1 files changed, 38 insertions, 0 deletions
diff --git a/kvm/user/test/x86/tsc.c b/kvm/user/test/x86/tsc.c
new file mode 100644
index 000000000..394a9c6b8
--- /dev/null
+++ b/kvm/user/test/x86/tsc.c
@@ -0,0 +1,38 @@
+#include "libcflat.h"
+
+u64 rdtsc(void)
+{
+	unsigned a, d;
+
+	asm volatile("rdtsc" : "=a"(a), "=d"(d));
+	return a | (u64)d << 32;
+}
+
+void wrtsc(u64 tsc)
+{
+	unsigned a = tsc, d = tsc >> 32;
+
+	asm volatile("wrmsr" : : "a"(a), "d"(d), "c"(0x10));
+}
+
+void test_wrtsc(u64 t1)
+{
+	u64 t2;
+
+	wrtsc(t1);
+	t2 = rdtsc();
+	printf("rdtsc after wrtsc(%lld): %lld\n", t1, t2);
+}
+
+int main()
+{
+	u64 t1, t2;
+
+	t1 = rdtsc();
+	t2 = rdtsc();
+	printf("rdtsc latency %lld\n", (unsigned)(t2 - t1));
+
+	test_wrtsc(0);
+	test_wrtsc(100000000000ull);
+	return 0;
+}