From 0f9eb0ff2b25787be62fceb036dba7c3f54fde2d Mon Sep 17 00:00:00 2001
From: Zhao Liu <zhao1.liu@intel.com>
Date: Tue, 21 Jan 2025 22:04:56 +0800
Subject: rust/qdev: Make REALIZE safe

A safe REALIZE accepts immutable reference.

Since current PL011's realize() only calls a char binding function (
qemu_chr_fe_set_handlers), it is possible to convert mutable reference
(&mut self) to immutable reference (&self), which only needs to convert
the pointers passed to C to mutable pointers.

Thus, make REALIZE accept immutable reference.

Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
Link: https://lore.kernel.org/r/20250121140457.84631-2-zhao1.liu@intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 rust/qemu-api/src/qdev.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'rust/qemu-api/src')

diff --git a/rust/qemu-api/src/qdev.rs b/rust/qemu-api/src/qdev.rs
index 686054e..a5121e3 100644
--- a/rust/qemu-api/src/qdev.rs
+++ b/rust/qemu-api/src/qdev.rs
@@ -23,7 +23,7 @@ pub trait DeviceImpl {
     ///
     /// If not `None`, the parent class's `realize` method is overridden
     /// with the function pointed to by `REALIZE`.
-    const REALIZE: Option<fn(&mut Self)> = None;
+    const REALIZE: Option<fn(&Self)> = None;
 
     /// If not `None`, the parent class's `reset` method is overridden
     /// with the function pointed to by `RESET`.
-- 
cgit v1.1


From 0d43ddae35a29d1822ec3f35a31bfe7c91618ef4 Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Sun, 8 Dec 2024 12:16:56 +0100
Subject: rust: vmstate: add new type safe implementation

The existing translation of the C macros for vmstate does not make
any attempt to type-check vmstate declarations against the struct, so
introduce a new system that computes VMStateField based on the actual
struct declaration.

Macros do not have full access to the type system, therefore a full
implementation of this scheme requires a helper trait to analyze the
type and produce a VMStateField from it; a macro "vmstate_of!" accepts
arguments similar to "offset_of!" and tricks the compiler into looking
up the trait for the right type.

The patch introduces not just vmstate_of!, but also the slightly too
clever enabling macro call_func_with_field!.  The particular trick used
here was proposed on the users.rust-lang.org forum, so I take no merit
and all the blame.

Introduce the trait and some functions to access it; the actual
implementation comes later.

Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 rust/qemu-api/src/prelude.rs |   2 +
 rust/qemu-api/src/vmstate.rs | 113 ++++++++++++++++++++++++++++++++++++++++---
 2 files changed, 109 insertions(+), 6 deletions(-)

(limited to 'rust/qemu-api/src')

diff --git a/rust/qemu-api/src/prelude.rs b/rust/qemu-api/src/prelude.rs
index 4ea70b9..2dc86e1 100644
--- a/rust/qemu-api/src/prelude.rs
+++ b/rust/qemu-api/src/prelude.rs
@@ -18,3 +18,5 @@ pub use crate::qom::ObjectType;
 pub use crate::qom_isa;
 
 pub use crate::sysbus::SysBusDeviceMethods;
+
+pub use crate::vmstate::VMState;
diff --git a/rust/qemu-api/src/vmstate.rs b/rust/qemu-api/src/vmstate.rs
index 63c897a..b839a7d 100644
--- a/rust/qemu-api/src/vmstate.rs
+++ b/rust/qemu-api/src/vmstate.rs
@@ -4,13 +4,114 @@
 
 //! Helper macros to declare migration state for device models.
 //!
-//! Some macros are direct equivalents to the C macros declared in
-//! `include/migration/vmstate.h` while
-//! [`vmstate_subsections`](crate::vmstate_subsections) and
-//! [`vmstate_fields`](crate::vmstate_fields) are meant to be used when
-//! declaring a device model state struct.
+//! This module includes three families of macros:
+//!
+//! * [`vmstate_unused!`](crate::vmstate_unused) and
+//!   [`vmstate_of!`](crate::vmstate_of), which are used to express the
+//!   migration format for a struct.  This is based on the [`VMState`] trait,
+//!   which is defined by all migrateable types.
+//!
+//! * helper macros to declare a device model state struct, in particular
+//!   [`vmstate_subsections`](crate::vmstate_subsections) and
+//!   [`vmstate_fields`](crate::vmstate_fields).
+//!
+//! * direct equivalents to the C macros declared in
+//!   `include/migration/vmstate.h`. These are not type-safe and should not be
+//!   used if the equivalent functionality is available with `vmstate_of!`.
+
+use core::marker::PhantomData;
+
+pub use crate::bindings::{VMStateDescription, VMStateField};
+
+/// This macro is used to call a function with a generic argument bound
+/// to the type of a field.  The function must take a
+/// [`PhantomData`]`<T>` argument; `T` is the type of
+/// field `$field` in the `$typ` type.
+///
+/// # Examples
+///
+/// ```
+/// # use qemu_api::call_func_with_field;
+/// # use core::marker::PhantomData;
+/// const fn size_of_field<T>(_: PhantomData<T>) -> usize {
+///     std::mem::size_of::<T>()
+/// }
+///
+/// struct Foo {
+///     x: u16,
+/// };
+/// // calls size_of_field::<u16>()
+/// assert_eq!(call_func_with_field!(size_of_field, Foo, x), 2);
+/// ```
+#[macro_export]
+macro_rules! call_func_with_field {
+    // Based on the answer by user steffahn (Frank Steffahn) at
+    // https://users.rust-lang.org/t/inferring-type-of-field/122857
+    // and used under MIT license
+    ($func:expr, $typ:ty, $($field:tt).+) => {
+        $func(loop {
+            #![allow(unreachable_code)]
+            const fn phantom__<T>(_: &T) -> ::core::marker::PhantomData<T> { ::core::marker::PhantomData }
+            // Unreachable code is exempt from checks on uninitialized values.
+            // Use that trick to infer the type of this PhantomData.
+            break ::core::marker::PhantomData;
+            break phantom__(&{ let value__: $typ; value__.$($field).+ });
+        })
+    };
+}
 
-pub use crate::bindings::VMStateDescription;
+/// A trait for types that can be included in a device's migration stream.  It
+/// provides the base contents of a `VMStateField` (minus the name and offset).
+///
+/// # Safety
+///
+/// The contents of this trait go straight into structs that are parsed by C
+/// code and used to introspect into other structs.  Be careful.
+pub unsafe trait VMState {
+    /// The base contents of a `VMStateField` (minus the name and offset) for
+    /// the type that is implementing the trait.
+    const BASE: VMStateField;
+}
+
+/// Internal utility function to retrieve a type's `VMStateField`;
+/// used by [`vmstate_of!`](crate::vmstate_of).
+pub const fn vmstate_base<T: VMState>(_: PhantomData<T>) -> VMStateField {
+    T::BASE
+}
+
+/// Return the `VMStateField` for a field of a struct.  The field must be
+/// visible in the current scope.
+///
+/// In order to support other types, the trait `VMState` must be implemented
+/// for them.
+#[macro_export]
+macro_rules! vmstate_of {
+    ($struct_name:ty, $field_name:ident $(,)?) => {
+        $crate::bindings::VMStateField {
+            name: ::core::concat!(::core::stringify!($field_name), "\0")
+                .as_bytes()
+                .as_ptr() as *const ::std::os::raw::c_char,
+            offset: $crate::offset_of!($struct_name, $field_name),
+            // Compute most of the VMStateField from the type of the field.
+            ..$crate::call_func_with_field!(
+                $crate::vmstate::vmstate_base,
+                $struct_name,
+                $field_name
+            )
+        }
+    };
+}
+
+// Add a couple builder-style methods to VMStateField, allowing
+// easy derivation of VMStateField constants from other types.
+impl VMStateField {
+    #[must_use]
+    pub const fn with_version_id(mut self, version_id: i32) -> Self {
+        assert!(version_id >= 0);
+        self.version_id = version_id;
+        self
+    }
+}
 
 #[doc(alias = "VMSTATE_UNUSED_BUFFER")]
 #[macro_export]
-- 
cgit v1.1


From 80aa3045bd42bec287d1f9bcc94be32a4c1b582e Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Sun, 29 Dec 2024 12:29:45 +0100
Subject: rust: vmstate: implement VMState for non-leaf types

Arrays, pointers and cells use a VMStateField that is based on that
for the inner type.  The implementation therefore delegates to the
VMState implementation of the inner type.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 rust/qemu-api/src/vmstate.rs | 79 +++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 78 insertions(+), 1 deletion(-)

(limited to 'rust/qemu-api/src')

diff --git a/rust/qemu-api/src/vmstate.rs b/rust/qemu-api/src/vmstate.rs
index b839a7d..211c3d0 100644
--- a/rust/qemu-api/src/vmstate.rs
+++ b/rust/qemu-api/src/vmstate.rs
@@ -19,8 +19,9 @@
 //!   `include/migration/vmstate.h`. These are not type-safe and should not be
 //!   used if the equivalent functionality is available with `vmstate_of!`.
 
