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[PATCH 12/26] rust: qdev: move bridge for realize and reset functions ou
From: |
Paolo Bonzini |
Subject: |
[PATCH 12/26] rust: qdev: move bridge for realize and reset functions out of pl011 |
Date: |
Mon, 9 Dec 2024 13:37:03 +0100 |
Allow the DeviceImpl trait to expose safe Rust functions.
rust_device_class_init<> adds thunks around the functions
in DeviceImpl.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
rust/hw/char/pl011/src/device.rs | 5 ++--
rust/hw/char/pl011/src/device_class.rs | 26 -------------------
rust/qemu-api/src/definitions.rs | 2 +-
rust/qemu-api/src/device_class.rs | 36 +++++++++++++++++++++-----
4 files changed, 33 insertions(+), 36 deletions(-)
diff --git a/rust/hw/char/pl011/src/device.rs b/rust/hw/char/pl011/src/device.rs
index 28b1924337d..56403c36609 100644
--- a/rust/hw/char/pl011/src/device.rs
+++ b/rust/hw/char/pl011/src/device.rs
@@ -125,9 +125,8 @@ fn properties() -> &'static [Property] {
fn vmsd() -> Option<&'static VMStateDescription> {
Some(&device_class::VMSTATE_PL011)
}
- const REALIZE: Option<unsafe extern "C" fn(*mut DeviceState, *mut *mut
Error)> =
- Some(device_class::pl011_realize);
- const RESET: Option<unsafe extern "C" fn(*mut DeviceState)> =
Some(device_class::pl011_reset);
+ const REALIZE: Option<fn(&mut Self)> = Some(Self::realize);
+ const RESET: Option<fn(&mut Self)> = Some(Self::reset);
}
impl_device_class!(PL011State);
diff --git a/rust/hw/char/pl011/src/device_class.rs
b/rust/hw/char/pl011/src/device_class.rs
index c61b6bb0258..975c3d42be7 100644
--- a/rust/hw/char/pl011/src/device_class.rs
+++ b/rust/hw/char/pl011/src/device_class.rs
@@ -92,29 +92,3 @@ extern "C" fn pl011_post_load(opaque: *mut c_void,
version_id: c_int) -> c_int {
default = true
),
}
-
-/// # Safety
-///
-/// We expect the FFI user of this function to pass a valid pointer, that has
-/// the same size as [`PL011State`]. We also expect the device is
-/// readable/writeable from one thread at any time.
-pub unsafe extern "C" fn pl011_realize(dev: *mut DeviceState, _errp: *mut *mut
Error) {
- unsafe {
- assert!(!dev.is_null());
- let mut state = NonNull::new_unchecked(dev.cast::<PL011State>());
- state.as_mut().realize();
- }
-}
-
-/// # Safety
-///
-/// We expect the FFI user of this function to pass a valid pointer, that has
-/// the same size as [`PL011State`]. We also expect the device is
-/// readable/writeable from one thread at any time.
-pub unsafe extern "C" fn pl011_reset(dev: *mut DeviceState) {
- unsafe {
- assert!(!dev.is_null());
- let mut state = NonNull::new_unchecked(dev.cast::<PL011State>());
- state.as_mut().reset();
- }
-}
diff --git a/rust/qemu-api/src/definitions.rs b/rust/qemu-api/src/definitions.rs
index 487712611f6..0467e6290e0 100644
--- a/rust/qemu-api/src/definitions.rs
+++ b/rust/qemu-api/src/definitions.rs
@@ -47,7 +47,7 @@ pub trait ObjectImpl: ClassInitImpl + Sized {
/// Each QOM type has one such class struct.
///
/// The Rust implementation of methods will usually come from a trait
-/// like [`ObjectImpl`].
+/// like [`ObjectImpl`] or [`DeviceImpl`](crate::device_class::DeviceImpl).
pub trait ClassInitImpl {
/// Function that is called after all parent class initialization
/// has occurred. On entry, the virtual method pointers are set to
diff --git a/rust/qemu-api/src/device_class.rs
b/rust/qemu-api/src/device_class.rs
index f683f94f2a5..f25904be4f6 100644
--- a/rust/qemu-api/src/device_class.rs
+++ b/rust/qemu-api/src/device_class.rs
@@ -17,14 +17,14 @@ pub trait DeviceImpl {
///
/// If not `None`, the parent class's `realize` method is overridden
/// with the function pointed to by `REALIZE`.
- const REALIZE: Option<unsafe extern "C" fn(*mut DeviceState, *mut *mut
Error)> = None;
+ 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<unsafe extern "C" fn(dev: *mut DeviceState)> = None;
+ const RESET: Option<fn(&mut Self)> = None;
/// An array providing the properties that the user can set on the
/// device. Not a `const` because referencing statics in constants
@@ -41,6 +41,30 @@ fn vmsd() -> Option<&'static VMStateDescription> {
}
}
+/// # Safety
+///
+/// This function is only called through the QOM machinery and
+/// the `impl_device_class!` macro.
+/// 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_realize_fn<T: DeviceImpl>(dev: *mut DeviceState,
_errp: *mut *mut Error) {
+ assert!(!dev.is_null());
+ let state = dev.cast::<T>();
+ 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 });
+}
+
/// # Safety
///
/// We expect the FFI user of this function to pass a valid pointer that
@@ -53,11 +77,11 @@ fn vmsd() -> Option<&'static VMStateDescription> {
let mut dc =
::core::ptr::NonNull::new(klass.cast::<DeviceClass>()).unwrap();
unsafe {
let dc = dc.as_mut();
- if let Some(realize_fn) = <T as DeviceImpl>::REALIZE {
- dc.realize = Some(realize_fn);
+ if <T as DeviceImpl>::REALIZE.is_some() {
+ dc.realize = Some(rust_realize_fn::<T>);
}
- if let Some(reset_fn) = <T as DeviceImpl>::RESET {
- bindings::device_class_set_legacy_reset(dc, Some(reset_fn));
+ if <T as DeviceImpl>::RESET.is_some() {
+ bindings::device_class_set_legacy_reset(dc,
Some(rust_reset_fn::<T>));
}
if let Some(vmsd) = <T as DeviceImpl>::vmsd() {
dc.vmsd = vmsd;
--
2.47.1
- Re: [PATCH 04/26] rust: define prelude, (continued)
- [PATCH 08/26] rust: qom: rename Class trait to ClassInitImpl, Paolo Bonzini, 2024/12/09
- [PATCH 06/26] rust: add a bit operation module, Paolo Bonzini, 2024/12/09
- [PATCH 10/26] rust: qom: move ClassInitImpl to the instance side, Paolo Bonzini, 2024/12/09
- [PATCH 09/26] rust: qom: convert type_info! macro to an associated const, Paolo Bonzini, 2024/12/09
- [PATCH 12/26] rust: qdev: move bridge for realize and reset functions out of pl011,
Paolo Bonzini <=
- [PATCH 13/26] rust: qom: automatically use Drop trait to implement instance_finalize, Paolo Bonzini, 2024/12/09
- [PATCH 14/26] rust: qom: move bridge for TypeInfo functions out of pl011, Paolo Bonzini, 2024/12/09