On 1/22/25 13:33, Zhao Liu wrote:
On Fri, Jan 17, 2025 at 10:00:41AM +0100, Paolo Bonzini wrote:
Date: Fri, 17 Jan 2025 10:00:41 +0100
From: Paolo Bonzini <pbonz...@redhat.com>
Subject: [PATCH 05/10] rust: vmstate: implement VMState for scalar types
X-Mailer: git-send-email 2.47.1
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 <pbonz...@redhat.com>
---
rust/qemu-api/src/vmstate.rs | 128 ++++++++++++++++++++++++++++++++++-
1 file changed, 126 insertions(+), 2 deletions(-)
/// 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>) -> VMStateField
/// 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 to any of the above, possibly wrapped with `Option`
I just found your rust-next has already updated and removed `Option` :-)
+/// * 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.
Rebase mistake? This comment seems no need to be deleted.
It's moved below because there's now more than one call_func_with_field
call. I can make it so that the phrasing and placement remains the same
throughout the series.
Paolo
$(.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
+ )),
Only a nit above,
Reviewed-by: Zhao Liu <zhao1....@intel.com>
