rust: repurpose qemu_api -> tests

The crate purpose is only to provide integration tests at this point,
that can't easily be moved to a specific crate.

It's also often a good practice to have a single integration test crate
(see for ex https://github.com/rust-lang/cargo/issues/4867)

Drop README.md, use docs/devel/rust.rst instead.

Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
Link: https://lore.kernel.org/r/20250827104147.717203-20-marcandre.lureau@redhat.com
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

rust/tests/Cargo.toml

@@ -0,0 +1,27 @@
+[package]
+name = "tests"
+version = "0.1.0"
+description = "Rust integration tests for QEMU"
+resolver = "2"
+publish = false
+
+authors.workspace = true
+edition.workspace = true
+homepage.workspace = true
+license.workspace = true
+repository.workspace = true
+rust-version.workspace = true
+
+[dependencies]
+common = { path = "../common" }
+chardev = { path = "../chardev" }
+hwcore = { path = "../hw/core" }
+migration = { path = "../migration" }
+util = { path = "../util" }
+bql = { path = "../bql" }
+qemu_macros = { path = "../qemu-macros" }
+qom = { path = "../qom" }
+system = { path = "../system" }
+
+[lints]
+workspace = true

rust/tests/meson.build

@@ -0,0 +1,14 @@
+test('rust-integration',
+    executable(
+        'rust-integration',
+        files('tests/vmstate_tests.rs'),
+        override_options: ['rust_std=2021', 'build.rust_std=2021'],
+        rust_args: ['--test'],
+        install: false,
+        dependencies: [bql_rs, common_rs, util_rs, migration_rs, qom_rs]),
+    args: [
+        '--test', '--test-threads', '1',
+        '--format', 'pretty',
+    ],
+    protocol: 'rust',
+    suite: ['unit', 'rust'])

rust/tests/tests/vmstate_tests.rs

@@ -0,0 +1,541 @@
+// Copyright (C) 2025 Intel Corporation.
+// Author(s): Zhao Liu <zhao1.liu@intel.com>
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+use std::{
+    ffi::{c_void, CStr},
+    mem::size_of,
+    ptr::NonNull,
+    slice,
+};
+
+use bql::BqlCell;
+use common::Opaque;
+use migration::{
+    bindings::{
+        vmstate_info_bool, vmstate_info_int32, vmstate_info_int64, vmstate_info_int8,
+        vmstate_info_uint64, vmstate_info_uint8, vmstate_info_unused_buffer, VMStateFlags,
+    },
+    impl_vmstate_forward, impl_vmstate_struct,
+    vmstate::{VMStateDescription, VMStateDescriptionBuilder, VMStateField},
+    vmstate_fields, vmstate_of, vmstate_unused, vmstate_validate,
+};
+
+const FOO_ARRAY_MAX: usize = 3;
+
+// =========================== Test VMSTATE_FOOA ===========================
+// Test the use cases of the vmstate macro, corresponding to the following C
+// macro variants:
+//   * VMSTATE_FOOA:
+//     - VMSTATE_U16
+//     - VMSTATE_UNUSED
+//     - VMSTATE_VARRAY_UINT16_UNSAFE
+//     - VMSTATE_VARRAY_MULTIPLY
+#[repr(C)]
+#[derive(Default)]
+struct FooA {
+    arr: [u8; FOO_ARRAY_MAX],
+    num: u16,
+    arr_mul: [i8; FOO_ARRAY_MAX],
+    num_mul: u32,
+    elem: i8,
+}
+
+static VMSTATE_FOOA: VMStateDescription<FooA> = VMStateDescriptionBuilder::<FooA>::new()
+    .name(c"foo_a")
+    .version_id(1)
+    .minimum_version_id(1)
+    .fields(vmstate_fields! {
+        vmstate_of!(FooA, elem),
+        vmstate_unused!(size_of::<i64>()),
+        vmstate_of!(FooA, arr[0 .. num]).with_version_id(0),
+        vmstate_of!(FooA, arr_mul[0 .. num_mul * 16]),
+    })
+    .build();
+
+impl_vmstate_struct!(FooA, VMSTATE_FOOA);
