rust: qdev: const_refs_to_static Now that const_refs_static can be assumed, convert the members of the DeviceImpl trait from functions to constants. This lets the compiler know that they have a 'static lifetime, and removes the need for the weird "Box::leak()". Reviewed-by: Zhao Liu <zhao1.liu@intel.com> Link: https://lore.kernel.org/r/20250908105005.2119297-10-pbonzini@redhat.com Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
diff --git a/rust/hw/char/pl011/src/device.rs b/rust/hw/char/pl011/src/device.rs index 87a1771..8411db8 100644 --- a/rust/hw/char/pl011/src/device.rs +++ b/rust/hw/char/pl011/src/device.rs
@@ -172,9 +172,7 @@ impl ObjectImpl for PL011State { } impl DeviceImpl for PL011State { - fn vmsd() -> Option<VMStateDescription<Self>> { - Some(VMSTATE_PL011) - } + const VMSTATE: Option<VMStateDescription<Self>> = Some(VMSTATE_PL011); const REALIZE: Option<fn(&Self) -> qemu_api::Result<()>> = Some(Self::realize); }
diff --git a/rust/hw/timer/hpet/src/device.rs b/rust/hw/timer/hpet/src/device.rs index eb5bd04..dd5326a 100644 --- a/rust/hw/timer/hpet/src/device.rs +++ b/rust/hw/timer/hpet/src/device.rs
@@ -1008,16 +1008,11 @@ impl ObjectImpl for HPETState { // SAFETY: HPET_PROPERTIES is a valid Property array constructed with the // qemu_api::declare_properties macro. unsafe impl qemu_api::qdev::DevicePropertiesImpl for HPETState { - fn properties() -> &'static [Property] { - &HPET_PROPERTIES - } + const PROPERTIES: &'static [Property] = &HPET_PROPERTIES; } impl DeviceImpl for HPETState { - fn vmsd() -> Option<VMStateDescription<Self>> { - Some(VMSTATE_HPET) - } - + const VMSTATE: Option<VMStateDescription<Self>> = Some(VMSTATE_HPET); const REALIZE: Option<fn(&Self) -> qemu_api::Result<()>> = Some(Self::realize); }
diff --git a/rust/qemu-api-macros/src/lib.rs b/rust/qemu-api-macros/src/lib.rs index 97b2c21..a65a7ce 100644 --- a/rust/qemu-api-macros/src/lib.rs +++ b/rust/qemu-api-macros/src/lib.rs
@@ -289,11 +289,9 @@ macro_rules! str_to_c_str { Ok(quote_spanned! {input.span() => unsafe impl ::qemu_api::qdev::DevicePropertiesImpl for #name { - fn properties() -> &'static [::qemu_api::bindings::Property] { - static PROPERTIES: &[::qemu_api::bindings::Property] = &[#(#properties_expanded),*]; - - PROPERTIES - } + const PROPERTIES: &'static [::qemu_api::bindings::Property] = &[ + #(#properties_expanded),* + ]; } }) }
diff --git a/rust/qemu-api-macros/src/tests.rs b/rust/qemu-api-macros/src/tests.rs index aafffcd..0e5a572 100644 --- a/rust/qemu-api-macros/src/tests.rs +++ b/rust/qemu-api-macros/src/tests.rs
@@ -101,18 +101,16 @@ pub struct DummyState { }, quote! { unsafe impl ::qemu_api::qdev::DevicePropertiesImpl for DummyState { - fn properties() -> &'static [::qemu_api::bindings::Property] { - static PROPERTIES: &[::qemu_api::bindings::Property] = - &[::qemu_api::bindings::Property { - name: ::std::ffi::CStr::as_ptr(c"migrate_clock"), - info: <bool as ::qemu_api::qdev::QDevProp>::VALUE, - offset: ::core::mem::offset_of!(DummyState, migrate_clock) as isize, - set_default: true, - defval: ::qemu_api::bindings::Property__bindgen_ty_1 { u: true as u64 }, - ..::qemu_api::zeroable::Zeroable::ZERO - }]; - PROPERTIES - } + const PROPERTIES: &'static [::qemu_api::bindings::Property] = &[ + ::qemu_api::bindings::Property { + name: ::std::ffi::CStr::as_ptr(c"migrate_clock"), + info: <bool as ::qemu_api::qdev::QDevProp>::VALUE, + offset: ::core::mem::offset_of!