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rust/qdev: Refine the documentation for QDevProp trait

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Refine the documentation to clarify:
 * `unsfae` requires that `VALUE` must be valid.
 * using `*const` instead of `&` because the latter will cause compiler
   error.

Signed-off-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Link: https://lore.kernel.org/r/20250920160520.3699591-7-zhao1.liu@intel.com
This commit is contained in:
Manos Pitsidianakis 2025-09-21 00:05:14 +08:00 • committed by Paolo Bonzini
parent 51d736cd71
commit bed2a37b20
1 changed files with 11 additions and 4 deletions
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15
rust/hw/core/src/qdev.rs
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@ -109,9 +109,16 @@ unsafe extern "C" fn rust_resettable_exit_fn<T: ResettablePhasesImpl>(
///
/// # Safety
///
/// This trait is marked as `unsafe` because currently having a `const` refer to
/// an `extern static` as a reference instead of a raw pointer results in this
/// compiler error:
/// This trait is marked as `unsafe` because `VALUE` must be a valid raw
/// reference to a [`bindings::PropertyInfo`].
///
/// Note we could not use a regular reference:
///
/// ```text
/// const VALUE: &bindings::PropertyInfo = ...
/// ```
///
/// because this results in the following compiler error:
///
/// ```text
/// constructing invalid value: encountered reference to `extern` static in `const`
@ -119,7 +126,7 @@ unsafe extern "C" fn rust_resettable_exit_fn<T: ResettablePhasesImpl>(
///
/// This is because the compiler generally might dereference a normal reference
/// during const evaluation, but not in this case (if it did, it'd need to
/// dereference the raw pointer so this would fail to compile).
/// dereference the raw pointer so using a `*const` would also fail to compile).
///
/// It is the implementer's responsibility to provide a valid
/// [`bindings::PropertyInfo`] pointer for the trait implementation to be safe.