From 567c0c41a6700be72eb9e040ba0b8d7bf0cc5919 Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Thu, 13 Feb 2025 12:36:42 +0100
Subject: [PATCH] rust: pl011, qemu_api tests: do not use ClassInitImpl

Outside the qemu_api crate, orphan rules make the usage of ClassInitImpl
unwieldy.  Now that it is optional, do not use it.

For PL011Class, this makes it easier to provide a PL011Impl trait similar
to the ones in the qemu_api crate.  The device id consts are moved there.

Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 rust/hw/char/pl011/src/device.rs | 38 ++++++++++++++++----------------
 rust/qemu-api/tests/tests.rs     | 33 ++++++++++-----------------
 2 files changed, 31 insertions(+), 40 deletions(-)

diff --git a/rust/hw/char/pl011/src/device.rs b/rust/hw/char/pl011/src/device.rs
index ead361b3f5..094049cb9e 100644
--- a/rust/hw/char/pl011/src/device.rs
+++ b/rust/hw/char/pl011/src/device.rs
@@ -50,11 +50,6 @@ impl std::ops::Index<hwaddr> for DeviceId {
     }
 }
 
-impl DeviceId {
-    const ARM: Self = Self(&[0x11, 0x10, 0x14, 0x00, 0x0d, 0xf0, 0x05, 0xb1]);
-    const LUMINARY: Self = Self(&[0x11, 0x00, 0x18, 0x01, 0x0d, 0xf0, 0x05, 0xb1]);
-}
-
 // FIFOs use 32-bit indices instead of usize, for compatibility with
 // the migration stream produced by the C version of this device.
 #[repr(transparent)]
@@ -143,16 +138,24 @@ pub struct PL011Class {
     device_id: DeviceId,
 }
 
+trait PL011Impl: SysBusDeviceImpl + IsA<PL011State> {
+    const DEVICE_ID: DeviceId;
+}
+
+impl PL011Class {
+    fn class_init<T: PL011Impl>(&mut self) {
+        self.device_id = T::DEVICE_ID;
+        <T as ClassInitImpl<SysBusDeviceClass>>::class_init(&mut self.parent_class);
+    }
+}
+
 unsafe impl ObjectType for PL011State {
     type Class = PL011Class;
     const TYPE_NAME: &'static CStr = crate::TYPE_PL011;
 }
 
-impl ClassInitImpl<PL011Class> for PL011State {
-    fn class_init(klass: &mut PL011Class) {
-        klass.device_id = DeviceId::ARM;
-        <Self as ClassInitImpl<SysBusDeviceClass>>::class_init(&mut klass.parent_class);
-    }
+impl PL011Impl for PL011State {
+    const DEVICE_ID: DeviceId = DeviceId(&[0x11, 0x10, 0x14, 0x00, 0x0d, 0xf0, 0x05, 0xb1]);
 }
 
 impl ObjectImpl for PL011State {
@@ -160,7 +163,7 @@ impl ObjectImpl for PL011State {
 
     const INSTANCE_INIT: Option<unsafe fn(&mut Self)> = Some(Self::init);
     const INSTANCE_POST_INIT: Option<fn(&Self)> = Some(Self::post_init);
-    const CLASS_INIT: fn(&mut Self::Class) = <Self as ClassInitImpl<Self::Class>>::class_init;
+    const CLASS_INIT: fn(&mut Self::Class) = Self::Class::class_init::<Self>;
 }
 
 impl DeviceImpl for PL011State {
@@ -729,13 +732,6 @@ pub struct PL011Luminary {
     parent_obj: ParentField<PL011State>,
 }
 
-impl ClassInitImpl<PL011Class> for PL011Luminary {
-    fn class_init(klass: &mut PL011Class) {
-        klass.device_id = DeviceId::LUMINARY;
-        <Self as ClassInitImpl<SysBusDeviceClass>>::class_init(&mut klass.parent_class);
-    }
-}
-
 qom_isa!(PL011Luminary : PL011State, SysBusDevice, DeviceState, Object);
 
 unsafe impl ObjectType for PL011Luminary {
@@ -746,7 +742,11 @@ unsafe impl ObjectType for PL011Luminary {
 impl ObjectImpl for PL011Luminary {
     type ParentType = PL011State;
 