(DummyState, migrate_clock) as isize, + set_default: true, + defval: ::qemu_api::bindings::Property__bindgen_ty_1 { u: true as u64 }, + ..::qemu_api::zeroable::Zeroable::ZERO + } + ]; } } ); @@ -130,18 +128,16 @@ pub struct DummyState { }, quote! { unsafe impl ::qemu_api::qdev::DevicePropertiesImpl for DummyState { - fn properties() -> &'static [::qemu_api::bindings::Property] { - static PROPERTIES: &[::qemu_api::bindings::Property] = - &[::qemu_api::bindings::Property { - name: ::std::ffi::CStr::as_ptr(c"migrate-clk"), - info: <bool as ::qemu_api::qdev::QDevProp>::VALUE, - offset: ::core::mem::offset_of!(DummyState, migrate_clock) as isize, - set_default: true, - defval: ::qemu_api::bindings::Property__bindgen_ty_1 { u: true as u64 }, - ..::qemu_api::zeroable::Zeroable::ZERO - }]; - PROPERTIES - } + const PROPERTIES: &'static [::qemu_api::bindings::Property] = &[ + ::qemu_api::bindings::Property { + name: ::std::ffi::CStr::as_ptr(c"migrate-clk"), + info: <bool as ::qemu_api::qdev::QDevProp>::VALUE, + offset: ::core::mem::offset_of!(DummyState, migrate_clock) as isize, + set_default: true, + defval: ::qemu_api::bindings::Property__bindgen_ty_1 { u: true as u64 }, + ..::qemu_api::zeroable::Zeroable::ZERO + } + ]; } } );
diff --git a/rust/qemu-api/src/qdev.rs b/rust/qemu-api/src/qdev.rs index 4dda8c8..436142d 100644 --- a/rust/qemu-api/src/qdev.rs +++ b/rust/qemu-api/src/qdev.rs
@@ -151,11 +151,8 @@ unsafe impl QDevProp for crate::chardev::CharBackend { /// Caller is responsible for the validity of properties array. pub unsafe 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] { - &[] - } + /// device. + const PROPERTIES: &'static [Property] = &[]; } /// Trait providing the contents of [`DeviceClass`]. @@ -173,9 +170,7 @@ pub trait DeviceImpl: /// A `VMStateDescription` providing the migration format for the device /// Not a `const` because referencing statics in constants is unstable /// until Rust 1.83.0. - fn vmsd() -> Option<VMStateDescription<Self>> { - None - } + const VMSTATE: Option<VMStateDescription<Self>> = None; } /// # Safety @@ -224,12 +219,10 @@ pub fn class_init<T: DeviceImpl>(&mut self) { if <T as DeviceImpl>::REALIZE.is_some() { self.realize = Some(rust_realize_fn::<T>); } - if let Some(vmsd) = <T as DeviceImpl>::vmsd() { - // Give a 'static lifetime to the return value of vmsd(). - // Temporary until vmsd() can be changed into a const. - self.vmsd = Box::leak(Box::new(vmsd.get())); + if let Some(ref vmsd) = <T as DeviceImpl>::VMSTATE { + self.vmsd = vmsd.as_ref(); } - let prop = <T as DevicePropertiesImpl>::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 4d4e465..1349568 100644 --- a/rust/qemu-api/tests/tests.rs +++ b/rust/qemu-api/tests/tests.rs
@@ -56,9 +56,7 @@ impl ObjectImpl for DummyState { impl ResettablePhasesImpl for DummyState {} impl DeviceImpl for DummyState { - fn vmsd() -> Option<VMStateDescription<Self>> { - Some(VMSTATE) - } + const VMSTATE: Option<VMStateDescription<Self>> = Some(VMSTATE); } #[repr(C)]