+
+#[test]
+fn test_vmstate_uint16() {
+    let foo_fields: &[VMStateField] =
+        unsafe { slice::from_raw_parts(VMSTATE_FOOA.as_ref().fields, 5) };
+
+    // 1st VMStateField ("elem") in VMSTATE_FOOA (corresponding to VMSTATE_UINT16)
+    assert_eq!(
+        unsafe { CStr::from_ptr(foo_fields[0].name) }.to_bytes_with_nul(),
+        b"elem\0"
+    );
+    assert_eq!(foo_fields[0].offset, 16);
+    assert_eq!(foo_fields[0].num_offset, 0);
+    assert_eq!(foo_fields[0].info, unsafe { &vmstate_info_int8 });
+    assert_eq!(foo_fields[0].version_id, 0);
+    assert_eq!(foo_fields[0].size, 1);
+    assert_eq!(foo_fields[0].num, 0);
+    assert_eq!(foo_fields[0].flags, VMStateFlags::VMS_SINGLE);
+    assert!(foo_fields[0].vmsd.is_null());
+    assert!(foo_fields[0].field_exists.is_none());
+}
+
+#[test]
+fn test_vmstate_unused() {
+    let foo_fields: &[VMStateField] =
+        unsafe { slice::from_raw_parts(VMSTATE_FOOA.as_ref().fields, 5) };
+
+    // 2nd VMStateField ("unused") in VMSTATE_FOOA (corresponding to VMSTATE_UNUSED)
+    assert_eq!(
+        unsafe { CStr::from_ptr(foo_fields[1].name) }.to_bytes_with_nul(),
+        b"unused\0"
+    );
+    assert_eq!(foo_fields[1].offset, 0);
+    assert_eq!(foo_fields[1].num_offset, 0);
+    assert_eq!(foo_fields[1].info, unsafe { &vmstate_info_unused_buffer });
+    assert_eq!(foo_fields[1].version_id, 0);
+    assert_eq!(foo_fields[1].size, 8);
+    assert_eq!(foo_fields[1].num, 0);
+    assert_eq!(foo_fields[1].flags, VMStateFlags::VMS_BUFFER);
+    assert!(foo_fields[1].vmsd.is_null());
+    assert!(foo_fields[1].field_exists.is_none());
+}
+
+#[test]
+fn test_vmstate_varray_uint16_unsafe() {
+    let foo_fields: &[VMStateField] =
+        unsafe { slice::from_raw_parts(VMSTATE_FOOA.as_ref().fields, 5) };
+
+    // 3rd VMStateField ("arr") in VMSTATE_FOOA (corresponding to
+    // VMSTATE_VARRAY_UINT16_UNSAFE)
+    assert_eq!(
+        unsafe { CStr::from_ptr(foo_fields[2].name) }.to_bytes_with_nul(),
+        b"arr\0"
+    );
+    assert_eq!(foo_fields[2].offset, 0);
+    assert_eq!(foo_fields[2].num_offset, 4);
+    assert_eq!(foo_fields[2].info, unsafe { &vmstate_info_uint8 });
+    assert_eq!(foo_fields[2].version_id, 0);
+    assert_eq!(foo_fields[2].size, 1);
+    assert_eq!(foo_fields[2].num, 0);
+    assert_eq!(foo_fields[2].flags, VMStateFlags::VMS_VARRAY_UINT16);
+    assert!(foo_fields[2].vmsd.is_null());
+    assert!(foo_fields[2].field_exists.is_none());
+}
+
+#[test]
+fn test_vmstate_varray_multiply() {
+    let foo_fields: &[VMStateField] =
+        unsafe { slice::from_raw_parts(VMSTATE_FOOA.as_ref().fields, 5) };
+
+    // 4th VMStateField ("arr_mul") in VMSTATE_FOOA (corresponding to
+    // VMSTATE_VARRAY_MULTIPLY)
+    assert_eq!(
+        unsafe { CStr::from_ptr(foo_fields[3].name) }.to_bytes_with_nul(),
+        b"arr_mul\0"
+    );
+    assert_eq!(foo_fields[3].offset, 6);
+    assert_eq!(foo_fields[3].num_offset, 12);
+    assert_eq!(foo_fields[3].info, unsafe { &vmstate_info_int8 });
+    assert_eq!(foo_fields[3].version_id, 0);
+    assert_eq!(foo_fields[3].size, 1);
+    assert_eq!(foo_fields[3].num, 16);
+    assert_eq!(
+        foo_fields[3].flags.0,
+        VMStateFlags::VMS_VARRAY_UINT32.0 | VMStateFlags::VMS_MULTIPLY_ELEMENTS.0
+    );
+    assert!(foo_fields[3].vmsd.is_null());
+    assert!(foo_fields[3].field_exists.is_none());
+
+    // The last VMStateField in VMSTATE_FOOA.
