perf kvm: Use macro to replace variable 'decode_str_len'

The variable 'decode_str_len' defines the string length for KVM event
name and every arch defines its own values.

This introduces complexity that the variable definition are spreading in
multiple source files under arch folder.  This patch refactors code to
use a macro KVM_EVENT_NAME_LEN to define event name length and thus
remove the definitions in arch files.

Signed-off-by: Leo Yan <leo.yan@linaro.org>
Cc: Adrian Hunter <adrian.hunter@intel.com>
Cc: Alexander Shishkin <alexander.shishkin@linux.intel.com>
Cc: Ian Rogers <irogers@google.com>
Cc: Ingo Molnar <mingo@redhat.com>
Cc: James Clark <james.clark@arm.com>
Cc: Jiri Olsa <jolsa@kernel.org>
Cc: John Garry <john.g.garry@oracle.com>
Cc: Mark Rutland <mark.rutland@arm.com>
Cc: Namhyung Kim <namhyung@kernel.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: linux-arm-kernel@lists.infradead.org
Link: https://lore.kernel.org/r/20230315145112.186603-2-leo.yan@linaro.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/arch/arm64/util/kvm-stat.c

@@ -11,7 +11,6 @@ define_exit_reasons_table(arm64_trap_exit_reasons, kvm_arm_exception_class);
 
 const char *kvm_trap_exit_reason = "esr_ec";
 const char *vcpu_id_str = "id";
-const int decode_str_len = 20;
 const char *kvm_exit_reason = "ret";
 const char *kvm_entry_trace = "kvm:kvm_entry";
 const char *kvm_exit_trace = "kvm:kvm_exit";

tools/perf/arch/powerpc/util/kvm-stat.c

@@ -14,7 +14,6 @@
 #define NR_TPS 4
 
 const char *vcpu_id_str = "vcpu_id";
-const int decode_str_len = 40;
 const char *kvm_entry_trace = "kvm_hv:kvm_guest_enter";
 const char *kvm_exit_trace = "kvm_hv:kvm_guest_exit";
 
@@ -80,7 +79,7 @@ static void hcall_event_decode_key(struct perf_kvm_stat *kvm __maybe_unused,
 {
 	const char *hcall_reason = get_hcall_exit_reason(key->key);
 
-	scnprintf(decode, decode_str_len, "%s", hcall_reason);
+	scnprintf(decode, KVM_EVENT_NAME_LEN, "%s", hcall_reason);
 }
 
 static struct kvm_events_ops hcall_events = {

tools/perf/arch/s390/util/kvm-stat.c

@@ -19,7 +19,6 @@ define_exit_reasons_table(sie_diagnose_codes, diagnose_codes);
 define_exit_reasons_table(sie_icpt_prog_codes, icpt_prog_codes);
 
 const char *vcpu_id_str = "id";
-const int decode_str_len = 40;
 const char *kvm_exit_reason = "icptcode";
 const char *kvm_entry_trace = "kvm:kvm_s390_sie_enter";
 const char *kvm_exit_trace = "kvm:kvm_s390_sie_exit";

tools/perf/arch/x86/util/kvm-stat.c

@@ -18,7 +18,6 @@ static struct kvm_events_ops exit_events = {
 };
 
 const char *vcpu_id_str = "vcpu_id";
-const int decode_str_len = 20;
 const char *kvm_exit_reason = "exit_reason";
 const char *kvm_entry_trace = "kvm:kvm_entry";
 const char *kvm_exit_trace = "kvm:kvm_exit";
@@ -77,7 +76,7 @@ static void mmio_event_decode_key(struct perf_kvm_stat *kvm __maybe_unused,
 				  struct event_key *key,
 				  char *decode)
 {
-	scnprintf(decode, decode_str_len, "%#lx:%s",
+	scnprintf(decode, KVM_EVENT_NAME_LEN, "%#lx:%s",
 		  (unsigned long)key->key,
 		  key->info == KVM_TRACE_MMIO_WRITE ? "W" : "R");
 }
@@ -121,7 +120,7 @@ static void ioport_event_decode_key(struct perf_kvm_stat *kvm __maybe_unused,
 				    struct event_key *key,
 				    char *decode)
 {
-	scnprintf(decode, decode_str_len, "%#llx:%s",
+	scnprintf(decode, KVM_EVENT_NAME_LEN, "%#llx:%s",
 		  (unsigned long long)key->key,
 		  key->info ? "POUT" : "PIN");
 }
@@ -165,7 +164,7 @@ static void msr_event_decode_key(struct perf_kvm_stat *kvm __maybe_unused,
 				    struct event_key *key,
 				    char *decode)
 {
-	scnprintf(decode, decode_str_len, "%#llx:%s",
+	scnprintf(decode, KVM_EVENT_NAME_LEN, "%#llx:%s",
 		  (unsigned long long)key->key,
 		  key->info ? "W" : "R");
 }

tools/perf/builtin-kvm.c

@@ -161,7 +161,7 @@ void exit_event_decode_key(struct perf_kvm_stat *kvm,
 	const char *exit_reason = get_exit_reason(kvm, key->exit_reasons,
 						  key->key);
 
-	scnprintf(decode, decode_str_len, "%s", exit_reason);
+	scnprintf(decode, KVM_EVENT_NAME_LEN, "%s", exit_reason);
 }
 
 static bool register_kvm_events_ops(struct perf_kvm_stat *kvm)
@@ -434,7 +434,7 @@ 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[decode_str_len];
+		char decode[KVM_EVENT_NAME_LEN];
 
 		kvm->events_ops->decode_key(kvm, &event->key, decode);
 		if (!skip_event(decode)) {
@@ -605,7 +605,7 @@ static void show_timeofday(void)
 
 static void print_result(struct perf_kvm_stat *kvm)
 {
-	char decode[decode_str_len];
+	char decode[KVM_EVENT_NAME_LEN];
 	struct kvm_event *event;
 	int vcpu = kvm->trace_vcpu;
 
@@ -616,7 +616,7 @@ static void print_result(struct perf_kvm_stat *kvm)
 
 	pr_info("\n\n");
 	print_vcpu_info(kvm);
-	pr_info("%*s ", decode_str_len, kvm->events_ops->name);
+	pr_info("%*s ", KVM_EVENT_NAME_LEN, kvm->events_ops->name);
 	pr_info("%10s ", "Samples");
 	pr_info("%9s ", "Samples%");
 
@@ -635,7 +635,7 @@ 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("%*s ", decode_str_len, decode);
+		pr_info("%*s ", KVM_EVENT_NAME_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);

tools/perf/util/kvm-stat.h

@@ -8,6 +8,8 @@
 #include "stat.h"
 #include "record.h"
 
+#define KVM_EVENT_NAME_LEN	40
+
 struct evsel;
 struct evlist;
 struct perf_session;
@@ -143,7 +145,6 @@ extern const char *kvm_events_tp[];
 extern struct kvm_reg_events_ops kvm_reg_events_ops[];
 extern const char * const kvm_skip_events[];
 extern const char *vcpu_id_str;
-extern const int decode_str_len;
 extern const char *kvm_exit_reason;
 extern const char *kvm_entry_trace;
 extern const char *kvm_exit_trace;