Merge tag 'for-upstream' of https://gitlab.com/bonzini/qemu into staging

* rust: more qdev bindings
* rust: HPET device model with timer and GPIO bindings
* rust: small cleanups and fixes; run doctests during CI
* ui/sdl2: reenable the SDL2 Windows keyboard hook procedure

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# gpg: Signature made Thu 13 Feb 2025 07:50:49 EST
# gpg:                using RSA key F13338574B662389866C7682BFFBD25F78C7AE83
# gpg:                issuer "pbonzini@redhat.com"
# gpg: Good signature from "Paolo Bonzini <bonzini@gnu.org>" [full]
# gpg:                 aka "Paolo Bonzini <pbonzini@redhat.com>" [full]
# Primary key fingerprint: 46F5 9FBD 57D6 12E7 BFD4  E2F7 7E15 100C CD36 69B1
#      Subkey fingerprint: F133 3857 4B66 2389 866C  7682 BFFB D25F 78C7 AE83

* tag 'for-upstream' of https://gitlab.com/bonzini/qemu: (27 commits)
  ui/sdl2: reenable the SDL2 Windows keyboard hook procedure
  rust: fix doctests
  rust: vmstate: remove redundant link targets
  rust: qemu_api: add a documentation header for all modules
  i386: enable rust hpet for pc when rust is enabled
  rust/timer/hpet: add qom and qdev APIs support
  rust/timer/hpet: add basic HPET timer and HPETState
  rust/timer/hpet: define hpet_fw_cfg
  rust: add bindings for timer
  rust: add bindings for memattrs
  rust: add bindings for gpio_{in|out} initialization
  rust/irq: Add a helper to convert [InterruptSource] to pointer
  rust/qdev: add the macro to define bit property
  i386/fw_cfg: move hpet_cfg definition to hpet.c
  rust: pl011: convert pl011_create to safe Rust
  rust: chardev, qdev: add bindings to qdev_prop_set_chr
  rust: irq: define ObjectType for IRQState
  rust: bindings for MemoryRegionOps
  rust: bindings: add Send and Sync markers for types that have bindings
  rust: qdev: switch from legacy reset to Resettable
  ...

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>

16 files changed, 1037 insertions, 47 deletions

diff --git a/rust/qemu-api/src/assertions.rs b/rust/qemu-api/src/assertions.rs
index 6e42046..fa1a18d 100644
--- a/rust/qemu-api/src/assertions.rs
+++ b/rust/qemu-api/src/assertions.rs
@@ -2,9 +2,13 @@
 // Author(s): Paolo Bonzini <pbonzini@redhat.com>
 // SPDX-License-Identifier: GPL-2.0-or-later
 
+#![doc(hidden)]
 //! This module provides macros to check the equality of types and
 //! the type of `struct` fields.  This can be useful to ensure that
 //! types match the expectations of C code.
+//!
+//! Documentation is hidden because it only exposes macros, which
+//! are exported directly from `qemu_api`.
 
 // Based on https://stackoverflow.com/questions/64251852/x/70978292#70978292
 // (stackoverflow answers are released under MIT license).
diff --git a/rust/qemu-api/src/bindings.rs b/rust/qemu-api/src/bindings.rs
index 8a9b821..d286863 100644
--- a/rust/qemu-api/src/bindings.rs
+++ b/rust/qemu-api/src/bindings.rs
@@ -15,15 +15,63 @@
     clippy::missing_safety_doc
 )]
 
+//! `bindgen`-generated declarations.
+
 #[cfg(MESON)]
 include!("bindings.inc.rs");
 
 #[cfg(not(MESON))]
 include!(concat!(env!("OUT_DIR"), "/bindings.inc.rs"));
 
+// SAFETY: these are implemented in C; the bindings need to assert that the
+// BQL is taken, either directly or via `BqlCell` and `BqlRefCell`.
+unsafe impl Send for BusState {}
+unsafe impl Sync for BusState {}
+
+unsafe impl Send for CharBackend {}
+unsafe impl Sync for CharBackend {}
+
+unsafe impl Send for Chardev {}
+unsafe impl Sync for Chardev {}
+
+unsafe impl Send for Clock {}
+unsafe impl Sync for Clock {}
+
+unsafe impl Send for DeviceState {}
+unsafe impl Sync for DeviceState {}
+
+unsafe impl Send for MemoryRegion {}
+unsafe impl Sync for MemoryRegion {}
+
+unsafe impl Send for ObjectClass {}
+unsafe impl Sync for ObjectClass {}
+
+unsafe impl Send for Object {}
+unsafe impl Sync for Object {}
+
+unsafe impl Send for SysBusDevice {}
+unsafe impl Sync for SysBusDevice {}
+
+// SAFETY: this is a pure data struct
+unsafe impl Send for CoalescedMemoryRange {}
+unsafe impl Sync for CoalescedMemoryRange {}
+
+// SAFETY: these are constants and vtables; the Send and Sync requirements
+// are deferred to the unsafe callbacks that they contain
+unsafe impl Send for MemoryRegionOps {}
+unsafe impl Sync for MemoryRegionOps {}
+
 unsafe impl Send for Property {}
 unsafe impl Sync for Property {}
+
+unsafe impl Send for TypeInfo {}
 unsafe impl Sync for TypeInfo {}
+
+unsafe impl Send for VMStateDescription {}
 unsafe impl Sync for VMStateDescription {}
+
+unsafe impl Send for VMStateField {}
 unsafe impl Sync for VMStateField {}
+
+unsafe impl Send for VMStateInfo {}
 unsafe impl Sync for VMStateInfo {}
diff --git a/rust/qemu-api/src/c_str.rs b/rust/qemu-api/src/c_str.rs
index 4cd96da..3fa61b5 100644
--- a/rust/qemu-api/src/c_str.rs
+++ b/rust/qemu-api/src/c_str.rs
@@ -2,6 +2,14 @@
 // Author(s): Paolo Bonzini <pbonzini@redhat.com>
 // SPDX-License-Identifier: GPL-2.0-or-later
 
