Methods for read after write forwarding using a virtual address are disclosed. A method includes determining when a virtual address has been remapped from corresponding to a first physical address to a second physical address and determining if all stores occupying a store queue before the remapping have been retired from the store queue. Loads that are younger than the stores that occupied the store queue before the remapping are prevented from being dispatched and executed until the stores that occupied the store queue before the remapping have left the store queue and become globally visible.

The creation, maintenance, and accessing of page tables is done by a virtual machine monitor running on a computing system rather than the guest operating systems. This allows page table walks to be completed in fewer memory accesses when compared to the guest operating system's maintenance of the page tables. In addition, the virtual machine monitor may utilize additional resources to offload page table access and maintenance functions from the CPU to another device, such as a page table management device or page table management node. Offloading some or all page table access and maintenance functions to a specialized device or node enables the CPU to perform other tasks during page table walks and/or other page table maintenance functions.

A data storage system includes a memory including a plurality of memory cells; and control logic configured to receive a first data string and determine a data type of the first data string. If the first data string is a combination command, the control logic obtains a plurality of sub-commands based on the first data string. Meanwhile, the control logic receives a second data string, determines that it represents an address, and decodes the address. While decoding the address or otherwise processing the second data string, the control logic performs a system operation specified by one of the sub-commands. The control logic also performs a memory operation, specified by another of the sub-commands, on one or more of the plurality of memory cells in accordance with the decoded address.

Systems, methods, and apparatuses relating to circuitry to implement a pipelined out of order page miss handler are described. In one embodiment, a hardware processor core includes an execution circuit to generate data storage requests for virtual addresses, a translation lookaside buffer to translate the virtual addresses to physical addresses, and a single page miss handler circuit comprising a plurality of pipelined page walk stages, wherein the single page miss handler circuit is to contemporaneously perform a first page walk within a first stage of the plurality of pipelined page walk stages for a first miss of a first virtual address in the translation lookaside buffer, and a second page walk within a second stage of the plurality of pipelined page walk stages for a second miss of a second virtual address in the translation lookaside buffer.

A method includes receiving a memory access request comprising a first memory address and translating the first memory address to a second memory address using a first page table associated with the first virtual machine. The first page table indicates whether the memory of the first virtual machine is encrypted. The method further includes determining that the first virtual machine is nested within a second virtual machine and translating the second memory address to a third memory address using a second page table associated with the second virtual machine. The second page table indicates whether the memory of the second virtual machine is encrypted.

A processor includes a page table walk cache that stores address translation information, and a page table walker. The page table walker fetches first output addresses indicated by first indexes of a first input address by looking up the address translation information and at least a part of page tables, and compares a matching level between second indexes of a second input address and the first indexes of the first input address with a walk cache hit level obtained by looking up the page table walk cache using the second indexes.

A method for testing an integrated circuit, comprising: accessing a database associated with a test template, wherein said test template is configured to test a selected function of the integrated circuit; storing, in said database, data corresponding to at least partial predicted results of one or more random instruction sequences generated based on said test template; generating, by an automated test generation tool, a random instruction sequence based on said test template; executing said instruction sequence by a hardware exerciser, in the integrated circuit; and comparing results of said instruction sequence with said at least partial predicted results, to verify a function of said integrated circuit.

An apparatus and method is provided, the apparatus comprising a processor pipeline to execute instructions, a cache structure to store information for reference by the processor pipeline when executing said instructions; and pref etch circuitry to issue prefetch requests to the cache structure to cause the cache structure to prefetch information into the cache structure in anticipation of a demand request for that information being issued to the cache structure by the processor pipeline. The processor pipeline is arranged to issue a trigger to the prefetch circuitry on detection of a given event that will result in a reduced level of demand requests being issued by the processor pipeline, and the prefetch circuitry is configured to control issuing of pref etch requests in dependence on reception of the trigger.

Methods, systems, and apparatuses provide support for multiple address spaces in order to facilitate data movement. One apparatus includes an input/output memory management unit (IOMMU) comprising: a plurality of memory-mapped input/output (MMIO) registers that map memory address spaces belonging to the IOMMU and at least a second IOMMU; and hardware control logic operative to: synchronize the plurality of MMIO registers of the at least the second IOMMU; receive, from a peripheral component endpoint coupled to the IOMMU, a direct memory access (DMA) request, the DMA request to a memory address space belonging to the at least the second IOMMU; access the plurality of MMIO registers of the IOMMU based on context data of the DMA request; and access, from the IOMMU, a function assigned to the memory address space belonging to the at least the second IOMMU based on the accessed plurality of MMIO registers.

Techniques and mechanisms for providing information to determine whether a software prefetch instruction is to be executed. In an embodiment, one or more entries of a translation lookaside buffer (TLB) each include a respective value which indicates whether, according to one or more criteria, corresponding data has been sufficiently utilized. Insufficiently utilized data is indicated in a TLB entry with an identifier of an executed instruction to prefetch the corresponding data. An eviction of the TLB entry results in the creation of an entry in a registry of prefetch instructions. The entry in the registry includes the identifier of the executed prefetch instruction, and a value indicating a number of times that one or more future prefetch instructions are to be dropped. In another embodiment, execution of a subsequent prefetch instruction—which also corresponds to the identifier—is prevented based on the registry entry.