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-rw-r--r--rust/hw/char/pl011/src/device.rs52
-rw-r--r--rust/hw/timer/hpet/src/device.rs58
-rw-r--r--rust/meson.build4
-rw-r--r--rust/qemu-api/build.rs2
-rw-r--r--rust/qemu-api/meson.build45
-rw-r--r--rust/qemu-api/src/lib.rs2
-rw-r--r--rust/qemu-api/src/log.rs73
-rw-r--r--rust/qemu-api/src/memory.rs12
-rw-r--r--rust/qemu-api/src/prelude.rs2
-rw-r--r--rust/qemu-api/src/qdev.rs49
-rw-r--r--rust/qemu-api/src/qom.rs186
-rw-r--r--rust/qemu-api/src/uninit.rs85
-rw-r--r--rust/qemu-api/wrapper.h (renamed from rust/wrapper.h)2
13 files changed, 490 insertions, 82 deletions
diff --git a/rust/hw/char/pl011/src/device.rs b/rust/hw/char/pl011/src/device.rs
index be8387f..5b53f26 100644
--- a/rust/hw/char/pl011/src/device.rs
+++ b/rust/hw/char/pl011/src/device.rs
@@ -2,18 +2,21 @@
// Author(s): Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
// SPDX-License-Identifier: GPL-2.0-or-later
-use std::{ffi::CStr, mem::size_of, ptr::addr_of_mut};
+use std::{ffi::CStr, mem::size_of};
use qemu_api::{
chardev::{CharBackend, Chardev, Event},
impl_vmstate_forward,
irq::{IRQState, InterruptSource},
+ log::Log,
+ log_mask_ln,
memory::{hwaddr, MemoryRegion, MemoryRegionOps, MemoryRegionOpsBuilder},
prelude::*,
qdev::{Clock, ClockEvent, DeviceImpl, DeviceState, Property, ResetType, ResettablePhasesImpl},
- qom::{ObjectImpl, Owned, ParentField},
+ qom::{ObjectImpl, Owned, ParentField, ParentInit},
static_assert,
sysbus::{SysBusDevice, SysBusDeviceImpl},
+ uninit_field_mut,
vmstate::VMStateDescription,
};
@@ -163,7 +166,7 @@ impl PL011Impl for PL011State {
impl ObjectImpl for PL011State {
type ParentType = SysBusDevice;
- const INSTANCE_INIT: Option<unsafe fn(&mut Self)> = Some(Self::init);
+ const INSTANCE_INIT: Option<unsafe fn(ParentInit<Self>)> = Some(Self::init);
const INSTANCE_POST_INIT: Option<fn(&Self)> = Some(Self::post_init);
const CLASS_INIT: fn(&mut Self::Class) = Self::Class::class_init::<Self>;
}
@@ -275,8 +278,7 @@ impl PL011Registers {
DMACR => {
self.dmacr = value;
if value & 3 > 0 {
- // qemu_log_mask(LOG_UNIMP, "pl011: DMA not implemented\n");
- eprintln!("pl011: DMA not implemented");
+ log_mask_ln!(Log::Unimp, "pl011: DMA not implemented");
}
}
}
@@ -303,6 +305,12 @@ impl PL011Registers {
}
fn write_data_register(&mut self, value: u32) -> bool {
+ if !self.control.enable_uart() {
+ log_mask_ln!(Log::GuestError, "PL011 data written to disabled UART");
+ }
+ if !self.control.enable_transmit() {
+ log_mask_ln!(Log::GuestError, "PL011 data written to disabled TX UART");
+ }
// interrupts always checked
let _ = self.loopback_tx(value.into());
self.int_level |= Interrupt::TX;
@@ -488,7 +496,7 @@ impl PL011State {
/// `PL011State` type. It must not be called more than once on the same
/// location/instance. All its fields are expected to hold uninitialized
/// values with the sole exception of `parent_obj`.
- unsafe fn init(&mut self) {
+ unsafe fn init(mut this: ParentInit<Self>) {
static PL011_OPS: MemoryRegionOps<PL011State> = MemoryRegionOpsBuilder::<PL011State>::new()
.read(&PL011State::read)
.write(&PL011State::write)
@@ -496,28 +504,23 @@ impl PL011State {
.impl_sizes(4, 4)
.build();
- // SAFETY:
- //
- // self and self.iomem are guaranteed to be valid at this point since callers
- // must make sure the `self` reference is valid.
