Advanced Micro Devices Corporation

Ati Technologies Ulc

Jelena Ilic

Michael T Clark

Tahsin Askar

Hamilton B Carter

Paul W Berndt

Mike Lowe

Enrique Rendon

Mark LaVine

David S Christie

David A Kaplan

Vilas K Sridharan

Kelvin Domnic Goveas

Hanwoo Cho

Richard W Reeves

Ashraf Ahmed

Dean A Liberty

Michael Thomas Dibrino

Cristian Constantinescu

Syed Faisal Ahmed

James R Williamson

Kelvin Goveas

A computing device comprises a processor, a table walker, and a memory storing a segmented reverse map table in multiple non-contiguous portions of the memory. The table walker is configured to translate a virtual memory address specified by a memory access request to a physical memory address associated with the virtual memory address; and provide a requester associated with the memory access request with access to the associated physical memory address in response to an indication at the reverse map table that the requester is authorized to access the associated physical memory address.

Segmented non-contiguous reverse map table

A virtualized computing environment is protected from a malicious hypervisor by restricting the hypervisor's access to one or more portions of an event (interrupt or exception) handling pathway of a guest virtual machine, wherein the guest virtual machine includes both a secure layer to manage security for the guest and one or more non-secure layers to handle event processing. The hypervisor is restricted from providing normal exception information to the guest virtual machine (referred to simply as a 'guest' herein), and instead is only permitted to provide an event signal to the secure layer of the guest. In response to the event signal, the secure layer of the guest accesses a specified region of memory for the event information, reviews the information, and provides the information to another, non-secure, layer of the guest for processing only if the event information complies with specified security protocols.

Hypervisor secure event handling at a processor

Systems, apparatuses, and methods for implementing a hardware enforcement mechanism to enable platform-specific firmware visibility into an error state ahead of the operating system are disclosed. A system includes at least one or more processor cores, control logic, a plurality of registers, platform-specific firmware, and an operating system (OS). The control logic allows the platform-specific firmware to decide if and when the error state is visible to the OS. In some cases, the platform-specific firmware blocks the OS from accessing the error state. In other cases, the platform-specific firmware allows the OS to access the error state such as when the OS needs to unmap a page. The control logic enables the platform-specific firmware, rather than the OS, to make decisions about the replacement of faulty components in the system.

Platform first error handling

In an embodiment, a microcode unit for a processor is contemplated. The microcode unit comprises a microcode memory storing a plurality of microcode routines executable by the processor, wherein each microcode routine comprises two or more microcode operations. Coupled to the microcode memory, the sequence control unit is configured to control reading microcode operations from the microcode memory to be issued for execution by the processor. The sequence control unit is configured to stall issuance of microcode operations forming a body of a loop in a first routine of the plurality of microcode routines until a loop counter value that indicates a number of iterations of the loop is received by the sequence control unit.

Precise counter hardware for microcode loops

A technique of operating a processor includes determining whether a floating point unit (FPU) of the processor is to operate in a full-bit mode or a reduced-bit mode. An instruction is fetched and the instruction is decoded into a single operation, when the full-bit mode is indicated, or multiple operations, when the reduced-bit mode is indicated.

Processor with power saving reconfigurable floating point unit decoding an instruction to single full bit operation or multiple reduced bit operations

A method is provided for selectively using a PCIXCAP pin input to detect PCI/PCI-X bus mode or as DC pin input. The method provides a PCI/PCI-X device having PCIXCAP pin input, and a circuit having a plurality of voltage level detection structures and an output corresponding to each voltage level detection structure. Each output is received by a first logic to detect the PCI bus mode of a device defining a first, PCIXCAP mode for the pin input. The method ensures that one of the plurality of voltage level detection structures may be used as a DC signal logic to provide a DC output signal to a second logic. A mode of the PCIXCAP pin input is selected so as to provide the DC output signal under conditions where the PCI/PCI-X bus mode is not being detected. In an embodiment, the DC output signal is used in as a PCI Hot-Plug interface signal.

PCIXCAP pin input sharing configuration for additional use as PCI hot plug interface pin input

A system and method for memory incoherent verification of functionality of an HDL (Hardware Description Language) design of a computer system component is disclosed. A simulated model of the HDL design receives a memory read stimulus from a stimulus file through a simulated first bus. The simulated model of the HDL design is configured to send its response to the stimulus onto a simulated second bus. A transaction checker receives the response from the simulated second bus and analyzes it to verify operation of the HDL design of the computer system component. The stimulus file and the transaction checker are both stored in the computer system memory. The simulated model's response to the memory read stimulus is evaluated by the transaction checker independently of any previous memory write stimulus from the stimulus file. There is no need to have a previous memory write operation or a master initialization of the system memory for every memory read operation. This enhances the sequences of operations that may be applied to a device under test. Multiple simulated models may read or write into the memory without timing constraints.

Memory incoherent verification methodology

A verification system and method for verifying operation of an HDL (Hardware Description Language) design of a computer system component are disclosed. The computer system is configured to interface between a first bus and second bus. During verification, a simulated model of the HDL design is coupled to a simulated first bus and a simulated second bus. A designated stimulus is applied to the simulated model through the simulated first bus. A stimulus file stored in the computer system memory is configured to specify the designated stimulus to be applied. In response to the designated stimulus, the simulated model initiates bus cycles on the simulated second bus. A transaction checker is provided in the computer system memory to receive information relating to these bus cycles from said simulated second bus. By employing two different busses--one to apply a stimulus and the other to resolve the bus cycle through transaction checking--an effective decoupling of test stimulus from the checking environment is achieved. Due to decoupling, the test environment can be made more robust, and can be used to generate random responses, remap memory, inject errors into data streams etc.

Growing community of inventors

Austin, TX, United States of America

Jelena Ilic