perf kvm: Use perf_session_env for reading cpuid

We have processed and saved cpuid information to perf_session_env so
reuse it for get_cpu_isa().

Signed-off-by: Namhyung Kim <namhyung@kernel.org>
Cc: David Ahern <dsahern@gmail.com>
Cc: Dong Hao <haodong@linux.vnet.ibm.com>
Cc: Ingo Molnar <mingo@kernel.org>
Cc: Paul Mackerras <paulus@samba.org>
Cc: Peter Zijlstra <a.p.zijlstra@chello.nl>
Cc: Stephane Eranian <eranian@google.com>
Cc: Xiao Guangrong <xiaoguangrong@linux.vnet.ibm.com>
Link: http://lkml.kernel.org/r/1348474503-15070-6-git-send-email-namhyung@kernel.org
Signed-off-by: Arnaldo Carvalho de Melo <acme@redhat.com>

tools/perf/builtin-kvm.c

@@ -664,16 +664,9 @@ static struct perf_tool eops = {
 
 static int get_cpu_isa(struct perf_session *session)
 {
-	char *cpuid;
+	char *cpuid = session->header.env.cpuid;
 	int isa;
 
-	cpuid = perf_header__read_feature(session, HEADER_CPUID);
-
-	if (!cpuid) {
-		pr_err("read HEADER_CPUID failed.\n");
-		return -ENOTSUP;
-	}
-
 	if (strstr(cpuid, "Intel"))
 		isa = 1;
 	else if (strstr(cpuid, "AMD"))
@@ -683,7 +676,6 @@ static int get_cpu_isa(struct perf_session *session)
 		isa = -ENOTSUP;
 	}
 
-	free(cpuid);
 	return isa;
 }