+ // SAFETY: this and this.iomem are guaranteed to be valid at this point
MemoryRegion::init_io(
- unsafe { &mut *addr_of_mut!(self.iomem) },
- addr_of_mut!(*self),
+ &mut uninit_field_mut!(*this, iomem),
&PL011_OPS,
"pl011",
0x1000,
);
- self.regs = Default::default();
+ uninit_field_mut!(*this, regs).write(Default::default());
- // SAFETY:
- //
- // self.clock is not initialized at this point; but since `Owned<_>` is
- // not Drop, we can overwrite the undefined value without side effects;
- // it's not sound but, because for all PL011State instances are created
- // by QOM code which calls this function to initialize the fields, at
- // leastno code is able to access an invalid self.clock value.
- self.clock = self.init_clock_in("clk", &Self::clock_update, ClockEvent::ClockUpdate);
+ let clock = DeviceState::init_clock_in(
+ &mut this,
+ "clk",
+ &Self::clock_update,
+ ClockEvent::ClockUpdate,
+ );
+ uninit_field_mut!(*this, clock).write(clock);
}
const fn clock_update(&self, _event: ClockEvent) {
@@ -538,7 +541,7 @@ impl PL011State {
u64::from(device_id[(offset - 0xfe0) >> 2])
}
Err(_) => {
- // qemu_log_mask(LOG_GUEST_ERROR, "pl011_read: Bad offset 0x%x\n", (int)offset);
+ log_mask_ln!(Log::GuestError, "PL011State::read: Bad offset {offset}");
0
}
Ok(field) => {
@@ -570,7 +573,10 @@ impl PL011State {
.borrow_mut()
.write(field, value as u32, &self.char_backend);
} else {
- eprintln!("write bad offset {offset} value {value}");
+ log_mask_ln!(
+ Log::GuestError,
+ "PL011State::write: Bad offset {offset} value {value}"
+ );
}
if update_irq {
self.update();
diff --git a/rust/hw/timer/hpet/src/device.rs b/rust/hw/timer/hpet/src/device.rs
index 735b2fb..acf7251 100644
--- a/rust/hw/timer/hpet/src/device.rs
+++ b/rust/hw/timer/hpet/src/device.rs
@@ -4,6 +4,7 @@
use std::{
ffi::{c_int, c_void, CStr},
+ mem::MaybeUninit,
pin::Pin,
ptr::{addr_of_mut, null_mut, NonNull},
slice::from_ref,
@@ -20,11 +21,12 @@ use qemu_api::{
hwaddr, MemoryRegion, MemoryRegionOps, MemoryRegionOpsBuilder, MEMTXATTRS_UNSPECIFIED,
},
prelude::*,
- qdev::{DeviceImpl, DeviceMethods, DeviceState, Property, ResetType, ResettablePhasesImpl},
- qom::{ObjectImpl, ObjectType, ParentField},
+ qdev::{DeviceImpl, DeviceState, Property, ResetType, ResettablePhasesImpl},
+ qom::{ObjectImpl, ObjectType, ParentField, ParentInit},
qom_isa,
sysbus::{SysBusDevice, SysBusDeviceImpl},
timer::{Timer, CLOCK_VIRTUAL, NANOSECONDS_PER_SECOND},
+ uninit_field_mut,
vmstate::VMStateDescription,
vmstate_fields, vmstate_of, vmstate_struct, vmstate_subsections, vmstate_validate,
zeroable::Zeroable,
@@ -212,13 +214,13 @@ pub struct HPETTimer {
}
impl HPETTimer {
- fn init(&mut self, index: u8, state: &HPETState) {
- *self = HPETTimer {
+ fn new(index: u8, state: *const HPETState) -> HPETTimer {
+ HPETTimer {
index,
// SAFETY: the HPETTimer will only be used after the timer
// is initialized below.
qemu_timer: unsafe { Timer::new() },
- state: NonNull::new((state as *const HPETState).cast_mut()).unwrap(),
+ state: NonNull::new(state.cast_mut()).unwrap(),
config: 0,
cmp: 0,
fsb: 0,
@@ -226,19 +228,15 @@ impl HPETTimer {
period: 0,
wrap_flag: 0,
last: 0,
- };
+ }
+ }
+ fn init_timer_with_cell(cell: &BqlRefCell<Self>) {
+ let mut timer = cell.borrow_mut();
// SAFETY: HPETTimer is only used as part of HPETState, which is
// always pinned.
- let qemu_timer = unsafe { Pin::new_unchecked(&mut self.qemu_timer) };
- qemu_timer.init_full(
- None,
- CLOCK_VIRTUAL,
- Timer::NS,
- 0,
- timer_handler,
- &state.timers[self.index as usize],
- )
+ let qemu_timer = unsafe { Pin::new_unchecked(&mut timer.qemu_timer) };
+ qemu_timer.init_full(None, CLOCK_VIRTUAL, Timer::NS, 0, timer_handler, cell);
}
fn get_state(&self) -> &HPETState {
@@ -607,9 +605,18 @@ impl HPETState {
}
}
- fn init_timer(&self) {
- for (index, timer) in self.timers.iter().enumerate() {
- timer.borrow_mut().init(index.try_into().unwrap(), self);
+ fn init_timers(this: &mut MaybeUninit<Self>) {
+ let state = this.as_ptr();
+ for index in 0..HPET_MAX_TIMERS {
+ let mut timer = uninit_field_mut!(*this, timers[index]);
+
+ // Initialize in two steps, to avoid calling Timer::init_full on a
+ // temporary that can be moved.
