Add derive macro for declaring qdev properties directly above the field definitions. To do this, we split DeviceImpl::properties method on a separate trait so we can implement only that part in the derive macro expansion (we cannot partially implement the DeviceImpl trait).
Adding a `property` attribute above the field declaration will generate a `qemu_api::bindings::Property` array member in the device's property list. Signed-off-by: Manos Pitsidianakis <manos.pitsidiana...@linaro.org> --- TODOs: - Update hpet code to use the derive macro - Change MacroError use to syn::Error use if changed in upstream too Changes in v2: - Rewrite to take advantage of const_refs_to_static feature, we still need to update to a newer MSRV. - Use existing get_fields function (Paolo) - return errors instead of panicking (Paolo) - Link to v1: https://lore.kernel.org/qemu-devel/20250522-rust-qdev-properties-v1-1-5b18b218b...@linaro.org --- rust/hw/char/pl011/src/device.rs | 13 +- rust/hw/char/pl011/src/device_class.rs | 26 +--- rust/hw/timer/hpet/src/device.rs | 4 +- rust/qemu-api-macros/src/lib.rs | 217 ++++++++++++++++++++++++++++++++- rust/qemu-api/src/qdev.rs | 57 +++++++-- rust/qemu-api/tests/tests.rs | 9 +- 6 files changed, 282 insertions(+), 44 deletions(-) diff --git a/rust/hw/char/pl011/src/device.rs b/rust/hw/char/pl011/src/device.rs index 5b53f2649f161287f40f79075afba47db6d9315c..b2b8dcdfeb6797286918a5ec3e94e1c254e176fe 100644 --- a/rust/hw/char/pl011/src/device.rs +++ b/rust/hw/char/pl011/src/device.rs @@ -12,7 +12,10 @@ log_mask_ln, memory::{hwaddr, MemoryRegion, MemoryRegionOps, MemoryRegionOpsBuilder}, prelude::*, - qdev::{Clock, ClockEvent, DeviceImpl, DeviceState, Property, ResetType, ResettablePhasesImpl}, + qdev::{ + Clock, ClockEvent, DeviceImpl, DevicePropertiesImpl, DeviceState, ResetType, + ResettablePhasesImpl, + }, qom::{ObjectImpl, Owned, ParentField, ParentInit}, static_assert, sysbus::{SysBusDevice, SysBusDeviceImpl}, @@ -101,12 +104,13 @@ pub struct PL011Registers { } #[repr(C)] -#[derive(qemu_api_macros::Object)] +#[derive(qemu_api_macros::Object, qemu_api_macros::DeviceProperties)] /// PL011 Device Model in QEMU pub struct PL011State { pub parent_obj: ParentField<SysBusDevice>, pub iomem: MemoryRegion, #[doc(alias = "chr")] + #[property(rename = "chardev")] pub char_backend: CharBackend, pub regs: BqlRefCell<PL011Registers>, /// QEMU interrupts @@ -125,6 +129,7 @@ pub struct PL011State { #[doc(alias = "clk")] pub clock: Owned<Clock>, #[doc(alias = "migrate_clk")] + #[property(rename = "migrate-clk", default = true)] pub migrate_clock: bool, } @@ -172,9 +177,6 @@ impl ObjectImpl for PL011State { } impl DeviceImpl for PL011State { - fn properties() -> &'static [Property] { - &device_class::PL011_PROPERTIES - } fn vmsd() -> Option<&'static VMStateDescription> { Some(&device_class::VMSTATE_PL011) } @@ -709,6 +711,7 @@ impl PL011Impl for PL011Luminary { const DEVICE_ID: DeviceId = DeviceId(&[0x11, 0x00, 0x18, 0x01, 0x0d, 0xf0, 0x05, 0xb1]); } +impl DevicePropertiesImpl for PL011Luminary {} impl DeviceImpl for PL011Luminary {} impl ResettablePhasesImpl for PL011Luminary {} impl SysBusDeviceImpl for PL011Luminary {} diff --git