rust: add crate to expose bindings and interfaces
Add rust/qemu-api, which exposes rust-bindgen generated FFI bindings and
provides some declaration macros for symbols visible to the rest of
QEMU.
Co-authored-by: Junjie Mao <junjie.mao@intel.com>
Co-authored-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Junjie Mao <junjie.mao@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
Link: https://lore.kernel.org/r/0fb23fbe211761b263aacec03deaf85c0cc39995.1727961605.git.manos.pitsidianakis@linaro.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/MAINTAINERS b/MAINTAINERS
index f090295..de583a1 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -3291,6 +3291,12 @@
F: include/hw/register.h
F: include/hw/registerfields.h
+Rust
+M: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
+S: Maintained
+F: rust/qemu-api
+F: rust/rustfmt.toml
+
SLIRP
M: Samuel Thibault <samuel.thibault@ens-lyon.org>
S: Maintained
diff --git a/rust/meson.build b/rust/meson.build
index e69de29..4a58d10 100644
--- a/rust/meson.build
+++ b/rust/meson.build
@@ -0,0 +1 @@
+subdir('qemu-api')
diff --git a/rust/qemu-api/.gitignore b/rust/qemu-api/.gitignore
new file mode 100644
index 0000000..b9e7e00
--- /dev/null
+++ b/rust/qemu-api/.gitignore
@@ -0,0 +1,2 @@
+# Ignore generated bindings file overrides.
+src/bindings.rs
diff --git a/rust/qemu-api/Cargo.lock b/rust/qemu-api/Cargo.lock
new file mode 100644
index 0000000..e9c51a2
--- /dev/null
+++ b/rust/qemu-api/Cargo.lock
@@ -0,0 +1,7 @@
+# This file is automatically @generated by Cargo.
+# It is not intended for manual editing.
+version = 3
+
+[[package]]
+name = "qemu_api"
+version = "0.1.0"
diff --git a/rust/qemu-api/Cargo.toml b/rust/qemu-api/Cargo.toml
new file mode 100644
index 0000000..3677def
--- /dev/null
+++ b/rust/qemu-api/Cargo.toml
@@ -0,0 +1,26 @@
+[package]
+name = "qemu_api"
+version = "0.1.0"
+edition = "2021"
+authors = ["Manos Pitsidianakis <manos.pitsidianakis@linaro.org>"]
+license = "GPL-2.0-or-later"
+readme = "README.md"
+homepage = "https://www.qemu.org"
+description = "Rust bindings for QEMU"
+repository = "https://gitlab.com/qemu-project/qemu/"
+resolver = "2"
+publish = false
+keywords = []
+categories = []
+
+[dependencies]
+
+[features]
+default = []
+allocator = []
+
+# Do not include in any global workspace
+[workspace]
+
+[lints.rust]
+unexpected_cfgs = { level = "warn", check-cfg = ['cfg(MESON)', 'cfg(HAVE_GLIB_WITH_ALIGNED_ALLOC)'] }
diff --git a/rust/qemu-api/README.md b/rust/qemu-api/README.md
new file mode 100644
index 0000000..7588fa2
--- /dev/null
+++ b/rust/qemu-api/README.md
@@ -0,0 +1,17 @@
+# QEMU bindings and API wrappers
+
+This library exports helper Rust types, Rust macros and C FFI bindings for internal QEMU APIs.
+
+The C bindings can be generated with `bindgen`, using this build target:
+
+```console
+$ ninja bindings.rs
+```
+
+## Generate Rust documentation
+
+To generate docs for this crate, including private items:
+
+```sh
+cargo doc --no-deps --document-private-items
+```
diff --git a/rust/qemu-api/build.rs b/rust/qemu-api/build.rs
new file mode 100644
index 0000000..419b154
--- /dev/null
+++ b/rust/qemu-api/build.rs
@@ -0,0 +1,14 @@
+// Copyright 2024, Linaro Limited
+// Author(s): Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+use std::path::Path;
+
+fn main() {
+ if !Path::new("src/bindings.rs").exists() {
+ panic!(
+ "No generated C bindings found! Either build them manually with bindgen or with meson \
+ (`ninja bindings.rs`) and copy them to src/bindings.rs, or build through meson."