+ let timer = timer.write(BqlRefCell::new(HPETTimer::new(
+ index.try_into().unwrap(),
+ state,
+ )));
+ HPETTimer::init_timer_with_cell(timer);
}
}
@@ -690,7 +697,7 @@ impl HPETState {
.set(self.counter.get().deposit(shift, len, val));
}
- unsafe fn init(&mut self) {
+ unsafe fn init(mut this: ParentInit<Self>) {
static HPET_RAM_OPS: MemoryRegionOps<HPETState> =
MemoryRegionOpsBuilder::<HPETState>::new()
.read(&HPETState::read)
@@ -700,16 +707,14 @@ impl HPETState {
.impl_sizes(4, 8)
.build();
- // SAFETY:
- // self and self.iomem are guaranteed to be valid at this point since callers
- // must make sure the `self` reference is valid.
MemoryRegion::init_io(
- unsafe { &mut *addr_of_mut!(self.iomem) },
- addr_of_mut!(*self),
+ &mut uninit_field_mut!(*this, iomem),
&HPET_RAM_OPS,
"hpet",
HPET_REG_SPACE_LEN,
);
+
+ Self::init_timers(&mut this);
}
fn post_init(&self) {
@@ -731,7 +736,6 @@ impl HPETState {
self.hpet_id.set(HPETFwConfig::assign_hpet_id()?);
- self.init_timer();
// 64-bit General Capabilities and ID Register; LegacyReplacementRoute.
self.capability.set(
HPET_CAP_REV_ID_VALUE << HPET_CAP_REV_ID_SHIFT |
@@ -767,7 +771,7 @@ impl HPETState {
self.rtc_irq_level.set(0);
}
- fn decode(&self, mut addr: hwaddr, size: u32) -> HPETAddrDecode {
+ fn decode(&self, mut addr: hwaddr, size: u32) -> HPETAddrDecode<'_> {
let shift = ((addr & 4) * 8) as u32;
let len = std::cmp::min(size * 8, 64 - shift);
@@ -892,7 +896,7 @@ unsafe impl ObjectType for HPETState {
impl ObjectImpl for HPETState {
type ParentType = SysBusDevice;
- const INSTANCE_INIT: Option<unsafe fn(&mut Self)> = Some(Self::init);
+ const INSTANCE_INIT: Option<unsafe fn(ParentInit<Self>)> = Some(Self::init);
const INSTANCE_POST_INIT: Option<fn(&Self)> = Some(Self::post_init);
const CLASS_INIT: fn(&mut Self::Class) = Self::Class::class_init::<Self>;
}
diff --git a/rust/meson.build b/rust/meson.build
index 99ae795..331f11b 100644
--- a/rust/meson.build
+++ b/rust/meson.build
@@ -20,6 +20,8 @@ proc_macro2_rs_native = dependency('proc-macro2-1-rs', native: true)
qemuutil_rs = qemuutil.partial_dependency(link_args: true, links: true)
+genrs = []
+
subdir('qemu-api-macros')
subdir('bits')
subdir('qemu-api')
@@ -33,5 +35,5 @@ if cargo.found()
command: [config_host['MESON'], 'devenv',
'--workdir', '@CURRENT_SOURCE_DIR@',
cargo, 'fmt'],
- depends: bindings_rs)
+ depends: genrs)
endif
diff --git a/rust/qemu-api/build.rs b/rust/qemu-api/build.rs
index 1e72064..7849486 100644
--- a/rust/qemu-api/build.rs
+++ b/rust/qemu-api/build.rs
@@ -14,7 +14,7 @@ fn main() -> Result<()> {
let path = env::var("MESON_BUILD_ROOT")
.unwrap_or_else(|_| format!("{}/src", env!("CARGO_MANIFEST_DIR")));
- let file = format!("{path}/bindings.inc.rs");
+ let file = format!("{path}/rust/qemu-api/bindings.inc.rs");
let file = Path::new(&file);
if !Path::new(&file).exists() {
panic!(concat!(
diff --git a/rust/qemu-api/meson.build b/rust/qemu-api/meson.build
index cac8595..a090297 100644
--- a/rust/qemu-api/meson.build
+++ b/rust/qemu-api/meson.build
@@ -7,6 +7,47 @@ if get_option('debug_mutex')
_qemu_api_cfg += ['--cfg', 'feature="debug_cell"']
endif
+c_enums = [
+ 'DeviceCategory',
+ 'GpioPolarity',
+ 'MachineInitPhase',
+ 'MemoryDeviceInfoKind',
+ 'MigrationPolicy',
+ 'MigrationPriority',
+ 'QEMUChrEvent',
+ 'QEMUClockType',
+ 'ResetType',
+ 'device_endian',
+ 'module_init_type',
+]
+_qemu_api_bindgen_args = []
+foreach enum : c_enums
+ _qemu_api_bindgen_args += ['--rustified-enum', enum]
+endforeach
+c_bitfields = [
+ 'ClockEvent',
+ 'VMStateFlags',
+]
+foreach enum : c_bitfields
+ _qemu_api_bindgen_args += ['--bitfield-enum', enum]
+endforeach
+
+# TODO: Remove this comment when the clang/libclang mismatch issue is solved.
