xref: /qemu/rust/qemu-api/tests/vmstate_tests.rs (revision 98721058d6d50ef218e0c26e4f67c8ef96965859)
1 // Copyright (C) 2025 Intel Corporation.
2 // Author(s): Zhao Liu <zhao1.liu@intel.com>
3 // SPDX-License-Identifier: GPL-2.0-or-later
4 
5 use std::{
6     ffi::{c_void, CStr},
7     mem::size_of,
8     ptr::NonNull,
9     slice,
10 };
11 
12 use qemu_api::{
13     bindings::{
14         vmstate_info_bool, vmstate_info_int32, vmstate_info_int64, vmstate_info_int8,
15         vmstate_info_uint64, vmstate_info_uint8, vmstate_info_unused_buffer, VMStateFlags,
16     },
17     cell::{BqlCell, Opaque},
18     impl_vmstate_forward,
19     vmstate::{VMStateDescription, VMStateField},
20     vmstate_fields, vmstate_of, vmstate_struct, vmstate_unused, vmstate_validate,
21     zeroable::Zeroable,
22 };
23 
24 const FOO_ARRAY_MAX: usize = 3;
25 
26 // =========================== Test VMSTATE_FOOA ===========================
27 // Test the use cases of the vmstate macro, corresponding to the following C
28 // macro variants:
29 //   * VMSTATE_FOOA:
30 //     - VMSTATE_U16
31 //     - VMSTATE_UNUSED
32 //     - VMSTATE_VARRAY_UINT16_UNSAFE
33 //     - VMSTATE_VARRAY_MULTIPLY
34 #[repr(C)]
35 #[derive(Default)]
36 struct FooA {
37     arr: [u8; FOO_ARRAY_MAX],
38     num: u16,
39     arr_mul: [i8; FOO_ARRAY_MAX],
40     num_mul: u32,
41     elem: i8,
42 }
43 
44 static VMSTATE_FOOA: VMStateDescription = VMStateDescription {
45     name: c"foo_a".as_ptr(),
46     version_id: 1,
47     minimum_version_id: 1,
48     fields: vmstate_fields! {
49         vmstate_of!(FooA, elem),
50         vmstate_unused!(size_of::<i64>()),
51         vmstate_of!(FooA, arr[0 .. num]).with_version_id(0),
52         vmstate_of!(FooA, arr_mul[0 .. num_mul * 16]),
53     },
54     ..Zeroable::ZERO
55 };
56 
57 #[test]
test_vmstate_uint16()58 fn test_vmstate_uint16() {
59     let foo_fields: &[VMStateField] = unsafe { slice::from_raw_parts(VMSTATE_FOOA.fields, 5) };
60 
61     // 1st VMStateField ("elem") in VMSTATE_FOOA (corresponding to VMSTATE_UINT16)
62     assert_eq!(
63         unsafe { CStr::from_ptr(foo_fields[0].name) }.to_bytes_with_nul(),
64         b"elem\0"
65     );
66     assert_eq!(foo_fields[0].offset, 16);
67     assert_eq!(foo_fields[0].num_offset, 0);
68     assert_eq!(foo_fields[0].info, unsafe { &vmstate_info_int8 });
69     assert_eq!(foo_fields[0].version_id, 0);
70     assert_eq!(foo_fields[0].size, 1);
71     assert_eq!(foo_fields[0].num, 0);
72     assert_eq!(foo_fields[0].flags, VMStateFlags::VMS_SINGLE);
73     assert!(foo_fields[0].vmsd.is_null());
74     assert!(foo_fields[0].field_exists.is_none());
75 }
76 
77 #[test]
test_vmstate_unused()78 fn test_vmstate_unused() {
