perf kvm: Add stat support on s390

On s390, the vmexit event has a tree-like structure: between
exit_event_begin and exit_event_end several other events may happen and
with each of them refining the previous ones.

This patch adds a decoder for such events to the generic code and also
the files <asm/kvm_perf.h> and kvm-stat.c for s390.

Commands 'perf kvm stat record', 'report' and 'live' are supported.

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: Ingo Molnar <mingo@kernel.org>
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/1404397747-20939-5-git-send-email-yarygin@linux.vnet.ibm.com
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>
diff --git a/tools/perf/util/kvm-stat.h b/tools/perf/util/kvm-stat.h
index ba937ca..0b5a8cd 100644
--- a/tools/perf/util/kvm-stat.h
+++ b/tools/perf/util/kvm-stat.h
@@ -12,6 +12,7 @@
 	#define INVALID_KEY     (~0ULL)
 	u64 key;
 	int info;
+	struct exit_reasons_table *exit_reasons;
 };
 
 struct kvm_event_stats {
@@ -41,12 +42,20 @@
 
 struct perf_kvm_stat;
 
+struct child_event_ops {
+	void (*get_key)(struct perf_evsel *evsel,
+			struct perf_sample *sample,
+			struct event_key *key);
+	const char *name;
+};
+
 struct kvm_events_ops {
 	bool (*is_begin_event)(struct perf_evsel *evsel,
 			       struct perf_sample *sample,
 			       struct event_key *key);
 	bool (*is_end_event)(struct perf_evsel *evsel,
 			     struct perf_sample *sample, struct event_key *key);
+	struct child_event_ops *child_ops;
 	void (*decode_key)(struct perf_kvm_stat *kvm, struct event_key *key,
 			   char *decode);
 	const char *name;