[s390] provides an instruction to retrieve status information about all existing facilities (aka features). In most cases, this information is sufficient to decide if an instruction can be exploited.

There exist some cases, however, where the CPU capability alone is not enough. The vector facility is such an example. It needs the operating system to support the additional registers in its data structures. If OS support is not available, each attempt to execute a vector instruction will raise a SIGFPE signal.

During vm startup, after the facility list is retrieved, we test-execute a vector instruction if the vector facility is indicated available. The potential SIGFPE is caught and the feature is disabled.