+ );
+ }
+}
diff --git a/rust/qemu-api/meson.build b/rust/qemu-api/meson.build
new file mode 100644
index 0000000..439ef73
--- /dev/null
+++ b/rust/qemu-api/meson.build
@@ -0,0 +1,21 @@
+_qemu_api_rs = static_library(
+ 'qemu_api',
+ structured_sources(
+ [
+ 'src/lib.rs',
+ 'src/definitions.rs',
+ 'src/device_class.rs',
+ ],
+ {'.' : bindings_rs},
+ ),
+ override_options: ['rust_std=2021', 'build.rust_std=2021'],
+ rust_abi: 'rust',
+ rust_args: rustc_args + [
+ '--cfg', 'MESON',
+ # '--cfg', 'feature="allocator"',
+ ],
+)
+
+qemu_api = declare_dependency(
+ link_with: _qemu_api_rs,
+)
diff --git a/rust/qemu-api/src/definitions.rs b/rust/qemu-api/src/definitions.rs
new file mode 100644
index 0000000..60bd3f8
--- /dev/null
+++ b/rust/qemu-api/src/definitions.rs
@@ -0,0 +1,97 @@
+// Copyright 2024, Linaro Limited
+// Author(s): Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! Definitions required by QEMU when registering a device.
+
+use ::core::ffi::{c_void, CStr};
+
+use crate::bindings::{Object, ObjectClass, TypeInfo};
+
+/// Trait a type must implement to be registered with QEMU.
+pub trait ObjectImpl {
+ type Class;
+ const TYPE_INFO: TypeInfo;
+ const TYPE_NAME: &'static CStr;
+ const PARENT_TYPE_NAME: Option<&'static CStr>;
+ const ABSTRACT: bool;
+ const INSTANCE_INIT: Option<unsafe extern "C" fn(obj: *mut Object)>;
+ const INSTANCE_POST_INIT: Option<unsafe extern "C" fn(obj: *mut Object)>;
+ const INSTANCE_FINALIZE: Option<unsafe extern "C" fn(obj: *mut Object)>;
+}
+
+pub trait Class {
+ const CLASS_INIT: Option<unsafe extern "C" fn(klass: *mut ObjectClass, data: *mut c_void)>;
+ const CLASS_BASE_INIT: Option<
+ unsafe extern "C" fn(klass: *mut ObjectClass, data: *mut c_void),
+ >;
+}
+
+#[macro_export]
+macro_rules! module_init {
+ ($func:expr, $type:expr) => {
+ #[used]
+ #[cfg_attr(target_os = "linux", link_section = ".ctors")]
+ #[cfg_attr(target_os = "macos", link_section = "__DATA,__mod_init_func")]
+ #[cfg_attr(target_os = "windows", link_section = ".CRT$XCU")]
+ pub static LOAD_MODULE: extern "C" fn() = {
+ extern "C" fn __load() {
+ unsafe {
+ $crate::bindings::register_module_init(Some($func), $type);
+ }
+ }
+
+ __load
+ };
+ };
+ (qom: $func:ident => $body:block) => {
+ // NOTE: To have custom identifiers for the ctor func we need to either supply
+ // them directly as a macro argument or create them with a proc macro.