-use core::marker::PhantomData;
+use core::{marker::PhantomData, mem, ptr::NonNull};
 
+use crate::bindings::VMStateFlags;
 pub use crate::bindings::{VMStateDescription, VMStateField};
 
 /// This macro is used to call a function with a generic argument bound
@@ -102,6 +103,15 @@ macro_rules! vmstate_of {
     };
 }
 
+impl VMStateFlags {
+    const VMS_VARRAY_FLAGS: VMStateFlags = VMStateFlags(
+        VMStateFlags::VMS_VARRAY_INT32.0
+            | VMStateFlags::VMS_VARRAY_UINT8.0
+            | VMStateFlags::VMS_VARRAY_UINT16.0
+            | VMStateFlags::VMS_VARRAY_UINT32.0,
+    );
+}
+
 // Add a couple builder-style methods to VMStateField, allowing
 // easy derivation of VMStateField constants from other types.
 impl VMStateField {
@@ -111,6 +121,73 @@ impl VMStateField {
         self.version_id = version_id;
         self
     }
+
+    #[must_use]
+    pub const fn with_array_flag(mut self, num: usize) -> Self {
+        assert!(num <= 0x7FFF_FFFFusize);
+        assert!((self.flags.0 & VMStateFlags::VMS_ARRAY.0) == 0);
+        assert!((self.flags.0 & VMStateFlags::VMS_VARRAY_FLAGS.0) == 0);
+        if (self.flags.0 & VMStateFlags::VMS_POINTER.0) != 0 {
+            self.flags = VMStateFlags(self.flags.0 & !VMStateFlags::VMS_POINTER.0);
+            self.flags = VMStateFlags(self.flags.0 | VMStateFlags::VMS_ARRAY_OF_POINTER.0);
+        }
+        self.flags = VMStateFlags(self.flags.0 & !VMStateFlags::VMS_SINGLE.0);
+        self.flags = VMStateFlags(self.flags.0 | VMStateFlags::VMS_ARRAY.0);
+        self.num = num as i32;
+        self
+    }
+
+    #[must_use]
+    pub const fn with_pointer_flag(mut self) -> Self {
+        assert!((self.flags.0 & VMStateFlags::VMS_POINTER.0) == 0);
+        self.flags = VMStateFlags(self.flags.0 | VMStateFlags::VMS_POINTER.0);
+        self
+    }
+}
+
+// Transparent wrappers: just use the internal type
+
+macro_rules! impl_vmstate_transparent {
+    ($type:ty where $base:tt: VMState $($where:tt)*) => {
+        unsafe impl<$base> VMState for $type where $base: VMState $($where)* {
+            const BASE: VMStateField = VMStateField {
+                size: mem::size_of::<$type>(),
+                ..<$base as VMState>::BASE
+            };
+        }
+    };
+}
+
+impl_vmstate_transparent!(std::cell::Cell<T> where T: VMState);
+impl_vmstate_transparent!(std::cell::UnsafeCell<T> where T: VMState);
+impl_vmstate_transparent!(crate::cell::BqlCell<T> where T: VMState);
+impl_vmstate_transparent!(crate::cell::BqlRefCell<T> where T: VMState);
+
+// Pointer types using the underlying type's VMState plus VMS_POINTER
+// Note that references are not supported, though references to cells
+// could be allowed.
+
+macro_rules! impl_vmstate_pointer {
+    ($type:ty where $base:tt: VMState $($where:tt)*) => {
+        unsafe impl<$base> VMState for $type where $base: VMState $($where)* {
+            const BASE: VMStateField = <$base as VMState>::BASE.with_pointer_flag();
+        }
+    };
+}
+
+impl_vmstate_pointer!(*const T where T: VMState);
+impl_vmstate_pointer!(*mut T where T: VMState);
+impl_vmstate_pointer!(NonNull<T> where T: VMState);
+
+// Unlike C pointers, Box is always non-null therefore there is no need
+// to specify VMS_ALLOC.
+impl_vmstate_pointer!(Box<T> where T: VMState);
+
+// Arrays using the underlying type's VMState plus
+// VMS_ARRAY/VMS_ARRAY_OF_POINTER
+
+unsafe impl<T: VMState, const N: usize> VMState for [T; N] {
+    const BASE: VMStateField = <T as VMState>::BASE.with_array_flag(N);
 }
 
 #[doc(alias = "VMSTATE_UNUSED_BUFFER")]
-- 
cgit v1.1


From 5b024b4e73f180402fde8485e8d4a51383592940 Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Thu, 19 Dec 2024 18:05:23 +0100
Subject: rust: vmstate: add varray support to vmstate_of!

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 rust/qemu-api/src/vmstate.rs | 42 ++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 40 insertions(+), 2 deletions(-)

(limited to 'rust/qemu-api/src')

diff --git a/rust/qemu-api/src/vmstate.rs b/rust/qemu-api/src/vmstate.rs
index 211c3d0..2b14d48 100644
--- a/rust/qemu-api/src/vmstate.rs
+++ b/rust/qemu-api/src/vmstate.rs
@@ -72,6 +72,15 @@ pub unsafe trait VMState {
     /// The base contents of a `VMStateField` (minus the name and offset) for
     /// the type that is implementing the trait.
     const BASE: VMStateField;
+
+    /// A flag that is added to another field's `VMStateField` to specify the
+    /// length's type in a variable-sized array.  If this is not a supported
+    /// type for the length (i.e. if it is not `u8`, `u16`, `u32`), using it
+    /// in a call to [`vmstate_of!`](crate::vmstate_of) will cause a
+    /// compile-time error.
+    const VARRAY_FLAG: VMStateFlags = {
+        panic!("invalid type for variable-sized array");
+    };
 }
 
 /// Internal utility function to retrieve a type's `VMStateField`;
@@ -80,6 +89,13 @@ pub const fn vmstate_base<T: VMState>(_: PhantomData<T>) -> VMStateField {
     T::BASE
 }
 
+/// Internal utility function to retrieve a type's `VMStateFlags` when it
+/// is used as the element count of a `VMSTATE_VARRAY`; used by
+/// [`vmstate_of!`](crate::vmstate_of).
+pub const fn vmstate_varray_flag<T: VMState>(_: PhantomData<T>) -> VMStateFlags {
+    T::VARRAY_FLAG
+}
+
 /// Return the `VMStateField` for a field of a struct.  The field must be
 /// visible in the current scope.
 ///
@@ -87,18 +103,23 @@ pub const fn vmstate_base<T: VMState>(_: PhantomData<T>) -> VMStateField {
 /// for them.
 #[macro_export]
 macro_rules! vmstate_of {
-    ($struct_name:ty, $field_name:ident $(,)?) => {
+    ($struct_name:ty, $field_name:ident $([0 .. $num:ident $(* $factor:expr)?])? $(,)?) => {
         $crate::bindings::VMStateField {
             name: ::core::concat!(::core::stringify!($field_name), "\0")
                 .as_bytes()
                 .as_ptr() as *const ::std::os::raw::c_char,
             offset: $crate::offset_of!($struct_name, $field_name),
             // Compute most of the VMStateField from the type of the field.
+            $(.num_offset: $crate::offset_of!($struct_name, $num),)?
             ..$crate::call_func_with_field!(
                 $crate::vmstate::vmstate_base,
                 $struct_name,
                 $field_name
-            )
+            )$(.with_varray_flag($crate::call_func_with_field!(
+                    $crate::vmstate::vmstate_varray_flag,
+                    $struct_name,
+                    $num))
+               $(.with_varray_multiply($factor))?)?
         }
     };
 }
@@ -143,6 +164,22 @@ impl VMStateField {
         self.flags = VMStateFlags(self.flags.0 | VMStateFlags::VMS_POINTER.0);
         self
     }
+
+    #[must_use]
+    pub const fn with_varray_flag<T: VMState>(mut self, flag: VMStateFlags) -> VMStateField {
+        assert!((self.flags.0 & VMStateFlags::VMS_ARRAY.0) != 0);
+        self.flags = VMStateFlags(self.flags.0 & !VMStateFlags::VMS_ARRAY.0);
+        self.flags = VMStateFlags(self.flags.0 | flag.0);
+        self
+    }
+
+    #[must_use]
+    pub const fn with_varray_multiply(mut self, num: u32) -> VMStateField {
+        assert!(num <= 0x7FFF_FFFFu32);
+        self.flags = VMStateFlags(self.flags.0 | VMStateFlags::VMS_MULTIPLY_ELEMENTS.0);
+        self.num = num as i32;
+        self
+    }
 }
 
