[Qemu-devel] [PATCH 2/4] tests/test-vmstate.c: prove VMStateField.start broken

[Halil Pasic <pasic@linux.vnet.ibm.com>]

The handling of VMStateField.start is currently quite broken if
VMS_ALLOC is present (that is for VMSTATE_VBUFFER_ALLOC_UINT32) but
fortunately also quite underutilized -- nobody is using .start != 0.

Let's prove with this patch that it's really broken (as a first
step towards fixing things up).

Signed-off-by: Halil Pasic <pasic@linux.vnet.ibm.com>
Reviewed-by: Guenther Hutzl <hutzl@linux.vnet.ibm.com>
---

The idea is to remove .start support and this patch should
be reverted, as soon this happens, or even better just
dropped. If however dropping the support for .start encounters
resistance, this patch should prove useful in an unexpected
way.
---
 tests/test-vmstate.c | 49 ++++++++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 48 insertions(+), 1 deletion(-)

diff --git a/tests/test-vmstate.c b/tests/test-vmstate.c
index 9a57aa0..a2ef4a8 100644
--- a/tests/test-vmstate.c
+++ b/tests/test-vmstate.c
@@ -588,6 +588,53 @@ static void test_complex_vbuffer(void)
 #undef FIELD_EQUAL
 #undef BUFFER_EQUAL
 
+typedef struct {
+    uint32_t vbuff_size;
+    uint8_t *vbuff;
+    uint64_t stuff;
+} TestVBufStart;
+
+static const VMStateDescription vmstate_vbuff_alloc_start = {
+    .name = "test/vbuff_alloc_start",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT64(stuff, TestVBufStart),
+        VMSTATE_UINT32(vbuff_size, TestVBufStart),
+        VMSTATE_VBUFFER_ALLOC_UINT32(vbuff, TestVBufStart, 1, 0, 1, vbuff_size),
+        VMSTATE_END_OF_LIST()
+    }
+
+};
+
+static void load_vmstate_one_obj(const VMStateDescription *vmsd, void *obj,
+        int version_id)
+{
+        QEMUFile *fload = open_test_file(false);
+
+        SUCCESS(vmstate_load_state(fload, vmsd, obj, version_id));
+        qemu_fclose(fload);
+}
+
+static void test_vbuff_alloc_start(void)
+{
+    uint8_t my_vbuff1[] = {0, 1, 2, 3};
+    uint8_t my_vbuff2[] = {0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff};
+    TestVBufStart sample = {
+        .stuff = 1,
+        .vbuff_size = 3,
+        .vbuff = my_vbuff1,
+    };
+    TestVBufStart load_obj = {
+        .vbuff = my_vbuff2,
+    };
+
+    save_vmstate(&vmstate_vbuff_alloc_start, &sample);
+    load_vmstate_one_obj(&vmstate_vbuff_alloc_start, &load_obj, 1);
+    g_assert_cmpint(load_obj.stuff, ==, 0);
+    g_assert_cmpint((uint64_t) load_obj.vbuff, !=, (uint64_t) my_vbuff2);
+}
+
 int main(int argc, char **argv)
 {
     temp_fd = mkstemp(temp_file);
@@ -603,8 +650,8 @@ int main(int argc, char **argv)
     g_test_add_func("/vmstate/field_exists/save/noskip", test_save_noskip);
     g_test_add_func("/vmstate/field_exists/save/skip", test_save_skip);
     g_test_add_func("/vmstate/complex/vbuffer", test_complex_vbuffer);
+    g_test_add_func("/vmstate/vbuff/alloc_start", test_vbuff_alloc_start);
     g_test_run();
-
     close(temp_fd);
     unlink(temp_file);
 
-- 
2.8.4