+#
+# Rust bindings generation with `bindgen` might fail in some cases where the
+# detected `libclang` does not match the expected `clang` version/target. In
+# this case you must pass the path to `clang` and `libclang` to your build
+# command invocation using the environment variables CLANG_PATH and
+# LIBCLANG_PATH
+_qemu_api_bindings_inc_rs = rust.bindgen(
+ input: 'wrapper.h',
+ dependencies: common_ss.all_dependencies(),
+ output: 'bindings.inc.rs',
+ include_directories: bindings_incdir,
+ bindgen_version: ['>=0.60.0'],
+ args: bindgen_args_common + _qemu_api_bindgen_args,
+ )
+
_qemu_api_rs = static_library(
'qemu_api',
structured_sources(
@@ -21,6 +62,7 @@ _qemu_api_rs = static_library(
'src/errno.rs',
'src/error.rs',
'src/irq.rs',
+ 'src/log.rs',
'src/memory.rs',
'src/module.rs',
'src/prelude.rs',
@@ -28,10 +70,11 @@ _qemu_api_rs = static_library(
'src/qom.rs',
'src/sysbus.rs',
'src/timer.rs',
+ 'src/uninit.rs',
'src/vmstate.rs',
'src/zeroable.rs',
],
- {'.' : bindings_rs},
+ {'.' : _qemu_api_bindings_inc_rs},
),
override_options: ['rust_std=2021', 'build.rust_std=2021'],
rust_abi: 'rust',
diff --git a/rust/qemu-api/src/lib.rs b/rust/qemu-api/src/lib.rs
index 93902fc..86dcd8e 100644
--- a/rust/qemu-api/src/lib.rs
+++ b/rust/qemu-api/src/lib.rs
@@ -21,12 +21,14 @@ pub mod chardev;
pub mod errno;
pub mod error;
pub mod irq;
+pub mod log;
pub mod memory;
pub mod module;
pub mod qdev;
pub mod qom;
pub mod sysbus;
pub mod timer;
+pub mod uninit;
pub mod vmstate;
pub mod zeroable;
diff --git a/rust/qemu-api/src/log.rs b/rust/qemu-api/src/log.rs
new file mode 100644
index 0000000..d6c3d6c
--- /dev/null
+++ b/rust/qemu-api/src/log.rs
@@ -0,0 +1,73 @@
+// Copyright 2025 Bernhard Beschow <shentey@gmail.com>
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! Bindings for QEMU's logging infrastructure
+
+#[repr(u32)]
+/// Represents specific error categories within QEMU's logging system.
+///
+/// The `Log` enum provides a Rust abstraction for logging errors, corresponding
+/// to a subset of the error categories defined in the C implementation.
+pub enum Log {
+ /// Log invalid access caused by the guest.
+ /// Corresponds to `LOG_GUEST_ERROR` in the C implementation.
+ GuestError = crate::bindings::LOG_GUEST_ERROR,
+
+ /// Log guest access of unimplemented functionality.
+ /// Corresponds to `LOG_UNIMP` in the C implementation.
+ Unimp = crate::bindings::LOG_UNIMP,
+}
+
+/// A macro to log messages conditionally based on a provided mask.
+///
+/// The `log_mask_ln` macro checks whether the given mask matches the current
+/// log level and, if so, formats and logs the message. It is the Rust
+/// counterpart of the `qemu_log_mask()` macro in the C implementation.
+///
+/// # Parameters
+///
+/// - `$mask`: A log level mask. This should be a variant of the `Log` enum.
+/// - `$fmt`: A format string following the syntax and rules of the `format!`
+/// macro. It specifies the structure of the log message.
+/// - `$args`: Optional arguments to be interpolated into the format string.