+#![doc(hidden)]
+//! This module provides a macro to define a constant of type
+//! [`CStr`](std::ffi::CStr), for compatibility with versions of
+//! Rust that lack `c""` literals.
+//!
+//! Documentation is hidden because it only exposes macros, which
+//! are exported directly from `qemu_api`.
+
 #[macro_export]
 /// Given a string constant _without_ embedded or trailing NULs, return
 /// a `CStr`.
diff --git a/rust/qemu-api/src/callbacks.rs b/rust/qemu-api/src/callbacks.rs
index 314f9dc..9642a16 100644
--- a/rust/qemu-api/src/callbacks.rs
+++ b/rust/qemu-api/src/callbacks.rs
@@ -79,6 +79,31 @@ use std::{mem, ptr::NonNull};
 /// call_it(&move |_| String::from(x), "hello workd");
 /// ```
 ///
+/// `()` can be used to indicate "no function":
+///
+/// ```
+/// # use qemu_api::callbacks::FnCall;
+/// fn optional<F: for<'a> FnCall<(&'a str,), String>>(_f: &F, s: &str) -> Option<String> {
+///     if F::IS_SOME {
+///         Some(F::call((s,)))
+///     } else {
+///         None
+///     }
+/// }
+///
+/// assert!(optional(&(), "hello world").is_none());
+/// ```
+///
+/// Invoking `F::call` will then be a run-time error.
+///
+/// ```should_panic
+/// # use qemu_api::callbacks::FnCall;
+/// # fn call_it<F: for<'a> FnCall<(&'a str,), String>>(_f: &F, s: &str) -> String {
+/// #     F::call((s,))
+/// # }
+/// let s: String = call_it(&(), "hello world"); // panics
+/// ```
+///
 /// # Safety
 ///
 /// Because `Self` is a zero-sized type, all instances of the type are
@@ -93,10 +118,70 @@ pub unsafe trait FnCall<Args, R = ()>: 'static + Sync + Sized {
     /// Rust 1.79.0+.
     const ASSERT_ZERO_SIZED: () = { assert!(mem::size_of::<Self>() == 0) };
 
+    /// Referring to this constant asserts that the `Self` type is an actual
+    /// function type, which can be used to catch incorrect use of `()`
+    /// at compile time.
+    ///
+    /// # Examples
+    ///
+    /// ```compile_fail
+    /// # use qemu_api::callbacks::FnCall;
+    /// fn call_it<F: for<'a> FnCall<(&'a str,), String>>(_f: &F, s: &str) -> String {
+    ///     let _: () = F::ASSERT_IS_SOME;
+    ///     F::call((s,))
+    /// }
+    ///
+    /// let s: String = call_it((), "hello world"); // does not compile
+    /// ```
+    ///
+    /// Note that this can be more simply `const { assert!(F::IS_SOME) }` in
+    /// Rust 1.79.0 or newer.
+    const ASSERT_IS_SOME: () = { assert!(Self::IS_SOME) };
+
+    /// `true` if `Self` is an actual function type and not `()`.
+    ///
+    /// # Examples
+    ///
+    /// You can use `IS_SOME` to catch this at compile time:
+    ///
+    /// ```compile_fail
+    /// # use qemu_api::callbacks::FnCall;
+    /// fn call_it<F: for<'a> FnCall<(&'a str,), String>>(_f: &F, s: &str) -> String {
+    ///     const { assert!(F::IS_SOME) }
+    ///     F::call((s,))
+    /// }
+    ///
+    /// let s: String = call_it((), "hello world"); // does not compile
+    /// ```
+    const IS_SOME: bool;
+
+    /// `false` if `Self` is an actual function type, `true` if it is `()`.
+    fn is_none() -> bool {
+        !Self::IS_SOME
+    }
+
+    /// `true` if `Self` is an actual function type, `false` if it is `()`.
+    fn is_some() -> bool {
+        Self::IS_SOME
+    }
+
     /// Call the function with the arguments in args.
     fn call(a: Args) -> R;
 }
 
+/// `()` acts as a "null" callback.  Using `()` and `function` is nicer
+/// than `None` and `Some(function)`, because the compiler is unable to
+/// infer the type of just `None`.  Therefore, the trait itself acts as the
+/// option type, with functions [`FnCall::is_some`] and [`FnCall::is_none`].
+unsafe impl<Args, R> FnCall<Args, R> for () {
+    const IS_SOME: bool = false;
+
+    /// Call the function with the arguments in args.
+    fn call(_a: Args) -> R {
+        panic!("callback not specified")
+    }
+}
+
 macro_rules! impl_call {
     ($($args:ident,)* ) => (
         // SAFETY: because each function is treated as a separate type,
@@ -106,6 +191,8 @@ macro_rules! impl_call {
         where
             F: 'static + Sync + Sized + Fn($($args, )*) -> R,
         {
+            const IS_SOME: bool = true;
+
             #[inline(always)]
             fn call(a: ($($args,)*)) -> R {
                 let _: () = Self::ASSERT_ZERO_SIZED;
@@ -141,4 +228,14 @@ mod tests {
     fn test_call() {
         assert_eq!(do_test_call(&str::to_owned), "hello world")
     }
+
+    // The `_f` parameter is unused but it helps the compiler infer `F`.
+    fn do_test_is_some<'a, F: FnCall<(&'a str,), String>>(_f: &F) {
+        assert!(F::is_some());
+    }
+
+    #[test]
+    fn test_is_some() {
+        do_test_is_some(&str::to_owned);
+    }
 }
diff --git a/rust/qemu-api/src/chardev.rs b/rust/qemu-api/src/chardev.rs
new file mode 100644
index 0000000..74cfb63
--- /dev/null
+++ b/rust/qemu-api/src/chardev.rs
@@ -0,0 +1,19 @@
+// Copyright 2024 Red Hat, Inc.
+// Author(s): Paolo Bonzini <pbonzini@redhat.com>
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! Bindings for character devices
+
+use std::ffi::CStr;
+
+use crate::{bindings, prelude::*};
+
+pub type Chardev = bindings::Chardev;
+pub type ChardevClass = bindings::ChardevClass;
+
+unsafe impl ObjectType for Chardev {
+    type Class = ChardevClass;
+    const TYPE_NAME: &'static CStr =
+        unsafe { CStr::from_bytes_with_nul_unchecked(bindings::TYPE_CHARDEV) };
+}
+qom_isa!(Chardev: Object);
diff --git a/rust/qemu-api/src/irq.rs b/rust/qemu-api/src/irq.rs
index 378e520..d1c9dc9 100644
--- a/rust/qemu-api/src/irq.rs
+++ b/rust/qemu-api/src/irq.rs
@@ -5,11 +5,12 @@
 //! Bindings for interrupt sources
 