+    assert_eq!(foo_fields[4].flags, VMStateFlags::VMS_END);
+}
+
+// =========================== Test VMSTATE_FOOB ===========================
+// Test the use cases of the vmstate macro, corresponding to the following C
+// macro variants:
+//   * VMSTATE_FOOB:
+//     - VMSTATE_BOOL_V
+//     - VMSTATE_U64
+//     - VMSTATE_STRUCT_VARRAY_UINT8
+//     - (no C version) MULTIPLY variant of VMSTATE_STRUCT_VARRAY_UINT32
+//     - VMSTATE_ARRAY
+//     - VMSTATE_STRUCT_VARRAY_UINT8 with BqlCell wrapper & test_fn
+#[repr(C)]
+#[derive(Default)]
+struct FooB {
+    arr_a: [FooA; FOO_ARRAY_MAX],
+    num_a: u8,
+    arr_a_mul: [FooA; FOO_ARRAY_MAX],
+    num_a_mul: u32,
+    wrap: BqlCell<u64>,
+    val: bool,
+    // FIXME: Use Timer array. Now we can't since it's hard to link savevm.c to test.
+    arr_i64: [i64; FOO_ARRAY_MAX],
+    arr_a_wrap: [FooA; FOO_ARRAY_MAX],
+    num_a_wrap: BqlCell<u32>,
+}
+
+fn validate_foob(_state: &FooB, _version_id: u8) -> bool {
+    true
+}
+
+static VMSTATE_FOOB: VMStateDescription<FooB> = VMStateDescriptionBuilder::<FooB>::new()
+    .name(c"foo_b")
+    .version_id(2)
+    .minimum_version_id(1)
+    .fields(vmstate_fields! {
+        vmstate_of!(FooB, val).with_version_id(2),
+        vmstate_of!(FooB, wrap),
+        vmstate_of!(FooB, arr_a[0 .. num_a]).with_version_id(1),
+        vmstate_of!(FooB, arr_a_mul[0 .. num_a_mul * 32]).with_version_id(2),
+        vmstate_of!(FooB, arr_i64),
+        vmstate_of!(FooB, arr_a_wrap[0 .. num_a_wrap], validate_foob),
+    })
+    .build();
+
+#[test]
+fn test_vmstate_bool_v() {
+    let foo_fields: &[VMStateField] =
+        unsafe { slice::from_raw_parts(VMSTATE_FOOB.as_ref().fields, 7) };
+
+    // 1st VMStateField ("val") in VMSTATE_FOOB (corresponding to VMSTATE_BOOL_V)
+    assert_eq!(
+        unsafe { CStr::from_ptr(foo_fields[0].name) }.to_bytes_with_nul(),
+        b"val\0"
+    );
+    assert_eq!(foo_fields[0].offset, 136);
+    assert_eq!(foo_fields[0].num_offset, 0);
+    assert_eq!(foo_fields[0].info, unsafe { &vmstate_info_bool });
+    assert_eq!(foo_fields[0].version_id, 2);
+    assert_eq!(foo_fields[0].size, 1);
+    assert_eq!(foo_fields[0].num, 0);
+    assert_eq!(foo_fields[0].flags, VMStateFlags::VMS_SINGLE);
+    assert!(foo_fields[0].vmsd.is_null());
+    assert!(foo_fields[0].field_exists.is_none());
+}
+
+#[test]
+fn test_vmstate_uint64() {