79     let foo_fields: &[VMStateField] = unsafe { slice::from_raw_parts(VMSTATE_FOOA.fields, 5) };
80 
81     // 2nd VMStateField ("unused") in VMSTATE_FOOA (corresponding to VMSTATE_UNUSED)
82     assert_eq!(
83         unsafe { CStr::from_ptr(foo_fields[1].name) }.to_bytes_with_nul(),
84         b"unused\0"
85     );
86     assert_eq!(foo_fields[1].offset, 0);
87     assert_eq!(foo_fields[1].num_offset, 0);
88     assert_eq!(foo_fields[1].info, unsafe { &vmstate_info_unused_buffer });
89     assert_eq!(foo_fields[1].version_id, 0);
90     assert_eq!(foo_fields[1].size, 8);
91     assert_eq!(foo_fields[1].num, 0);
92     assert_eq!(foo_fields[1].flags, VMStateFlags::VMS_BUFFER);
93     assert!(foo_fields[1].vmsd.is_null());
94     assert!(foo_fields[1].field_exists.is_none());
95 }
96 
97 #[test]
test_vmstate_varray_uint16_unsafe()98 fn test_vmstate_varray_uint16_unsafe() {
99     let foo_fields: &[VMStateField] = unsafe { slice::from_raw_parts(VMSTATE_FOOA.fields, 5) };
100 
101     // 3rd VMStateField ("arr") in VMSTATE_FOOA (corresponding to
102     // VMSTATE_VARRAY_UINT16_UNSAFE)
103     assert_eq!(
104         unsafe { CStr::from_ptr(foo_fields[2].name) }.to_bytes_with_nul(),
105         b"arr\0"
106     );
107     assert_eq!(foo_fields[2].offset, 0);
108     assert_eq!(foo_fields[2].num_offset, 4);
109     assert_eq!(foo_fields[2].info, unsafe { &vmstate_info_uint8 });
110     assert_eq!(foo_fields[2].version_id, 0);
111     assert_eq!(foo_fields[2].size, 1);
112     assert_eq!(foo_fields[2].num, 0);
113     assert_eq!(foo_fields[2].flags, VMStateFlags::VMS_VARRAY_UINT16);
114     assert!(foo_fields[2].vmsd.is_null());
115     assert!(foo_fields[2].field_exists.is_none());
116 }
117 
118 #[test]
test_vmstate_varray_multiply()119 fn test_vmstate_varray_multiply() {
120     let foo_fields: &[VMStateField] = unsafe { slice::from_raw_parts(VMSTATE_FOOA.fields, 5) };
121 
122     // 4th VMStateField ("arr_mul") in VMSTATE_FOOA (corresponding to
123     // VMSTATE_VARRAY_MULTIPLY)
124     assert_eq!(
125         unsafe { CStr::from_ptr(foo_fields[3].name) }.to_bytes_with_nul(),
126         b"arr_mul\0"
127     );
128     assert_eq!(foo_fields[3].offset, 6);
129     assert_eq!(foo_fields[3].num_offset, 12);
130     assert_eq!(foo_fields[3].info, unsafe { &vmstate_info_int8 });
131     assert_eq!(foo_fields[3].version_id, 0);
132     assert_eq!(foo_fields[3].size, 1);
133     assert_eq!(foo_fields[3].num, 16);
134     assert_eq!(
135         foo_fields[3].flags.0,
136         VMStateFlags::VMS_VARRAY_UINT32.0 | VMStateFlags::VMS_MULTIPLY_ELEMENTS.0
137     );
138     assert!(foo_fields[3].vmsd.is_null());
139     assert!(foo_fields[3].field_exists.is_none());
140 
141     // The last VMStateField in VMSTATE_FOOA.