 // Transparent wrappers: just use the internal type
@@ -154,6 +191,7 @@ macro_rules! impl_vmstate_transparent {
                 size: mem::size_of::<$type>(),
                 ..<$base as VMState>::BASE
             };
+            const VARRAY_FLAG: VMStateFlags = <$base as VMState>::VARRAY_FLAG;
         }
     };
 }
-- 
cgit v1.1


From 2537f8309885013c4b04ae7b2888591ba0cb6ca7 Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Sun, 29 Dec 2024 12:15:36 +0100
Subject: rust: vmstate: implement Zeroable for VMStateField

This shortens a bit the constants.  Do not bother using it
in the vmstate macros since most of them will go away soon.

Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 rust/qemu-api/src/vmstate.rs  | 18 +++---------------
 rust/qemu-api/src/zeroable.rs | 31 +++++++++++++++++++++++++++++++
 2 files changed, 34 insertions(+), 15 deletions(-)

(limited to 'rust/qemu-api/src')

diff --git a/rust/qemu-api/src/vmstate.rs b/rust/qemu-api/src/vmstate.rs
index 2b14d48..7652930 100644
--- a/rust/qemu-api/src/vmstate.rs
+++ b/rust/qemu-api/src/vmstate.rs
@@ -21,8 +21,8 @@
 
 use core::{marker::PhantomData, mem, ptr::NonNull};
 
-use crate::bindings::VMStateFlags;
 pub use crate::bindings::{VMStateDescription, VMStateField};
+use crate::bindings::VMStateFlags;
 
 /// This macro is used to call a function with a generic argument bound
 /// to the type of a field.  The function must take a
@@ -503,20 +503,8 @@ macro_rules! vmstate_fields {
         static _FIELDS: &[$crate::bindings::VMStateField] = &[
             $($field),*,
             $crate::bindings::VMStateField {
-                name: ::core::ptr::null(),
-                err_hint: ::core::ptr::null(),
-                offset: 0,
-                size: 0,
-                start: 0,
-                num: 0,
-                num_offset: 0,
-                size_offset: 0,
-                info: ::core::ptr::null(),
-                flags: VMStateFlags::VMS_END,
-                vmsd: ::core::ptr::null(),
-                version_id: 0,
-                struct_version_id: 0,
-                field_exists: None,
+                flags: $crate::bindings::VMStateFlags::VMS_END,
+                ..$crate::zeroable::Zeroable::ZERO
             }
         ];
         _FIELDS.as_ptr()
diff --git a/rust/qemu-api/src/zeroable.rs b/rust/qemu-api/src/zeroable.rs
index 6125aee..57cac96 100644
--- a/rust/qemu-api/src/zeroable.rs
+++ b/rust/qemu-api/src/zeroable.rs
@@ -49,6 +49,37 @@ unsafe impl Zeroable for crate::bindings::Property {
     };
 }
 
+// bindgen does not derive Default here
+#[allow(clippy::derivable_impls)]
+impl Default for crate::bindings::VMStateFlags {
+    fn default() -> Self {
+        Self(0)
+    }
+}
+
+unsafe impl Zeroable for crate::bindings::VMStateFlags {
+    const ZERO: Self = Self(0);
+}
+
+unsafe impl Zeroable for crate::bindings::VMStateField {
+    const ZERO: Self = Self {
+        name: ptr::null(),
+        err_hint: ptr::null(),
+        offset: 0,
+        size: 0,
+        start: 0,
+        num: 0,
+        num_offset: 0,
+        size_offset: 0,
+        info: ptr::null(),
+        flags: Zeroable::ZERO,
+        vmsd: ptr::null(),
+        version_id: 0,
+        struct_version_id: 0,
+        field_exists: None,
+    };
+}
+
 unsafe impl Zeroable for crate::bindings::VMStateDescription {
     const ZERO: Self = Self {
         name: ptr::null(),
-- 
cgit v1.1


From f2cb78bdbe5f9ff61366beb216971a8502456c3a Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Sun, 29 Dec 2024 11:59:34 +0100
Subject: rust: vmstate: implement VMState for scalar types

Scalar types are those that have their own VMStateInfo.  This poses
a problem in that references to VMStateInfo can only be included in
associated consts starting with Rust 1.83.0, when the const_refs_static
was stabilized.  Removing the requirement is done by placing a limited
list of VMStateInfos in an enum, and going from enum to &VMStateInfo
only when building the VMStateField.

The same thing cannot be done with VMS_STRUCT because the set of
VMStateDescriptions extends to structs defined by the devices.
Therefore, structs and cells cannot yet use vmstate_of!.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 rust/qemu-api/src/vmstate.rs | 128 ++++++++++++++++++++++++++++++++++++++++++-
 1 file changed, 126 insertions(+), 2 deletions(-)

(limited to 'rust/qemu-api/src')

diff --git a/rust/qemu-api/src/vmstate.rs b/rust/qemu-api/src/vmstate.rs
index 7652930..a262c31 100644
--- a/rust/qemu-api/src/vmstate.rs
+++ b/rust/qemu-api/src/vmstate.rs
@@ -22,7 +22,10 @@
 use core::{marker::PhantomData, mem, ptr::NonNull};
 
 pub use crate::bindings::{VMStateDescription, VMStateField};
-use crate::bindings::VMStateFlags;
+use crate::{
+    bindings::{self, VMStateFlags},
+    zeroable::Zeroable,
+};
 
 /// This macro is used to call a function with a generic argument bound
 /// to the type of a field.  The function must take a
@@ -61,6 +64,70 @@ macro_rules! call_func_with_field {
     };
 }
 
+/// Workaround for lack of `const_refs_static`: references to global variables
+/// can be included in a `static`, but not in a `const`; unfortunately, this
+/// is exactly what would go in the `VMStateField`'s `info` member.
+///
+/// This enum contains the contents of the `VMStateField`'s `info` member,
+/// but as an `enum` instead of a pointer.
+#[allow(non_camel_case_types)]
+pub enum VMStateFieldType {
+    null,
+    vmstate_info_bool,
+    vmstate_info_int8,
+    vmstate_info_int16,
+    vmstate_info_int32,
+    vmstate_info_int64,
+    vmstate_info_uint8,
+    vmstate_info_uint16,
+    vmstate_info_uint32,
+    vmstate_info_uint64,
+    vmstate_info_timer,
+}
+
+/// Workaround for lack of `const_refs_static`.  Converts a `VMStateFieldType`
+/// to a `*const VMStateInfo`, for inclusion in a `VMStateField`.
+#[macro_export]
+macro_rules! info_enum_to_ref {
+    ($e:expr) => {
+        unsafe {
+            match $e {
+                $crate::vmstate::VMStateFieldType::null => ::core::ptr::null(),
+                $crate::vmstate::VMStateFieldType::vmstate_info_bool => {
+                    ::core::ptr::addr_of!($crate::bindings::vmstate_info_bool)
+                }
+                $crate::vmstate::VMStateFieldType::vmstate_info_int8 => {
+                    ::core::ptr::addr_of!($crate::bindings::vmstate_info_int8)
+                }
+                $crate::vmstate::VMStateFieldType::vmstate_info_int16 => {
+                    ::core::ptr::addr_of!($crate::bindings::vmstate_info_int16)
+                }
+                $crate::vmstate::VMStateFieldType::vmstate_info_int32 => {
+                    ::core::ptr::addr_of!($crate::bindings::vmstate_info_int32)
+                }
+                $crate::vmstate::VMStateFieldType::vmstate_info_int64 => {
+                    ::core::ptr::addr_of!($crate::bindings::vmstate_info_int64)
+                }
+                $crate::vmstate::VMStateFieldType::vmstate_info_uint8 => {
+                    ::core::ptr::addr_of!($crate::bindings::vmstate_info_uint8)
+                }
+                $crate::vmstate::VMStateFieldType::vmstate_info_uint16 => {
+                    ::core::ptr::addr_of!($crate::bindings::vmstate_info_uint16)
+                }
+                $crate::vmstate::VMStateFieldType::vmstate_info_uint32 => {
+                    ::core::ptr::addr_of!($crate::bindings::vmstate_info_uint32)
+                }
+                $crate::vmstate::VMStateFieldType::vmstate_info_uint64 => {
+                    ::core::ptr::addr_of!($crate::bindings::vmstate_info_uint64)
+                }
+                $crate::vmstate::VMStateFieldType::vmstate_info_timer => {
+                    ::core::ptr::addr_of!($crate::bindings::vmstate_info_timer)
+                }
+            }
+        }
+    };
+}
+
 /// A trait for types that can be included in a device's migration stream.  It
 /// provides the base contents of a `VMStateField` (minus the name and offset).
 ///
@@ -69,6 +136,12 @@ macro_rules! call_func_with_field {
 /// The contents of this trait go straight into structs that are parsed by C
 /// code and used to introspect into other structs.  Be careful.
 pub unsafe trait VMState {
+    /// The `info` member of a `VMStateField` is a pointer and as such cannot
+    /// yet be included in the [`BASE`](VMState::BASE) associated constant;
+    /// this is only allowed by Rust 1.83.0 and newer.  For now, include the
+    /// member as an enum which is stored in a separate constant.
+    const SCALAR_TYPE: VMStateFieldType = VMStateFieldType::null;
+
     /// The base contents of a `VMStateField` (minus the name and offset) for
     /// the type that is implementing the trait.
     const BASE: VMStateField;
@@ -83,6 +156,12 @@ pub unsafe trait VMState {
     };
 }
 
