perf: 'perf kvm' tool for monitoring guest performance from host

Here is the patch of userspace perf tool.

Signed-off-by: Zhang Yanmin <yanmin_zhang@linux.intel.com>
Signed-off-by: Avi Kivity <avi@redhat.com>
diff --git a/tools/perf/builtin-annotate.c b/tools/perf/builtin-annotate.c
index 06eaebe..f924b43 100644
--- a/tools/perf/builtin-annotate.c
+++ b/tools/perf/builtin-annotate.c
@@ -571,7 +571,7 @@
 		perf_session__fprintf(session, stdout);
 
 	if (verbose > 2)
-		dsos__fprintf(stdout);
+		dsos__fprintf(&session->kerninfo_root, stdout);
 
 	perf_session__collapse_resort(&session->hists);
 	perf_session__output_resort(&session->hists, session->event_total[0]);