142     assert_eq!(foo_fields[4].flags, VMStateFlags::VMS_END);
143 }
144 
145 // =========================== Test VMSTATE_FOOB ===========================
146 // Test the use cases of the vmstate macro, corresponding to the following C
147 // macro variants:
148 //   * VMSTATE_FOOB:
149 //     - VMSTATE_BOOL_V
150 //     - VMSTATE_U64
151 //     - VMSTATE_STRUCT_VARRAY_UINT8
152 //     - (no C version) MULTIPLY variant of VMSTATE_STRUCT_VARRAY_UINT32
153 //     - VMSTATE_ARRAY
154 //     - VMSTATE_STRUCT_VARRAY_UINT8 with BqlCell wrapper & test_fn
155 #[repr(C)]
156 #[derive(Default)]
157 struct FooB {
158     arr_a: [FooA; FOO_ARRAY_MAX],
159     num_a: u8,
160     arr_a_mul: [FooA; FOO_ARRAY_MAX],
161     num_a_mul: u32,
162     wrap: BqlCell<u64>,
163     val: bool,
164     // FIXME: Use Timer array. Now we can't since it's hard to link savevm.c to test.
165     arr_i64: [i64; FOO_ARRAY_MAX],
166     arr_a_wrap: [FooA; FOO_ARRAY_MAX],
167     num_a_wrap: BqlCell<u32>,
168 }
169 
validate_foob(_state: &FooB, _version_id: u8) -> bool170 fn validate_foob(_state: &FooB, _version_id: u8) -> bool {
171     true
172 }
173 
174 static VMSTATE_FOOB: VMStateDescription = VMStateDescription {
175     name: c"foo_b".as_ptr(),
176     version_id: 2,
177     minimum_version_id: 1,
178     fields: vmstate_fields! {
179         vmstate_of!(FooB, val).with_version_id(2),
180         vmstate_of!(FooB, wrap),
181         vmstate_struct!(FooB, arr_a[0 .. num_a], &VMSTATE_FOOA, FooA).with_version_id(1),
182         vmstate_struct!(FooB, arr_a_mul[0 .. num_a_mul * 32], &VMSTATE_FOOA, FooA).with_version_id(2),
183         vmstate_of!(FooB, arr_i64),
184         vmstate_struct!(FooB, arr_a_wrap[0 .. num_a_wrap], &VMSTATE_FOOA, FooA, validate_foob),
185     },
186     ..Zeroable::ZERO
187 };
188 
189 #[test]
test_vmstate_bool_v()190 fn test_vmstate_bool_v() {
191     let foo_fields: &[VMStateField] = unsafe { slice::from_raw_parts(VMSTATE_FOOB.fields, 7) };
192 
193     // 1st VMStateField ("val") in VMSTATE_FOOB (corresponding to VMSTATE_BOOL_V)
194     assert_eq!(
195         unsafe { CStr::from_ptr(foo_fields[0].name) }.to_bytes_with_nul(),
196         b"val\0"
197     );
198     assert_eq!(foo_fields[0].offset, 136);
199     assert_eq!(foo_fields[0].num_offset, 0);
200     assert_eq!(foo_fields[0].info, unsafe { &vmstate_info_bool });
201     assert_eq!(foo_fields[0].version_id, 2);
202     assert_eq!(foo_fields[0].size, 1);
203     assert_eq!(foo_fields[0].num, 0);
204     assert_eq!(foo_fields[0].flags, VMStateFlags::VMS_SINGLE);
205     assert!(foo_fields[0].vmsd.is_null());
206     assert!(foo_fields[0].field_exists.is_none());