 use core::ptr;
-use std::{marker::PhantomData, os::raw::c_int};
+use std::{ffi::CStr, marker::PhantomData, os::raw::c_int};
 
 use crate::{
-    bindings::{qemu_set_irq, IRQState},
+    bindings::{self, qemu_set_irq},
     prelude::*,
+    qom::ObjectClass,
 };
 
 /// Interrupt sources are used by devices to pass changes to a value (typically
@@ -21,7 +22,8 @@ use crate::{
 /// method sends a `true` value to the sink.  If the guest has to see a
 /// different polarity, that change is performed by the board between the
 /// device and the interrupt controller.
-///
+pub type IRQState = bindings::IRQState;
+
 /// Interrupts are implemented as a pointer to the interrupt "sink", which has
 /// type [`IRQState`].  A device exposes its source as a QOM link property using
 /// a function such as [`SysBusDeviceMethods::init_irq`], and
@@ -43,6 +45,9 @@ where
     _marker: PhantomData<T>,
 }
 
+// SAFETY: the implementation asserts via `BqlCell` that the BQL is taken
+unsafe impl<T> Sync for InterruptSource<T> where c_int: From<T> {}
+
 impl InterruptSource<bool> {
     /// Send a low (`false`) value to the interrupt sink.
     pub fn lower(&self) {
@@ -78,6 +83,11 @@ where
     pub(crate) const fn as_ptr(&self) -> *mut *mut IRQState {
         self.cell.as_ptr()
     }
+
+    pub(crate) const fn slice_as_ptr(slice: &[Self]) -> *mut *mut IRQState {
+        assert!(!slice.is_empty());
+        slice[0].as_ptr()
+    }
 }
 
 impl Default for InterruptSource {
@@ -88,3 +98,10 @@ impl Default for InterruptSource {
         }
     }
 }
+
+unsafe impl ObjectType for IRQState {
+    type Class = ObjectClass;
+    const TYPE_NAME: &'static CStr =
+        unsafe { CStr::from_bytes_with_nul_unchecked(bindings::TYPE_IRQ) };
+}
+qom_isa!(IRQState: Object);
diff --git a/rust/qemu-api/src/lib.rs b/rust/qemu-api/src/lib.rs
index 3cf9371..ed1a8f9 100644
--- a/rust/qemu-api/src/lib.rs
+++ b/rust/qemu-api/src/lib.rs
@@ -18,12 +18,15 @@ pub mod bitops;
 pub mod c_str;
 pub mod callbacks;
 pub mod cell;
+pub mod chardev;
 pub mod irq;
+pub mod memory;
 pub mod module;
 pub mod offset_of;
 pub mod qdev;
 pub mod qom;
 pub mod sysbus;
+pub mod timer;
 pub mod vmstate;
 pub mod zeroable;
 