+    let foo_fields: &[VMStateField] =
+        unsafe { slice::from_raw_parts(VMSTATE_FOOB.as_ref().fields, 7) };
+
+    // 2nd VMStateField ("wrap") in VMSTATE_FOOB (corresponding to VMSTATE_U64)
+    assert_eq!(
+        unsafe { CStr::from_ptr(foo_fields[1].name) }.to_bytes_with_nul(),
+        b"wrap\0"
+    );
+    assert_eq!(foo_fields[1].offset, 128);
+    assert_eq!(foo_fields[1].num_offset, 0);
+    assert_eq!(foo_fields[1].info, unsafe { &vmstate_info_uint64 });
+    assert_eq!(foo_fields[1].version_id, 0);
+    assert_eq!(foo_fields[1].size, 8);
+    assert_eq!(foo_fields[1].num, 0);
+    assert_eq!(foo_fields[1].flags, VMStateFlags::VMS_SINGLE);
+    assert!(foo_fields[1].vmsd.is_null());
+    assert!(foo_fields[1].field_exists.is_none());
+}
+
+#[test]
+fn test_vmstate_struct_varray_uint8() {
+    let foo_fields: &[VMStateField] =
+        unsafe { slice::from_raw_parts(VMSTATE_FOOB.as_ref().fields, 7) };
+
+    // 3rd VMStateField ("arr_a") in VMSTATE_FOOB (corresponding to
+    // VMSTATE_STRUCT_VARRAY_UINT8)
+    assert_eq!(
+        unsafe { CStr::from_ptr(foo_fields[2].name) }.to_bytes_with_nul(),
+        b"arr_a\0"
+    );
+    assert_eq!(foo_fields[2].offset, 0);
+    assert_eq!(foo_fields[2].num_offset, 60);
+    assert!(foo_fields[2].info.is_null()); // VMSTATE_STRUCT_VARRAY_UINT8 doesn't set info field.
+    assert_eq!(foo_fields[2].version_id, 1);
+    assert_eq!(foo_fields[2].size, 20);
+    assert_eq!(foo_fields[2].num, 0);
+    assert_eq!(
+        foo_fields[2].flags.0,
+        VMStateFlags::VMS_STRUCT.0 | VMStateFlags::VMS_VARRAY_UINT8.0
+    );
+    assert_eq!(foo_fields[2].vmsd, VMSTATE_FOOA.as_ref());
+    assert!(foo_fields[2].field_exists.is_none());
+}
+
+#[test]
+fn test_vmstate_struct_varray_uint32_multiply() {
+    let foo_fields: &[VMStateField] =
+        unsafe { slice::from_raw_parts(VMSTATE_FOOB.as_ref().fields, 7) };
+
+    // 4th VMStateField ("arr_a_mul") in VMSTATE_FOOB (corresponding to
+    // (no C version) MULTIPLY variant of VMSTATE_STRUCT_VARRAY_UINT32)
+    assert_eq!(
+        unsafe { CStr::from_ptr(foo_fields[3].name) }.to_bytes_with_nul(),
+        b"arr_a_mul\0"
+    );
+    assert_eq!(foo_fields[3].offset, 64);
+    assert_eq!(foo_fields[3].num_offset, 124);
+    assert!(foo_fields[3].info.is_null()); // VMSTATE_STRUCT_VARRAY_UINT8 doesn't set info field.
