diff mbox series

[08/10] rust: qdev: switch from legacy reset to Resettable

Message ID 20250117194003.1173231-9-pbonzini@redhat.com (mailing list archive)
State New
Headers show
Series rust: remaining part of qdev bindings | expand

Commit Message

Paolo Bonzini Jan. 17, 2025, 7:40 p.m. UTC
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 meson.build                      |   1 +
 rust/hw/char/pl011/src/device.rs |  10 ++-
 rust/qemu-api/src/qdev.rs        | 116 ++++++++++++++++++++++++-------
 rust/qemu-api/tests/tests.rs     |   5 +-
 4 files changed, 102 insertions(+), 30 deletions(-)
diff mbox series

Patch

diff --git a/meson.build b/meson.build
index d06f59095c6..2d9fa87af83 100644
--- a/meson.build
+++ b/meson.build
@@ -4065,6 +4065,7 @@  if have_rust
     'MigrationPriority',
     'QEMUChrEvent',
     'QEMUClockType',
+    'ResetType',
     'device_endian',
     'module_init_type',
   ]
diff --git a/rust/hw/char/pl011/src/device.rs b/rust/hw/char/pl011/src/device.rs
index dfe199ad0ed..259efacb046 100644
--- a/rust/hw/char/pl011/src/device.rs
+++ b/rust/hw/char/pl011/src/device.rs
@@ -13,7 +13,7 @@ 
     c_str, impl_vmstate_forward,
     irq::InterruptSource,
     prelude::*,
-    qdev::{Clock, ClockEvent, DeviceImpl},
+    qdev::{Clock, ClockEvent, DeviceImpl, ResettablePhasesImpl, ResetType},
     qom::{ClassInitImpl, ObjectImpl, Owned, ParentField},
 };
 
@@ -164,7 +164,10 @@  fn vmsd() -> Option<&'static VMStateDescription> {
         Some(&device_class::VMSTATE_PL011)
     }
     const REALIZE: Option<fn(&mut Self)> = Some(Self::realize);
-    const RESET: Option<fn(&Self)> = Some(Self::reset);
+}
+
+impl ResettablePhasesImpl for PL011State {
+    const HOLD: Option<fn(&Self, ResetType)> = Some(Self::reset_hold);
 }
 
 impl PL011Registers {
@@ -601,7 +604,7 @@  pub fn realize(&mut self) {
         }
     }
 
-    pub fn reset(&self) {
+    pub fn reset_hold(&self, _type: ResetType) {
         self.regs.borrow_mut().reset();
     }
 
@@ -723,3 +726,4 @@  impl ObjectImpl for PL011Luminary {
 }
 
 impl DeviceImpl for PL011Luminary {}
+impl ResettablePhasesImpl for PL011Luminary {}
diff --git a/rust/qemu-api/src/qdev.rs b/rust/qemu-api/src/qdev.rs
index ab883e2faef..8f0b279003a 100644
--- a/rust/qemu-api/src/qdev.rs
+++ b/rust/qemu-api/src/qdev.rs
@@ -9,19 +9,83 @@ 
     os::raw::c_void,
 };
 
-pub use bindings::{Clock, ClockEvent, DeviceClass, DeviceState, Property};
+pub use bindings::{Clock, ClockEvent, DeviceClass, DeviceState, Property, ResetType};
 
 use crate::{
-    bindings::{self, Error},
+    bindings::{self, Error, ResettableClass},
     callbacks::FnCall,
     cell::bql_locked,
     prelude::*,
-    qom::{ClassInitImpl, ObjectClass, Owned},
+    qom::{ClassInitImpl, ObjectClass, ObjectImpl, Owned},
     vmstate::VMStateDescription,
 };
 
+/// Trait providing the contents of [`ResettablePhases`].
+pub trait ResettablePhasesImpl {
+    /// If not None, this is called when the object enters reset. It
+    /// can reset local state of the object, but it must not do anything that
+    /// has a side-effect on other objects, such as raising or lowering a
+    /// [`qemu_irq`] line or reading or writing guest memory. It takes the
+    /// reset's type as argument.
+    const ENTER: Option<fn(&Self, ResetType)> = None;
+
+    /// If not None, this is called when the object for entry into reset, once
+    /// every object in the system which is being reset has had its
+    /// @phases.enter method called. At this point devices can do actions
+    /// that affect other objects.
+    ///
+    /// If in doubt, implement this method.
+    const HOLD: Option<fn(&Self, ResetType)> = None;
+
+    /// If not None, this phase is called when the object leaves the reset
+    /// state. Actions affecting other objects are permitted.
+    const EXIT: Option<fn(&Self, ResetType)> = None;
+}
+
+/// # Safety
+///
+/// We expect the FFI user of this function to pass a valid pointer that
+/// can be downcasted to type `T`. We also expect the device is
+/// readable/writeable from one thread at any time.
+unsafe extern "C" fn rust_resettable_enter_fn<T: ResettablePhasesImpl>(
+    obj: *mut Object,
+    typ: ResetType,
+) {
+    assert!(!obj.is_null());
+    let state = obj.cast::<T>();
+    T::ENTER.unwrap()(unsafe { &mut *state }, typ);
+}
+
+/// # Safety
+///
+/// We expect the FFI user of this function to pass a valid pointer that
+/// can be downcasted to type `T`. We also expect the device is
+/// readable/writeable from one thread at any time.
+unsafe extern "C" fn rust_resettable_hold_fn<T: ResettablePhasesImpl>(
+    obj: *mut Object,
+    typ: ResetType,
+) {
+    assert!(!obj.is_null());
+    let state = obj.cast::<T>();
+    T::HOLD.unwrap()(unsafe { &mut *state }, typ);
+}
+
+/// # Safety
+///
+/// We expect the FFI user of this function to pass a valid pointer that
+/// can be downcasted to type `T`. We also expect the device is
+/// readable/writeable from one thread at any time.
+unsafe extern "C" fn rust_resettable_exit_fn<T: ResettablePhasesImpl>(
+    obj: *mut Object,
+    typ: ResetType,
+) {
+    assert!(!obj.is_null());
+    let state = obj.cast::<T>();
+    T::EXIT.unwrap()(unsafe { &mut *state }, typ);
+}
+
 /// Trait providing the contents of [`DeviceClass`].
-pub trait DeviceImpl: ObjectImpl {
+pub trait DeviceImpl: ObjectImpl + ResettablePhasesImpl {
     /// _Realization_ is the second stage of device creation. It contains
     /// all operations that depend on device properties and can fail (note:
     /// this is not yet supported for Rust devices).
@@ -30,13 +94,6 @@  pub trait DeviceImpl: ObjectImpl {
     /// with the function pointed to by `REALIZE`.
     const REALIZE: Option<fn(&mut Self)> = None;
 