+ #[used]
+ #[cfg_attr(target_os = "linux", link_section = ".ctors")]
+ #[cfg_attr(target_os = "macos", link_section = "__DATA,__mod_init_func")]
+ #[cfg_attr(target_os = "windows", link_section = ".CRT$XCU")]
+ pub static LOAD_MODULE: extern "C" fn() = {
+ extern "C" fn __load() {
+ #[no_mangle]
+ unsafe extern "C" fn $func() {
+ $body
+ }
+
+ unsafe {
+ $crate::bindings::register_module_init(
+ Some($func),
+ $crate::bindings::module_init_type::MODULE_INIT_QOM,
+ );
+ }
+ }
+
+ __load
+ };
+ };
+}
+
+#[macro_export]
+macro_rules! type_info {
+ ($t:ty) => {
+ $crate::bindings::TypeInfo {
+ name: <$t as $crate::definitions::ObjectImpl>::TYPE_NAME.as_ptr(),
+ parent: if let Some(pname) = <$t as $crate::definitions::ObjectImpl>::PARENT_TYPE_NAME {
+ pname.as_ptr()
+ } else {
+ ::core::ptr::null_mut()
+ },
+ instance_size: ::core::mem::size_of::<$t>() as $crate::bindings::size_t,
+ instance_align: ::core::mem::align_of::<$t>() as $crate::bindings::size_t,
+ instance_init: <$t as $crate::definitions::ObjectImpl>::INSTANCE_INIT,
+ instance_post_init: <$t as $crate::definitions::ObjectImpl>::INSTANCE_POST_INIT,
+ instance_finalize: <$t as $crate::definitions::ObjectImpl>::INSTANCE_FINALIZE,
+ abstract_: <$t as $crate::definitions::ObjectImpl>::ABSTRACT,
+ class_size: ::core::mem::size_of::<<$t as $crate::definitions::ObjectImpl>::Class>() as $crate::bindings::size_t,
+ class_init: <<$t as $crate::definitions::ObjectImpl>::Class as $crate::definitions::Class>::CLASS_INIT,
+ class_base_init: <<$t as $crate::definitions::ObjectImpl>::Class as $crate::definitions::Class>::CLASS_BASE_INIT,
+ class_data: ::core::ptr::null_mut(),
+ interfaces: ::core::ptr::null_mut(),
+ };
+ }
+}
diff --git a/rust/qemu-api/src/device_class.rs b/rust/qemu-api/src/device_class.rs
new file mode 100644
index 0000000..1ea95be
--- /dev/null
+++ b/rust/qemu-api/src/device_class.rs
@@ -0,0 +1,128 @@
+// Copyright 2024, Linaro Limited
+// Author(s): Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+use std::sync::OnceLock;
+
+use crate::bindings::Property;
+
+#[macro_export]
+macro_rules! device_class_init {
+ ($func:ident, props => $props:ident, realize_fn => $realize_fn:expr, legacy_reset_fn => $legacy_reset_fn:expr, vmsd => $vmsd:ident$(,)*) => {
+ #[no_mangle]
+ pub unsafe extern "C" fn $func(
+ klass: *mut $crate::bindings::ObjectClass,
+ _: *mut ::core::ffi::c_void,
+ ) {
+ let mut dc =
+ ::core::ptr::NonNull::new(klass.cast::<$crate::bindings::DeviceClass>()).unwrap();
+ dc.as_mut().realize = $realize_fn;
+ dc.as_mut().vmsd = &$vmsd;
+ $crate::bindings::device_class_set_legacy_reset(dc.as_mut(), $legacy_reset_fn);
+ $crate::bindings::device_class_set_props(dc.as_mut(), $props.as_mut_ptr());
+ }
+ };
+}
+
+#[macro_export]
+macro_rules! define_property {
+ ($name:expr, $state:ty, $field:expr, $prop:expr, $type:expr, default = $defval:expr$(,)*) => {
+ $crate::bindings::Property {
+ name: {
+ #[used]
+ static _TEMP: &::core::ffi::CStr = $name;
+ _TEMP.as_ptr()
+ },
+ info: $prop,
