From f75fb90ff2af75cd4405fe4c6ba0c0c38a120590 Mon Sep 17 00:00:00 2001 From: Paolo Bonzini Date: Tue, 12 Nov 2024 17:08:07 +0100 Subject: [PATCH] rust: qdev: move bridge for realize and reset functions out of pl011 Allow the DeviceImpl trait to expose safe Rust functions. rust_device_class_init<> adds thunks around the functions in DeviceImpl. Reviewed-by: Zhao Liu Signed-off-by: Paolo Bonzini --- 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 28b1924337..56403c3660 100644 --- a/rust/hw/char/pl011/src/device.rs +++ b/rust/hw/char/pl011/src/device.rs @@ -125,9 +125,8 @@ impl DeviceImpl for PL011State { fn vmsd() -> Option<&'static VMStateDescription> { Some(&device_class::VMSTATE_PL011) } - const REALIZE: Option = - Some(device_class::pl011_realize); - const RESET: Option = Some(device_class::pl011_reset); + const REALIZE: Option = Some(Self::realize); + const RESET: Option = 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 c61b6bb025..975c3d42be 100644 --- a/rust/hw/char/pl011/src/device_class.rs +++ b/rust/hw/char/pl011/src/device_class.rs @@ -92,29 +92,3 @@ qemu_api::declare_properties! { 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::()); - 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::()); - state.as_mut().reset(); - } -} diff --git a/rust/qemu-api/src/definitions.rs b/rust/qemu-api/src/definitions.rs index 487712611f..0467e6290e 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 f683f94f2a..f25904be4f 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 = None; + const REALIZE: Option = 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 = None; + const RESET: Option = 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 @@ pub trait DeviceImpl { } } +/// # 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(dev: *mut DeviceState, _errp: *mut *mut Error) { + assert!(!dev.is_null()); + let state = dev.cast::(); + 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(dev: *mut DeviceState) { + assert!(!dev.is_null()); + let state = dev.cast::(); + 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 @@ pub unsafe extern "C" fn rust_device_class_init( let mut dc = ::core::ptr::NonNull::new(klass.cast::()).unwrap(); unsafe { let dc = dc.as_mut(); - if let Some(realize_fn) = ::REALIZE { - dc.realize = Some(realize_fn); + if ::REALIZE.is_some() { + dc.realize = Some(rust_realize_fn::); } - if let Some(reset_fn) = ::RESET { - bindings::device_class_set_legacy_reset(dc, Some(reset_fn)); + if ::RESET.is_some() { + bindings::device_class_set_legacy_reset(dc, Some(rust_reset_fn::)); } if let Some(vmsd) = ::vmsd() { dc.vmsd = vmsd; -- 2.30.2