+/// Internal utility function to retrieve a type's `VMStateFieldType`;
+/// used by [`vmstate_of!`](crate::vmstate_of).
+pub const fn vmstate_scalar_type<T: VMState>(_: PhantomData<T>) -> VMStateFieldType {
+    T::SCALAR_TYPE
+}
+
 /// Internal utility function to retrieve a type's `VMStateField`;
 /// used by [`vmstate_of!`](crate::vmstate_of).
 pub const fn vmstate_base<T: VMState>(_: PhantomData<T>) -> VMStateField {
@@ -99,6 +178,15 @@ pub const fn vmstate_varray_flag<T: VMState>(_: PhantomData<T>) -> VMStateFlags
 /// Return the `VMStateField` for a field of a struct.  The field must be
 /// visible in the current scope.
 ///
+/// Only a limited set of types is supported out of the box:
+/// * scalar types (integer and `bool`)
+/// * the C struct `QEMUTimer`
+/// * a transparent wrapper for any of the above (`Cell`, `UnsafeCell`,
+///   [`BqlCell`](crate::cell::BqlCell), [`BqlRefCell`](crate::cell::BqlRefCell)
+/// * a raw pointer to any of the above
+/// * a `NonNull` pointer or a `Box` for any of the above
+/// * an array of any of the above
+///
 /// In order to support other types, the trait `VMState` must be implemented
 /// for them.
 #[macro_export]
@@ -109,8 +197,14 @@ macro_rules! vmstate_of {
                 .as_bytes()
                 .as_ptr() as *const ::std::os::raw::c_char,
             offset: $crate::offset_of!($struct_name, $field_name),
-            // Compute most of the VMStateField from the type of the field.
             $(.num_offset: $crate::offset_of!($struct_name, $num),)?
+            // The calls to `call_func_with_field!` are the magic that
+            // computes most of the VMStateField from the type of the field.
+            info: $crate::info_enum_to_ref!($crate::call_func_with_field!(
+                $crate::vmstate::vmstate_scalar_type,
+                $struct_name,
+                $field_name
+            )),
             ..$crate::call_func_with_field!(
                 $crate::vmstate::vmstate_base,
                 $struct_name,
@@ -187,6 +281,7 @@ impl VMStateField {
 macro_rules! impl_vmstate_transparent {
     ($type:ty where $base:tt: VMState $($where:tt)*) => {
         unsafe impl<$base> VMState for $type where $base: VMState $($where)* {
+            const SCALAR_TYPE: VMStateFieldType = <$base as VMState>::SCALAR_TYPE;
             const BASE: VMStateField = VMStateField {
                 size: mem::size_of::<$type>(),
                 ..<$base as VMState>::BASE
@@ -201,6 +296,33 @@ impl_vmstate_transparent!(std::cell::UnsafeCell<T> where T: VMState);
 impl_vmstate_transparent!(crate::cell::BqlCell<T> where T: VMState);
 impl_vmstate_transparent!(crate::cell::BqlRefCell<T> where T: VMState);
 
+// Scalar types using predefined VMStateInfos
+
+macro_rules! impl_vmstate_scalar {
+    ($info:ident, $type:ty$(, $varray_flag:ident)?) => {
+        unsafe impl VMState for $type {
+            const SCALAR_TYPE: VMStateFieldType = VMStateFieldType::$info;
+            const BASE: VMStateField = VMStateField {
+                size: mem::size_of::<$type>(),
+                flags: VMStateFlags::VMS_SINGLE,
+                ..Zeroable::ZERO
+            };
+            $(const VARRAY_FLAG: VMStateFlags = VMStateFlags::$varray_flag;)?
+        }
+    };
+}
+
+impl_vmstate_scalar!(vmstate_info_bool, bool);
+impl_vmstate_scalar!(vmstate_info_int8, i8);
+impl_vmstate_scalar!(vmstate_info_int16, i16);
+impl_vmstate_scalar!(vmstate_info_int32, i32);
+impl_vmstate_scalar!(vmstate_info_int64, i64);
+impl_vmstate_scalar!(vmstate_info_uint8, u8, VMS_VARRAY_UINT8);
+impl_vmstate_scalar!(vmstate_info_uint16, u16, VMS_VARRAY_UINT16);
+impl_vmstate_scalar!(vmstate_info_uint32, u32, VMS_VARRAY_UINT32);
+impl_vmstate_scalar!(vmstate_info_uint64, u64);
+impl_vmstate_scalar!(vmstate_info_timer, bindings::QEMUTimer);
+
 // Pointer types using the underlying type's VMState plus VMS_POINTER
 // Note that references are not supported, though references to cells
 // could be allowed.
@@ -208,6 +330,7 @@ impl_vmstate_transparent!(crate::cell::BqlRefCell<T> where T: VMState);
 macro_rules! impl_vmstate_pointer {
     ($type:ty where $base:tt: VMState $($where:tt)*) => {
         unsafe impl<$base> VMState for $type where $base: VMState $($where)* {
+            const SCALAR_TYPE: VMStateFieldType = <T as VMState>::SCALAR_TYPE;
             const BASE: VMStateField = <$base as VMState>::BASE.with_pointer_flag();
         }
     };
@@ -225,6 +348,7 @@ impl_vmstate_pointer!(Box<T> where T: VMState);
 // VMS_ARRAY/VMS_ARRAY_OF_POINTER
 
 unsafe impl<T: VMState, const N: usize> VMState for [T; N] {
+    const SCALAR_TYPE: VMStateFieldType = <T as VMState>::SCALAR_TYPE;
     const BASE: VMStateField = <T as VMState>::BASE.with_array_flag(N);
 }
 
-- 
cgit v1.1


From 00f89716a8858f6b9274dd4067740fb40212e88b Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Sat, 21 Dec 2024 13:42:41 +0100
Subject: rust: vmstate: add public utility macros to implement VMState

Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 rust/qemu-api/src/vmstate.rs | 61 +++++++++++++++++++++++++++++++++++++++++---
 1 file changed, 58 insertions(+), 3 deletions(-)

(limited to 'rust/qemu-api/src')

diff --git a/rust/qemu-api/src/vmstate.rs b/rust/qemu-api/src/vmstate.rs
index a262c31..9ac699b 100644
--- a/rust/qemu-api/src/vmstate.rs
+++ b/rust/qemu-api/src/vmstate.rs
@@ -4,13 +4,18 @@
 
