1 files changed, 52 insertions, 0 deletions
diff --git a/kvm/user/test/x86/msr.c b/kvm/user/test/x86/msr.c
new file mode 100644
index 000000000..92102fa47
--- /dev/null
+++ b/kvm/user/test/x86/msr.c
@@ -0,0 +1,52 @@
+/* msr tests */
+
+#include "libcflat.h"
+
+#define MSR_KERNEL_GS_BASE	0xc0000102 /* SwapGS GS shadow */
+
+int nr_passed, nr_tests;
+
+#ifdef __x86_64__
+static void report(const char *name, int passed)
+{
+	++nr_tests;
+	if (passed)
+		++nr_passed;
+	printf("%s: %s\n", name, passed ? "PASS" : "FAIL");
+}
+
+static void wrmsr(unsigned index, unsigned long long value)
+{
+	asm volatile ("wrmsr" : : "c"(index), "A"(value));
+}
+
+static unsigned long long rdmsr(unsigned index)
+{
+	unsigned long long value;
+
+	asm volatile ("rdmsr" : "=A"(value) : "c"(index));
+
+	return value;
+}
+#endif
+
+static void test_kernel_gs_base(void)
+{
+#ifdef __x86_64__
+	unsigned long long v1 = 0x123456789abcdef, v2;
+
+	wrmsr(MSR_KERNEL_GS_BASE, v1);
+	v2 = rdmsr(MSR_KERNEL_GS_BASE);
+	report("MSR_KERNEL_GS_BASE", v1 == v2);
+#endif
+}
+
+int main(int ac, char **av)
+{
+	test_kernel_gs_base();
+
+	printf("%d tests, %d failures\n", nr_tests, nr_tests - nr_passed);
+
+	return nr_passed == nr_tests ? 0 : 1;
+}
+