Otherwise, a single user may be able to consume all of an enclave’s available memory and crash the enclave (try running cat /dev/zero inside the enclave to see how it behaves when a large amount of memory is consumed). A less common source of security issues is an enclave’s time source—namely, from where the enclave gets its time. Enclaves should have two sources: tsc and kvm-clock (you can see them if you run a sample enclave and check its sources); the latter is enabled by default, as can be checked in the current_clocksource file.