 //! Helper macros to declare migration state for device models.
 //!
-//! This module includes three families of macros:
+//! This module includes four families of macros:
 //!
 //! * [`vmstate_unused!`](crate::vmstate_unused) and
 //!   [`vmstate_of!`](crate::vmstate_of), which are used to express the
 //!   migration format for a struct.  This is based on the [`VMState`] trait,
 //!   which is defined by all migrateable types.
 //!
+//! * [`impl_vmstate_forward`](crate::impl_vmstate_forward) and
+//!   [`impl_vmstate_bitsized`](crate::impl_vmstate_bitsized), which help with
+//!   the definition of the [`VMState`] trait (respectively for transparent
+//!   structs and for `bilge`-defined types)
+//!
 //! * helper macros to declare a device model state struct, in particular
 //!   [`vmstate_subsections`](crate::vmstate_subsections) and
 //!   [`vmstate_fields`](crate::vmstate_fields).
@@ -134,7 +139,9 @@ macro_rules! info_enum_to_ref {
 /// # Safety
 ///
 /// The contents of this trait go straight into structs that are parsed by C
-/// code and used to introspect into other structs.  Be careful.
+/// code and used to introspect into other structs.  Generally, you don't need
+/// to implement it except via macros that do it for you, such as
+/// `impl_vmstate_bitsized!`.
 pub unsafe trait VMState {
     /// The `info` member of a `VMStateField` is a pointer and as such cannot
     /// yet be included in the [`BASE`](VMState::BASE) associated constant;
@@ -188,7 +195,9 @@ pub const fn vmstate_varray_flag<T: VMState>(_: PhantomData<T>) -> VMStateFlags
 /// * an array of any of the above
 ///
 /// In order to support other types, the trait `VMState` must be implemented
-/// for them.
+/// for them.  The macros
+/// [`impl_vmstate_bitsized!`](crate::impl_vmstate_bitsized)
+/// and [`impl_vmstate_forward!`](crate::impl_vmstate_forward) help with this.
 #[macro_export]
 macro_rules! vmstate_of {
     ($struct_name:ty, $field_name:ident $([0 .. $num:ident $(* $factor:expr)?])? $(,)?) => {
@@ -276,6 +285,32 @@ impl VMStateField {
     }
 }
 
+/// This macro can be used (by just passing it a type) to forward the `VMState`
+/// trait to the first field of a tuple.  This is a workaround for lack of
+/// support of nested [`offset_of`](core::mem::offset_of) until Rust 1.82.0.
+///
+/// # Examples
+///
+/// ```
+/// # use qemu_api::vmstate::impl_vmstate_forward;
+/// pub struct Fifo([u8; 16]);
+/// impl_vmstate_forward!(Fifo);
+/// ```
+#[macro_export]
+macro_rules! impl_vmstate_forward {
+    // This is similar to impl_vmstate_transparent below, but it
+    // uses the same trick as vmstate_of! to obtain the type of
+    // the first field of the tuple
+    ($tuple:ty) => {
+        unsafe impl $crate::vmstate::VMState for $tuple {
+            const SCALAR_TYPE: $crate::vmstate::VMStateFieldType =
+                $crate::call_func_with_field!($crate::vmstate::vmstate_scalar_type, $tuple, 0);
+            const BASE: $crate::bindings::VMStateField =
+                $crate::call_func_with_field!($crate::vmstate::vmstate_base, $tuple, 0);
+        }
+    };
+}
+
 // Transparent wrappers: just use the internal type
 
 macro_rules! impl_vmstate_transparent {
@@ -296,6 +331,26 @@ impl_vmstate_transparent!(std::cell::UnsafeCell<T> where T: VMState);
 impl_vmstate_transparent!(crate::cell::BqlCell<T> where T: VMState);
 impl_vmstate_transparent!(crate::cell::BqlRefCell<T> where T: VMState);
 
+#[macro_export]
+macro_rules! impl_vmstate_bitsized {
+    ($type:ty) => {
+        unsafe impl $crate::vmstate::VMState for $type {
+            const SCALAR_TYPE: $crate::vmstate::VMStateFieldType =
+                                        <<<$type as ::bilge::prelude::Bitsized>::ArbitraryInt
+                                          as ::bilge::prelude::Number>::UnderlyingType
+                                         as $crate::vmstate::VMState>::SCALAR_TYPE;
+            const BASE: $crate::bindings::VMStateField =
+                                        <<<$type as ::bilge::prelude::Bitsized>::ArbitraryInt
+                                          as ::bilge::prelude::Number>::UnderlyingType
+                                         as $crate::vmstate::VMState>::BASE;
+            const VARRAY_FLAG: $crate::bindings::VMStateFlags =
+                                        <<<$type as ::bilge::prelude::Bitsized>::ArbitraryInt
+                                          as ::bilge::prelude::Number>::UnderlyingType
+                                         as $crate::vmstate::VMState>::VARRAY_FLAG;
+        }
+    };
+}
+
 // Scalar types using predefined VMStateInfos
 
 macro_rules! impl_vmstate_scalar {
-- 
cgit v1.1


From 9a2ba4882d320a650b4f98f92b49bb45956d227e Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Sat, 21 Dec 2024 16:28:29 +0100
Subject: rust: qemu_api: add vmstate_struct

It is not type safe, but it's the best that can be done without
const_refs_static.  It can also be used with BqlCell and BqlRefCell.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 rust/qemu-api/src/vmstate.rs | 33 +++++++++++++++++++++++++++++++++
 1 file changed, 33 insertions(+)

(limited to 'rust/qemu-api/src')

diff --git a/rust/qemu-api/src/vmstate.rs b/rust/qemu-api/src/vmstate.rs
index 9ac699b..d3a9cff 100644
--- a/rust/qemu-api/src/vmstate.rs
+++ b/rust/qemu-api/src/vmstate.rs
@@ -628,6 +628,39 @@ macro_rules! vmstate_array_of_pointer_to_struct {
     }};
 }
 
+// FIXME: including the `vmsd` field in a `const` is not possible without
+// the const_refs_static feature (stabilized in Rust 1.83.0).  Without it,
+// it is not possible to use VMS_STRUCT in a transparent manner using
+// `vmstate_of!`.  While VMSTATE_CLOCK can at least try to be type-safe,
+// VMSTATE_STRUCT includes $type only for documentation purposes; it
+// is checked against $field_name and $struct_name, but not against $vmsd
+// which is what really would matter.
+#[doc(alias = "VMSTATE_STRUCT")]
+#[macro_export]
+macro_rules! vmstate_struct {
+    ($struct_name:ty, $field_name:ident $([0 .. $num:ident $(* $factor:expr)?])?, $vmsd:expr, $type:ty $(,)?) => {
+        $crate::bindings::VMStateField {
+            name: ::core::concat!(::core::stringify!($field_name), "\0")
+                .as_bytes()
+                .as_ptr() as *const ::std::os::raw::c_char,
+            $(.num_offset: $crate::offset_of!($struct_name, $num),)?
+            offset: {
+                $crate::assert_field_type!($struct_name, $field_name, $type);
+                $crate::offset_of!($struct_name, $field_name)
+            },
+            size: ::core::mem::size_of::<$type>(),
+            flags: $crate::bindings::VMStateFlags::VMS_STRUCT,
+            vmsd: unsafe { $vmsd },
+            ..$crate::zeroable::Zeroable::ZERO $(
+                .with_varray_flag($crate::call_func_with_field!(
+                    $crate::vmstate::vmstate_varray_flag,
+                    $struct_name,
+                    $num))
+               $(.with_varray_multiply($factor))?)?
+        }
+    };
+}
+
 #[doc(alias = "VMSTATE_CLOCK_V")]
 #[macro_export]
 macro_rules! vmstate_clock_v {
-- 
cgit v1.1


From 9d4899496b555751c8ea4155d6da4fc3dbd7edae Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Tue, 7 Jan 2025 10:29:27 +0100
Subject: rust: vmstate: remove translation of C vmstate macros

Keep vmstate_clock!; because it uses a field of type VMStateDescription,
it cannot be converted to the VMState trait without access to the
const_refs_static feature.

Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 rust/qemu-api/src/vmstate.rs | 274 ++++---------------------------------------
 1 file changed, 23 insertions(+), 251 deletions(-)

(limited to 'rust/qemu-api/src')

diff --git a/rust/qemu-api/src/vmstate.rs b/rust/qemu-api/src/vmstate.rs
index d3a9cff..120933e 100644
--- a/rust/qemu-api/src/vmstate.rs
+++ b/rust/qemu-api/src/vmstate.rs
@@ -21,8 +21,8 @@
 //!   [`vmstate_fields`](crate::vmstate_fields).
 //!
 //! * direct equivalents to the C macros declared in
-//!   `include/migration/vmstate.h`. These are not type-safe and should not be
-//!   used if the equivalent functionality is available with `vmstate_of!`.
+//!   `include/migration/vmstate.h`. These are not type-safe and only provide
+//!   functionality that is missing from `vmstate_of!`.
 
 use core::{marker::PhantomData, mem, ptr::NonNull};
 
@@ -407,223 +407,16 @@ unsafe impl<T: VMState, const N: usize> VMState for [T; N] {
     const BASE: VMStateField = <T as VMState>::BASE.with_array_flag(N);
 }
 
-#[doc(alias = "VMSTATE_UNUSED_BUFFER")]
-#[macro_export]
-macro_rules! vmstate_unused_buffer {
-    ($field_exists_fn:expr, $version_id:expr, $size:expr) => {{
-        $crate::bindings::VMStateField {
-            name: c_str!("unused").as_ptr(),
-            err_hint: ::core::ptr::null(),
-            offset: 0,
-            size: $size,
-            start: 0,
-            num: 0,
-            num_offset: 0,
-            size_offset: 0,
-            info: unsafe { ::core::ptr::addr_of!($crate::bindings::vmstate_info_unused_buffer) },
-            flags: VMStateFlags::VMS_BUFFER,
-            vmsd: ::core::ptr::null(),
-            version_id: $version_id,
-            struct_version_id: 0,
-            field_exists: $field_exists_fn,
-        }
-    }};
-}
-
-#[doc(alias = "VMSTATE_UNUSED_V")]
-#[macro_export]
-macro_rules! vmstate_unused_v {
-    ($version_id:expr, $size:expr) => {{
-        $crate::vmstate_unused_buffer!(None, $version_id, $size)
-    }};
-}
-
 #[doc(alias = "VMSTATE_UNUSED")]
 #[macro_export]
 macro_rules! vmstate_unused {
     ($size:expr) => {{
-        $crate::vmstate_unused_v!(0, $size)
-    }};
-}
-
-#[doc(alias = "VMSTATE_SINGLE_TEST")]
-#[macro_export]
-macro_rules! vmstate_single_test {
-    ($field_name:ident, $struct_name:ty, $field_exists_fn:expr, $version_id:expr, $info:expr, $size:expr) => {{
-        $crate::bindings::VMStateField {
-            name: ::core::concat!(::core::stringify!($field_name), 0)
-                .as_bytes()
-                .as_ptr() as *const ::std::os::raw::c_char,
-            err_hint: ::core::ptr::null(),
-            offset: $crate::offset_of!($struct_name, $field_name),
-            size: $size,
-            start: 0,
-            num: 0,
-            num_offset: 0,
-            size_offset: 0,
-            info: unsafe { $info },
-            flags: VMStateFlags::VMS_SINGLE,
-            vmsd: ::core::ptr::null(),
-            version_id: $version_id,
-            struct_version_id: 0,
-            field_exists: $field_exists_fn,
-        }
-    }};
-}
-
-#[doc(alias = "VMSTATE_SINGLE")]
-#[macro_export]
-macro_rules! vmstate_single {
-    ($field_name:ident, $struct_name:ty, $version_id:expr, $info:expr, $size:expr) => {{
-        $crate::vmstate_single_test!($field_name, $struct_name, None, $version_id, $info, $size)
-    }};
-}
-
-#[doc(alias = "VMSTATE_UINT32_V")]
-#[macro_export]
-macro_rules! vmstate_uint32_v {
-    ($field_name:ident, $struct_name:ty, $version_id:expr) => {{
-        $crate::vmstate_single!(
-            $field_name,
-            $struct_name,
-            $version_id,
-            ::core::ptr::addr_of!($crate::bindings::vmstate_info_uint32),
-            ::core::mem::size_of::<u32>()
-        )
-    }};
-}
-
-#[doc(alias = "VMSTATE_UINT32")]
-#[macro_export]
-macro_rules! vmstate_uint32 {
-    ($field_name:ident, $struct_name:ty) => {{
-        $crate::vmstate_uint32_v!($field_name, $struct_name, 0)
-    }};
-}
-
-#[doc(alias = "VMSTATE_ARRAY")]
-#[macro_export]
-macro_rules! vmstate_array {
-    ($field_name:ident, $struct_name:ty, $length:expr, $version_id:expr, $info:expr, $size:expr) => {{
         $crate::bindings::VMStateField {
-            name: ::core::concat!(::core::stringify!($field_name), 0)
-                .as_bytes()
-                .as_ptr() as *const ::std::os::raw::c_char,
-            err_hint: ::core::ptr::null(),
-            offset: $crate::offset_of!($struct_name, $field_name),
+            name: $crate::c_str!("unused").as_ptr(),
             size: $size,
-            start: 0,
-            num: $length as _,
-            num_offset: 0,
-            size_offset: 0,
-            info: unsafe { $info },
-            flags: VMStateFlags::VMS_ARRAY,
-            vmsd: ::core::ptr::null(),
-            version_id: $version_id,
-            struct_version_id: 0,
-            field_exists: None,
-        }
-    }};
-}
-
-#[doc(alias = "VMSTATE_UINT32_ARRAY_V")]
-#[macro_export]
-macro_rules! vmstate_uint32_array_v {
-    ($field_name:ident, $struct_name:ty, $length:expr, $version_id:expr) => {{
-        $crate::vmstate_array!(
-            $field_name,
-            $struct_name,
-            $length,
-            $version_id,
-            ::core::ptr::addr_of!($crate::bindings::vmstate_info_uint32),
-            ::core::mem::size_of::<u32>()
-        )
-    }};
-}
-
-#[doc(alias = "VMSTATE_UINT32_ARRAY")]
-#[macro_export]
-macro_rules! vmstate_uint32_array {
-    ($field_name:ident, $struct_name:ty, $length:expr) => {{
-        $crate::vmstate_uint32_array_v!($field_name, $struct_name, $length, 0)
-    }};
-}
-
-#[doc(alias = "VMSTATE_STRUCT_POINTER_V")]
-#[macro_export]
-macro_rules! vmstate_struct_pointer_v {
-    ($field_name:ident, $struct_name:ty, $version_id:expr, $vmsd:expr, $type:ty) => {{
-        $crate::bindings::VMStateField {
-            name: ::core::concat!(::core::stringify!($field_name), 0)
-                .as_bytes()
-                .as_ptr() as *const ::std::os::raw::c_char,
-            err_hint: ::core::ptr::null(),
-            offset: $crate::offset_of!($struct_name, $field_name),
-            size: ::core::mem::size_of::<*const $type>(),
-            start: 0,
-            num: 0,
-            num_offset: 0,
-            size_offset: 0,
-            info: ::core::ptr::null(),
-            flags: VMStateFlags(VMStateFlags::VMS_STRUCT.0 | VMStateFlags::VMS_POINTER.0),
-            vmsd: unsafe { $vmsd },
-            version_id: $version_id,
-            struct_version_id: 0,
-            field_exists: None,
-        }
-    }};
-}
-
-#[doc(alias = "VMSTATE_ARRAY_OF_POINTER")]
-#[macro_export]
-macro_rules! vmstate_array_of_pointer {
-    ($field_name:ident, $struct_name:ty, $num:expr, $version_id:expr, $info:expr, $type:ty) => {{
-        $crate::bindings::VMStateField {
-            name: ::core::concat!(::core::stringify!($field_name), 0)
-                .as_bytes()
-                .as_ptr() as *const ::std::os::raw::c_char,
-            version_id: $version_id,
-            num: $num as _,
-            info: unsafe { $info },
-            size: ::core::mem::size_of::<*const $type>(),
-            flags: VMStateFlags(VMStateFlags::VMS_ARRAY.0 | VMStateFlags::VMS_ARRAY_OF_POINTER.0),
-            offset: $crate::offset_of!($struct_name, $field_name),
-            err_hint: ::core::ptr::null(),
-            start: 0,
-            num_offset: 0,
-            size_offset: 0,
-            vmsd: ::core::ptr::null(),
-            struct_version_id: 0,
-            field_exists: None,
-        }
-    }};
-}
-
-#[doc(alias = "VMSTATE_ARRAY_OF_POINTER_TO_STRUCT")]
-#[macro_export]
-macro_rules! vmstate_array_of_pointer_to_struct {
-    ($field_name:ident, $struct_name:ty, $num:expr, $version_id:expr, $vmsd:expr, $type:ty) => {{
-        $crate::bindings::VMStateField {
-            name: ::core::concat!(::core::stringify!($field_name), 0)
-                .as_bytes()
-                .as_ptr() as *const ::std::os::raw::c_char,
-            version_id: $version_id,
-            num: $num as _,
-            vmsd: unsafe { $vmsd },
-            size: ::core::mem::size_of::<*const $type>(),
-            flags: VMStateFlags(
-                VMStateFlags::VMS_ARRAY.0
-                    | VMStateFlags::VMS_STRUCT.0
-                    | VMStateFlags::VMS_ARRAY_OF_POINTER.0,
-            ),
-            offset: $crate::offset_of!($struct_name, $field_name),
-            err_hint: ::core::ptr::null(),
-            start: 0,
-            num_offset: 0,
-            size_offset: 0,
-            vmsd: ::core::ptr::null(),
-            struct_version_id: 0,
-            field_exists: None,
+            info: unsafe { ::core::ptr::addr_of!($crate::bindings::vmstate_info_unused_buffer) },
+            flags: $crate::bindings::VMStateFlags::VMS_BUFFER,
+            ..$crate::zeroable::Zeroable::ZERO
         }
     }};
 }
@@ -661,48 +454,27 @@ macro_rules! vmstate_struct {
     };
 }
 