diff --git a/rust/qemu-api/src/memory.rs b/rust/qemu-api/src/memory.rs
new file mode 100644
index 0000000..682951a
--- /dev/null
+++ b/rust/qemu-api/src/memory.rs
@@ -0,0 +1,203 @@
+// Copyright 2024 Red Hat, Inc.
+// Author(s): Paolo Bonzini <pbonzini@redhat.com>
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! Bindings for `MemoryRegion`, `MemoryRegionOps` and `MemTxAttrs`
+
+use std::{
+    ffi::{CStr, CString},
+    marker::{PhantomData, PhantomPinned},
+    os::raw::{c_uint, c_void},
+    ptr::addr_of,
+};
+
+pub use bindings::{hwaddr, MemTxAttrs};
+
+use crate::{
+    bindings::{self, device_endian, memory_region_init_io},
+    callbacks::FnCall,
+    prelude::*,
+    zeroable::Zeroable,
+};
+
+pub struct MemoryRegionOps<T>(
+    bindings::MemoryRegionOps,
+    // Note: quite often you'll see PhantomData<fn(&T)> mentioned when discussing
+    // covariance and contravariance; you don't need any of those to understand
+    // this usage of PhantomData.  Quite simply, MemoryRegionOps<T> *logically*
+    // holds callbacks that take an argument of type &T, except the type is erased
+    // before the callback is stored in the bindings::MemoryRegionOps field.
+    // The argument of PhantomData is a function pointer in order to represent
+    // that relationship; while that will also provide desirable and safe variance
+    // for T, variance is not the point but just a consequence.
+    PhantomData<fn(&T)>,
+);
+
+// SAFETY: When a *const T is passed to the callbacks, the call itself
+// is done in a thread-safe manner.  The invocation is okay as long as
+// T itself is `Sync`.
+unsafe impl<T: Sync> Sync for MemoryRegionOps<T> {}
+
+#[derive(Clone)]
+pub struct MemoryRegionOpsBuilder<T>(bindings::MemoryRegionOps, PhantomData<fn(&T)>);
+
+unsafe extern "C" fn memory_region_ops_read_cb<T, F: for<'a> FnCall<(&'a T, hwaddr, u32), u64>>(
+    opaque: *mut c_void,
+    addr: hwaddr,
+    size: c_uint,
+) -> u64 {
+    F::call((unsafe { &*(opaque.cast::<T>()) }, addr, size))
+}
+
+unsafe extern "C" fn memory_region_ops_write_cb<T, F: for<'a> FnCall<(&'a T, hwaddr, u64, u32)>>(
+    opaque: *mut c_void,
+    addr: hwaddr,
+    data: u64,
+    size: c_uint,
+) {
+    F::call((unsafe { &*(opaque.cast::<T>()) }, addr, data, size))
+}
+
+impl<T> MemoryRegionOpsBuilder<T> {
+    #[must_use]
+    pub const fn read<F: for<'a> FnCall<(&'a T, hwaddr, u32), u64>>(mut self, _f: &F) -> Self {
+        self.0.read = Some(memory_region_ops_read_cb::<T, F>);
+        self
+    }
+
+    #[must_use]
+    pub const fn write<F: for<'a> FnCall<(&'a T, hwaddr, u64, u32)>>(mut self, _f: &F) -> Self {
+        self.0.write = Some(memory_region_ops_write_cb::<T, F>);
+        self
+    }
+
+    #[must_use]
+    pub const fn big_endian(mut self) -> Self {
+        self.0.endianness = device_endian::DEVICE_BIG_ENDIAN;
+        self
+    }
+
+    #[must_use]
+    pub const fn little_endian(mut self) -> Self {
+        self.0.endianness = device_endian::DEVICE_LITTLE_ENDIAN;
+        self
+    }
+
+    #[must_use]
+    pub const fn native_endian(mut self) -> Self {
+        self.0.endianness = device_endian::DEVICE_NATIVE_ENDIAN;
+        self
+    }
+
+    #[must_use]
+    pub const fn valid_sizes(mut self, min: u32, max: u32) -> Self {
+        self.0.valid.min_access_size = min;
+        self.0.valid.max_access_size = max;
+        self
+    }
+
+    #[must_use]
+    pub const fn valid_unaligned(mut self) -> Self {
+        self.0.valid.unaligned = true;
+        self
+    }
+
+    #[must_use]
+    pub const fn impl_sizes(mut self, min: u32, max: u32) -> Self {
+        self.0.impl_.min_access_size = min;
+        self.0.impl_.max_access_size = max;
+        self
+    }
+
+    #[must_use]
+    pub const fn impl_unaligned(mut self) -> Self {
+        self.0.impl_.unaligned = true;
+        self
+    }
+
+    #[must_use]
+    pub const fn build(self) -> MemoryRegionOps<T> {
+        MemoryRegionOps::<T>(self.0, PhantomData)
+    }
+
+    #[must_use]
+    pub const fn new() -> Self {
+        Self(bindings::MemoryRegionOps::ZERO, PhantomData)
+    }
+}
+
+impl<T> Default for MemoryRegionOpsBuilder<T> {
+    fn default() -> Self {
+        Self::new()
+    }
+}
+
+/// A safe wrapper around [`bindings::MemoryRegion`].  Compared to the
+/// underlying C struct it is marked as pinned because the QOM tree
+/// contains a pointer to it.
+pub struct MemoryRegion {
+    inner: bindings::MemoryRegion,
+    _pin: PhantomPinned,
+}
+
+impl MemoryRegion {
+    // inline to ensure that it is not included in tests, which only
+    // link to hwcore and qom.  FIXME: inlining is actually the opposite
+    // of what we want, since this is the type-erased version of the
+    // init_io function below.  Look into splitting the qemu_api crate.
+    #[inline(always)]
+    unsafe fn do_init_io(
+        slot: *mut bindings::MemoryRegion,
+        owner: *mut Object,
+        ops: &'static bindings::MemoryRegionOps,
+        name: &'static str,
+        size: u64,
+    ) {
+        unsafe {
+            let cstr = CString::new(name).unwrap();
+            memory_region_init_io(
+                slot,
+                owner.cast::<Object>(),
+                ops,
+                owner.cast::<c_void>(),
+                cstr.as_ptr(),
+                size,
+            );
+        }
+    }
+
+    pub fn init_io<T: IsA<Object>>(
+        &mut self,
+        owner: *mut T,
+        ops: &'static MemoryRegionOps<T>,
+        name: &'static str,
+        size: u64,
+    ) {
+        unsafe {
+            Self::do_init_io(&mut self.inner, owner.cast::<Object>(), &ops.0, name, size);
+        }
+    }
+
+    pub(crate) const fn as_mut_ptr(&self) -> *mut bindings::MemoryRegion {
+        addr_of!(self.inner) as *mut _
+    }
+}
+
+unsafe impl ObjectType for MemoryRegion {
+    type Class = bindings::MemoryRegionClass;
+    const TYPE_NAME: &'static CStr =
+        unsafe { CStr::from_bytes_with_nul_unchecked(bindings::TYPE_MEMORY_REGION) };
+}
+qom_isa!(MemoryRegion: Object);
+
+/// A special `MemTxAttrs` constant, used to indicate that no memory
+/// attributes are specified.
+///
+/// Bus masters which don't specify any attributes will get this,
+/// which has all attribute bits clear except the topmost one
+/// (so that we can distinguish "all attributes deliberately clear"
+/// from "didn't specify" if necessary).
+pub const MEMTXATTRS_UNSPECIFIED: MemTxAttrs = MemTxAttrs {
+    unspecified: true,
+    ..Zeroable::ZERO
+};
diff --git a/rust/qemu-api/src/offset_of.rs b/rust/qemu-api/src/offset_of.rs
index 075e98f..373229b 100644
--- a/rust/qemu-api/src/offset_of.rs
+++ b/rust/qemu-api/src/offset_of.rs
@@ -1,5 +1,12 @@
 // SPDX-License-Identifier: MIT
 
+#![doc(hidden)]
+//! This module provides macros that emulate the functionality of
+//! `core::mem::offset_of` on older versions of Rust.
+//!
+//! Documentation is hidden because it only exposes macros, which
+//! are exported directly from `qemu_api`.
+
 /// This macro provides the same functionality as `core::mem::offset_of`,
 /// except that only one level of field access is supported.  The declaration
 /// of the struct must be wrapped with `with_offsets! { }`.
diff --git a/rust/qemu-api/src/prelude.rs b/rust/qemu-api/src/prelude.rs
index 2dc86e1..fbf0ee2 100644
--- a/rust/qemu-api/src/prelude.rs
+++ b/rust/qemu-api/src/prelude.rs
@@ -2,16 +2,22 @@
 // Author(s): Paolo Bonzini <pbonzini@redhat.com>
 // SPDX-License-Identifier: GPL-2.0-or-later
 
