rust: add SysBusDeviceImpl

The only function, right now, is to ensure that anything with a
SysBusDeviceClass class is a SysBusDevice.

Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

3 files changed, 12 insertions, 5 deletions

diff --git a/rust/hw/char/pl011/src/device.rs b/rust/hw/char/pl011/src/device.rs
index 59a689fdcd..bea9723aed 100644
--- a/rust/hw/char/pl011/src/device.rs
+++ b/rust/hw/char/pl011/src/device.rs
@@ -20,7 +20,7 @@ use qemu_api::{
     prelude::*,
     qdev::{Clock, ClockEvent, DeviceImpl, DeviceState, Property, ResetType, ResettablePhasesImpl},
     qom::{ClassInitImpl, ObjectImpl, Owned, ParentField},
-    sysbus::{SysBusDevice, SysBusDeviceClass},
+    sysbus::{SysBusDevice, SysBusDeviceClass, SysBusDeviceImpl},
     vmstate::VMStateDescription,
 };
 
@@ -176,6 +176,8 @@ impl ResettablePhasesImpl for PL011State {
     const HOLD: Option<fn(&Self, ResetType)> = Some(Self::reset_hold);
 }
 
+impl SysBusDeviceImpl for PL011State {}
+
 impl PL011Registers {
     pub(self) fn read(&mut self, offset: RegisterOffset) -> (bool, u32) {
         use RegisterOffset::*;
@@ -746,3 +748,4 @@ impl ObjectImpl for PL011Luminary {
 
 impl DeviceImpl for PL011Luminary {}
 impl ResettablePhasesImpl for PL011Luminary {}
+impl SysBusDeviceImpl for PL011Luminary {}
diff --git a/rust/hw/timer/hpet/src/hpet.rs b/rust/hw/timer/hpet/src/hpet.rs
index 75ff5b3e8d..b4ffccf815 100644
--- a/rust/hw/timer/hpet/src/hpet.rs
+++ b/rust/hw/timer/hpet/src/hpet.rs
@@ -23,7 +23,7 @@ use qemu_api::{
     qdev::{DeviceImpl, DeviceMethods, DeviceState, Property, ResetType, ResettablePhasesImpl},
     qom::{ObjectImpl, ObjectType, ParentField},
     qom_isa,
-    sysbus::SysBusDevice,
+    sysbus::{SysBusDevice, SysBusDeviceImpl},
     timer::{Timer, CLOCK_VIRTUAL},
 };
 
@@ -887,3 +887,5 @@ impl DeviceImpl for HPETState {
 impl ResettablePhasesImpl for HPETState {
     const HOLD: Option<fn(&Self, ResetType)> = Some(Self::reset_hold);
 }
+
+impl SysBusDeviceImpl for HPETState {}
diff --git a/rust/qemu-api/src/sysbus.rs b/rust/qemu-api/src/sysbus.rs
index fa36e12178..fee2e3d478 100644
--- a/rust/qemu-api/src/sysbus.rs
+++ b/rust/qemu-api/src/sysbus.rs
@@ -14,7 +14,7 @@ use crate::{
     irq::{IRQState, InterruptSource},
     memory::MemoryRegion,
     prelude::*,
-    qdev::{DeviceClass, DeviceState},
+    qdev::{DeviceClass, DeviceImpl, DeviceState},
     qom::{ClassInitImpl, Owned},
 };
 
@@ -25,10 +25,12 @@ unsafe impl ObjectType for SysBusDevice {
 }
 qom_isa!(SysBusDevice: DeviceState, Object);
 
-// TODO: add SysBusDeviceImpl
+// TODO: add virtual methods
+pub trait SysBusDeviceImpl: DeviceImpl + IsA<SysBusDevice> {}
+
 impl<T> ClassInitImpl<SysBusDeviceClass> for T
 where
-    T: ClassInitImpl<DeviceClass>,
+    T: SysBusDeviceImpl + ClassInitImpl<DeviceClass>,
 {
     fn class_init(sdc: &mut SysBusDeviceClass) {
         <T as ClassInitImpl<DeviceClass>>::class_init(&mut sdc.parent_class);