libcpumf: Detect PMU pai_nnpa

Add a check to detect Processor Activity Instrumentation (PAI)
Extension 1 facility unit. This covers the counter set for
Neural Network Processing Assist (NNPA) counters.

Signed-off-by: Thomas Richter <tmricht@linux.ibm.com>
Reviewed-by: Jan Höppner <hoeppner@linux.ibm.com>
Signed-off-by: Jan Höppner <hoeppner@linux.ibm.com>

libcpumf/libcpumf_example.c

@@ -83,5 +83,7 @@ int main(void)
 		printf("PMU type 10 PMU name %s\n", pmuname);
 		free(pmuname);
 	}
+
+	printf("PAI NNPA support %d\n", libcpumf_have_pai_nnpa());
 	return EXIT_SUCCESS;
 }

libcpumf/libcpumf_support.c

@@ -146,3 +146,10 @@ bool libcpumf_have_pai_crypto(void)
 
 	return (stat(S390_SYSFS_PAI_CRYPTO, &statbuf) == -1) ? false : true;
 }
+
+bool libcpumf_have_pai_nnpa(void)
+{
+	struct stat statbuf;
+
+	return (stat(S390_SYSFS_PAI_NNPA, &statbuf) == -1) ? false : true;
+}