+//! Commonly used traits and types for QEMU.
+
 pub use crate::bitops::IntegerExt;
 
 pub use crate::cell::BqlCell;
 pub use crate::cell::BqlRefCell;
 
+pub use crate::qdev::DeviceMethods;
+
+pub use crate::qom::InterfaceType;
 pub use crate::qom::IsA;
 pub use crate::qom::Object;
 pub use crate::qom::ObjectCast;
 pub use crate::qom::ObjectCastMut;
 pub use crate::qom::ObjectDeref;
+pub use crate::qom::ObjectClassMethods;
 pub use crate::qom::ObjectMethods;
 pub use crate::qom::ObjectType;
 
diff --git a/rust/qemu-api/src/qdev.rs b/rust/qemu-api/src/qdev.rs
index f4c75c7..3a7aa4d 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);
diff --git a/rust/qemu-api/src/qom.rs b/rust/qemu-api/src/qom.rs
index f50ee37..3d5ab2d 100644
--- a/rust/qemu-api/src/qom.rs
+++ b/rust/qemu-api/src/qom.rs
@@ -56,6 +56,7 @@
 use std::{
     ffi::CStr,
     fmt,
+    mem::ManuallyDrop,
     ops::{Deref, DerefMut},
     os::raw::c_void,
     ptr::NonNull,
@@ -63,7 +64,13 @@ use std::{
 
 pub use bindings::{Object, ObjectClass};
 
-use crate::bindings::{self, object_dynamic_cast, object_get_class, object_get_typename, TypeInfo};
+use crate::{
+    bindings::{
+        self, object_class_dynamic_cast, object_dynamic_cast, object_get_class,
+        object_get_typename, object_new, object_ref, object_unref, TypeInfo,
+    },
+    cell::bql_locked,
+};
 
 /// Marker trait: `Self` can be statically upcasted to `P` (i.e. `P` is a direct
 /// or indirect parent of `Self`).
@@ -256,6 +263,47 @@ pub unsafe trait ObjectType: Sized {
     }
 }
 
+/// Trait exposed by all structs corresponding to QOM interfaces.
+/// Unlike `ObjectType`, it is implemented on the class type (which provides
+/// the vtable for the interfaces).
+///
+/// # Safety
+///
+/// `TYPE` must match the contents of the `TypeInfo` as found in the C code;
+/// right now, interfaces can only be declared in C.
+pub unsafe trait InterfaceType: Sized {
+    /// The name of the type, which can be passed to
+    /// `object_class_dynamic_cast()` to obtain the pointer to the vtable
+    /// for this interface.
+    const TYPE_NAME: &'static CStr;
+
+    /// Initialize the vtable for the interface; the generic argument `T` is the
+    /// type being initialized, while the generic argument `U` is the type that
+    /// lists the interface in its `TypeInfo`.
+    ///
+    /// # Panics
+    ///
+    /// Panic if the incoming argument if `T` does not implement the interface.
+    fn interface_init<
+        T: ObjectType + ClassInitImpl<Self> + ClassInitImpl<U::Class>,
+        U: ObjectType,
+    >(
+        klass: &mut U::Class,
+    ) {
+        unsafe {
+            // SAFETY: upcasting to ObjectClass is always valid, and the
+            // return type is either NULL or the argument itself
+            let result: *mut Self = object_class_dynamic_cast(
+                (klass as *mut U::Class).cast(),
+                Self::TYPE_NAME.as_ptr(),
+            )
+            .cast();
+
+            <T as ClassInitImpl<Self>>::class_init(result.as_mut().unwrap())
+        }
+    }
+}
+
 /// This trait provides safe casting operations for QOM objects to raw pointers,
 /// to be used for example for FFI. The trait can be applied to any kind of
 /// reference or smart pointers, and enforces correctness through the [`IsA`]
@@ -280,10 +328,10 @@ where
     ///
     /// # Safety
     ///
-    /// This method is unsafe because it overrides const-ness of `&self`.
-    /// Bindings to C APIs will use it a lot, but otherwise it should not
-    /// be necessary.
-    unsafe fn as_mut_ptr<U: ObjectType>(&self) -> *mut U
+    /// This method is safe because only the actual dereference of the pointer
+    /// has to be unsafe.  Bindings to C APIs will use it a lot, but care has
+    /// to be taken because it overrides the const-ness of `&self`.
+    fn as_mut_ptr<U: ObjectType>(&self) -> *mut U
     where
         Self::Target: IsA<U>,
     {
@@ -610,6 +658,166 @@ unsafe impl ObjectType for Object {
         unsafe { CStr::from_bytes_with_nul_unchecked(bindings::TYPE_OBJECT) };
 }
 
