From: Paolo Bonzini <pbonzini@redhat.com>
Date: Tue, 28 Oct 2025 11:21:29 +0000 (+0100)
Subject: rust: migration: allow passing ParentField<> to vmstate_of!
X-Git-Tag: v10.2.0-rc1~40^2
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=d4fbf6ff8d12cd11d53f7baa408f50fbb0441d87;p=thirdparty%2Fqemu.git

rust: migration: allow passing ParentField<> to vmstate_of!

The common superclass for devices could have its own migration state;
for it to be included in the subclass's VMState, ParentField<> must
implement the VMState trait.

Reported-by: Chen Miao <chenmiao@openatom.club>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---

diff --git a/rust/migration/src/vmstate.rs b/rust/migration/src/vmstate.rs
index 42e5df8d81..5a237c409a 100644
--- a/rust/migration/src/vmstate.rs
+++ b/rust/migration/src/vmstate.rs
@@ -268,7 +268,7 @@ macro_rules! impl_vmstate_transparent {
     ($type:ty where $base:tt: VMState $($where:tt)*) => {
         unsafe impl<$base> $crate::vmstate::VMState for $type where $base: $crate::vmstate::VMState $($where)* {
             const BASE: $crate::vmstate::VMStateField = $crate::vmstate::VMStateField {
-                size: mem::size_of::<$type>(),
+                size: ::core::mem::size_of::<$type>(),
                 ..<$base as $crate::vmstate::VMState>::BASE
             };
             const VARRAY_FLAG: $crate::bindings::VMStateFlags = <$base as $crate::vmstate::VMState>::VARRAY_FLAG;
@@ -282,6 +282,7 @@ impl_vmstate_transparent!(std::cell::Cell<T> where T: VMState);
 impl_vmstate_transparent!(std::cell::UnsafeCell<T> where T: VMState);
 impl_vmstate_transparent!(std::pin::Pin<T> where T: VMState);
 impl_vmstate_transparent!(common::Opaque<T> where T: VMState);
+impl_vmstate_transparent!(std::mem::ManuallyDrop<T> where T: VMState);
 
 #[macro_export]
 macro_rules! impl_vmstate_bitsized {
diff --git a/rust/qom/src/qom.rs b/rust/qom/src/qom.rs
index 5808051cd7..84455cea79 100644
--- a/rust/qom/src/qom.rs
+++ b/rust/qom/src/qom.rs
@@ -102,7 +102,7 @@ use std::{
 };
 
 use common::Opaque;
-use migration::impl_vmstate_pointer;
+use migration::{impl_vmstate_pointer, impl_vmstate_transparent};
 
 use crate::bindings::{
     self, object_class_dynamic_cast, object_dynamic_cast, object_get_class, object_get_typename,
@@ -182,6 +182,7 @@ macro_rules! qom_isa {
 #[derive(Debug)]
 #[repr(transparent)]
 pub struct ParentField<T: ObjectType>(std::mem::ManuallyDrop<T>);
+impl_vmstate_transparent!(ParentField<T> where T: VMState + ObjectType);
 
 impl<T: ObjectType> Deref for ParentField<T> {
     type Target = T;