+///
+/// # Example
+///
+/// ```
+/// use qemu_api::{log::Log, log_mask_ln};
+///
+/// let error_address = 0xbad;
+/// log_mask_ln!(Log::GuestError, "Address 0x{error_address:x} out of range");
+/// ```
+///
+/// It is also possible to use printf-style formatting, as well as having a
+/// trailing `,`:
+///
+/// ```
+/// use qemu_api::{log::Log, log_mask_ln};
+///
+/// let error_address = 0xbad;
+/// log_mask_ln!(
+/// Log::GuestError,
+/// "Address 0x{:x} out of range",
+/// error_address,
+/// );
+/// ```
+#[macro_export]
+macro_rules! log_mask_ln {
+ ($mask:expr, $fmt:tt $($args:tt)*) => {{
+ // Type assertion to enforce type `Log` for $mask
+ let _: Log = $mask;
+
+ if unsafe {
+ (::qemu_api::bindings::qemu_loglevel & ($mask as std::os::raw::c_int)) != 0
+ } {
+ let formatted_string = format!("{}\n", format_args!($fmt $($args)*));
+ let c_string = std::ffi::CString::new(formatted_string).unwrap();
+
+ unsafe {
+ ::qemu_api::bindings::qemu_log(c_string.as_ptr());
+ }
+ }
+ }};
+}
diff --git a/rust/qemu-api/src/memory.rs b/rust/qemu-api/src/memory.rs
index 9ef2694..e40fad6 100644
--- a/rust/qemu-api/src/memory.rs
+++ b/rust/qemu-api/src/memory.rs
@@ -16,6 +16,7 @@ use crate::{
callbacks::FnCall,
cell::Opaque,
prelude::*,
+ uninit::MaybeUninitField,
zeroable::Zeroable,
};
@@ -147,7 +148,7 @@ impl MemoryRegion {
#[inline(always)]
unsafe fn do_init_io(
slot: *mut bindings::MemoryRegion,
- owner: *mut Object,
+ owner: *mut bindings::Object,
ops: &'static bindings::MemoryRegionOps,
name: &'static str,
size: u64,
@@ -156,7 +157,7 @@ impl MemoryRegion {
let cstr = CString::new(name).unwrap();
memory_region_init_io(
slot,
- owner.cast::<bindings::Object>(),
+ owner,
ops,
owner.cast::<c_void>(),
cstr.as_ptr(),
@@ -166,16 +167,15 @@ impl MemoryRegion {
}
pub fn init_io<T: IsA<Object>>(
- &mut self,
- owner: *mut T,
+ this: &mut MaybeUninitField<'_, T, Self>,
ops: &'static MemoryRegionOps<T>,
name: &'static str,
size: u64,
) {
unsafe {
Self::do_init_io(
- self.0.as_mut_ptr(),
- owner.cast::<Object>(),
+ this.as_mut_ptr().cast(),
+ MaybeUninitField::parent_mut(this).cast(),
&ops.0,
name,
size,
diff --git a/rust/qemu-api/src/prelude.rs b/rust/qemu-api/src/prelude.rs
index 43bfcd5..8f9e23e 100644
--- a/rust/qemu-api/src/prelude.rs
+++ b/rust/qemu-api/src/prelude.rs
@@ -11,6 +11,8 @@ pub use crate::cell::BqlRefCell;
pub use crate::errno;
+pub use crate::log_mask_ln;
+
pub use crate::qdev::DeviceMethods;
pub use crate::qom::InterfaceType;
diff --git a/rust/qemu-api/src/qdev.rs b/rust/qemu-api/src/qdev.rs
index 0610959..36f02fb 100644
--- a/rust/qemu-api/src/qdev.rs
+++ b/rust/qemu-api/src/qdev.rs
@@ -19,7 +19,7 @@ use crate::{
error::{Error, Result},
irq::InterruptSource,
prelude::*,
- qom::{ObjectClass, ObjectImpl, Owned},
+ qom::{ObjectClass, ObjectImpl, Owned, ParentInit},
vmstate::VMStateDescription,
};
@@ -247,15 +247,9 @@ unsafe impl ObjectType for DeviceState {
}
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>,
-{
+/// Initialization methods take a [`ParentInit`] and can be called as
+/// associated functions.
+impl DeviceState {
/// Add an input clock named `name`. Invoke the callback with
/// `self` as the first parameter for the events that are requested.