+ offset: ::core::mem::offset_of!($state, $field)
+ .try_into()
+ .expect("Could not fit offset value to type"),
+ bitnr: 0,
+ bitmask: 0,
+ set_default: true,
+ defval: $crate::bindings::Property__bindgen_ty_1 { u: $defval.into() },
+ arrayoffset: 0,
+ arrayinfo: ::core::ptr::null(),
+ arrayfieldsize: 0,
+ link_type: ::core::ptr::null(),
+ }
+ };
+ ($name:expr, $state:ty, $field:expr, $prop:expr, $type:expr$(,)*) => {
+ $crate::bindings::Property {
+ name: {
+ #[used]
+ static _TEMP: &::core::ffi::CStr = $name;
+ _TEMP.as_ptr()
+ },
+ info: $prop,
+ offset: ::core::mem::offset_of!($state, $field)
+ .try_into()
+ .expect("Could not fit offset value to type"),
+ bitnr: 0,
+ bitmask: 0,
+ set_default: false,
+ defval: $crate::bindings::Property__bindgen_ty_1 { i: 0 },
+ arrayoffset: 0,
+ arrayinfo: ::core::ptr::null(),
+ arrayfieldsize: 0,
+ link_type: ::core::ptr::null(),
+ }
+ };
+}
+
+#[repr(C)]
+pub struct Properties<const N: usize>(pub OnceLock<[Property; N]>, pub fn() -> [Property; N]);
+
+impl<const N: usize> Properties<N> {
+ pub fn as_mut_ptr(&mut self) -> *mut Property {
+ _ = self.0.get_or_init(self.1);
+ self.0.get_mut().unwrap().as_mut_ptr()
+ }
+}
+
+#[macro_export]
+macro_rules! declare_properties {
+ ($ident:ident, $($prop:expr),*$(,)*) => {
+
+ const fn _calc_prop_len() -> usize {
+ let mut len = 1;
+ $({
+ _ = stringify!($prop);
+ len += 1;
+ })*
+ len
+ }
+ const PROP_LEN: usize = _calc_prop_len();
+
+ fn _make_properties() -> [$crate::bindings::Property; PROP_LEN] {
+ [
+ $($prop),*,
+ unsafe { ::core::mem::MaybeUninit::<$crate::bindings::Property>::zeroed().assume_init() },
+ ]
+ }
+
+ #[no_mangle]
+ pub static mut $ident: $crate::device_class::Properties<PROP_LEN> = $crate::device_class::Properties(::std::sync::OnceLock::new(), _make_properties);
+ };
+}
+
+#[macro_export]
+macro_rules! vm_state_description {
+ ($(#[$outer:meta])*
+ $name:ident,
+ $(name: $vname:expr,)*
+ $(unmigratable: $um_val:expr,)*
+ ) => {
+ #[used]
+ $(#[$outer])*
+ pub static $name: $crate::bindings::VMStateDescription = $crate::bindings::VMStateDescription {
+ $(name: {
+ #[used]
+ static VMSTATE_NAME: &::core::ffi::CStr = $vname;
+ $vname.as_ptr()
+ },)*
+ unmigratable: true,
+ ..unsafe { ::core::mem::MaybeUninit::<$crate::bindings::VMStateDescription>::zeroed().assume_init() }
+ };
+ }
+}
diff --git a/rust/qemu-api/src/lib.rs b/rust/qemu-api/src/lib.rs
new file mode 100644
index 0000000..e72fb4b
--- /dev/null
+++ b/rust/qemu-api/src/lib.rs
@@ -0,0 +1,166 @@
+// Copyright 2024, Linaro Limited
+// Author(s): Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#![cfg_attr(not(MESON), doc = include_str!("../README.md"))]
+
+#[allow(
+ dead_code,
+ improper_ctypes_definitions,
+ improper_ctypes,
+ non_camel_case_types,
+ non_snake_case,
+ non_upper_case_globals,
+ unsafe_op_in_unsafe_fn,
+ clippy::missing_const_for_fn,
+ clippy::too_many_arguments,
+ clippy::approx_constant,
+ clippy::use_self,
+ clippy::useless_transmute,
+ clippy::missing_safety_doc,
+)]
+#[rustfmt::skip]
+pub mod bindings;