+    assert_eq!(foo_fields[3].version_id, 2);
+    assert_eq!(foo_fields[3].size, 20);
+    assert_eq!(foo_fields[3].num, 32);
+    assert_eq!(
+        foo_fields[3].flags.0,
+        VMStateFlags::VMS_STRUCT.0
+            | VMStateFlags::VMS_VARRAY_UINT32.0
+            | VMStateFlags::VMS_MULTIPLY_ELEMENTS.0
+    );
+    assert_eq!(foo_fields[3].vmsd, VMSTATE_FOOA.as_ref());
+    assert!(foo_fields[3].field_exists.is_none());
+}
+
+#[test]
+fn test_vmstate_macro_array() {
+    let foo_fields: &[VMStateField] =
+        unsafe { slice::from_raw_parts(VMSTATE_FOOB.as_ref().fields, 7) };
+
+    // 5th VMStateField ("arr_i64") in VMSTATE_FOOB (corresponding to
+    // VMSTATE_ARRAY)
+    assert_eq!(
+        unsafe { CStr::from_ptr(foo_fields[4].name) }.to_bytes_with_nul(),
+        b"arr_i64\0"
+    );
+    assert_eq!(foo_fields[4].offset, 144);
+    assert_eq!(foo_fields[4].num_offset, 0);
+    assert_eq!(foo_fields[4].info, unsafe { &vmstate_info_int64 });
+    assert_eq!(foo_fields[4].version_id, 0);
+    assert_eq!(foo_fields[4].size, 8);
+    assert_eq!(foo_fields[4].num, FOO_ARRAY_MAX as i32);
+    assert_eq!(foo_fields[4].flags, VMStateFlags::VMS_ARRAY);
+    assert!(foo_fields[4].vmsd.is_null());
+    assert!(foo_fields[4].field_exists.is_none());
+}
+
+#[test]
+fn test_vmstate_struct_varray_uint8_wrapper() {
+    let foo_fields: &[VMStateField] =
+        unsafe { slice::from_raw_parts(VMSTATE_FOOB.as_ref().fields, 7) };
+    let mut foo_b: FooB = Default::default();
+    let foo_b_p = std::ptr::addr_of_mut!(foo_b).cast::<c_void>();
+
+    // 6th VMStateField ("arr_a_wrap") in VMSTATE_FOOB (corresponding to
+    // VMSTATE_STRUCT_VARRAY_UINT8). Other fields are checked in
+    // test_vmstate_struct_varray_uint8.
+    assert_eq!(
+        unsafe { CStr::from_ptr(foo_fields[5].name) }.to_bytes_with_nul(),
+        b"arr_a_wrap\0"
+    );
+    assert_eq!(foo_fields[5].num_offset, 228);
+    assert!(unsafe { foo_fields[5].field_exists.unwrap()(foo_b_p, 0) });
+
+    // The last VMStateField in VMSTATE_FOOB.
+    assert_eq!(foo_fields[6].flags, VMStateFlags::VMS_END);
+}
+
+// =========================== Test VMSTATE_FOOC ===========================
+// Test the use cases of the vmstate macro, corresponding to the following C
+// macro variants:
+//   * VMSTATE_FOOC:
+//     - VMSTATE_POINTER
+//     - VMSTATE_ARRAY_OF_POINTER
+struct FooCWrapper([Opaque<*mut u8>; FOO_ARRAY_MAX]); // Though Opaque<> array is almost impossible.
+
+impl_vmstate_forward!(FooCWrapper);
+
+#[repr(C)]
+struct FooC {
+    ptr: *const i32,
+    ptr_a: NonNull<FooA>,
+    arr_ptr: [Box<u8>; FOO_ARRAY_MAX],
+    arr_ptr_wrap: FooCWrapper,
+}
+
+unsafe impl Sync for FooC {}
+
+static VMSTATE_FOOC: VMStateDescription<FooC> = VMStateDescriptionBuilder::<FooC>::new()
+    .name(c"foo_c")
+    .version_id(3)
+    .minimum_version_id(1)
+    .fields(vmstate_fields! {
+        vmstate_of!(FooC, ptr).with_version_id(2),
+        vmstate_of!(FooC, ptr_a),
+        vmstate_of!(FooC, arr_ptr),
+        vmstate_of!(FooC, arr_ptr_wrap),
+    })
+    .build();
+
+const PTR_SIZE: usize = size_of::<*mut ()>();
+
+#[test]
+fn test_vmstate_pointer() {
+    let foo_fields: &[VMStateField] =
+        unsafe { slice::from_raw_parts(VMSTATE_FOOC.as_ref().fields, 6) };
+
+    // 1st VMStateField ("ptr") in VMSTATE_FOOC (corresponding to VMSTATE_POINTER)
+    assert_eq!(
+        unsafe { CStr::from_ptr(foo_fields[0].name) }.to_bytes_with_nul(),