207 }
208 
209 #[test]
test_vmstate_uint64()210 fn test_vmstate_uint64() {
211     let foo_fields: &[VMStateField] = unsafe { slice::from_raw_parts(VMSTATE_FOOB.fields, 7) };
212 
213     // 2nd VMStateField ("wrap") in VMSTATE_FOOB (corresponding to VMSTATE_U64)
214     assert_eq!(
215         unsafe { CStr::from_ptr(foo_fields[1].name) }.to_bytes_with_nul(),
216         b"wrap\0"
217     );
218     assert_eq!(foo_fields[1].offset, 128);
219     assert_eq!(foo_fields[1].num_offset, 0);
220     assert_eq!(foo_fields[1].info, unsafe { &vmstate_info_uint64 });
221     assert_eq!(foo_fields[1].version_id, 0);
222     assert_eq!(foo_fields[1].size, 8);
223     assert_eq!(foo_fields[1].num, 0);
224     assert_eq!(foo_fields[1].flags, VMStateFlags::VMS_SINGLE);
225     assert!(foo_fields[1].vmsd.is_null());
226     assert!(foo_fields[1].field_exists.is_none());
227 }
228 
229 #[test]
test_vmstate_struct_varray_uint8()230 fn test_vmstate_struct_varray_uint8() {
231     let foo_fields: &[VMStateField] = unsafe { slice::from_raw_parts(VMSTATE_FOOB.fields, 7) };
232 
233     // 3rd VMStateField ("arr_a") in VMSTATE_FOOB (corresponding to
234     // VMSTATE_STRUCT_VARRAY_UINT8)
235     assert_eq!(
236         unsafe { CStr::from_ptr(foo_fields[2].name) }.to_bytes_with_nul(),
237         b"arr_a\0"
238     );
239     assert_eq!(foo_fields[2].offset, 0);
240     assert_eq!(foo_fields[2].num_offset, 60);
241     assert!(foo_fields[2].info.is_null()); // VMSTATE_STRUCT_VARRAY_UINT8 doesn't set info field.
242     assert_eq!(foo_fields[2].version_id, 1);
243     assert_eq!(foo_fields[2].size, 20);
244     assert_eq!(foo_fields[2].num, 0);
245     assert_eq!(
246         foo_fields[2].flags.0,
247         VMStateFlags::VMS_STRUCT.0 | VMStateFlags::VMS_VARRAY_UINT8.0
248     );
249     assert_eq!(foo_fields[2].vmsd, &VMSTATE_FOOA);
250     assert!(foo_fields[2].field_exists.is_none());
251 }
252 
253 #[test]
test_vmstate_struct_varray_uint32_multiply()254 fn test_vmstate_struct_varray_uint32_multiply() {
255     let foo_fields: &[VMStateField] = unsafe { slice::from_raw_parts(VMSTATE_FOOB.fields, 7) };
256 
257     // 4th VMStateField ("arr_a_mul") in VMSTATE_FOOB (corresponding to
258     // (no C version) MULTIPLY variant of VMSTATE_STRUCT_VARRAY_UINT32)
259     assert_eq!(
260         unsafe { CStr::from_ptr(foo_fields[3].name) }.to_bytes_with_nul(),
261         b"arr_a_mul\0"
262     );
263     assert_eq!(foo_fields[3].offset, 64);
264     assert_eq!(foo_fields[3].num_offset, 124);
265     assert!(foo_fields[3].info.is_null()); // VMSTATE_STRUCT_VARRAY_UINT8 doesn't set info field.
