[PULL 10/38] rust: qom: make INSTANCE_POST_INIT take a shared reference

[Paolo Bonzini]

Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 rust/hw/char/pl011/src/device.rs | 4 ++--
 rust/qemu-api/src/qom.rs         | 8 ++------
 2 files changed, 4 insertions(+), 8 deletions(-)

diff --git a/rust/hw/char/pl011/src/device.rs b/rust/hw/char/pl011/src/device.rs
index 72a4cea042c..6792d13fb77 100644
--- a/rust/hw/char/pl011/src/device.rs
+++ b/rust/hw/char/pl011/src/device.rs
@@ -145,7 +145,7 @@ impl ObjectImpl for PL011State {
     type ParentType = SysBusDevice;
 
     const INSTANCE_INIT: Option<unsafe fn(&mut Self)> = Some(Self::init);
-    const INSTANCE_POST_INIT: Option<fn(&mut Self)> = Some(Self::post_init);
+    const INSTANCE_POST_INIT: Option<fn(&Self)> = Some(Self::post_init);
 }
 
 impl DeviceImpl for PL011State {
@@ -206,7 +206,7 @@ unsafe fn init(&mut self) {
         }
     }
 
-    fn post_init(&mut self) {
+    fn post_init(&self) {
         let sbd: &SysBusDevice = self.upcast();
 
         sbd.init_mmio(&self.iomem);
diff --git a/rust/qemu-api/src/qom.rs b/rust/qemu-api/src/qom.rs
index b0332ba2477..97901fb9084 100644
--- a/rust/qemu-api/src/qom.rs
+++ b/rust/qemu-api/src/qom.rs
@@ -163,11 +163,7 @@ fn fmt(&self, f: &mut fmt::Formatter<'_>) -> Result<(), 
fmt::Error> {
     // SAFETY: obj is an instance of T, since rust_instance_post_init<T>
     // is called from QOM core as the instance_post_init function
     // for class T
-    //
-    // FIXME: it's not really guaranteed that there are no backpointers to
-    // obj; it's quite possible that they have been created by instance_init().
-    // The receiver should be &self, not &mut self.
-    T::INSTANCE_POST_INIT.unwrap()(unsafe { &mut *obj.cast::<T>() })
+    T::INSTANCE_POST_INIT.unwrap()(unsafe { &*obj.cast::<T>() })
 }
 
 unsafe extern "C" fn rust_class_init<T: ObjectType + ClassInitImpl<T::Class>>(
@@ -463,7 +459,7 @@ pub trait ObjectImpl: ObjectType + 
ClassInitImpl<Self::Class> {
 
     /// Function that is called to finish initialization of an object, once
     /// `INSTANCE_INIT` functions have been called.
-    const INSTANCE_POST_INIT: Option<fn(&mut Self)> = None;
+    const INSTANCE_POST_INIT: Option<fn(&Self)> = None;
 
     /// Called on descendent classes after all parent class initialization
     /// has occurred, but before the class itself is initialized.  This
-- 
2.47.1