a/rust/hw/char/pl011/src/device_class.rs b/rust/hw/char/pl011/src/device_class.rs index d328d846323f6080a9573053767e51481eb32941..83d70d7d82aac4a3252a0b4cb24af705b01d3635 100644 --- a/rust/hw/char/pl011/src/device_class.rs +++ b/rust/hw/char/pl011/src/device_class.rs @@ -8,11 +8,8 @@ }; use qemu_api::{ - bindings::{qdev_prop_bool, qdev_prop_chr}, - prelude::*, - vmstate::VMStateDescription, - vmstate_clock, vmstate_fields, vmstate_of, vmstate_struct, vmstate_subsections, vmstate_unused, - zeroable::Zeroable, + prelude::*, vmstate::VMStateDescription, vmstate_clock, vmstate_fields, vmstate_of, + vmstate_struct, vmstate_subsections, vmstate_unused, zeroable::Zeroable, }; use crate::device::{PL011Registers, PL011State}; @@ -82,22 +79,3 @@ extern "C" fn pl011_post_load(opaque: *mut c_void, version_id: c_int) -> c_int { }, ..Zeroable::ZERO }; - -qemu_api::declare_properties! { - PL011_PROPERTIES, - qemu_api::define_property!( - c"chardev", - PL011State, - char_backend, - unsafe { &qdev_prop_chr }, - CharBackend - ), - qemu_api::define_property!( - c"migrate-clk", - PL011State, - migrate_clock, - unsafe { &qdev_prop_bool }, - bool, - default = true - ), -} diff --git a/rust/hw/timer/hpet/src/device.rs b/rust/hw/timer/hpet/src/device.rs index acf7251029e912f18a5690b0d6cf04ea8151c5e1..35b8e57fa897f625a6b3e266f9a751a630c21a64 100644 --- a/rust/hw/timer/hpet/src/device.rs +++ b/rust/hw/timer/hpet/src/device.rs @@ -1031,11 +1031,13 @@ impl ObjectImpl for HPETState { ..Zeroable::ZERO }; -impl DeviceImpl for HPETState { +impl qemu_api::qdev::DevicePropertiesImpl for HPETState { fn properties() -> &'static [Property] { &HPET_PROPERTIES } +} +impl DeviceImpl for HPETState { fn vmsd() -> Option<&'static VMStateDescription> { Some(&VMSTATE_HPET) } diff --git a/rust/qemu-api-macros/src/lib.rs b/rust/qemu-api-macros/src/lib.rs index c18bb4e036f4e7737f9b95ac300b7d1e8742ef1f..1746da4d967b7ec733c0d97c26d3275fb1cd6645 100644 --- a/rust/qemu-api-macros/src/lib.rs +++ b/rust/qemu-api-macros/src/lib.rs @@ -3,10 +3,11 @@ // SPDX-License-Identifier: GPL-2.0-or-later use proc_macro::TokenStream; -use quote::quote; +use quote::{quote, quote_spanned, ToTokens}; use syn::{ - parse_macro_input, parse_quote, punctuated::Punctuated, spanned::Spanned, token::Comma, Data, - DeriveInput, Field, Fields, FieldsUnnamed, Ident, Meta, Path, Token, Variant, + parse::Parse, parse_macro_input, parse_quote, punctuated::Punctuated, spanned::Spanned, + token::Comma, Data, DeriveInput, Field, Fields, FieldsUnnamed, Ident, Meta, Path, Token, + Variant, }; mod utils; @@ -146,6 +147,216 @@ pub const fn raw_get(slot: *mut Self) -> *mut <Self as crate::cell::Wrapper>::Wr }) } +#[derive(Debug)] +enum DevicePropertyName { + CStr(syn::LitCStr), + Str(syn::LitStr), +} + +#[derive(Debug)] +struct DeviceProperty { + rename: Option<DevicePropertyName>, + qdev_prop: Option<syn::Path>, + bitnr: Option<syn::Expr>, + defval: Option<syn::Expr>, +} + +impl Parse for DeviceProperty { + fn parse(input: syn::parse::ParseStream) -> syn::Result<Self> { + let _: syn::Token![#] = input.parse()?; + let bracketed; + _ = syn::bracketed!(bracketed in input); + let _attribute = bracketed.parse::<syn::Ident>()?; + debug_assert_eq!