rust: qdev: add clock creation

Add a Rust version of qdev_init_clock_in, which can be used in
instance_init.  There are a couple differences with the C
version:

- in Rust the object keeps its own reference to the clock (in addition to
  the one embedded in the NamedClockList), and the reference is dropped
  automatically by instance_finalize(); this is encoded in the signature
  of DeviceClassMethods::init_clock_in, which makes the lifetime of the
  clock independent of that of the object it holds.  This goes unnoticed
  in the C version and is due to the existence of aliases.

- also, anything that happens during instance_init uses the pinned_init
  framework to operate on a partially initialized object, and is done
  through class methods (i.e. through DeviceClassMethods rather than
  DeviceMethods) because the device does not exist yet.  Therefore, Rust
  code *must* create clocks from instance_init, which is stricter than C.

Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

1 files changed, 2 insertions, 2 deletions

diff --git a/rust/qemu-api/src/vmstate.rs b/rust/qemu-api/src/vmstate.rs
index 11d21b8791..164effc655 100644
--- a/rust/qemu-api/src/vmstate.rs
+++ b/rust/qemu-api/src/vmstate.rs
@@ -470,11 +470,11 @@ macro_rules! vmstate_clock {
                 $crate::assert_field_type!(
                     $struct_name,
                     $field_name,
-                    core::ptr::NonNull<$crate::bindings::Clock>
+                    $crate::qom::Owned<$crate::bindings::Clock>
                 );
                 $crate::offset_of!($struct_name, $field_name)
             },
-            size: ::core::mem::size_of::<*const $crate::bindings::Clock>(),
+            size: ::core::mem::size_of::<*const $crate::qdev::Clock>(),
             flags: VMStateFlags(VMStateFlags::VMS_STRUCT.0 | VMStateFlags::VMS_POINTER.0),
             vmsd: unsafe { ::core::ptr::addr_of!($crate::bindings::vmstate_clock) },
             ..$crate::zeroable::Zeroable::ZERO