+        b"ptr\0"
+    );
+    assert_eq!(foo_fields[0].offset, 0);
+    assert_eq!(foo_fields[0].num_offset, 0);
+    assert_eq!(foo_fields[0].info, unsafe { &vmstate_info_int32 });
+    assert_eq!(foo_fields[0].version_id, 2);
+    assert_eq!(foo_fields[0].size, 4);
+    assert_eq!(foo_fields[0].num, 0);
+    assert_eq!(
+        foo_fields[0].flags.0,
+        VMStateFlags::VMS_SINGLE.0 | VMStateFlags::VMS_POINTER.0
+    );
+    assert!(foo_fields[0].vmsd.is_null());
+    assert!(foo_fields[0].field_exists.is_none());
+}
+
+#[test]
+fn test_vmstate_struct_pointer() {
+    let foo_fields: &[VMStateField] =
+        unsafe { slice::from_raw_parts(VMSTATE_FOOC.as_ref().fields, 6) };
+
+    // 2st VMStateField ("ptr_a") in VMSTATE_FOOC (corresponding to
+    // VMSTATE_STRUCT_POINTER)
+    assert_eq!(
+        unsafe { CStr::from_ptr(foo_fields[1].name) }.to_bytes_with_nul(),
+        b"ptr_a\0"
+    );
+    assert_eq!(foo_fields[1].offset, PTR_SIZE);
+    assert_eq!(foo_fields[1].num_offset, 0);
+    assert_eq!(foo_fields[1].vmsd, VMSTATE_FOOA.as_ref());
+    assert_eq!(foo_fields[1].version_id, 0);
+    assert_eq!(foo_fields[1].size, size_of::<FooA>());
+    assert_eq!(foo_fields[1].num, 0);
+    assert_eq!(
+        foo_fields[1].flags.0,
+        VMStateFlags::VMS_STRUCT.0 | VMStateFlags::VMS_POINTER.0
+    );
+    assert!(foo_fields[1].info.is_null());
+    assert!(foo_fields[1].field_exists.is_none());
+}
+
+#[test]
+fn test_vmstate_macro_array_of_pointer() {
+    let foo_fields: &[VMStateField] =
+        unsafe { slice::from_raw_parts(VMSTATE_FOOC.as_ref().fields, 6) };
+
+    // 3rd VMStateField ("arr_ptr") in VMSTATE_FOOC (corresponding to
+    // VMSTATE_ARRAY_OF_POINTER)
+    assert_eq!(
+        unsafe { CStr::from_ptr(foo_fields[2].name) }.to_bytes_with_nul(),
+        b"arr_ptr\0"
+    );
+    assert_eq!(foo_fields[2].offset, 2 * PTR_SIZE);
+    assert_eq!(foo_fields[2].num_offset, 0);
+    assert_eq!(foo_fields[2].info, unsafe { &vmstate_info_uint8 });
+    assert_eq!(foo_fields[2].version_id, 0);
+    assert_eq!(foo_fields[2].size, PTR_SIZE);
+    assert_eq!(foo_fields[2].num, FOO_ARRAY_MAX as i32);
+    assert_eq!(
+        foo_fields[2].flags.0,
+        VMStateFlags::VMS_ARRAY.0 | VMStateFlags::VMS_ARRAY_OF_POINTER.0
+    );
+    assert!(foo_fields[2].vmsd.is_null());
+    assert!(foo_fields[2].field_exists.is_none());
+}
+
+#[test]
+fn test_vmstate_macro_array_of_pointer_wrapped() {
+    let foo_fields: &[VMStateField] =
+        unsafe { slice::from_raw_parts(VMSTATE_FOOC.as_ref().fields, 6) };
+
+    // 4th VMStateField ("arr_ptr_wrap") in VMSTATE_FOOC (corresponding to
+    // VMSTATE_ARRAY_OF_POINTER)
+    assert_eq!(
+        unsafe { CStr::from_ptr(foo_fields[3].name) }.to_bytes_with_nul(),
+        b"arr_ptr_wrap\0"
+    );
+    assert_eq!(foo_fields[3].offset, (FOO_ARRAY_MAX + 2) * PTR_SIZE);
+    assert_eq!(foo_fields[3].num_offset, 0);
+    assert_eq!(foo_fields[3].info, unsafe { &vmstate_info_uint8 });
+    assert_eq!(foo_fields[3].version_id, 0);
+    assert_eq!(foo_fields[3].size, PTR_SIZE);
+    assert_eq!(foo_fields[3].num, FOO_ARRAY_MAX as i32);
+    assert_eq!(
+        foo_fields[3].flags.0,
+        VMStateFlags::VMS_ARRAY.0 | VMStateFlags::VMS_ARRAY_OF_POINTER.0
+    );
+    assert!(foo_fields[3].vmsd.is_null());
+    assert!(foo_fields[3].field_exists.is_none());
+
+    // The last VMStateField in VMSTATE_FOOC.
