence participants in the first coherency domain provides partial responses for the memory access request to an early combined response generator. Based on the partial responses, the early combined response generator generates and transmits, to a memory controller of a system memory in the first coherency domain, an early combined response of only the first coherency domain. Based on the early combined response, the memory controller transmits, to the master prior to receipt by the memory controller of a systemwide combined response for the memory access request, data associated with a target memory address and/or coherence permission for the target memory address.

Abstract: A cache coherent data processing system includes at least non-overlapping first, second, and third coherency domains. A master in the first coherency domain of the cache coherent data processing system selects a scope of an initial broadcast of an interconnect operation from among a set of scopes including (1) a remote scope including both the first coherency domain and the second coherency domain, but excluding the third coherency domain that is a peer of the first coherency domain, and (2) a local scope including only the first coherency domain. The master then performs an initial broadcast of the interconnect operation within the cache coherent data processing system utilizing the selected scope, where performing the initial broadcast includes the master initiating broadcast of the interconnect operation within the first coherency domain.

Abstract: A data processing system includes first and second coherency domains and employs a snoop-based coherence protocol. In response to receipt by the first coherency domain of a memory access request originating from a master in the second coherency domain, a plurality of coherence participants in the first coherency domain provides partial responses for the memory access request to an early combined response generator. Based on the partial responses, the early combined response generator generates and transmits, to a memory controller of a system memory in the first coherency domain, an early combined response of only the first coherency domain. Based on the early combined response, the memory controller transmits, to the master prior to receipt by the memory controller of a systemwide combined response for the memory access request, data associated with a target memory address and/or coherence permission for the target memory address.

Abstract: In response to receipt by a first coherency domain of a memory access request originating from a master in a second coherency domain and excluding from its scope a third coherency domain, coherence participants in the first coherency domain provide partial responses, and one of the coherence participants speculatively provides, to the master, data from a target memory block. The data includes a memory domain indicator indicating whether the memory block is cached, if at all, only within the first coherency domain. Based on the partial responses a combined response is generated representing a systemwide coherence response to the memory access request. In response to the combined response indicating success and the memory domain indicator indicating that a valid copy of the memory block may be cached outside the first coherence domain, the master discards the speculatively provided data and reissues the memory access request with a larger broadcast scope.

Abstract: An embodiment involves secure memory implementation for secure execution of virtual machines. Data is processed in a first mode and a second mode, and commands are sent to a chip interconnect bus using real addresses, wherein the chip interconnect bus includes a number of bits for the real addresses. A memory controller is operatively coupled to a memory component. A secure memory range is specified by using range registers. If the real address is detected to be in the secure memory range to match a memory component address, a real address bit is set. If the real address is in the memory address hole, a security access violation is detected. If the real address is not in the secure address range and the real address bit is set, the security access violation is detected.

Abstract: A technique for operating a data processing system that implements a split transaction coherency protocol that has an address tenure and a data tenure includes receiving, at a data source, a command (that includes an address tenure for requested data) that is issued from a data sink. The data source issues a response that indicates data associated with the address tenure is available to be transferred to the data sink during a data tenure. In response to determining that the data is available subsequent to issuing the response, the data source issues a first data packet to the data sink that includes the data during the data tenure. In response to determining that the data is not available subsequent to issuing the response, the data source issues a second data packet to the data sink that includes a data header that indicates the data is unavailable.

Abstract: An integrated circuit includes a transmitting circuit configured to be coupled to a physical serial interface having a bit width. The transmitting circuit is configured to transmit, via the physical serial interface, a frame including multiple aligned flits all of an equal fixed length that is an integer multiple of the bit width of the physical serial interface. The multiple flits include both a control flit specifying at least a command to be performed by a recipient of the command and a data flit providing data to be operated upon through performance of the command. The control flit includes a data protection code computed over the control flit and a data flit of a previously transmitted frame.

Abstract: Reducing translation latency within a memory management unit (MMU) using external caching structures including requesting, by the MMU on a node, page table entry (PTE) data and coherent ownership of the PTE data from a page table in memory; receiving, by the MMU, the PTE data, a source flag, and an indication that the MMU has coherent ownership of the PTE data, wherein the source flag identifies a source location of the PTE data; performing a lateral cast out to a local high-level cache on the node in response to determining that the source flag indicates that the source location of the PTE data is external to the node; and directing at least one subsequent request for the PTE data to the local high-level cache.

Abstract: Reducing translation latency within a memory management unit (MMU) using external caching structures including requesting, by the MMU on a node, page table entry (PTE) data and coherent ownership of the PTE data from a page table in memory; receiving, by the MMU, the PTE data, a source flag, and an indication that the MMU has coherent ownership of the PTE data, wherein the source flag identifies a source location of the PTE data; performing a lateral cast out to a local high-level cache on the node in response to determining that the source flag indicates that the source location of the PTE data is external to the node; and directing at least one subsequent request for the PTE data to the local high-level cache.

Abstract: A serial communication system includes a transmitting circuit for serially transmitting data via a serial communication link including N channels where N is an integer greater than 1. The transmitting circuit includes an input buffer having storage for input data frames each including M bytes forming N segments of M/N contiguous bytes. The transmitting circuit additionally includes a reordering circuit coupled to the input buffer. The reordering circuit includes a reorder buffer including multiple entries. The reordering circuit buffers, in each of multiple entries of the reorder buffer, a byte in a common byte position in each of the N segments of an input data frame. The reordering circuit sequentially outputs the contents of the entries of the reorder buffer via the N channels of the serial communication link.

Abstract: A set-associative cache memory includes a plurality of ways and a plurality of congruence classes. Each of the plurality of congruence classes includes a plurality of members each belonging to a respective one of the plurality of ways. In the cache memory, a data structure records a history of an immediately previous N ways from which cache lines have been evicted. In response to receipt of a memory access request specifying a target address, a selected congruence class among a plurality of congruence classes is selected based on the target address. At least one member of the selected congruence class is removed as a candidate for selection for victimization based on the history recorded in the data structure, and a member from among the remaining members of the selected congruence class is selected. The cache memory then evicts the victim cache line cached in the selected member of the selected congruence class.

Abstract: A technique for operating a data processing system includes transitioning, by a cache, to a highest point of coherency (HPC) for a cache line in a required state without receiving data for one or more segments of the cache line that are needed. The cache issues a command to a lowest point of coherency (LPC) that requests data for the one or more segments of the cache line that were not received and are needed. The cache receives the data for the one or more segments of the cache line from the LPC that were not previously received and were needed.

Abstract: Secure memory implementation for secure execution of virtual machines. Data is processed in a first mode and a second mode, and commands are sent to a chip interconnect bus using real addresses, wherein the chip interconnect bus includes a number of bits for the real addresses. A memory controller is operatively coupled to a memory component. A secure memory range is specified by using range registers. If the real address is detected to be in the secure memory range to match a memory component address, a real address bit is inverted. If the real address is in the secure memory address hole, a security access violation is detected. If the real address is not in the secure address range and the real address bit is set, the security access violation is detected.