(&_attribute.to_string(), "property"); + let mut retval = Self { + rename: None, + qdev_prop: None, + bitnr: None, + defval: None, + }; + let content; + _ = syn::parenthesized!(content in bracketed); + while !content.is_empty() { + let value: syn::Ident = content.parse()?; + if value == "rename" { + let _: syn::Token![=] = content.parse()?; + if retval.rename.is_some() { + return Err(syn::Error::new( + value.span(), + "`rename` can only be used at most once", + )); + } + if content.peek(syn::LitStr) { + retval.rename = Some(DevicePropertyName::Str(content.parse::<syn::LitStr>()?)); + } else { + retval.rename = + Some(DevicePropertyName::CStr(content.parse::<syn::LitCStr>()?)); + } + } else if value == "qdev_prop" { + let _: syn::Token![=] = content.parse()?; + if retval.qdev_prop.is_some() { + return Err(syn::Error::new( + value.span(), + "`qdev_prop` can only be used at most once", + )); + } + retval.qdev_prop = Some(content.parse()?); + } else if value == "bitnr" { + let _: syn::Token![=] = content.parse()?; + if retval.bitnr.is_some() { + return Err(syn::Error::new( + value.span(), + "`bitnr` can only be used at most once", + )); + } + retval.bitnr = Some(content.parse()?); + } else if value == "default" { + let _: syn::Token![=] = content.parse()?; + if retval.defval.is_some() { + return Err(syn::Error::new( + value.span(), + "`default` can only be used at most once", + )); + } + retval.defval = Some(content.parse()?); + } else { + return Err(syn::Error::new( + value.span(), + format!("unrecognized field `{value}`"), + )); + } + + if !content.is_empty() { + let _: syn::Token![,] = content.parse()?; + } + } + Ok(retval) + } +} + +#[proc_macro_derive(DeviceProperties, attributes(property))] +pub fn derive_device_properties(input: TokenStream) -> TokenStream { + let input = parse_macro_input!(input as DeriveInput); + let expanded = derive_device_properties_or_error(input).unwrap_or_else(Into::into); + + TokenStream::from(expanded) +} + +fn derive_device_properties_or_error( + input: DeriveInput, +) -> Result<proc_macro2::TokenStream, MacroError> { + let span = proc_macro::Span::call_site(); + let properties: Vec<(syn::Field, proc_macro2::Span, DeviceProperty)> = + get_fields(&input, "#[derive(DeviceProperties)]")? + .iter() + .flat_map(|f| { + f.attrs + .iter() + .filter(|a| a.path().is_ident("property")) + .map(|a| { + Ok(( + f.clone(), + f.span(), + syn::parse(a.to_token_stream().into()).map_err(|err| { + MacroError::Message( + format!("Could not parse `property` attribute: {err}"), + f.span(), + ) + })?, + )) + }) + }) + .collect::<Result<Vec<_>, MacroError>>()?; + let name = &input.ident; + let mut properties_expanded = vec![]; + let zero = syn::Expr::Verbatim(quote! { 0 }); + + for (field, field_span, prop) in properties { + let DeviceProperty { + rename, + qdev_prop, + bitnr, + defval, + } = prop; + let field_name = field.ident.as_ref().unwrap(); + let prop_name = rename + .as_ref() + .map(|lit| -> Result<proc_macro2::TokenStream, MacroError> { + match lit { + DevicePropertyName::CStr(lit) => { + let span = lit.span(); + Ok(quote_spanned! {span=> + #lit + }) + } + DevicePropertyName::Str(lit) => { + let span = lit.span(); + let value = lit.value(); + let lit = std::ffi::CString::new(value.as_str()) + .map_err(|err| { + MacroError::Message( + format!