An apparatus, a method, and a computer program product are provided that provide confidential computing on virtual machines by securing input/output operations between a virtual machine and a device. The method includes receiving an input/output (I/O) transaction from an I/O device requesting data stored memory from a virtual machine. The I/O transaction includes a virtual memory address and a bus device function. The method also includes associating the I/O transaction with a key slot associated with the virtual machine and retrieving, using the key slot, an encryption key used to encrypt and decrypt the data. The method further includes retrieving the data located at a physical memory address in physical memory relating to the virtual memory address of the data being requested and decrypting, during a read operation, the data using the encryption key for I/O transmission. The method also includes transmitting the decrypted data to the I/O device.

A method of operating a cache system is disclosed. Information indicating a link between associated header and payload cache entries is maintained. The link information may be used to reduce cache coherency traffic.

Process isolation for a PIM device includes: receiving, from a process, a call to allocate a virtual address space where the process stores a PIM configuration context; allocating the virtual address space including mapping a physical address space including PIM device configuration registers to the virtual address space only if the physical address space is not mapped to another process's virtual address space; and programming the PIM device configuration space according to the configuration context. When a PIM command is executed, a translation mechanism determines whether there is a valid mapping of a virtual address of the PIM command to a physical address of a PIM resource, such as a LIS entry. If a valid mapping exists, the translation is completed and the resource is accessed, but if there is not a valid mapping, the translation fails and the process is blocked from accessing the PIM resource.

A circuit includes a Virtually Indexed Physically Tagged (VIPT) cache and a cache coherency circuit. The VIPT cache includes a plurality of sets and performs a memory operation by selecting, using a Virtual Set Address (VSA), a first tag of a first set. The cache coherency circuit is to detect cache aliasing during memory operations of the VIPT cache when a second tag maps a physical address to a second set of the VIPT cache, the second set being different than the first set. A method of managing a VIPT cache includes performing, by the VIPT cache, a memory operation and determining, using a cache coherency protocol, that cache aliasing has occurred during the memory operation.

An apparatus includes circuitry couplable to a host system and a memory device. The circuitry is configured to determine whether a page table maintained on the circuitry includes a physical address of the memory device corresponding to a virtual address associated with a TLB fill request from the host system. Responsive to determining that the page table includes the physical address, the circuitry provides signaling indicative of a completion to the TLB fill request to the host system, prefetch a page of data at the physical address from the memory device using the physical address from the page table, and provide signaling indicative of the page of data to the host system.

One embodiment provides for a graphics processor comprising a translation lookaside buffer (TLB) to cache a first page table entry for a virtual to physical address mapping for use by the graphics processor, the first page table entry to indicate that a first virtual page is a valid page that is cleared to a clear color and graphics pipeline circuitry to bypass a memory access for the first virtual page based on the first page table entry in response to determination that the first virtual page is cleared to the clear color and determine a color associated with the first virtual page without performing a memory access to the first virtual page.

Systems, apparatuses, and methods for limiting translation lookaside buffer (TLB) searches using active page size are described. A TLB stores virtual-to-physical address translations for a plurality of different page sizes. When the TLB receives a command to invalidate a TLB entry corresponding to a specified virtual address, the TLB performs, for the plurality of different pages sizes, multiple different lookups of the indices corresponding to the specified virtual address. In order to reduce the number of lookups that are performed, the TLB relies on a page size presence vector and an age matrix to determine which page sizes to search for and in which order. The page size presence vector indicates which page sizes may be stored for the specified virtual address. The age matrix stores a preferred search order with the most probable page size first and the least probable page size last.

Address translation circuitry (16) translates a virtual address specified by a memory access request issued by requester circuitry into a target physical address (PA). Requester-side filtering circuitry (20) performs a granule protection lookup based on the target PA and a selected physical address space (PAS) associated with the memory access request, to determine whether to allow the memory access request to be passed to a cache or interconnect. In the granule protection lookup, the requester-side filtering circuitry obtains granule protection information corresponding to a target granule of physical addresses including the target PA, which indicates at least one allowed PAS associated with the target granule, and blocks the memory access request when the granule protection information indicates that the selected PAS is not an allowed PAS.

Aspects of the embodiments are directed to systems and methods for providing and using hints in data packets to perform memory transaction optimization processes prior to receiving one or more data packets that rely on memory transactions. The systems and methods can include receiving, from a device connected to the root complex across a PCIe-compliant link, a data packet; identifying from the received device a memory transaction hint bit; determining a memory transaction from the memory transaction hint bit; and performing an optimization process based, at least in part, on the determined memory transaction.

A cache memory device is provided in the disclosure. The cache memory device includes a first AGC, a compression circuit, a second AGC, a virtual tag array, and a comparator circuit. The first AGC generates a virtual address based on a load instruction. The compression circuit obtains the higher part of the virtual address and generates a target hash value based on the higher part of the virtual address. The second AGC generates the lower part of the virtual address based on the load instruction. The virtual tag array obtains the lower part and selects a set of memory units. The comparator circuit compares the target hash value to a hash value stored in each memory unit of the set of memory units. When the comparator circuit generates the virtual tag miss signal, the comparator circuit transmits the virtual tag miss signal to the reservation station.