266     assert_eq!(foo_fields[3].version_id, 2);
267     assert_eq!(foo_fields[3].size, 20);
268     assert_eq!(foo_fields[3].num, 32);
269     assert_eq!(
270         foo_fields[3].flags.0,
271         VMStateFlags::VMS_STRUCT.0
272             | VMStateFlags::VMS_VARRAY_UINT32.0
273             | VMStateFlags::VMS_MULTIPLY_ELEMENTS.0
274     );
275     assert_eq!(foo_fields[3].vmsd, &VMSTATE_FOOA);
276     assert!(foo_fields[3].field_exists.is_none());
277 }
278 
279 #[test]
test_vmstate_macro_array()280 fn test_vmstate_macro_array() {
281     let foo_fields: &[VMStateField] = unsafe { slice::from_raw_parts(VMSTATE_FOOB.fields, 7) };
282 
283     // 5th VMStateField ("arr_i64") in VMSTATE_FOOB (corresponding to
284     // VMSTATE_ARRAY)
285     assert_eq!(
286         unsafe { CStr::from_ptr(foo_fields[4].name) }.to_bytes_with_nul(),
287         b"arr_i64\0"
288     );
289     assert_eq!(foo_fields[4].offset, 144);
290     assert_eq!(foo_fields[4].num_offset, 0);
291     assert_eq!(foo_fields[4].info, unsafe { &vmstate_info_int64 });
292     assert_eq!(foo_fields[4].version_id, 0);
293     assert_eq!(foo_fields[4].size, 8);
294     assert_eq!(foo_fields[4].num, FOO_ARRAY_MAX as i32);
295     assert_eq!(foo_fields[4].flags, VMStateFlags::VMS_ARRAY);
296     assert!(foo_fields[4].vmsd.is_null());
297     assert!(foo_fields[4].field_exists.is_none());
298 }
299 
300 #[test]
test_vmstate_struct_varray_uint8_wrapper()301 fn test_vmstate_struct_varray_uint8_wrapper() {
302     let foo_fields: &[VMStateField] = unsafe { slice::from_raw_parts(VMSTATE_FOOB.fields, 7) };
303     let mut foo_b: FooB = Default::default();
304     let foo_b_p = std::ptr::addr_of_mut!(foo_b).cast::<c_void>();
305 
306     // 6th VMStateField ("arr_a_wrap") in VMSTATE_FOOB (corresponding to
307     // VMSTATE_STRUCT_VARRAY_UINT8). Other fields are checked in
308     // test_vmstate_struct_varray_uint8.
309     assert_eq!(
310         unsafe { CStr::from_ptr(foo_fields[5].name) }.to_bytes_with_nul(),
311         b"arr_a_wrap\0"
312     );
313     assert_eq!(foo_fields[5].num_offset, 228);
314     assert!(unsafe { foo_fields[5].field_exists.unwrap()(foo_b_p, 0) });
315 
316     // The last VMStateField in VMSTATE_FOOB.
317     assert_eq!(foo_fields[6].flags, VMStateFlags::VMS_END);
318 }
319 
320 // =========================== Test VMSTATE_FOOC ===========================
321 // Test the use cases of the vmstate macro, corresponding to the following C
322 // macro variants:
323 //   * VMSTATE_FOOC:
324 //     - VMSTATE_POINTER
325 //     - VMSTATE_ARRAY_OF_POINTER
326 struct FooCWrapper([Opaque<*mut u8>; FOO_ARRAY_MAX]); // Though Opaque<> array is almost impossible.
327 
328 impl_vmstate_forward!(FooCWrapper);
329 
330 #[repr(C)]
331 struct FooC {
332     ptr: *const i32,
333     ptr_a: NonNull<FooA>,
334     arr_ptr: [Box<u8>; FOO_ARRAY_MAX],
335     arr_ptr_wrap: FooCWrapper,
336 }
337 
338 static VMSTATE_FOOC: VMStateDescription = VMStateDescription {
339     name: c"foo_c".as_ptr(),
340     version_id: 3,
341     minimum_version_id: 1,
342     fields: vmstate_fields! {
343         vmstate_of!(FooC, ptr).with_version_id(2),
344         // FIXME: Currently vmstate_struct doesn't support the pointer to structure.