+/// A reference-counted pointer to a QOM object.
+///
+/// `Owned<T>` wraps `T` with automatic reference counting.  It increases the
+/// reference count when created via [`Owned::from`] or cloned, and decreases
+/// it when dropped.  This ensures that the reference count remains elevated
+/// as long as any `Owned<T>` references to it exist.
+///
+/// `Owned<T>` can be used for two reasons:
+/// * because the lifetime of the QOM object is unknown and someone else could
+///   take a reference (similar to `Arc<T>`, for example): in this case, the
+///   object can escape and outlive the Rust struct that contains the `Owned<T>`
+///   field;
+///
+/// * to ensure that the object stays alive until after `Drop::drop` is called
+///   on the Rust struct: in this case, the object will always die together with
+///   the Rust struct that contains the `Owned<T>` field.
+///
+/// Child properties are an example of the second case: in C, an object that
+/// is created with `object_initialize_child` will die *before*
+/// `instance_finalize` is called, whereas Rust expects the struct to have valid
+/// contents when `Drop::drop` is called.  Therefore Rust structs that have
+/// child properties need to keep a reference to the child object.  Right now
+/// this can be done with `Owned<T>`; in the future one might have a separate
+/// `Child<'parent, T>` smart pointer that keeps a reference to a `T`, like
+/// `Owned`, but does not allow cloning.
+///
+/// Note that dropping an `Owned<T>` requires the big QEMU lock to be taken.
+#[repr(transparent)]
+#[derive(PartialEq, Eq, Hash, PartialOrd, Ord)]
+pub struct Owned<T: ObjectType>(NonNull<T>);
+
+// The following rationale for safety is taken from Linux's kernel::sync::Arc.
+
+// SAFETY: It is safe to send `Owned<T>` to another thread when the underlying
+// `T` is `Sync` because it effectively means sharing `&T` (which is safe
+// because `T` is `Sync`); additionally, it needs `T` to be `Send` because any
+// thread that has an `Owned<T>` may ultimately access `T` using a
+// mutable reference when the reference count reaches zero and `T` is dropped.
+unsafe impl<T: ObjectType + Send + Sync> Send for Owned<T> {}
+
+// SAFETY: It is safe to send `&Owned<T>` to another thread when the underlying
+// `T` is `Sync` because it effectively means sharing `&T` (which is safe
+// because `T` is `Sync`); additionally, it needs `T` to be `Send` because any
+// thread that has a `&Owned<T>` may clone it and get an `Owned<T>` on that
+// thread, so the thread may ultimately access `T` using a mutable reference
+// when the reference count reaches zero and `T` is dropped.
+unsafe impl<T: ObjectType + Sync + Send> Sync for Owned<T> {}
+
+impl<T: ObjectType> Owned<T> {
+    /// Convert a raw C pointer into an owned reference to the QOM
+    /// object it points to.  The object's reference count will be
+    /// decreased when the `Owned` is dropped.
+    ///
+    /// # Panics
+    ///
+    /// Panics if `ptr` is NULL.
+    ///
+    /// # Safety
+    ///
+    /// The caller must indeed own a reference to the QOM object.
+    /// The object must not be embedded in another unless the outer
+    /// object is guaranteed to have a longer lifetime.
+    ///
+    /// A raw pointer obtained via [`Owned::into_raw()`] can always be passed
+    /// back to `from_raw()` (assuming the original `Owned` was valid!),
+    /// since the owned reference remains there between the calls to
+    /// `into_raw()` and `from_raw()`.
+    pub unsafe fn from_raw(ptr: *const T) -> Self {
+        // SAFETY NOTE: while NonNull requires a mutable pointer, only
+        // Deref is implemented so the pointer passed to from_raw
+        // remains const
+        Owned(NonNull::new(ptr as *mut T).unwrap())
+    }
+
+    /// Obtain a raw C pointer from a reference.  `src` is consumed
+    /// and the reference is leaked.
+    #[allow(clippy::missing_const_for_fn)]
+    pub fn into_raw(src: Owned<T>) -> *mut T {
+        let src = ManuallyDrop::new(src);
+        src.0.as_ptr()
+    }
+
+    /// Increase the reference count of a QOM object and return
+    /// a new owned reference to it.
+    ///
+    /// # Safety
+    ///
+    /// The object must not be embedded in another, unless the outer
+    /// object is guaranteed to have a longer lifetime.
+    pub unsafe fn from(obj: &T) -> Self {
+        unsafe {
+            object_ref(obj.as_object_mut_ptr().cast::<c_void>());
+
+            // SAFETY NOTE: while NonNull requires a mutable pointer, only
+            // Deref is implemented so the reference passed to from_raw
+            // remains shared
+            Owned(NonNull::new_unchecked(obj.as_mut_ptr()))
+        }
+    }
+}
+
+impl<T: ObjectType> Clone for Owned<T> {
+    fn clone(&self) -> Self {
+        // SAFETY: creation method is unsafe; whoever calls it has
+        // responsibility that the pointer is valid, and remains valid
+        // throughout the lifetime of the `Owned<T>` and its clones.
+        unsafe { Owned::from(self.deref()) }
+    }
+}
+
+impl<T: ObjectType> Deref for Owned<T> {
+    type Target = T;
+
+    fn deref(&self) -> &Self::Target {
+        // SAFETY: creation method is unsafe; whoever calls it has
+        // responsibility that the pointer is valid, and remains valid
+        // throughout the lifetime of the `Owned<T>` and its clones.
+        // With that guarantee, reference counting ensures that
+        // the object remains alive.
+        unsafe { &*self.0.as_ptr() }
+    }
+}
+impl<T: ObjectType> ObjectDeref for Owned<T> {}
+
+impl<T: ObjectType> Drop for Owned<T> {
+    fn drop(&mut self) {
+        assert!(bql_locked());
+        // SAFETY: creation method is unsafe, and whoever calls it has
+        // responsibility that the pointer is valid, and remains valid
+        // throughout the lifetime of the `Owned<T>` and its clones.
+        unsafe {
+            object_unref(self.as_object_mut_ptr().cast::<c_void>());
+        }
+    }
+}
+
+impl<T: IsA<Object>> fmt::Debug for Owned<T> {
+    fn fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        self.deref().debug_fmt(f)
+    }
+}
+
+/// Trait for class methods exposed by the Object class.  The methods can be
+/// called on all objects that have the trait `IsA<Object>`.
+///
+/// The trait should only be used through the blanket implementation,
+/// which guarantees safety via `IsA`
+pub trait ObjectClassMethods: IsA<Object> {
+    /// Return a new reference counted instance of this class
+    fn new() -> Owned<Self> {
+        assert!(bql_locked());
+        // SAFETY: the object created by object_new is allocated on
+        // the heap and has a reference count of 1
+        unsafe {
+            let obj = &*object_new(Self::TYPE_NAME.as_ptr());
+            Owned::from_raw(obj.unsafe_cast::<Self>())
+        }
+    }
+}
+
 /// Trait for methods exposed by the Object class.  The methods can be
 /// called on all objects that have the trait `IsA<Object>`.
 ///
@@ -641,6 +849,14 @@ where
 
         klass
     }
+
+    /// Convenience function for implementing the Debug trait
+    fn debug_fmt(&self, f: &mut fmt::Formatter) -> fmt::Result {
+        f.debug_tuple(&self.typename())
+            .field(&(self as *const Self))
+            .finish()
+    }
 }
 