///
@@ -266,12 +260,15 @@ where
/// 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,
+ pub fn init_clock_in<T: DeviceImpl, F: for<'a> FnCall<(&'a T, ClockEvent)>>(
+ this: &mut ParentInit<T>,
name: &str,
_cb: &F,
events: ClockEvent,
- ) -> Owned<Clock> {
+ ) -> Owned<Clock>
+ where
+ T::ParentType: IsA<DeviceState>,
+ {
fn do_init_clock_in(
dev: &DeviceState,
name: &str,
@@ -287,10 +284,10 @@ where
unsafe {
let cstr = CString::new(name).unwrap();
let clk = bindings::qdev_init_clock_in(
- dev.as_mut_ptr(),
+ dev.0.as_mut_ptr(),
cstr.as_ptr(),
cb,
- dev.as_void_ptr(),
+ dev.0.as_void_ptr(),
events.0,
);
@@ -307,12 +304,12 @@ where
// 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>)
+ Some(rust_clock_cb::<T, F>)
} else {
None
};
- do_init_clock_in(self.upcast(), name, cb, events)
+ do_init_clock_in(unsafe { this.upcast_mut() }, name, cb, events)
}
/// Add an output clock named `name`.
@@ -324,16 +321,30 @@ where
/// 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> {
+ pub fn init_clock_out<T: DeviceImpl>(this: &mut ParentInit<T>, name: &str) -> Owned<Clock>
+ where
+ T::ParentType: IsA<DeviceState>,
+ {
unsafe {
let cstr = CString::new(name).unwrap();
- let clk = bindings::qdev_init_clock_out(self.upcast().as_mut_ptr(), cstr.as_ptr());
+ let dev: &mut DeviceState = this.upcast_mut();
+ let clk = bindings::qdev_init_clock_out(dev.0.as_mut_ptr(), cstr.as_ptr());
let clk: &Clock = Clock::from_raw(clk);
Owned::from(clk)
}
}
+}
+/// 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>,
+{
fn prop_set_chr(&self, propname: &str, chr: &Owned<Chardev>) {
assert!(bql_locked());
let c_propname = CString::new(propname).unwrap();
diff --git a/rust/qemu-api/src/qom.rs b/rust/qemu-api/src/qom.rs
index 14f98fe..e20ee01 100644
--- a/rust/qemu-api/src/qom.rs
+++ b/rust/qemu-api/src/qom.rs
@@ -95,7 +95,8 @@
use std::{
ffi::{c_void, CStr},
fmt,
- mem::ManuallyDrop,
+ marker::PhantomData,
+ mem::{ManuallyDrop, MaybeUninit},
ops::{Deref, DerefMut},
ptr::NonNull,
};
@@ -206,13 +207,190 @@ impl<T: fmt::Display + ObjectType> fmt::Display for ParentField<T> {
}
}
+/// This struct knows that the superclasses of the object have already been
+/// initialized.
+///
+/// The declaration of `ParentInit` is.. *"a kind of magic"*. It uses a
+/// technique that is found in several crates, the main ones probably being
+/// `ghost-cell` (in fact it was introduced by the [`GhostCell` paper](https://plv.mpi-sws.org/rustbelt/ghostcell/))
+/// and `generativity`.
+///
+/// The `PhantomData` makes the `ParentInit` type *invariant* with respect to
+/// the lifetime argument `'init`. This, together with the `for<'...>` in
+/// `[ParentInit::with]`, block any attempt of the compiler to be creative when
+/// operating on types of type `ParentInit` and to extend their lifetimes. In
+/// particular, it ensures that the `ParentInit` cannot be made to outlive the
+/// `rust_instance_init()` function that creates it, and therefore that the
+/// `&'init T` reference is valid.
+///
+/// This implementation of the same concept, without the QOM baggage, can help
+/// understanding the effect:
+///
+/// ```
+/// use std::marker::PhantomData;
+///
+/// #[derive(PartialEq, Eq)]
+/// pub struct Jail<'closure, T: Copy>(&'closure T, PhantomData<fn(&'closure ()) -> &'closure ()>);
+///
+/// impl<'closure, T: Copy> Jail<'closure, T> {
+/// fn get(&self) -> T {
+/// *self.0
+/// }
+///
+/// #[inline]
+/// fn with<U>(v: T, f: impl for<'id> FnOnce(Jail<'id, T>) -> U) -> U {
+/// let parent_init = Jail(&v, PhantomData);
+/// f(parent_init)
+/// }
+/// }
+/// ```
+///
+/// It's impossible to escape the `Jail`; `token1` cannot be moved out of the
+/// closure:
+///
+/// ```ignore
+/// let x = 42;
+/// let escape = Jail::with(&x, |token1| {
+/// println!("{}", token1.get());
+/// // fails to compile...
+/// token1
+/// });
+/// // ... so you cannot do this:
+/// println!("{}", escape.get());
+/// ```
+///
+/// Likewise, in the QOM case the `ParentInit` cannot be moved out of
+/// `instance_init()`. Without this trick it would be possible to stash a
+/// `ParentInit` and use it later to access uninitialized memory.