("Property name `{value}` cannot be represented as a C string: {err}"), + span + ) + })?; + let lit = syn::LitCStr::new(&lit, span); + Ok(quote_spanned! {span=> + #lit + }) + } + }}) + .unwrap_or_else(|| { + let span = field_name.span(); + let field_name_value = field_name.to_string(); + let lit = std::ffi::CString::new(field_name_value.as_str()).map_err(|err| { + MacroError::Message( + format!("Field `{field_name_value}` cannot be represented as a C string: {err}\nPlease set an explicit property name using the `rename=...` option in the field's `property` attribute."), + span + ) + })?; + let lit = syn::LitCStr::new(&lit, span); + Ok(quote_spanned! {span=> + #lit + }) + })?; + let field_ty = field.ty.clone(); + let qdev_prop = qdev_prop + .as_ref() + .map(|path| { + quote_spanned! {field_span=> + unsafe { &#path } + } + }) + .unwrap_or_else( + || quote_spanned! {field_span=> <#field_ty as ::qemu_api::qdev::QDevProp>::VALUE }, + ); + let set_default = defval.is_some(); + let bitnr = bitnr.as_ref().unwrap_or(&zero); + let defval = defval.as_ref().unwrap_or(&zero); + properties_expanded.push(quote_spanned! {field_span=> + ::qemu_api::bindings::Property { + name: ::std::ffi::CStr::as_ptr(#prop_name), + info: #qdev_prop , + offset: ::core::mem::offset_of!(#name, #field_name) as isize, + bitnr: #bitnr, + set_default: #set_default, + defval: ::qemu_api::bindings::Property__bindgen_ty_1 { u: #defval as u64 }, + ..::qemu_api::zeroable::Zeroable::ZERO + } + }); + } + + Ok(quote_spanned! {span.into()=> + impl ::qemu_api::qdev::DevicePropertiesImpl for #name { + fn properties() -> &'static [::qemu_api::bindings::Property] { + static PROPERTIES: &'static [::qemu_api::bindings::Property] = &[#(#properties_expanded),*]; + + PROPERTIES + } + } + }) +} + #[proc_macro_derive(Wrapper)] pub fn derive_opaque(input: TokenStream) -> TokenStream { let input = parse_macro_input!(input as DeriveInput); diff --git a/rust/qemu-api/src/qdev.rs b/rust/qemu-api/src/qdev.rs index 36f02fb57dbffafb21a2e7cc96419ca42e865269..01f199f198c6a5f8a761beb143e567fc267028aa 100644 --- a/rust/qemu-api/src/qdev.rs +++ b/rust/qemu-api/src/qdev.rs @@ -101,8 +101,54 @@ pub trait ResettablePhasesImpl { T::EXIT.unwrap()(unsafe { state.as_ref() }, typ); } +/// Helper trait to return pointer to a [`bindings::PropertyInfo`] for a type. +/// +/// This trait is used by [`qemu_api_macros::DeviceProperty`] derive macro. +/// +/// # Safety +/// +/// This trait is marked as `unsafe` because currently having a `const` refer to an `extern static` +/// results in this compiler error: +/// +/// ```text +/// constructing invalid value: encountered reference to `extern` static in `const` +/// ``` +/// +/// It is the implementer's responsibility to provide a valid [`bindings::PropertyInfo`] pointer +/// for the trait implementation to be safe. +pub unsafe trait QDevProp { + const VALUE: *const bindings::PropertyInfo; +} + +/// Use [`bindings::qdev_prop_bool`] for `bool`. +unsafe impl QDevProp for bool { + const VALUE: *const