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authorPeter Maydell <peter.maydell@linaro.org>2024-11-06 21:27:47 +0000
committerPeter Maydell <peter.maydell@linaro.org>2024-11-06 21:27:47 +0000
commita1dacb66915eb7d08a0596cc97068a37c39930d3 (patch)
treedaa33d1f6e890c744c85fc08a7b928d1d55b158a /rust/qemu-api/src/zeroable.rs
parent63dc36944383f70f1c7a20f6104966d8560300fa (diff)
parent951f71ad67bd474aba6925529daf45b747aac86e (diff)
downloadfocaccia-qemu-a1dacb66915eb7d08a0596cc97068a37c39930d3.tar.gz
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Merge tag 'for-upstream-rust' of https://gitlab.com/bonzini/qemu into staging
* rust: cleanups
* rust: integration tests
* rust/pl011: add support for migration
* rust/pl011: add TYPE_PL011_LUMINARY device
* rust: add support for older compilers and bindgen

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* tag 'for-upstream-rust' of https://gitlab.com/bonzini/qemu: (39 commits)
  dockerfiles: install bindgen from cargo on Ubuntu 22.04
  rust: make rustfmt optional
  rust: allow older version of bindgen
  rust: do not use --generate-cstr
  rust: allow version 1.63.0 of rustc
  rust: clean up detection of the language
  rust: do not use MaybeUninit::zeroed()
  rust: introduce alternative implementation of offset_of!
  rust: create a cargo workspace
  rust: synchronize dependencies between subprojects and Cargo.lock
  rust: silence unknown warnings for the sake of old compilers
  rust: introduce a c_str macro
  rust: use std::os::raw instead of core::ffi
  rust: fix cfgs of proc-macro2 for 1.63.0
  rust: patch bilge-impl to allow compilation with 1.63.0
  rust/pl011: Use correct masks for IBRD and FBRD
  rust/pl011: remove commented out C code
  rust/pl011: add TYPE_PL011_LUMINARY device
  rust/pl011: move CLK_NAME static to function scope
  rust/pl011: add support for migration
  ...

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
Diffstat (limited to 'rust/qemu-api/src/zeroable.rs')
-rw-r--r--rust/qemu-api/src/zeroable.rs86
1 files changed, 86 insertions, 0 deletions
diff --git a/rust/qemu-api/src/zeroable.rs b/rust/qemu-api/src/zeroable.rs
new file mode 100644
index 0000000000..13cdb2ccba
--- /dev/null
+++ b/rust/qemu-api/src/zeroable.rs
@@ -0,0 +1,86 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+use std::ptr;
+
+/// Encapsulates the requirement that
+/// `MaybeUninit::<Self>::zeroed().assume_init()` does not cause undefined
+/// behavior.  This trait in principle could be implemented as just:
+///
+/// ```
+///     const ZERO: Self = unsafe {
+///         ::core::mem::MaybeUninit::<$crate::bindings::Property>::zeroed().assume_init()
+///     },
+/// ```
+///
+/// The need for a manual implementation is only because `zeroed()` cannot
+/// be used as a `const fn` prior to Rust 1.75.0. Once we can assume a new
+/// enough version of the compiler, we could provide a `#[derive(Zeroable)]`
+/// macro to check at compile-time that all struct fields are Zeroable, and
+/// use the above blanket implementation of the `ZERO` constant.
+///
+/// # Safety
+///
+/// Because the implementation of `ZERO` is manual, it does not make
+/// any assumption on the safety of `zeroed()`.  However, other users of the
+/// trait could use it that way.  Do not add this trait to a type unless
+/// all-zeroes is a valid value for the type.  In particular, remember that
+/// raw pointers can be zero, but references and `NonNull<T>` cannot
+pub unsafe trait Zeroable: Default {
+    const ZERO: Self;
+}
+
+unsafe impl Zeroable for crate::bindings::Property__bindgen_ty_1 {
+    const ZERO: Self = Self { i: 0 };
+}
+
+unsafe impl Zeroable for crate::bindings::Property {
+    const ZERO: Self = Self {
+        name: ptr::null(),
+        info: ptr::null(),
+        offset: 0,
+        bitnr: 0,
+        bitmask: 0,
+        set_default: false,
+        defval: Zeroable::ZERO,
+        arrayoffset: 0,
+        arrayinfo: ptr::null(),
+        arrayfieldsize: 0,
+        link_type: ptr::null(),
+    };
+}
+
+unsafe impl Zeroable for crate::bindings::VMStateDescription {
+    const ZERO: Self = Self {
+        name: ptr::null(),
+        unmigratable: false,
+        early_setup: false,
+        version_id: 0,
+        minimum_version_id: 0,
+        priority: crate::bindings::MigrationPriority::MIG_PRI_DEFAULT,
+        pre_load: None,
+        post_load: None,
+        pre_save: None,
+        post_save: None,
+        needed: None,
+        dev_unplug_pending: None,
+        fields: ptr::null(),
+        subsections: ptr::null(),
+    };
+}
+
+unsafe impl Zeroable for crate::bindings::MemoryRegionOps__bindgen_ty_1 {
+    const ZERO: Self = Self {
+        min_access_size: 0,
+        max_access_size: 0,
+        unaligned: false,
+        accepts: None,
+    };
+}
+
+unsafe impl Zeroable for crate::bindings::MemoryRegionOps__bindgen_ty_2 {
+    const ZERO: Self = Self {
+        min_access_size: 0,
+        max_access_size: 0,
+        unaligned: false,
+    };
+}