-    /// If not `None`, the parent class's `reset` method is overridden
-    /// with the function pointed to by `RESET`.
-    ///
-    /// Rust does not yet support the three-phase reset protocol; this is
-    /// usually okay for leaf classes.
-    const RESET: Option<fn(&Self)> = None;
-
     /// An array providing the properties that the user can set on the
     /// device.  Not a `const` because referencing statics in constants
     /// is unstable until Rust 1.83.0.
@@ -65,30 +122,36 @@  fn vmsd() -> Option<&'static VMStateDescription> {
     T::REALIZE.unwrap()(unsafe { &mut *state });
 }
 
-/// # Safety
-///
-/// We expect the FFI user of this function to pass a valid pointer that
-/// can be downcasted to type `T`. We also expect the device is
-/// readable/writeable from one thread at any time.
-unsafe extern "C" fn rust_reset_fn<T: DeviceImpl>(dev: *mut DeviceState) {
-    assert!(!dev.is_null());
-    let state = dev.cast::<T>();
-    T::RESET.unwrap()(unsafe { &mut *state });
+unsafe impl InterfaceType for ResettableClass {
+    const TYPE_NAME: &'static CStr =
+        unsafe { CStr::from_bytes_with_nul_unchecked(bindings::TYPE_RESETTABLE_INTERFACE) };
+}
+
+impl<T> ClassInitImpl<ResettableClass> for T
+where
+    T: ResettablePhasesImpl,
+{
+    fn class_init(rc: &mut ResettableClass) {
+        if <T as ResettablePhasesImpl>::ENTER.is_some() {
+            rc.phases.enter = Some(rust_resettable_enter_fn::<T>);
+        }
+        if <T as ResettablePhasesImpl>::HOLD.is_some() {
+            rc.phases.hold = Some(rust_resettable_hold_fn::<T>);
+        }
+        if <T as ResettablePhasesImpl>::EXIT.is_some() {
+            rc.phases.exit = Some(rust_resettable_exit_fn::<T>);
+        }
+    }
 }
 
 impl<T> ClassInitImpl<DeviceClass> for T
 where
-    T: ClassInitImpl<ObjectClass> + DeviceImpl,
+    T: ClassInitImpl<ObjectClass> + ClassInitImpl<ResettableClass> + DeviceImpl,
 {
     fn class_init(dc: &mut DeviceClass) {
         if <T as DeviceImpl>::REALIZE.is_some() {
             dc.realize = Some(rust_realize_fn::<T>);
         }
-        if <T as DeviceImpl>::RESET.is_some() {
-            unsafe {
-                bindings::device_class_set_legacy_reset(dc, Some(rust_reset_fn::<T>));
-            }
-        }
         if let Some(vmsd) = <T as DeviceImpl>::vmsd() {
             dc.vmsd = vmsd;
         }
@@ -99,6 +162,7 @@  fn class_init(dc: &mut DeviceClass) {
             }
         }
 
+        ResettableClass::interface_init::<T, DeviceState>(dc);
         <T as ClassInitImpl<ObjectClass>>::class_init(&mut dc.parent_class);
     }
 }
diff --git a/rust/qemu-api/tests/tests.rs b/rust/qemu-api/tests/tests.rs
index 1944e65c8f3..178041ffaae 100644
--- a/rust/qemu-api/tests/tests.rs
+++ b/rust/qemu-api/tests/tests.rs
@@ -13,7 +13,7 @@ 
     cell::{self, BqlCell},
     declare_properties, define_property,
     prelude::*,
-    qdev::{DeviceClass, DeviceImpl, DeviceState, Property},
+    qdev::{DeviceClass, DeviceImpl, DeviceState, Property, ResettablePhasesImpl},
     qom::{ClassInitImpl, ObjectImpl, ParentField},
     vmstate::VMStateDescription,
     zeroable::Zeroable,
@@ -61,6 +61,8 @@  impl ObjectImpl for DummyState {
     const ABSTRACT: bool = false;
 }
 
+impl ResettablePhasesImpl for DummyState {}
+
 impl DeviceImpl for DummyState {
     fn properties() -> &'static [Property] {
         &DUMMY_PROPERTIES
@@ -101,6 +103,7 @@  impl ObjectImpl for DummyChildState {
     const ABSTRACT: bool = false;
 }
 
+impl ResettablePhasesImpl for DummyChildState {}
 impl DeviceImpl for DummyChildState {}
 
 impl ClassInitImpl<DummyClass> for DummyChildState {