345         // VMSTATE_STRUCT_POINTER: vmstate_struct!(FooC, ptr_a, VMSTATE_FOOA, NonNull<FooA>)
346         vmstate_unused!(size_of::<NonNull<FooA>>()),
347         vmstate_of!(FooC, arr_ptr),
348         vmstate_of!(FooC, arr_ptr_wrap),
349     },
350     ..Zeroable::ZERO
351 };
352 
353 const PTR_SIZE: usize = size_of::<*mut ()>();
354 
355 #[test]
test_vmstate_pointer()356 fn test_vmstate_pointer() {
357     let foo_fields: &[VMStateField] = unsafe { slice::from_raw_parts(VMSTATE_FOOC.fields, 6) };
358 
359     // 1st VMStateField ("ptr") in VMSTATE_FOOC (corresponding to VMSTATE_POINTER)
360     assert_eq!(
361         unsafe { CStr::from_ptr(foo_fields[0].name) }.to_bytes_with_nul(),
362         b"ptr\0"
363     );
364     assert_eq!(foo_fields[0].offset, 0);
365     assert_eq!(foo_fields[0].num_offset, 0);
366     assert_eq!(foo_fields[0].info, unsafe { &vmstate_info_int32 });
367     assert_eq!(foo_fields[0].version_id, 2);
368     assert_eq!(foo_fields[0].size, 4);
369     assert_eq!(foo_fields[0].num, 0);
370     assert_eq!(
371         foo_fields[0].flags.0,
372         VMStateFlags::VMS_SINGLE.0 | VMStateFlags::VMS_POINTER.0
373     );
374     assert!(foo_fields[0].vmsd.is_null());
375     assert!(foo_fields[0].field_exists.is_none());
376 }
377 
378 #[test]
test_vmstate_macro_array_of_pointer()379 fn test_vmstate_macro_array_of_pointer() {
380     let foo_fields: &[VMStateField] = unsafe { slice::from_raw_parts(VMSTATE_FOOC.fields, 6) };
381 
382     // 3rd VMStateField ("arr_ptr") in VMSTATE_FOOC (corresponding to
383     // VMSTATE_ARRAY_OF_POINTER)
384     assert_eq!(
385         unsafe { CStr::from_ptr(foo_fields[2].name) }.to_bytes_with_nul(),
386         b"arr_ptr\0"
387     );
388     assert_eq!(foo_fields[2].offset, 2 * PTR_SIZE);
389     assert_eq!(foo_fields[2].num_offset, 0);
390     assert_eq!(foo_fields[2].info, unsafe { &vmstate_info_uint8 });
391     assert_eq!(foo_fields[2].version_id, 0);
392     assert_eq!(foo_fields[2].size, PTR_SIZE);
393     assert_eq!(foo_fields[2].num, FOO_ARRAY_MAX as i32);
394     assert_eq!(
395         foo_fields[2].flags.0,
396         VMStateFlags::VMS_ARRAY.0 | VMStateFlags::VMS_ARRAY_OF_POINTER.0
397     );
398     assert!(foo_fields[2].vmsd.is_null());
399     assert!(foo_fields[2].field_exists.is_none());
400 }
401 
402 #[test]
test_vmstate_macro_array_of_pointer_wrapped()403 fn test_vmstate_macro_array_of_pointer_wrapped() {
404     let foo_fields: &[VMStateField] = unsafe { slice::from_raw_parts(VMSTATE_FOOC.fields, 6) };
405 
406     // 4th VMStateField ("arr_ptr_wrap") in VMSTATE_FOOC (corresponding to
407     // VMSTATE_ARRAY_OF_POINTER)
408     assert_eq!(
409         unsafe { CStr::from_ptr(foo_fields[3].name) }.to_bytes_with_nul(),
410         b"arr_ptr_wrap\0"
411     );
412     assert_eq!(foo_fields[3].offset, (FOO_ARRAY_MAX + 2) * PTR_SIZE);
413     assert_eq!(foo_fields[3].num_offset, 0);
414     assert_eq!(foo_fields[3].info, unsafe { &vmstate_info_uint8 });
415     assert_eq!(foo_fields[3].version_id, 0);
416     assert_eq!(foo_fields[3].size, PTR_SIZE);
417     assert_eq!(foo_fields[3].num, FOO_ARRAY_MAX as i32);
418     assert_eq!(
419         foo_fields[3].flags.0,
420         VMStateFlags::VMS_ARRAY.0 | VMStateFlags::VMS_ARRAY_OF_POINTER.0
421     );
422     assert!(foo_fields[3].vmsd.is_null());
423     assert!(foo_fields[3].field_exists.is_none());
424 
425     // The last VMStateField in VMSTATE_FOOC.