+
+unsafe impl Send for bindings::Property {}
+unsafe impl Sync for bindings::Property {}
+unsafe impl Sync for bindings::TypeInfo {}
+unsafe impl Sync for bindings::VMStateDescription {}
+
+pub mod definitions;
+pub mod device_class;
+
+#[cfg(test)]
+mod tests;
+
+use std::alloc::{GlobalAlloc, Layout};
+
+#[cfg(HAVE_GLIB_WITH_ALIGNED_ALLOC)]
+extern "C" {
+ fn g_aligned_alloc0(
+ n_blocks: bindings::gsize,
+ n_block_bytes: bindings::gsize,
+ alignment: bindings::gsize,
+ ) -> bindings::gpointer;
+ fn g_aligned_free(mem: bindings::gpointer);
+}
+
+#[cfg(not(HAVE_GLIB_WITH_ALIGNED_ALLOC))]
+extern "C" {
+ fn qemu_memalign(alignment: usize, size: usize) -> *mut ::core::ffi::c_void;
+ fn qemu_vfree(ptr: *mut ::core::ffi::c_void);
+}
+
+extern "C" {
+ fn g_malloc0(n_bytes: bindings::gsize) -> bindings::gpointer;
+ fn g_free(mem: bindings::gpointer);
+}
+
+/// An allocator that uses the same allocator as QEMU in C.
+///
+/// It is enabled by default with the `allocator` feature.
+///
+/// To set it up manually as a global allocator in your crate:
+///
+/// ```ignore
+/// use qemu_api::QemuAllocator;
+///
+/// #[global_allocator]
+/// static GLOBAL: QemuAllocator = QemuAllocator::new();
+/// ```
+#[derive(Clone, Copy, Debug)]
+#[repr(C)]
+pub struct QemuAllocator {
+ _unused: [u8; 0],
+}
+
+#[cfg_attr(all(feature = "allocator", not(test)), global_allocator)]
+pub static GLOBAL: QemuAllocator = QemuAllocator::new();
+
+impl QemuAllocator {
+ // From the glibc documentation, on GNU systems, malloc guarantees 16-byte
+ // alignment on 64-bit systems and 8-byte alignment on 32-bit systems. See
+ // https://www.gnu.org/software/libc/manual/html_node/Malloc-Examples.html.
+ // This alignment guarantee also applies to Windows and Android. On Darwin
+ // and OpenBSD, the alignment is 16 bytes on both 64-bit and 32-bit systems.
+ #[cfg(all(
+ target_pointer_width = "32",
+ not(any(target_os = "macos", target_os = "openbsd"))
+ ))]
+ pub const DEFAULT_ALIGNMENT_BYTES: Option<usize> = Some(8);
+ #[cfg(all(
+ target_pointer_width = "64",
+ not(any(target_os = "macos", target_os = "openbsd"))
+ ))]
+ pub const DEFAULT_ALIGNMENT_BYTES: Option<usize> = Some(16);
+ #[cfg(all(
+ any(target_pointer_width = "32", target_pointer_width = "64"),
+ any(target_os = "macos", target_os = "openbsd")
+ ))]
+ pub const DEFAULT_ALIGNMENT_BYTES: Option<usize> = Some(16);
+ #[cfg(not(any(target_pointer_width = "32", target_pointer_width = "64")))]
+ pub const DEFAULT_ALIGNMENT_BYTES: Option<usize> = None;
+
+ pub const fn new() -> Self {
+ Self { _unused: [] }
+ }
+}
+
+impl Default for QemuAllocator {
+ fn default() -> Self {
+ Self::new()
+ }
+}
+
+// Sanity check.
+const _: [(); 8] = [(); ::core::mem::size_of::<*mut ::core::ffi::c_void>()];
+
+unsafe impl GlobalAlloc for QemuAllocator {
+ unsafe fn alloc(&self, layout: Layout) -> *mut u8 {
+ if matches!(Self::DEFAULT_ALIGNMENT_BYTES, Some(default) if default.checked_rem(layout.align()) == Some(0))
+ {
+ // SAFETY: g_malloc0() is safe to call.
