Add a test case to verify that conversions between private and shared
memory work correctly when the memory is initially created as shared.

Signed-off-by: Ackerley Tng <ackerleytng@google.com>
Co-developed-by: Sean Christopherson <seanjc@google.com>
Signed-off-by: Sean Christopherson <seanjc@google.com>
---
 tools/testing/selftests/kvm/guest_memfd_conversions_test.c | 12 ++++++++++++
 1 file changed, 12 insertions(+)

diff --git a/tools/testing/selftests/kvm/guest_memfd_conversions_test.c b/tools/testing/selftests/kvm/guest_memfd_conversions_test.c
index 841b2824ae996..81cbdb5def565 100644
--- a/tools/testing/selftests/kvm/guest_memfd_conversions_test.c
+++ b/tools/testing/selftests/kvm/guest_memfd_conversions_test.c
@@ -99,6 +99,12 @@ static void __gmem_conversions_##test(test_data_t *t, int nr_pages)		\
 #define GMEM_CONVERSION_TEST_INIT_PRIVATE(test)					\
 	__GMEM_CONVERSION_TEST_INIT_PRIVATE(test, 1)
 
+#define __GMEM_CONVERSION_TEST_INIT_SHARED(test, __nr_pages)			\
+	GMEM_CONVERSION_TEST(test, __nr_pages, GUEST_MEMFD_FLAG_INIT_SHARED)
+
+#define GMEM_CONVERSION_TEST_INIT_SHARED(test)					\
+	__GMEM_CONVERSION_TEST_INIT_SHARED(test, 1)
+
 struct guest_check_data {
 	void *mem;
 	char expected_val;
@@ -192,6 +198,12 @@ GMEM_CONVERSION_TEST_INIT_PRIVATE(init_private)
 	test_convert_to_private(t, 0, 'C', 'E');
 }
 
+GMEM_CONVERSION_TEST_INIT_SHARED(init_shared)
+{
+	test_shared(t, 0, 0, 'A', 'B');
+	test_convert_to_private(t, 0, 'B', 'C');
+	test_convert_to_shared(t, 0, 'C', 'D', 'E');
+}
 
 int main(int argc, char *argv[])
 {

-- 
2.53.0.1018.g2bb0e51243-goog