+///
+/// Here is another example, showing how separately-created "identities" stay
+/// isolated:
+///
+/// ```ignore
+/// impl<'closure, T: Copy> Clone for Jail<'closure, T> {
+/// fn clone(&self) -> Jail<'closure, T> {
+/// Jail(self.0, PhantomData)
+/// }
+/// }
+///
+/// fn main() {
+/// Jail::with(42, |token1| {
+/// // this works and returns true: the clone has the same "identity"
+/// println!("{}", token1 == token1.clone());
+/// Jail::with(42, |token2| {
+/// // here the outer token remains accessible...
+/// println!("{}", token1.get());
+/// // ... but the two are separate: this fails to compile:
+/// println!("{}", token1 == token2);
+/// });
+/// });
+/// }
+/// ```
+pub struct ParentInit<'init, T>(
+ &'init mut MaybeUninit<T>,
+ PhantomData<fn(&'init ()) -> &'init ()>,
+);
+
+impl<'init, T> ParentInit<'init, T> {
+ #[inline]
+ pub fn with(obj: &'init mut MaybeUninit<T>, f: impl for<'id> FnOnce(ParentInit<'id, T>)) {
+ let parent_init = ParentInit(obj, PhantomData);
+ f(parent_init)
+ }
+}
+
+impl<T: ObjectType> ParentInit<'_, T> {
+ /// Return the receiver as a mutable raw pointer to Object.
+ ///
+ /// # Safety
+ ///
+ /// Fields beyond `Object` could be uninitialized and it's your
+ /// responsibility to avoid that they're used when the pointer is
+ /// dereferenced, either directly or through a cast.
+ pub fn as_object_mut_ptr(&self) -> *mut bindings::Object {
+ self.as_object_ptr().cast_mut()
+ }
+
+ /// Return the receiver as a mutable raw pointer to Object.
+ ///
+ /// # Safety
+ ///
+ /// Fields beyond `Object` could be uninitialized and it's your
+ /// responsibility to avoid that they're used when the pointer is
+ /// dereferenced, either directly or through a cast.
+ pub fn as_object_ptr(&self) -> *const bindings::Object {
+ self.0.as_ptr().cast()
+ }
+}
+
+impl<'a, T: ObjectImpl> ParentInit<'a, T> {
+ /// Convert from a derived type to one of its parent types, which
+ /// have already been initialized.
+ ///
+ /// # Safety
+ ///
+ /// Structurally this is always a safe operation; the [`IsA`] trait
+ /// provides static verification trait that `Self` dereferences to `U` or
+ /// a child of `U`, and only parent types of `T` are allowed.
+ ///
+ /// However, while the fields of the resulting reference are initialized,
+ /// calls might use uninitialized fields of the subclass. It is your
+ /// responsibility to avoid this.
+ pub unsafe fn upcast<U: ObjectType>(&self) -> &'a U
+ where
+ T::ParentType: IsA<U>,
+ {
+ // SAFETY: soundness is declared via IsA<U>, which is an unsafe trait;
+ // the parent has been initialized before `instance_init `is called
+ unsafe { &*(self.0.as_ptr().cast::<U>()) }
+ }
+
+ /// Convert from a derived type to one of its parent types, which
+ /// have already been initialized.
+ ///
+ /// # Safety
+ ///
+ /// Structurally this is always a safe operation; the [`IsA`] trait
+ /// provides static verification trait that `Self` dereferences to `U` or
+ /// a child of `U`, and only parent types of `T` are allowed.
+ ///
+ /// However, while the fields of the resulting reference are initialized,
+ /// calls might use uninitialized fields of the subclass. It is your
+ /// responsibility to avoid this.
+ pub unsafe fn upcast_mut<U: ObjectType>(&mut self) -> &'a mut U
+ where
+ T::ParentType: IsA<U>,
+ {
+ // SAFETY: soundness is declared via IsA<U>, which is an unsafe trait;
+ // the parent has been initialized before `instance_init `is called
+ unsafe { &mut *(self.0.as_mut_ptr().cast::<U>()) }
+ }
+}
+
+impl<T> Deref for ParentInit<'_, T> {
+ type Target = MaybeUninit<T>;
+
+ fn deref(&self) -> &Self::Target {
+ self.0
+ }
+}
+
+impl<T> DerefMut for ParentInit<'_, T> {
+ fn deref_mut(&mut self) -> &mut Self::Target {
+ self.0
+ }
+}
+
unsafe extern "C" fn rust_instance_init<T: ObjectImpl>(obj: *mut bindings::Object) {
- let mut state = NonNull::new(obj).unwrap().cast::<T>();
+ let mut state = NonNull::new(obj).unwrap().cast::<MaybeUninit<T>>();
+
// SAFETY: obj is an instance of T, since rust_instance_init<T>
// is called from QOM core as the instance_init function
// for class T
unsafe {
- T::INSTANCE_INIT.unwrap()(state.as_mut());
+ ParentInit::with(state.as_mut(), |parent_init| {
+ T::INSTANCE_INIT.unwrap()(parent_init);
+ });
}
}
@@ -479,7 +657,7 @@ pub trait ObjectImpl: ObjectType + IsA<Object> {
///
/// FIXME: The argument is not really a valid reference. `&mut
/// MaybeUninit<Self>` would be a better description.