bindings::PropertyInfo = unsafe { &bindings::qdev_prop_bool }; +} + +/// Use [`bindings::qdev_prop_uint64`] for `u64`. +unsafe impl QDevProp for u64 { + const VALUE: *const bindings::PropertyInfo = unsafe { &bindings::qdev_prop_uint64 }; +} + +/// Use [`bindings::qdev_prop_chr`] for [`crate::chardev::CharBackend`]. +unsafe impl QDevProp for crate::chardev::CharBackend { + const VALUE: *const bindings::PropertyInfo = unsafe { &bindings::qdev_prop_chr }; +} + +/// Trait to define device properties. +pub trait DevicePropertiesImpl { + /// 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. + fn properties() -> &'static [Property] { + &[] + } +} + /// Trait providing the contents of [`DeviceClass`]. -pub trait DeviceImpl: ObjectImpl + ResettablePhasesImpl + IsA<DeviceState> { +pub trait DeviceImpl: + ObjectImpl + ResettablePhasesImpl + DevicePropertiesImpl + IsA<DeviceState> +{ /// _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). @@ -111,13 +157,6 @@ pub trait DeviceImpl: ObjectImpl + ResettablePhasesImpl + IsA<DeviceState> { /// with the function pointed to by `REALIZE`. const REALIZE: Option<fn(&Self) -> Result<()>> = 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. - fn properties() -> &'static [Property] { - &[] - } - /// A `VMStateDescription` providing the migration format for the device /// Not a `const` because referencing statics in constants is unstable /// until Rust 1.83.0. @@ -175,7 +214,7 @@ pub fn class_init<T: DeviceImpl>(&mut self) { if let Some(vmsd) = <T as DeviceImpl>::vmsd() { self.vmsd = vmsd; } - let prop = <T as DeviceImpl>::properties(); + let prop = <T as DevicePropertiesImpl>::properties(); if !prop.is_empty() { unsafe { bindings::device_class_set_props_n(self, prop.as_ptr(), prop.len()); diff --git a/rust/qemu-api/tests/tests.rs b/rust/qemu-api/tests/tests.rs index a658a49fcfdda8fa4b9d139c10afb6ff3243790b..e8eadfd6e9add385ffc97de015b84aae825c18ee 100644 --- a/rust/qemu-api/tests/tests.rs +++ b/rust/qemu-api/tests/tests.rs @@ -9,7 +9,7 @@ cell::{self, BqlCell}, declare_properties, define_property, prelude::*, - qdev::{DeviceImpl, DeviceState, Property, ResettablePhasesImpl}, + qdev::{DeviceImpl, DevicePropertiesImpl, DeviceState, Property, ResettablePhasesImpl}, qom::{ObjectImpl, ParentField}, sysbus::SysBusDevice, vmstate::VMStateDescription, @@ -68,10 +68,13 @@ impl ObjectImpl for DummyState { impl ResettablePhasesImpl for DummyState {} -impl DeviceImpl for DummyState { +impl DevicePropertiesImpl for DummyState { fn properties() -> &'static [Property] { &DUMMY_PROPERTIES } +} + +impl DeviceImpl for DummyState { fn vmsd() -> Option<&'static VMStateDescription> { Some(&VMSTATE) } @@ -85,6 +88,8 @@ pub struct DummyChildState { qom_isa!(DummyChildState: Object, DeviceState, DummyState); +impl DevicePropertiesImpl for DummyChildState {} + pub struct DummyChildClass { parent_class: <DummyState as ObjectType>::Class, } --- base-commit: c77283dd5d79149f4e7e9edd00f65416c648ee59 change-id: 20250522-rust-qdev-properties-728e8f6a468e prerequisite-change-id: 20250703-rust_bindings_allow_unnecessary_transmutes-d614db4517a4:v1 prerequisite-patch-id: 570fede8eee168ade58c7c7599bdc8b94c8c1a22 -- γαῖα πυρί μιχθήτω