+impl<T> ObjectClassMethods for T where T: IsA<Object> {}
 impl<R: ObjectDeref> ObjectMethods for R where R::Target: IsA<Object> {}
diff --git a/rust/qemu-api/src/sysbus.rs b/rust/qemu-api/src/sysbus.rs
index e6762b5..fa36e12 100644
--- a/rust/qemu-api/src/sysbus.rs
+++ b/rust/qemu-api/src/sysbus.rs
@@ -2,17 +2,20 @@
 // Author(s): Paolo Bonzini <pbonzini@redhat.com>
 // SPDX-License-Identifier: GPL-2.0-or-later
 
-use std::{ffi::CStr, ptr::addr_of};
+//! Bindings to access `sysbus` functionality from Rust.
+
+use std::{ffi::CStr, ptr::addr_of_mut};
 
 pub use bindings::{SysBusDevice, SysBusDeviceClass};
 
 use crate::{
     bindings,
     cell::bql_locked,
-    irq::InterruptSource,
+    irq::{IRQState, InterruptSource},
+    memory::MemoryRegion,
     prelude::*,
     qdev::{DeviceClass, DeviceState},
-    qom::ClassInitImpl,
+    qom::{ClassInitImpl, Owned},
 };
 
 unsafe impl ObjectType for SysBusDevice {
@@ -42,10 +45,10 @@ where
     /// important, since whoever creates the sysbus device will refer to the
     /// region with a number that corresponds to the order of calls to
     /// `init_mmio`.
-    fn init_mmio(&self, iomem: &bindings::MemoryRegion) {
+    fn init_mmio(&self, iomem: &MemoryRegion) {
         assert!(bql_locked());
         unsafe {
-            bindings::sysbus_init_mmio(self.as_mut_ptr(), addr_of!(*iomem) as *mut _);
+            bindings::sysbus_init_mmio(self.as_mut_ptr(), iomem.as_mut_ptr());
         }
     }
 
@@ -59,6 +62,34 @@ where
             bindings::sysbus_init_irq(self.as_mut_ptr(), irq.as_ptr());
         }
     }
+
+    // TODO: do we want a type like GuestAddress here?
+    fn mmio_map(&self, id: u32, addr: u64) {
+        assert!(bql_locked());
+        let id: i32 = id.try_into().unwrap();
+        unsafe {
+            bindings::sysbus_mmio_map(self.as_mut_ptr(), id, addr);
+        }
+    }
+
+    // Owned<> is used here because sysbus_connect_irq (via
+    // object_property_set_link) adds a reference to the IRQState,
+    // which can prolong its life
+    fn connect_irq(&self, id: u32, irq: &Owned<IRQState>) {
+        assert!(bql_locked());
+        let id: i32 = id.try_into().unwrap();
+        unsafe {
+            bindings::sysbus_connect_irq(self.as_mut_ptr(), id, irq.as_mut_ptr());
+        }
+    }
+
+    fn sysbus_realize(&self) {
+        // TODO: return an Error
+        assert!(bql_locked());
+        unsafe {
+            bindings::sysbus_realize(self.as_mut_ptr(), addr_of_mut!(bindings::error_fatal));
+        }
+    }
 }
 
 impl<R: ObjectDeref> SysBusDeviceMethods for R where R::Target: IsA<SysBusDevice> {}
diff --git a/rust/qemu-api/src/timer.rs b/rust/qemu-api/src/timer.rs
new file mode 100644
index 0000000..a593538
--- /dev/null
+++ b/rust/qemu-api/src/timer.rs
@@ -0,0 +1,98 @@
+// Copyright (C) 2024 Intel Corporation.
+// Author(s): Zhao Liu <zhai1.liu@intel.com>
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+use std::os::raw::{c_int, c_void};
+
+use crate::{
+    bindings::{self, qemu_clock_get_ns, timer_del, timer_init_full, timer_mod, QEMUClockType},
+    callbacks::FnCall,
+};
+
+pub type Timer = bindings::QEMUTimer;
+pub type TimerListGroup = bindings::QEMUTimerListGroup;
+
+impl Timer {
+    pub const MS: u32 = bindings::SCALE_MS;
+    pub const US: u32 = bindings::SCALE_US;
+    pub const NS: u32 = bindings::SCALE_NS;
+
+    pub fn new() -> Self {
+        Default::default()
+    }
+
+    const fn as_mut_ptr(&self) -> *mut Self {
+        self as *const Timer as *mut _
+    }
+
+    pub fn init_full<'timer, 'opaque: 'timer, T, F>(
+        &'timer mut self,
+        timer_list_group: Option<&TimerListGroup>,
+        clk_type: ClockType,
+        scale: u32,
+        attributes: u32,
+        _cb: F,
+        opaque: &'opaque T,
+    ) where
+        F: for<'a> FnCall<(&'a T,)>,
+    {
+        let _: () = F::ASSERT_IS_SOME;
+
+        /// timer expiration callback
+        unsafe extern "C" fn rust_timer_handler<T, F: for<'a> FnCall<(&'a T,)>>(
+            opaque: *mut c_void,
+        ) {
+            // SAFETY: the opaque was passed as a reference to `T`.
+            F::call((unsafe { &*(opaque.cast::<T>()) },))
+        }
+
+        let timer_cb: unsafe extern "C" fn(*mut c_void) = rust_timer_handler::<T, F>;
+
+        // SAFETY: the opaque outlives the timer
+        unsafe {
+            timer_init_full(
+                self,
+                if let Some(g) = timer_list_group {
+                    g as *const TimerListGroup as *mut _
+                } else {
+                    ::core::ptr::null_mut()
+                },
+                clk_type.id,
+                scale as c_int,
+                attributes as c_int,
+                Some(timer_cb),
+                (opaque as *const T).cast::<c_void>() as *mut c_void,
+            )
+        }
+    }
+
+    pub fn modify(&self, expire_time: u64) {
+        unsafe { timer_mod(self.as_mut_ptr(), expire_time as i64) }
+    }
+
+    pub fn delete(&self) {
+        unsafe { timer_del(self.as_mut_ptr()) }
+    }
+}
+
+impl Drop for Timer {
+    fn drop(&mut self) {
+        self.delete()
+    }
+}
+
+pub struct ClockType {
+    id: QEMUClockType,
+}
+
+impl ClockType {
+    pub fn get_ns(&self) -> u64 {
+        // SAFETY: cannot be created outside this module, therefore id
+        // is valid
+        (unsafe { qemu_clock_get_ns(self.id) }) as u64
+    }
+}
+
+pub const CLOCK_VIRTUAL: ClockType = ClockType {
+    id: QEMUClockType::QEMU_CLOCK_VIRTUAL,
+};
diff --git a/rust/qemu-api/src/vmstate.rs b/rust/qemu-api/src/vmstate.rs
index 6ac432c..24a4dc8 100644
--- a/rust/qemu-api/src/vmstate.rs
+++ b/rust/qemu-api/src/vmstate.rs
@@ -29,6 +29,8 @@ use core::{marker::PhantomData, mem, ptr::NonNull};
 pub use crate::bindings::{VMStateDescription, VMStateField};
 use crate::{
     bindings::{self, VMStateFlags},
+    prelude::*,
+    qom::Owned,
     zeroable::Zeroable,
 };
 