- const INSTANCE_INIT: Option<unsafe fn(&mut Self)> = None;
+ const INSTANCE_INIT: Option<unsafe fn(ParentInit<Self>)> = None;
/// Function that is called to finish initialization of an object, once
/// `INSTANCE_INIT` functions have been called.
diff --git a/rust/qemu-api/src/uninit.rs b/rust/qemu-api/src/uninit.rs
new file mode 100644
index 0000000..04123b4
--- /dev/null
+++ b/rust/qemu-api/src/uninit.rs
@@ -0,0 +1,85 @@
+//! Access fields of a [`MaybeUninit`]
+
+use std::{
+ mem::MaybeUninit,
+ ops::{Deref, DerefMut},
+};
+
+pub struct MaybeUninitField<'a, T, U> {
+ parent: &'a mut MaybeUninit<T>,
+ child: *mut U,
+}
+
+impl<'a, T, U> MaybeUninitField<'a, T, U> {
+ #[doc(hidden)]
+ pub fn new(parent: &'a mut MaybeUninit<T>, child: *mut U) -> Self {
+ MaybeUninitField { parent, child }
+ }
+
+ /// Return a constant pointer to the containing object of the field.
+ ///
+ /// Because the `MaybeUninitField` remembers the containing object,
+ /// it is possible to use it in foreign APIs that initialize the
+ /// child.
+ pub fn parent(f: &Self) -> *const T {
+ f.parent.as_ptr()
+ }
+
+ /// Return a mutable pointer to the containing object.
+ ///
+ /// Because the `MaybeUninitField` remembers the containing object,
+ /// it is possible to use it in foreign APIs that initialize the
+ /// child.
+ pub fn parent_mut(f: &mut Self) -> *mut T {
+ f.parent.as_mut_ptr()
+ }
+}
+
+impl<'a, T, U> Deref for MaybeUninitField<'a, T, U> {
+ type Target = MaybeUninit<U>;
+
+ fn deref(&self) -> &MaybeUninit<U> {
+ // SAFETY: self.child was obtained by dereferencing a valid mutable
+ // reference; the content of the memory may be invalid or uninitialized
+ // but MaybeUninit<_> makes no assumption on it
+ unsafe { &*(self.child.cast()) }
+ }
+}
+
+impl<'a, T, U> DerefMut for MaybeUninitField<'a, T, U> {
+ fn deref_mut(&mut self) -> &mut MaybeUninit<U> {
+ // SAFETY: self.child was obtained by dereferencing a valid mutable
+ // reference; the content of the memory may be invalid or uninitialized
+ // but MaybeUninit<_> makes no assumption on it
+ unsafe { &mut *(self.child.cast()) }
+ }
+}
+
+/// ```
+/// #[derive(Debug)]
+/// struct S {
+/// x: u32,
+/// y: u32,
+/// }
+///
+/// # use std::mem::MaybeUninit;
+/// # use qemu_api::{assert_match, uninit_field_mut};
+///
+/// let mut s: MaybeUninit<S> = MaybeUninit::zeroed();
+/// uninit_field_mut!(s, x).write(5);
+/// let s = unsafe { s.assume_init() };
+/// assert_match!(s, S { x: 5, y: 0 });
+/// ```
+#[macro_export]
+macro_rules! uninit_field_mut {
+ ($container:expr, $($field:tt)+) => {{
+ let container__: &mut ::std::mem::MaybeUninit<_> = &mut $container;
+ let container_ptr__ = container__.as_mut_ptr();
+
+ // SAFETY: the container is not used directly, only through a MaybeUninit<>,
+ // so the safety is delegated to the caller and to final invocation of
+ // assume_init()
+ let target__ = unsafe { std::ptr::addr_of_mut!((*container_ptr__).$($field)+) };
+ $crate::uninit::MaybeUninitField::new(container__, target__)
+ }};
+}
diff --git a/rust/wrapper.h b/rust/qemu-api/wrapper.h
index 6060d3b..15a1b19 100644
--- a/rust/wrapper.h
+++ b/rust/qemu-api/wrapper.h
@@ -48,6 +48,8 @@ typedef enum memory_order {
#endif /* __CLANG_STDATOMIC_H */
#include "qemu/osdep.h"
+#include "qemu/log.h"
+#include "qemu/log-for-trace.h"
#include "qemu/module.h"
#include "qemu-io.h"
#include "system/system.h"
generated by cgit v1.1 at 2025-06-28 04:06:57 +0000