diff options
Diffstat (limited to 'rust/qemu-api/src/qdev.rs')
| -rw-r--r-- | rust/qemu-api/src/qdev.rs | 276 |
1 files changed, 250 insertions, 26 deletions
diff --git a/rust/qemu-api/src/qdev.rs b/rust/qemu-api/src/qdev.rs index f4c75c752f..3a7aa4def6 100644 --- a/rust/qemu-api/src/qdev.rs +++ b/rust/qemu-api/src/qdev.rs @@ -4,19 +4,89 @@ //! Bindings to create devices and access device functionality from Rust. -use std::{ffi::CStr, ptr::NonNull}; +use std::{ + ffi::{CStr, CString}, + os::raw::{c_int, c_void}, + ptr::NonNull, +}; -pub use bindings::{DeviceClass, DeviceState, Property}; +pub use bindings::{Clock, ClockEvent, DeviceClass, DeviceState, Property, ResetType}; use crate::{ - bindings::{self, Error}, + bindings::{self, qdev_init_gpio_in, qdev_init_gpio_out, Error, ResettableClass}, + callbacks::FnCall, + cell::bql_locked, + chardev::Chardev, + irq::InterruptSource, prelude::*, - qom::{ClassInitImpl, ObjectClass}, + qom::{ClassInitImpl, ObjectClass, ObjectImpl, Owned}, vmstate::VMStateDescription, }; +/// Trait providing the contents of the `ResettablePhases` struct, +/// which is part of the QOM `Resettable` interface. +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 an + /// [`InterruptSource`], 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 + /// `ResettablePhasesImpl::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, +) { + let state = NonNull::new(obj).unwrap().cast::<T>(); + T::ENTER.unwrap()(unsafe { state.as_ref() }, 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, +) { + let state = NonNull::new(obj).unwrap().cast::<T>(); + T::HOLD.unwrap()(unsafe { state.as_ref() }, 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, +) { + let state = NonNull::new(obj).unwrap().cast::<T>(); + T::EXIT.unwrap()(unsafe { state.as_ref() }, typ); +} + /// Trait providing the contents of [`DeviceClass`]. -pub trait DeviceImpl { +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). @@ -25,13 +95,6 @@ pub trait DeviceImpl { /// with the function pointed to by `REALIZE`. const REALIZE: Option<fn(&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. @@ -59,29 +122,36 @@ unsafe extern "C" fn rust_realize_fn<T: DeviceImpl>(dev: *mut DeviceState, _errp T::REALIZE.unwrap()(unsafe { state.as_ref() }); } -/// # 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) { - let mut state = NonNull::new(dev).unwrap().cast::<T>(); - T::RESET.unwrap()(unsafe { state.as_mut() }); +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; } @@ -92,12 +162,25 @@ where } } + ResettableClass::interface_init::<T, DeviceState>(dc); <T as ClassInitImpl<ObjectClass>>::class_init(&mut dc.parent_class); } } #[macro_export] macro_rules! define_property { + ($name:expr, $state:ty, $field:ident, $prop:expr, $type:ty, bit = $bitnr:expr, default = $defval:expr$(,)*) => { + $crate::bindings::Property { + // use associated function syntax for type checking + name: ::std::ffi::CStr::as_ptr($name), + info: $prop, + offset: $crate::offset_of!($state, $field) as isize, + bitnr: $bitnr, + set_default: true, + defval: $crate::bindings::Property__bindgen_ty_1 { u: $defval as u64 }, + ..$crate::zeroable::Zeroable::ZERO + } + }; ($name:expr, $state:ty, $field:ident, $prop:expr, $type:ty, default = $defval:expr$(,)*) => { $crate::bindings::Property { // use associated function syntax for type checking @@ -143,3 +226,144 @@ unsafe impl ObjectType for DeviceState { unsafe { CStr::from_bytes_with_nul_unchecked(bindings::TYPE_DEVICE) }; } qom_isa!