@@ -189,9 +191,9 @@ pub const fn vmstate_varray_flag<T: VMState>(_: PhantomData<T>) -> VMStateFlags
 /// * scalar types (integer and `bool`)
 /// * the C struct `QEMUTimer`
 /// * a transparent wrapper for any of the above (`Cell`, `UnsafeCell`,
-///   [`BqlCell`](crate::cell::BqlCell), [`BqlRefCell`](crate::cell::BqlRefCell)
+///   [`BqlCell`], [`BqlRefCell`]
 /// * a raw pointer to any of the above
-/// * a `NonNull` pointer or a `Box` for any of the above
+/// * a `NonNull` pointer, a `Box` or an [`Owned`] for any of the above
 /// * an array of any of the above
 ///
 /// In order to support other types, the trait `VMState` must be implemented
@@ -292,7 +294,7 @@ impl VMStateField {
 /// # Examples
 ///
 /// ```
-/// # use qemu_api::vmstate::impl_vmstate_forward;
+/// # use qemu_api::impl_vmstate_forward;
 /// pub struct Fifo([u8; 16]);
 /// impl_vmstate_forward!(Fifo);
 /// ```
@@ -398,6 +400,7 @@ impl_vmstate_pointer!(NonNull<T> where T: VMState);
 // Unlike C pointers, Box is always non-null therefore there is no need
 // to specify VMS_ALLOC.
 impl_vmstate_pointer!(Box<T> where T: VMState);
+impl_vmstate_pointer!(Owned<T> where T: VMState + ObjectType);
 
 // Arrays using the underlying type's VMState plus
 // VMS_ARRAY/VMS_ARRAY_OF_POINTER
@@ -466,11 +469,11 @@ macro_rules! vmstate_clock {
                 $crate::assert_field_type!(
                     $struct_name,
                     $field_name,
-                    core::ptr::NonNull<$crate::bindings::Clock>
+                    $crate::qom::Owned<$crate::bindings::Clock>
                 );
                 $crate::offset_of!($struct_name, $field_name)
             },
-            size: ::core::mem::size_of::<*const $crate::bindings::Clock>(),
+            size: ::core::mem::size_of::<*const $crate::qdev::Clock>(),
             flags: VMStateFlags(VMStateFlags::VMS_STRUCT.0 | VMStateFlags::VMS_POINTER.0),
             vmsd: unsafe { ::core::ptr::addr_of!($crate::bindings::vmstate_clock) },
             ..$crate::zeroable::Zeroable::ZERO
diff --git a/rust/qemu-api/src/zeroable.rs b/rust/qemu-api/src/zeroable.rs
index 7b04947..47b6977 100644
--- a/rust/qemu-api/src/zeroable.rs
+++ b/rust/qemu-api/src/zeroable.rs
@@ -1,11 +1,13 @@
 // SPDX-License-Identifier: GPL-2.0-or-later
 
+//! Defines a trait for structs that can be safely initialized with zero bytes.
+
 /// Encapsulates the requirement that
 /// `MaybeUninit::<Self>::zeroed().assume_init()` does not cause undefined
 /// behavior.  This trait in principle could be implemented as just:
 ///
 /// ```
-/// pub unsafe trait Zeroable {
+/// pub unsafe trait Zeroable: Default {
 ///     const ZERO: Self = unsafe { ::core::mem::MaybeUninit::<Self>::zeroed().assume_init() };
 /// }
 /// ```
@@ -56,6 +58,7 @@ pub unsafe trait Zeroable: Default {
 /// ## Differences with `core::mem::zeroed`
 ///
 /// `const_zero` zeroes padding bits, while `core::mem::zeroed` doesn't
+#[macro_export]
 macro_rules! const_zero {
     // This macro to produce a type-generic zero constant is taken from the
     // const_zero crate (v0.1.1):
@@ -77,10 +80,11 @@ macro_rules! const_zero {
 }
 
 /// A wrapper to implement the `Zeroable` trait through the `const_zero` macro.
+#[macro_export]
 macro_rules! impl_zeroable {
     ($type:ty) => {
-        unsafe impl Zeroable for $type {
-            const ZERO: Self = unsafe { const_zero!($type) };
+        unsafe impl $crate::zeroable::Zeroable for $type {
+            const ZERO: Self = unsafe { $crate::const_zero!($type) };
         }
     };
 }
@@ -100,3 +104,5 @@ impl_zeroable!(crate::bindings::VMStateField);
 impl_zeroable!(crate::bindings::VMStateDescription);
 impl_zeroable!(crate::bindings::MemoryRegionOps__bindgen_ty_1);
 impl_zeroable!(crate::bindings::MemoryRegionOps__bindgen_ty_2);
+impl_zeroable!(crate::bindings::MemoryRegionOps);
+impl_zeroable!(crate::bindings::MemTxAttrs);