-#[doc(alias = "VMSTATE_CLOCK_V")]
-#[macro_export]
-macro_rules! vmstate_clock_v {
-    ($field_name:ident, $struct_name:ty, $version_id:expr) => {{
-        $crate::vmstate_struct_pointer_v!(
-            $field_name,
-            $struct_name,
-            $version_id,
-            ::core::ptr::addr_of!($crate::bindings::vmstate_clock),
-            $crate::bindings::Clock
-        )
-    }};
-}
-
 #[doc(alias = "VMSTATE_CLOCK")]
 #[macro_export]
 macro_rules! vmstate_clock {
     ($field_name:ident, $struct_name:ty) => {{
-        $crate::vmstate_clock_v!($field_name, $struct_name, 0)
-    }};
-}
-
-#[doc(alias = "VMSTATE_ARRAY_CLOCK_V")]
-#[macro_export]
-macro_rules! vmstate_array_clock_v {
-    ($field_name:ident, $struct_name:ty, $num:expr, $version_id:expr) => {{
-        $crate::vmstate_array_of_pointer_to_struct!(
-            $field_name,
-            $struct_name,
-            $num,
-            $version_id,
-            ::core::ptr::addr_of!($crate::bindings::vmstate_clock),
-            $crate::bindings::Clock
-        )
-    }};
-}
-
-#[doc(alias = "VMSTATE_ARRAY_CLOCK")]
-#[macro_export]
-macro_rules! vmstate_array_clock {
-    ($field_name:ident, $struct_name:ty, $num:expr) => {{
-        $crate::vmstate_array_clock_v!($field_name, $struct_name, $name, 0)
+        $crate::bindings::VMStateField {
+            name: ::core::concat!(::core::stringify!($field_name), "\0")
+                .as_bytes()
+                .as_ptr() as *const ::std::os::raw::c_char,
+            offset: {
+                $crate::assert_field_type!(
+                    $struct_name,
+                    $field_name,
+                    core::ptr::NonNull<$crate::bindings::Clock>
+                );
+                $crate::offset_of!($struct_name, $field_name)
+            },
+            size: ::core::mem::size_of::<*const $crate::bindings::Clock>(),
+            flags: VMStateFlags(VMStateFlags::VMS_STRUCT.0 | VMStateFlags::VMS_POINTER.0),
+            vmsd: unsafe { ::core::ptr::addr_of!($crate::bindings::vmstate_clock) },
+            ..$crate::zeroable::Zeroable::ZERO
+        }
     }};
 }
 
-- 
cgit v1.1


From 24f0e8d818b931758b6dc47f973a6b1b80ecee1f Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Tue, 7 Jan 2025 10:30:41 +0100
Subject: rust: vmstate: make order of parameters consistent in vmstate_clock

Place struct_name before field_name, similar to offset_of.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 rust/qemu-api/src/vmstate.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'rust/qemu-api/src')

diff --git a/rust/qemu-api/src/vmstate.rs b/rust/qemu-api/src/vmstate.rs
index 120933e..6ac432c 100644
--- a/rust/qemu-api/src/vmstate.rs
+++ b/rust/qemu-api/src/vmstate.rs
@@ -457,7 +457,7 @@ macro_rules! vmstate_struct {
 #[doc(alias = "VMSTATE_CLOCK")]
 #[macro_export]
 macro_rules! vmstate_clock {
-    ($field_name:ident, $struct_name:ty) => {{
+    ($struct_name:ty, $field_name:ident) => {{
         $crate::bindings::VMStateField {
             name: ::core::concat!(::core::stringify!($field_name), "\0")
                 .as_bytes()
-- 
cgit v1.1


From 7d0520398f7f58214cf5242b34c1b46efa2fcf4f Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Thu, 23 Jan 2025 11:25:22 +0100
Subject: rust: prefer NonNull::new to assertions

Do not use new_unchecked; the effect is the same, but the
code is easier to read and unsafe regions become smaller.
Likewise, NonNull::new can be used instead of assertion and
followed by as_ref() or as_mut() instead of dereferencing the
pointer.

Suggested-by: Zhao Liu <zhao1.liu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 rust/qemu-api/src/qdev.rs | 12 +++++-------
 rust/qemu-api/src/qom.rs  | 21 +++++++++++++--------
 2 files changed, 18 insertions(+), 15 deletions(-)

(limited to 'rust/qemu-api/src')

diff --git a/rust/qemu-api/src/qdev.rs b/rust/qemu-api/src/qdev.rs
index a5121e3..4242990 100644
--- a/rust/qemu-api/src/qdev.rs
+++ b/rust/qemu-api/src/qdev.rs
@@ -4,7 +4,7 @@
 
 //! Bindings to create devices and access device functionality from Rust.
 
-use std::ffi::CStr;
+use std::{ffi::CStr, ptr::NonNull};
 
 pub use bindings::{DeviceClass, DeviceState, Property};
 
@@ -55,9 +55,8 @@ pub trait DeviceImpl {
 /// can be downcasted to type `T`. We also expect the device is
 /// readable/writeable from one thread at any time.
 unsafe extern "C" fn rust_realize_fn<T: DeviceImpl>(dev: *mut DeviceState, _errp: *mut *mut Error) {
-    assert!(!dev.is_null());
-    let state = dev.cast::<T>();
-    T::REALIZE.unwrap()(unsafe { &mut *state });
+    let state = NonNull::new(dev).unwrap().cast::<T>();
+    T::REALIZE.unwrap()(unsafe { state.as_ref() });
 }
 
 /// # Safety
@@ -66,9 +65,8 @@ unsafe extern "C" fn rust_realize_fn<T: DeviceImpl>(dev: *mut DeviceState, _errp
 /// can be downcasted to type `T`. We also expect the device is
 /// readable/writeable from one thread at any time.
 unsafe extern "C" fn rust_reset_fn<T: DeviceImpl>(dev: *mut DeviceState) {
-    assert!(!dev.is_null());
-    let state = dev.cast::<T>();
-    T::RESET.unwrap()(unsafe { &mut *state });
+    let mut state = NonNull::new(dev).unwrap().cast::<T>();
+    T::RESET.unwrap()(unsafe { state.as_mut() });
 }
 
 impl<T> ClassInitImpl<DeviceClass> for T
diff --git a/rust/qemu-api/src/qom.rs b/rust/qemu-api/src/qom.rs
index 97901fb..f50ee37 100644
--- a/rust/qemu-api/src/qom.rs
+++ b/rust/qemu-api/src/qom.rs
@@ -58,6 +58,7 @@ use std::{
     fmt,
     ops::{Deref, DerefMut},
     os::raw::c_void,
+    ptr::NonNull,
 };
 
 pub use bindings::{Object, ObjectClass};
@@ -153,27 +154,34 @@ impl<T: fmt::Display + ObjectType> fmt::Display for ParentField<T> {
 }
 
 unsafe extern "C" fn rust_instance_init<T: ObjectImpl>(obj: *mut Object) {
+    let mut state = NonNull::new(obj).unwrap().cast::<T>();
     // SAFETY: obj is an instance of T, since rust_instance_init<T>
     // is called from QOM core as the instance_init function
     // for class T
-    unsafe { T::INSTANCE_INIT.unwrap()(&mut *obj.cast::<T>()) }
+    unsafe {
+        T::INSTANCE_INIT.unwrap()(state.as_mut());
+    }
 }
 