+    assert_eq!(foo_fields[4].flags, VMStateFlags::VMS_END);
+}
+
+// =========================== Test VMSTATE_FOOD ===========================
+// Test the use cases of the vmstate macro, corresponding to the following C
+// macro variants:
+//   * VMSTATE_FOOD:
+//     - VMSTATE_VALIDATE
+
+// Add more member fields when vmstate_of support "test" parameter.
+struct FooD;
+
+impl FooD {
+    fn validate_food_0(&self, _version_id: u8) -> bool {
+        true
+    }
+
+    fn validate_food_1(_state: &FooD, _version_id: u8) -> bool {
+        false
+    }
+}
+
+fn validate_food_2(_state: &FooD, _version_id: u8) -> bool {
+    true
+}
+
+static VMSTATE_FOOD: VMStateDescription<FooD> = VMStateDescriptionBuilder::<FooD>::new()
+    .name(c"foo_d")
+    .version_id(3)
+    .minimum_version_id(1)
+    .fields(vmstate_fields! {
+        vmstate_validate!(FooD, c"foo_d_0", FooD::validate_food_0),
+        vmstate_validate!(FooD, c"foo_d_1", FooD::validate_food_1),
+        vmstate_validate!(FooD, c"foo_d_2", validate_food_2),
+    })
+    .build();
+
+#[test]
+fn test_vmstate_validate() {
+    let foo_fields: &[VMStateField] =
+        unsafe { slice::from_raw_parts(VMSTATE_FOOD.as_ref().fields, 4) };
+    let mut foo_d = FooD;
+    let foo_d_p = std::ptr::addr_of_mut!(foo_d).cast::<c_void>();
+
+    // 1st VMStateField in VMSTATE_FOOD
+    assert_eq!(
+        unsafe { CStr::from_ptr(foo_fields[0].name) }.to_bytes_with_nul(),
+        b"foo_d_0\0"
+    );
+    assert_eq!(foo_fields[0].offset, 0);
+    assert_eq!(foo_fields[0].num_offset, 0);
+    assert!(foo_fields[0].info.is_null());
+    assert_eq!(foo_fields[0].version_id, 0);
+    assert_eq!(foo_fields[0].size, 0);
+    assert_eq!(foo_fields[0].num, 0);
+    assert_eq!(
+        foo_fields[0].flags.0,
+        VMStateFlags::VMS_ARRAY.0 | VMStateFlags::VMS_MUST_EXIST.0
+    );
+    assert!(foo_fields[0].vmsd.is_null());
+    assert!(unsafe { foo_fields[0].field_exists.unwrap()(foo_d_p, 0) });
+
+    // 2nd VMStateField in VMSTATE_FOOD
+    assert_eq!(
+        unsafe { CStr::from_ptr(foo_fields[1].name) }.to_bytes_with_nul(),
+        b"foo_d_1\0"
+    );
+    assert!(!unsafe { foo_fields[1].field_exists.unwrap()(foo_d_p, 1) });
+
+    // 3rd VMStateField in VMSTATE_FOOD
+    assert_eq!(
+        unsafe { CStr::from_ptr(foo_fields[2].name) }.to_bytes_with_nul(),
+        b"foo_d_2\0"
+    );
+    assert!(unsafe { foo_fields[2].field_exists.unwrap()(foo_d_p, 2) });
+
+    // The last VMStateField in VMSTATE_FOOD.
+    assert_eq!(foo_fields[3].flags, VMStateFlags::VMS_END);
+}