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path: root/rust/qemu-api/src/vmstate.rs
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2025-02-13rust: qdev: add clock creationPaolo Bonzini1-2/+2
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>
2025-02-13rust: qom: add reference counting functionalityPaolo Bonzini1-1/+5
Add a smart pointer that allows to add and remove references from QOM objects. It's important to note that while all QOM objects have a reference count, in practice not all of them have their lifetime guarded by it. Embedded objects, specifically, are confined to the lifetime of the owner. When writing Rust bindings this is important, because embedded objects are *never* used through the "Owned<>" smart pointer that is introduced here. Reviewed-by: Zhao Liu <zhao1.liu@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2025-01-23rust: vmstate: make order of parameters consistent in vmstate_clockPaolo Bonzini1-1/+1
Place struct_name before field_name, similar to offset_of. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2025-01-23rust: vmstate: remove translation of C vmstate macrosPaolo Bonzini1-251/+23
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>
2025-01-23rust: qemu_api: add vmstate_structPaolo Bonzini1-0/+33
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>
2025-01-23rust: vmstate: add public utility macros to implement VMStatePaolo Bonzini1-3/+58
Reviewed-by: Zhao Liu <zhao1.liu@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2025-01-23rust: vmstate: implement VMState for scalar typesPaolo Bonzini1-2/+126
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>
2025-01-23rust: vmstate: implement Zeroable for VMStateFieldPaolo Bonzini1-15/+3
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>
2025-01-23rust: vmstate: add varray support to vmstate_of!Paolo Bonzini1-2/+40
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2025-01-23rust: vmstate: implement VMState for non-leaf typesPaolo Bonzini1-1/+78
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>
2025-01-23rust: vmstate: add new type safe implementationPaolo Bonzini1-6/+107
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>
2024-12-19rust: pl011: fix migration streamPaolo Bonzini1-22/+0
The Rust vmstate macros lack the type-safety of their C equivalents (so safe, much abstraction), and therefore they were predictably wrong. The registers have already been changed to 32-bits in the previous patch, but read_pos/read_count/read_trigger also have to be u32 instead of usize. The easiest way to do so is to let the FIFO use u32 indices instead of usize. My plan for making VMStateField typesafe is to have a trait to retrieve a basic VMStateField; for example something like vmstate_uint32 would become an implementation of the VMState trait on u32. Then you'd write something like "vmstate_of!(Type, field).with_version_id(2)". That is, vmstate_of retrieves the basic VMStateField and fills in the offset, and then more changes can be applied on top. Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-12-19rust: re-export C types from qemu-api submodulesPaolo Bonzini1-4/+5
Long term we do not want device code to use "bindings" at all, so make it possible to get the relevant types from the other modules of qemu-api. Reviewed-by: Zhao Liu <zhao1.liu@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-11-05rust: introduce alternative implementation of offset_of!Junjie Mao1-5/+5
offset_of! was stabilized in Rust 1.77.0. Use an alternative implemenation that was found on the Rust forums, and whose author agreed to license as MIT for use in QEMU. The alternative allows only one level of field access, but apart from this can be used just by replacing core::mem::offset_of! with qemu_api::offset_of!. The actual implementation of offset_of! is done in a declarative macro, but for simplicity and to avoid introducing an extra level of indentation, the trigger is a procedural macro #[derive(offsets)]. The procedural macro is perhaps a bit overengineered, but it helps introducing some idioms that will be useful in the future as well. Signed-off-by: Junjie Mao <junjie.mao@hotmail.com> Co-developed-by: Paolo Bonzini <pbonzini@redhat.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-11-05rust: introduce a c_str macroPaolo Bonzini1-1/+1
This allows CStr constants to be defined easily on Rust 1.63.0, while checking that there are no embedded NULs. c"" literals were only stabilized in Rust 1.77.0. Reviewed-by: Zhao Liu <zhao1.liu@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-11-05rust: use std::os::raw instead of core::ffiPaolo Bonzini1-5/+5
core::ffi::c_* types were introduced in Rust 1.64.0. Use the older types in std::os::raw, which are now aliases of the types in core::ffi. There is no need to compile QEMU as no_std, so this is acceptable as long as we support a version of Debian with Rust 1.63.0. Reviewed-by: Zhao Liu <zhao1.liu@intel.com> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-11-05rust: add definitions for vmstateManos Pitsidianakis1-0/+360
Add a new qemu_api module, `vmstate`. Declare a bunch of Rust macros declared that are equivalent in spirit to the C macros in include/migration/vmstate.h. For example the Rust of equivalent of the C macro: VMSTATE_UINT32(field_name, struct_name) is: vmstate_uint32!(field_name, StructName) This breathtaking development will allow us to reach feature parity between the Rust and C pl011 implementations. Extracted from a patch by Manos Pitsidianakis (https://lore.kernel.org/qemu-devel/20241024-rust-round-2-v1-4-051e7a25b978@linaro.org/). Signed-off-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org> Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>