 unsafe extern "C" fn rust_instance_post_init<T: ObjectImpl>(obj: *mut Object) {
+    let state = NonNull::new(obj).unwrap().cast::<T>();
     // SAFETY: obj is an instance of T, since rust_instance_post_init<T>
     // is called from QOM core as the instance_post_init function
     // for class T
-    T::INSTANCE_POST_INIT.unwrap()(unsafe { &*obj.cast::<T>() })
+    T::INSTANCE_POST_INIT.unwrap()(unsafe { state.as_ref() });
 }
 
 unsafe extern "C" fn rust_class_init<T: ObjectType + ClassInitImpl<T::Class>>(
     klass: *mut ObjectClass,
     _data: *mut c_void,
 ) {
+    let mut klass = NonNull::new(klass)
+        .unwrap()
+        .cast::<<T as ObjectType>::Class>();
     // SAFETY: klass is a T::Class, since rust_class_init<T>
     // is called from QOM core as the class_init function
     // for class T
-    T::class_init(unsafe { &mut *klass.cast::<T::Class>() })
+    T::class_init(unsafe { klass.as_mut() })
 }
 
 unsafe extern "C" fn drop_object<T: ObjectImpl>(obj: *mut Object) {
@@ -581,11 +589,8 @@ pub trait ClassInitImpl<T> {
 /// can be downcasted to type `T`. We also expect the device is
 /// readable/writeable from one thread at any time.
 unsafe extern "C" fn rust_unparent_fn<T: ObjectImpl>(dev: *mut Object) {
-    unsafe {
-        assert!(!dev.is_null());
-        let state = core::ptr::NonNull::new_unchecked(dev.cast::<T>());
-        T::UNPARENT.unwrap()(state.as_ref());
-    }
+    let state = NonNull::new(dev).unwrap().cast::<T>();
+    T::UNPARENT.unwrap()(unsafe { state.as_ref() });
 }
 
 impl<T> ClassInitImpl<ObjectClass> for T
-- 
cgit v1.1


From af7edb1d326de0af565b48c663163c7e5050e03c Mon Sep 17 00:00:00 2001
From: Paolo Bonzini <pbonzini@redhat.com>
Date: Mon, 2 Dec 2024 12:40:18 +0100
Subject: rust: qdev: make reset take a shared reference

Because register reset is within a borrow_mut() call, reset
does not need anymore a mut reference to the PL011State.

Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 rust/qemu-api/src/qdev.rs | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

(limited to 'rust/qemu-api/src')

diff --git a/rust/qemu-api/src/qdev.rs b/rust/qemu-api/src/qdev.rs
index 4242990..f4c75c7 100644
--- a/rust/qemu-api/src/qdev.rs
+++ b/rust/qemu-api/src/qdev.rs
@@ -30,7 +30,7 @@ pub trait DeviceImpl {
     ///
     /// Rust does not yet support the three-phase reset protocol; this is
     /// usually okay for leaf classes.
-    const RESET: Option<fn(&mut Self)> = None;
+    const RESET: Option<fn(&Self)> = None;
 
     /// An array providing the properties that the user can set on the
     /// device.  Not a `const` because referencing statics in constants
-- 
cgit v1.1


From aaf3778baaa6408460ec6e6636babbdf0b92c101 Mon Sep 17 00:00:00 2001
From: Zhao Liu <zhao1.liu@intel.com>
Date: Thu, 23 Jan 2025 19:07:28 +0100
Subject: rust/zeroable: Implement Zeroable with const_zero macro

The `const_zero` crate provides a nice macro to zero type-specific
constants, which doesn't need to enumerates the fields one by one.

Introduce the `const_zero` macro to QEMU (along with its documentation), and
use it to simplify the implementation of `Zeroable` trait.

Suggested-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
Link: https://lore.kernel.org/r/20250123163143.679841-1-zhao1.liu@intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 rust/qemu-api/src/zeroable.rs | 137 +++++++++++++++++++-----------------------
 1 file changed, 61 insertions(+), 76 deletions(-)

(limited to 'rust/qemu-api/src')

diff --git a/rust/qemu-api/src/zeroable.rs b/rust/qemu-api/src/zeroable.rs
index 57cac96..7b04947 100644
--- a/rust/qemu-api/src/zeroable.rs
+++ b/rust/qemu-api/src/zeroable.rs
@@ -1,13 +1,11 @@
 // 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:
 ///
 /// ```
-/// pub unsafe trait Zeroable: Default {
+/// pub unsafe trait Zeroable {
 ///     const ZERO: Self = unsafe { ::core::mem::MaybeUninit::<Self>::zeroed().assume_init() };
 /// }
 /// ```
@@ -29,23 +27,61 @@ pub unsafe trait Zeroable: Default {
     const ZERO: Self;
 }
 
-unsafe impl Zeroable for crate::bindings::Property__bindgen_ty_1 {
-    const ZERO: Self = Self { i: 0 };
+/// A macro that acts similarly to [`core::mem::zeroed()`], only is const
+///
+/// ## Safety
+///
+/// Similar to `core::mem::zeroed()`, except this zeroes padding bits. Zeroed
+/// padding usually isn't relevant to safety, but might be if a C union is used.
+///
+/// Just like for `core::mem::zeroed()`, an all zero byte pattern might not
+/// be a valid value for a type, as is the case for references `&T` and `&mut
+/// T`. Reference types trigger a (denied by default) lint and cause immediate
+/// undefined behavior if the lint is ignored
+///
+/// ```rust compile_fail
+/// use const_zero::const_zero;
+/// // error: any use of this value will cause an error
+/// // note: `#[deny(const_err)]` on by default
+/// const STR: &str = unsafe{const_zero!(&'static str)};
+/// ```
+///
+/// `const_zero` does not work on unsized types:
+///
+/// ```rust compile_fail
+/// use const_zero::const_zero;
+/// // error[E0277]: the size for values of type `[u8]` cannot be known at compilation time
+/// const BYTES: [u8] = unsafe{const_zero!([u8])};
+/// ```
+/// ## Differences with `core::mem::zeroed`
+///
+/// `const_zero` zeroes padding bits, while `core::mem::zeroed` doesn't
+macro_rules! const_zero {
+    // This macro to produce a type-generic zero constant is taken from the
+    // const_zero crate (v0.1.1):
+    //
+    //     https://docs.rs/const-zero/latest/src/const_zero/lib.rs.html
+    //
+    // and used under MIT license
+    ($type_:ty) => {{
+        const TYPE_SIZE: ::core::primitive::usize = ::core::mem::size_of::<$type_>();
+        union TypeAsBytes {
+            bytes: [::core::primitive::u8; TYPE_SIZE],
+            inner: ::core::mem::ManuallyDrop<$type_>,
+        }
+        const ZERO_BYTES: TypeAsBytes = TypeAsBytes {
+            bytes: [0; TYPE_SIZE],
+        };
+        ::core::mem::ManuallyDrop::<$type_>::into_inner(ZERO_BYTES.inner)
+    }};
 }
 
-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(),
+/// A wrapper to implement the `Zeroable` trait through the `const_zero` macro.
+macro_rules! impl_zeroable {
+    ($type:ty) => {
+        unsafe impl Zeroable for $type {
+            const ZERO: Self = unsafe { const_zero!($type) };
+        }
     };
 }
 
@@ -57,61 +93,10 @@ impl Default for crate::bindings::VMStateFlags {
     }
 }
 
-unsafe impl Zeroable for crate::bindings::VMStateFlags {
-    const ZERO: Self = Self(0);
-}
-
-unsafe impl Zeroable for crate::bindings::VMStateField {
-    const ZERO: Self = Self {
-        name: ptr::null(),
-        err_hint: ptr::null(),
-        offset: 0,
-        size: 0,
-        start: 0,
-        num: 0,
-        num_offset: 0,
-        size_offset: 0,
-        info: ptr::null(),
-        flags: Zeroable::ZERO,
-        vmsd: ptr::null(),
-        version_id: 0,
-        struct_version_id: 0,
-        field_exists: None,
-    };
-}
-
-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,
-    };
-}
+impl_zeroable!(crate::bindings::Property__bindgen_ty_1);
+impl_zeroable!(crate::bindings::Property);
+impl_zeroable!(crate::bindings::VMStateFlags);
+impl_zeroable!(crate::bindings::VMStateField);
+impl_zeroable!(crate::bindings::VMStateDescription);
+impl_zeroable!(crate::bindings::MemoryRegionOps__bindgen_ty_1);
+impl_zeroable!(crate::bindings::MemoryRegionOps__bindgen_ty_2);
-- 
cgit v1.1