[PATCH 08/11] perf kvm: allow for variable string sizes

[Christian Borntraeger]

From: Alexander Yarygin <yarygin@xxxxxxxxxxxxxxxxxx>

This makes it possible for other architectures to decode to different
string lengths.

Needed by follow-up patch "perf kvm: add stat support on s390".

Signed-off-by: Alexander Yarygin <yarygin@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Christian Borntraeger <borntraeger@xxxxxxxxxx>
---
 tools/perf/builtin-kvm.c | 38 +++++++++++++++++++++++---------------
 1 file changed, 23 insertions(+), 15 deletions(-)

diff --git a/tools/perf/builtin-kvm.c b/tools/perf/builtin-kvm.c
index 922706c..806c0e4 100644
--- a/tools/perf/builtin-kvm.c
+++ b/tools/perf/builtin-kvm.c
@@ -75,7 +75,7 @@ struct kvm_events_ops {
 	bool (*is_end_event)(struct perf_evsel *evsel,
 			     struct perf_sample *sample, struct event_key *key);
 	void (*decode_key)(struct perf_kvm_stat *kvm, struct event_key *key,
-			   char decode[20]);
+			   char *decode);
 	const char *name;
 };
 
@@ -84,6 +84,8 @@ struct exit_reasons_table {
 	const char *reason;
 };
 
+#define DECODE_STR_LEN_MAX 80
+
 #define EVENTS_BITS		12
 #define EVENTS_CACHE_SIZE	(1UL << EVENTS_BITS)
 
@@ -101,6 +103,8 @@ struct perf_kvm_stat {
 	struct exit_reasons_table *exit_reasons;
 	const char *exit_reasons_isa;
 
+	int decode_str_len;
+
 	struct kvm_events_ops *events_ops;
 	key_cmp_fun compare;
 	struct list_head kvm_events_cache[EVENTS_CACHE_SIZE];
@@ -182,12 +186,12 @@ static const char *get_exit_reason(struct perf_kvm_stat *kvm,
 
 static void exit_event_decode_key(struct perf_kvm_stat *kvm,
 				  struct event_key *key,
-				  char decode[20])
+				  char *decode)
 {
 	const char *exit_reason = get_exit_reason(kvm, kvm->exit_reasons,
 						  key->key);
 
-	scnprintf(decode, 20, "%s", exit_reason);
+	scnprintf(decode, kvm->decode_str_len, "%s", exit_reason);
 }
 
 static struct kvm_events_ops exit_events = {
@@ -249,10 +253,11 @@ static bool mmio_event_end(struct perf_evsel *evsel, struct perf_sample *sample,
 
 static void mmio_event_decode_key(struct perf_kvm_stat *kvm __maybe_unused,
 				  struct event_key *key,
-				  char decode[20])
+				  char *decode)
 {
-	scnprintf(decode, 20, "%#lx:%s", (unsigned long)key->key,
-				key->info == KVM_TRACE_MMIO_WRITE ? "W" : "R");
+	scnprintf(decode, kvm->decode_str_len, "%#lx:%s",
+		  (unsigned long)key->key,
+		  key->info == KVM_TRACE_MMIO_WRITE ? "W" : "R");
 }
 
 static struct kvm_events_ops mmio_events = {
@@ -292,10 +297,11 @@ static bool ioport_event_end(struct perf_evsel *evsel,
 
 static void ioport_event_decode_key(struct perf_kvm_stat *kvm __maybe_unused,
 				    struct event_key *key,
-				    char decode[20])
+				    char *decode)
 {
-	scnprintf(decode, 20, "%#llx:%s", (unsigned long long)key->key,
-				key->info ? "POUT" : "PIN");
+	scnprintf(decode, kvm->decode_str_len, "%#llx:%s",
+		  (unsigned long long)key->key,
+		  key->info ? "POUT" : "PIN");
 }
 
 static struct kvm_events_ops ioport_events = {
@@ -523,13 +529,13 @@ static bool handle_end_event(struct perf_kvm_stat *kvm,
 	time_diff = sample->time - time_begin;
 
 	if (kvm->duration && time_diff > kvm->duration) {
-		char decode[32];
+		char decode[DECODE_STR_LEN_MAX];
 
 		kvm->events_ops->decode_key(kvm, &event->key, decode);
 		if (strcmp(decode, "HLT")) {
-			pr_info("%" PRIu64 " VM %d, vcpu %d: %s event took %" PRIu64 "usec\n",
+			pr_info("%" PRIu64 " VM %d, vcpu %d: %*s event took %" PRIu64 "usec\n",
 				 sample->time, sample->pid, vcpu_record->vcpu_id,
-				 decode, time_diff/1000);
+				 32, decode, time_diff/1000);
 		}
 	}
 
@@ -738,7 +744,7 @@ static void show_timeofday(void)
 
 static void print_result(struct perf_kvm_stat *kvm)
 {
-	char decode[20];
+	char decode[DECODE_STR_LEN_MAX];
 	struct kvm_event *event;
 	int vcpu = kvm->trace_vcpu;
 
@@ -749,7 +755,7 @@ static void print_result(struct perf_kvm_stat *kvm)
 
 	pr_info("\n\n");
 	print_vcpu_info(kvm);
-	pr_info("%20s ", kvm->events_ops->name);
+	pr_info("%*s ", kvm->decode_str_len, kvm->events_ops->name);
 	pr_info("%10s ", "Samples");
 	pr_info("%9s ", "Samples%");
 
@@ -768,7 +774,7 @@ static void print_result(struct perf_kvm_stat *kvm)
 		min = get_event_min(event, vcpu);
 
 		kvm->events_ops->decode_key(kvm, &event->key, decode);
-		pr_info("%20s ", decode);
+		pr_info("%*s ", kvm->decode_str_len, decode);
 		pr_info("%10llu ", (unsigned long long)ecount);
 		pr_info("%8.2f%% ", (double)ecount / kvm->total_count * 100);
 		pr_info("%8.2f%% ", (double)etime / kvm->total_time * 100);
@@ -839,9 +845,11 @@ static int cpu_isa_init(struct perf_kvm_stat *kvm, const char *cpuid)
 	if (strstr(cpuid, "Intel")) {
 		kvm->exit_reasons = vmx_exit_reasons;
 		kvm->exit_reasons_isa = "VMX";
+		kvm->decode_str_len = 20;
 	} else if (strstr(cpuid, "AMD")) {
 		kvm->exit_reasons = svm_exit_reasons;
 		kvm->exit_reasons_isa = "SVM";
+		kvm->decode_str_len = 20;
 	} else {
 		pr_err("CPU %s is not supported.\n", cpuid);
 		return -ENOTSUP;
-- 
1.8.4.2

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