(DeviceState: Object); + +/// Trait for methods exposed by the [`DeviceState`] class. The methods can be +/// called on all objects that have the trait `IsA<DeviceState>`. +/// +/// The trait should only be used through the blanket implementation, +/// which guarantees safety via `IsA`. +pub trait DeviceMethods: ObjectDeref +where + Self::Target: IsA<DeviceState>, +{ + /// Add an input clock named `name`. Invoke the callback with + /// `self` as the first parameter for the events that are requested. + /// + /// The resulting clock is added as a child of `self`, but it also + /// stays alive until after `Drop::drop` is called because C code + /// keeps an extra reference to it until `device_finalize()` calls + /// `qdev_finalize_clocklist()`. Therefore (unlike most cases in + /// which Rust code has a reference to a child object) it would be + /// possible for this function to return a `&Clock` too. + #[inline] + fn init_clock_in<F: for<'a> FnCall<(&'a Self::Target, ClockEvent)>>( + &self, + name: &str, + _cb: &F, + events: ClockEvent, + ) -> Owned<Clock> { + fn do_init_clock_in( + dev: *mut DeviceState, + name: &str, + cb: Option<unsafe extern "C" fn(*mut c_void, ClockEvent)>, + events: ClockEvent, + ) -> Owned<Clock> { + assert!(bql_locked()); + + // SAFETY: the clock is heap allocated, but qdev_init_clock_in() + // does not gift the reference to its caller; so use Owned::from to + // add one. The callback is disabled automatically when the clock + // is unparented, which happens before the device is finalized. + unsafe { + let cstr = CString::new(name).unwrap(); + let clk = bindings::qdev_init_clock_in( + dev, + cstr.as_ptr(), + cb, + dev.cast::<c_void>(), + events.0, + ); + + Owned::from(&*clk) + } + } + + let cb: Option<unsafe extern "C" fn(*mut c_void, ClockEvent)> = if F::is_some() { + unsafe extern "C" fn rust_clock_cb<T, F: for<'a> FnCall<(&'a T, ClockEvent)>>( + opaque: *mut c_void, + event: ClockEvent, + ) { + // SAFETY: the opaque is "this", which is indeed a pointer to T + F::call((unsafe { &*(opaque.cast::<T>()) }, event)) + } + Some(rust_clock_cb::<Self::Target, F>) + } else { + None + }; + + do_init_clock_in(self.as_mut_ptr(), name, cb, events) + } + + /// Add an output clock named `name`. + /// + /// The resulting clock is added as a child of `self`, but it also + /// stays alive until after `Drop::drop` is called because C code + /// keeps an extra reference to it until `device_finalize()` calls + /// `qdev_finalize_clocklist()`. Therefore (unlike most cases in + /// which Rust code has a reference to a child object) it would be + /// possible for this function to return a `&Clock` too. + #[inline] + fn init_clock_out(&self, name: &str) -> Owned<Clock> { + unsafe { + let cstr = CString::new(name).unwrap(); + let clk = bindings::qdev_init_clock_out(self.as_mut_ptr(), cstr.as_ptr()); + + Owned::from(&*clk) + } + } + + fn prop_set_chr(&self, propname: &str, chr: &Owned<Chardev>) { + assert!(bql_locked()); + let c_propname = CString::new(propname).unwrap(); + unsafe { + bindings::qdev_prop_set_chr(self.as_mut_ptr(), c_propname.as_ptr(), chr.as_mut_ptr()); + } + } + + fn init_gpio_in<F: for<'a> FnCall<(&'a Self::Target, u32, u32)>>( + &self, + num_lines: u32, + _cb: F, + ) { + let _: () = F::ASSERT_IS_SOME; + + unsafe extern "C" fn rust_irq_handler<T, F: for<'a> FnCall<(&'a T, u32, u32)>>( + opaque: *mut c_void, + line: c_int, + level: c_int, + ) { + // SAFETY: the opaque was passed as a reference to `T` + F::call((unsafe { &*(opaque.cast::<T>()) }, line as u32, level as u32)) + } + + let gpio_in_cb: unsafe extern "C" fn(*mut c_void, c_int, c_int) = + rust_irq_handler::<Self::Target, F>; + + unsafe { + qdev_init_gpio_in( + self.as_mut_ptr::<DeviceState>(), + Some(gpio_in_cb), + num_lines as c_int, + ); + } + } + + fn init_gpio_out(&self, pins: &[InterruptSource]) { + unsafe { + qdev_init_gpio_out( + self.as_mut_ptr::<DeviceState>(), + InterruptSource::slice_as_ptr(pins), + pins.len() as c_int, + ); + } + } +} + +impl<R: ObjectDeref> DeviceMethods for R where R::Target: IsA<DeviceState> {} + +unsafe impl ObjectType for Clock { + type Class = ObjectClass; + const TYPE_NAME: &'static CStr = + unsafe { CStr::from_bytes_with_nul_unchecked(bindings::TYPE_CLOCK) }; +} +qom_isa!(Clock: Object); |