-    const CLASS_INIT: fn(&mut Self::Class) = <Self as ClassInitImpl<Self::Class>>::class_init;
+    const CLASS_INIT: fn(&mut Self::Class) = Self::Class::class_init::<Self>;
+}
+
+impl PL011Impl for PL011Luminary {
+    const DEVICE_ID: DeviceId = DeviceId(&[0x11, 0x00, 0x18, 0x01, 0x0d, 0xf0, 0x05, 0xb1]);
 }
 
 impl DeviceImpl for PL011Luminary {}
diff --git a/rust/qemu-api/tests/tests.rs b/rust/qemu-api/tests/tests.rs
index 9546e9d796..93c5637bbc 100644
--- a/rust/qemu-api/tests/tests.rs
+++ b/rust/qemu-api/tests/tests.rs
@@ -13,7 +13,7 @@ use qemu_api::{
     cell::{self, BqlCell},
     declare_properties, define_property,
     prelude::*,
-    qdev::{DeviceClass, DeviceImpl, DeviceState, Property, ResettablePhasesImpl},
+    qdev::{DeviceImpl, DeviceState, Property, ResettablePhasesImpl},
     qom::{ClassInitImpl, ObjectImpl, ParentField},
     sysbus::SysBusDevice,
     vmstate::VMStateDescription,
@@ -41,6 +41,12 @@ pub struct DummyClass {
     parent_class: <DeviceState as ObjectType>::Class,
 }
 
+impl DummyClass {
+    pub fn class_init<T: DeviceImpl>(self: &mut DummyClass) {
+        <T as ClassInitImpl<DeviceClass>>::class_init(&mut self.parent_class);
+    }
+}
+
 declare_properties! {
     DUMMY_PROPERTIES,
         define_property!(
@@ -60,7 +66,7 @@ unsafe impl ObjectType for DummyState {
 impl ObjectImpl for DummyState {
     type ParentType = DeviceState;
     const ABSTRACT: bool = false;
-    const CLASS_INIT: fn(&mut DummyClass) = <Self as ClassInitImpl<DummyClass>>::class_init;
+    const CLASS_INIT: fn(&mut DummyClass) = DummyClass::class_init::<Self>;
 }
 
 impl ResettablePhasesImpl for DummyState {}
@@ -74,14 +80,6 @@ impl DeviceImpl for DummyState {
     }
 }
 
-// `impl<T> ClassInitImpl<DummyClass> for T` doesn't work since it violates
-// orphan rule.
-impl ClassInitImpl<DummyClass> for DummyState {
-    fn class_init(klass: &mut DummyClass) {
-        <Self as ClassInitImpl<DeviceClass>>::class_init(&mut klass.parent_class);
-    }
-}
-
 #[derive(qemu_api_macros::offsets)]
 #[repr(C)]
 #[derive(qemu_api_macros::Object)]
@@ -103,22 +101,15 @@ unsafe impl ObjectType for DummyChildState {
 impl ObjectImpl for DummyChildState {
     type ParentType = DummyState;
     const ABSTRACT: bool = false;
-    const CLASS_INIT: fn(&mut DummyChildClass) =
-        <Self as ClassInitImpl<DummyChildClass>>::class_init;
+    const CLASS_INIT: fn(&mut DummyChildClass) = DummyChildClass::class_init::<Self>;
 }
 
 impl ResettablePhasesImpl for DummyChildState {}
 impl DeviceImpl for DummyChildState {}
 
-impl ClassInitImpl<DummyClass> for DummyChildState {
-    fn class_init(klass: &mut DummyClass) {
-        <Self as ClassInitImpl<DeviceClass>>::class_init(&mut klass.parent_class);
-    }
-}
-
-impl ClassInitImpl<DummyChildClass> for DummyChildState {
-    fn class_init(klass: &mut DummyChildClass) {
-        <Self as ClassInitImpl<DummyClass>>::class_init(&mut klass.parent_class);
+impl DummyChildClass {
+    pub fn class_init<T: DeviceImpl>(self: &mut DummyChildClass) {
+        self.parent_class.class_init::<T>();
     }
 }
 
-- 
2.30.2