Abstract: In an approach, responsibility for reissuing a fetch micro-operation is allocated to a reissue queue subsequent to a cache miss corresponding to a cache and the fetch micro-operation. Responsive to higher level cache returning data to the cache, an issue selection algorithm of the issue queue is overridden to prioritize reissuing the fetch micro-operation.

Abstract: A computer-implemented method for detecting vulnerabilities in microarchitectures. A non-limiting example of the computer-implemented method includes creating a simulation for execution on a model of a microarchitecture, the simulation including a set of instructions and a placeholder for holding a piece of secret data. The computer-implemented method executes the simulation a first time on the model of the microarchitecture with a first piece of secret data stored in the placeholder and stores a first output of the first executed simulation. The computer-implemented method executes the simulation a second time on the model of the microarchitecture with a second piece of secret data stored in the placeholder and stores a second output of the second executed simulation. The computer-implemented method compares the first output with the second output and provides an indication of a microarchitecture vulnerability when there is a difference between the first output and the second output.

Abstract: Methods and systems for controlling writing to register files in a processing system having at least two execution pipelines are provided. Aspects include obtaining a micro operation for execution by an execution unit of a first pipeline in the processing system, wherein the micro operation includes writing data to a register file. Aspects also include determining whether the data will be accessed by an execution unit of a second pipeline in the processing system. Based on a determination that the data will only be accessed by the execution unit of the first pipeline, aspects include blocking writing of the data to a register file of the second pipeline.

Abstract: Implementing processor instrumentation in a processor pipeline includes determining a pipeline depth of each micro-operator for an instruction group used in an execution phase of the processor pipeline. The pipeline depth corresponds with a duration of execution, each micro-operator performs a type of functional operation in the execution phase, and the instruction group includes all the micro-operators required for the execution phase. A targeted micro-operator is identified for which the processor instrumentation is being performed, and the pipeline depth corresponding with the targeted micro-operator is used to determine and report a performance of the targeted micro-operator as part of the processor instrumentation. Problems indicated by the processor instrumentation are diagnosed and addressed based on the performance of the targeted micro-operator.

Abstract: A computer-implemented method for detecting vulnerabilities in microarchitectures. A non-limiting example of the computer-implemented method includes creating a simulation for execution on a model of a microarchitecture, the simulation including a set of instructions and a placeholder for holding a piece of secret data. The computer-implemented method executes the simulation a first time on the model of the microarchitecture with a first piece of secret data stored in the placeholder and stores a first output of the first executed simulation. The computer-implemented method executes the simulation a second time on the model of the microarchitecture with a second piece of secret data stored in the placeholder and stores a second output of the second executed simulation. The computer-implemented method compares the first output with the second output and provides an indication of a microarchitecture vulnerability when there is a difference between the first output and the second output.

Abstract: Implementing processor instrumentation in a processor pipeline includes determining a pipeline depth of each micro-operator for an instruction group used in an execution phase of the processor pipeline. The pipeline depth corresponds with a duration of execution, each micro-operator performs a type of functional operation in the execution phase, and the instruction group includes all the micro-operators required for the execution phase. A targeted micro-operator is identified for which the processor instrumentation is being performed, and the pipeline depth corresponding with the targeted micro-operator is used to determine and report a performance of the targeted micro-operator as part of the processor instrumentation. Problems indicated by the processor instrumentation are diagnosed and addressed based on the performance of the targeted micro-operator.

Abstract: Methods and systems for controlling writing to register files in a processing system having at least two execution pipelines are provided. Aspects include obtaining a micro operation for execution by an execution unit of a first pipeline in the processing system, wherein the micro operation includes writing data to a register file. Aspects also include determining whether the data will be accessed by an execution unit of a second pipeline in the processing system. Based on a determination that the data will only be accessed by the execution unit of the first pipeline, aspects include blocking writing of the data to a register file of the second pipeline.