International Business Machines Corporation

John L Weber

Ali Y Duale

Shailesh Ratilal Gami

Dennis W Wittig

A computer-implemented method includes executing one or more tests on a computing device. The computing device has Instruction Execution Protection (IEP), and each test of the one or more tests includes selectively setting one or more IEP bits of one or more page tables, where each IEP bit prevents code in a respective storage block from being executed. During the one or more tests, an IEP exception is detected, by a computer processor, each time an attempt is made to execute code in a storage block for which a respective IEP bit is set. Test results of the one or more tests are determined based on the detecting. A remedial action is performed in response to the test results of the one or more tests.

Verifying proper operation of the instruction execution protection architecture

An aspect includes include selective purging of entries from translation look-aside buffers (TLBs). A method includes building multiple logical systems in a computing environment, the multiple logical systems including at least two level-two guests. TLB entries are created in a TLB for the level-two guests by executing fetch and store instructions. A subset of the TLB entries is purged in response to a selective TLB purge instruction, the subset including TLB entries created for a first one of the level-two guests. Subsequent to the purging, verifying that the subset of the TLB entries were purged from the TLB, and determining whether a second one of the level-two guests is operational, the determining including executing at least one instruction that accesses a TLB entry of the second one of the level-two guests. Test results are generated based on the verifying and the determining. The test results are output.

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John L Weber