perf kvm: Simplify exit reasons tables definitions

The perf_kvm_stat struct keeps the size of a table of exit reasons in
the field 'exit_reasons_size'.

The field is initialized and then used by get_exit_reason() for serial
access to the table, so that the calling function does not actually need
to know table size.

Usage of tables with 'end of sequence' marker simplifies the
get_exit_reason() function.

Also the patch introduces a define_exit_reasons_table, which makes it
easier to define new tables.

Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: David Ahern <dsahern@gmail.com>
Signed-off-by: Alexander Yarygin <yarygin@linux.vnet.ibm.com>
Acked-by: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Christian Borntraeger <borntraeger@de.ibm.com>
Cc: Cornelia Huck <cornelia.huck@de.ibm.com>
Cc: David Ahern <dsahern@gmail.com>
Cc: Jiri Olsa <jolsa@redhat.com>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Link: http://lkml.kernel.org/r/1404395992-17095-3-git-send-email-yarygin@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-kvm.c

@@ -99,7 +99,6 @@ struct perf_kvm_stat {
 	int trace_vcpu;
 
 	struct exit_reasons_table *exit_reasons;
-	int exit_reasons_size;
 	const char *exit_reasons_isa;
 
 	struct kvm_events_ops *events_ops;
@@ -158,20 +157,19 @@ static bool exit_event_end(struct perf_evsel *evsel,
 	return kvm_entry_event(evsel);
 }
 
-static struct exit_reasons_table vmx_exit_reasons[] = {
-	VMX_EXIT_REASONS
-};
+#define define_exit_reasons_table(name, symbols)	\
+	static struct exit_reasons_table name[] = {	\
+		symbols, { -1, NULL }			\
+	}
 
-static struct exit_reasons_table svm_exit_reasons[] = {
-	SVM_EXIT_REASONS
-};
+define_exit_reasons_table(vmx_exit_reasons, VMX_EXIT_REASONS);
+define_exit_reasons_table(svm_exit_reasons, SVM_EXIT_REASONS);
 
-static const char *get_exit_reason(struct perf_kvm_stat *kvm, u64 exit_code)
+static const char *get_exit_reason(struct perf_kvm_stat *kvm,
+				   struct exit_reasons_table *tbl,
+				   u64 exit_code)
 {
-	int i = kvm->exit_reasons_size;
-	struct exit_reasons_table *tbl = kvm->exit_reasons;
-
-	while (i--) {
+	while (tbl->reason != NULL) {
 		if (tbl->exit_code == exit_code)
 			return tbl->reason;
 		tbl++;
@@ -186,7 +184,8 @@ static void exit_event_decode_key(struct perf_kvm_stat *kvm,
 				  struct event_key *key,
 				  char decode[20])
 {
-	const char *exit_reason = get_exit_reason(kvm, key->key);
+	const char *exit_reason = get_exit_reason(kvm, kvm->exit_reasons,
+						  key->key);
 
 	scnprintf(decode, 20, "%s", exit_reason);
 }
@@ -862,7 +861,6 @@ static int cpu_isa_config(struct perf_kvm_stat *kvm)
 
 	if (isa == 1) {
 		kvm->exit_reasons = vmx_exit_reasons;
-		kvm->exit_reasons_size = ARRAY_SIZE(vmx_exit_reasons);
 		kvm->exit_reasons_isa = "VMX";
 	}
 
@@ -1586,7 +1584,6 @@ static int kvm_cmd_stat(const char *file_name, int argc, const char **argv)
 		.sort_key	= "sample",
 
 		.exit_reasons = svm_exit_reasons,
-		.exit_reasons_size = ARRAY_SIZE(svm_exit_reasons),
 		.exit_reasons_isa = "SVM",
 	};