+ unsafe { g_malloc0(layout.size().try_into().unwrap()).cast::<u8>() }
+ } else {
+ #[cfg(HAVE_GLIB_WITH_ALIGNED_ALLOC)]
+ {
+ // SAFETY: g_aligned_alloc0() is safe to call.
+ unsafe {
+ g_aligned_alloc0(
+ layout.size().try_into().unwrap(),
+ 1,
+ layout.align().try_into().unwrap(),
+ )
+ .cast::<u8>()
+ }
+ }
+ #[cfg(not(HAVE_GLIB_WITH_ALIGNED_ALLOC))]
+ {
+ // SAFETY: qemu_memalign() is safe to call.
+ unsafe { qemu_memalign(layout.align(), layout.size()).cast::<u8>() }
+ }
+ }
+ }
+
+ unsafe fn dealloc(&self, ptr: *mut u8, layout: Layout) {
+ if matches!(Self::DEFAULT_ALIGNMENT_BYTES, Some(default) if default.checked_rem(layout.align()) == Some(0))
+ {
+ // SAFETY: `ptr` must have been allocated by Self::alloc thus a valid
+ // glib-allocated pointer, so `g_free`ing is safe.
+ unsafe { g_free(ptr.cast::<_>()) }
+ } else {
+ #[cfg(HAVE_GLIB_WITH_ALIGNED_ALLOC)]
+ {
+ // SAFETY: `ptr` must have been allocated by Self::alloc thus a valid aligned
+ // glib-allocated pointer, so `g_aligned_free`ing is safe.
+ unsafe { g_aligned_free(ptr.cast::<_>()) }
+ }
+ #[cfg(not(HAVE_GLIB_WITH_ALIGNED_ALLOC))]
+ {
+ // SAFETY: `ptr` must have been allocated by Self::alloc thus a valid aligned
+ // glib-allocated pointer, so `qemu_vfree`ing is safe.
+ unsafe { qemu_vfree(ptr.cast::<_>()) }
+ }
+ }
+ }
+}
diff --git a/rust/qemu-api/src/tests.rs b/rust/qemu-api/src/tests.rs
new file mode 100644
index 0000000..df54edb
--- /dev/null
+++ b/rust/qemu-api/src/tests.rs
@@ -0,0 +1,49 @@
+// Copyright 2024, Linaro Limited
+// Author(s): Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+use crate::{
+ bindings::*, declare_properties, define_property, device_class_init, vm_state_description,
+};
+
+#[test]
+fn test_device_decl_macros() {
+ // Test that macros can compile.
+ vm_state_description! {
+ VMSTATE,
+ name: c"name",
+ unmigratable: true,
+ }
+
+ #[repr(C)]
+ pub struct DummyState {
+ pub char_backend: CharBackend,
+ pub migrate_clock: bool,
+ }
+
+ declare_properties! {
+ DUMMY_PROPERTIES,
+ define_property!(
+ c"chardev",
+ DummyState,
+ char_backend,
+ unsafe { &qdev_prop_chr },
+ CharBackend
+ ),
+ define_property!(
+ c"migrate-clk",
+ DummyState,
+ migrate_clock,
+ unsafe { &qdev_prop_bool },
+ bool
+ ),
+ }
+
+ device_class_init! {
+ dummy_class_init,
+ props => DUMMY_PROPERTIES,
+ realize_fn => None,
+ reset_fn => None,
+ vmsd => VMSTATE,
+ }
+}
diff --git a/rust/rustfmt.toml b/rust/rustfmt.toml
new file mode 100644
index 0000000..ebecb99
--- /dev/null
+++ b/rust/rustfmt.toml
@@ -0,0 +1,7 @@
+edition = "2021"
+format_generated_files = false
+format_code_in_doc_comments = true
+format_strings = true
+imports_granularity = "Crate"
+group_imports = "StdExternalCrate"
+wrap_comments = true