426     assert_eq!(foo_fields[4].flags, VMStateFlags::VMS_END);
427 }
428 
429 // =========================== Test VMSTATE_FOOD ===========================
430 // Test the use cases of the vmstate macro, corresponding to the following C
431 // macro variants:
432 //   * VMSTATE_FOOD:
433 //     - VMSTATE_VALIDATE
434 
435 // Add more member fields when vmstate_of/vmstate_struct support "test"
436 // parameter.
437 struct FooD;
438 
439 impl FooD {
validate_food_0(&self, _version_id: u8) -> bool440     fn validate_food_0(&self, _version_id: u8) -> bool {
441         true
442     }
443 
validate_food_1(_state: &FooD, _version_id: u8) -> bool444     fn validate_food_1(_state: &FooD, _version_id: u8) -> bool {
445         false
446     }
447 }
448 
validate_food_2(_state: &FooD, _version_id: u8) -> bool449 fn validate_food_2(_state: &FooD, _version_id: u8) -> bool {
450     true
451 }
452 
453 static VMSTATE_FOOD: VMStateDescription = VMStateDescription {
454     name: c"foo_d".as_ptr(),
455     version_id: 3,
456     minimum_version_id: 1,
457     fields: vmstate_fields! {
458         vmstate_validate!(FooD, c"foo_d_0", FooD::validate_food_0),
459         vmstate_validate!(FooD, c"foo_d_1", FooD::validate_food_1),
460         vmstate_validate!(FooD, c"foo_d_2", validate_food_2),
461     },
462     ..Zeroable::ZERO
463 };
464 
465 #[test]
test_vmstate_validate()466 fn test_vmstate_validate() {
467     let foo_fields: &[VMStateField] = unsafe { slice::from_raw_parts(VMSTATE_FOOD.fields, 4) };
468     let mut foo_d = FooD;
469     let foo_d_p = std::ptr::addr_of_mut!(foo_d).cast::<c_void>();
470 
471     // 1st VMStateField in VMSTATE_FOOD
472     assert_eq!(
473         unsafe { CStr::from_ptr(foo_fields[0].name) }.to_bytes_with_nul(),
474         b"foo_d_0\0"
475     );
476     assert_eq!(foo_fields[0].offset, 0);
477     assert_eq!(foo_fields[0].num_offset, 0);
478     assert!(foo_fields[0].info.is_null());
479     assert_eq!(foo_fields[0].version_id, 0);
480     assert_eq!(foo_fields[0].size, 0);
481     assert_eq!(foo_fields[0].num, 0);
482     assert_eq!(
483         foo_fields[0].flags.0,
484         VMStateFlags::VMS_ARRAY.0 | VMStateFlags::VMS_MUST_EXIST.0
485     );
486     assert!(foo_fields[0].vmsd.is_null());
487     assert!(unsafe { foo_fields[0].field_exists.unwrap()(foo_d_p, 0) });
488 
489     // 2nd VMStateField in VMSTATE_FOOD
490     assert_eq!(
491         unsafe { CStr::from_ptr(foo_fields[1].name) }.to_bytes_with_nul(),
492         b"foo_d_1\0"
493     );
494     assert!(!unsafe { foo_fields[1].field_exists.unwrap()(foo_d_p, 1) });
495 
496     // 3rd VMStateField in VMSTATE_FOOD
497     assert_eq!(
498         unsafe { CStr::from_ptr(foo_fields[2].name) }.to_bytes_with_nul(),
499         b"foo_d_2\0"
500     );
501     assert!(unsafe { foo_fields[2].field_exists.unwrap()(foo_d_p, 2) });
502 
503     // The last VMStateField in VMSTATE_FOOD.
504     assert_eq!(foo_fields[3].flags, VMStateFlags::VMS_END);
505 }
506