| 1 | // Copyright 2024, Linaro Limited |
| 2 | // Author(s): Manos Pitsidianakis <manos.pitsidianakis@linaro.org> |
| 3 | // SPDX-License-Identifier: GPL-2.0-or-later |
| 4 | |
| 5 | //! Helper macros to declare migration state for device models. |
| 6 | //! |
| 7 | //! This module includes four families of macros: |
| 8 | //! |
| 9 | //! * [`vmstate_unused!`](crate::vmstate_unused) and |
| 10 | //! [`vmstate_of!`](crate::vmstate_of), which are used to express the |
| 11 | //! migration format for a struct. This is based on the [`VMState`] trait, |
| 12 | //! which is defined by all migratable types. |
| 13 | //! |
| 14 | //! * [`impl_vmstate_forward`](crate::impl_vmstate_forward) and |
| 15 | //! [`impl_vmstate_struct`](crate::impl_vmstate_struct), which help with the |
| 16 | //! definition of the [`VMState`] trait (respectively for transparent structs, |
| 17 | //! nested structs and `bilge`-defined types) |
| 18 | //! |
| 19 | //! * helper macros to declare a device model state struct, in particular |
| 20 | //! [`vmstate_subsections`](crate::vmstate_subsections) and |
| 21 | //! [`vmstate_fields`](crate::vmstate_fields). |
| 22 | //! |
| 23 | //! * direct equivalents to the C macros declared in |
| 24 | //! `include/migration/vmstate.h`. These are not type-safe and only provide |
| 25 | //! functionality that is missing from `vmstate_of!`. |
| 26 | |
| 27 | pub use std::convert::Infallible; |
| 28 | use std::{ |
| 29 | error::Error, |
| 30 | ffi::{c_int, c_void, CStr}, |
| 31 | fmt, io, |
| 32 | marker::PhantomData, |
| 33 | mem, |
| 34 | ptr::{addr_of, NonNull}, |
| 35 | }; |
| 36 | |
| 37 | use common::{ |
| 38 | callbacks::FnCall, |
| 39 | errno::{into_neg_errno, Errno}, |
| 40 | Zeroable, |
| 41 | }; |
| 42 | |
| 43 | use crate::bindings::{self, VMStateFlags}; |
| 44 | pub use crate::bindings::{MigrationPriority, VMStateField, VMStateStructMember}; |
| 45 | |
| 46 | /// This macro is used to call a function with a generic argument bound |
| 47 | /// to the type of a field. The function must take a |
| 48 | /// [`PhantomData`]`<T>` argument; `T` is the type of |
| 49 | /// field `$field` in the `$typ` type. |
| 50 | /// |
| 51 | /// # Examples |
| 52 | /// |
| 53 | /// ``` |
| 54 | /// # use migration::call_func_with_field; |
| 55 | /// # use core::marker::PhantomData; |
| 56 | /// const fn size_of_field<T>(_: PhantomData<T>) -> usize { |
| 57 | /// std::mem::size_of::<T>() |
| 58 | /// } |
| 59 | /// |
| 60 | /// struct Foo { |
| 61 | /// x: u16, |
| 62 | /// }; |
| 63 | /// // calls size_of_field::<u16>() |
| 64 | /// assert_eq!(call_func_with_field!(size_of_field, Foo, x), 2); |
| 65 | /// ``` |
| 66 | #[macro_export] |
| 67 | macro_rules! call_func_with_field { |
| 68 | // Based on the answer by user steffahn (Frank Steffahn) at |
| 69 | // https://users.rust-lang.org/t/inferring-type-of-field/122857 |
| 70 | // and used under MIT license |
| 71 | ($func:expr, $typ:ty, $($field:tt).+) => { |
| 72 | $func(loop { |
| 73 | #![allow(unreachable_code)] |
| 74 | #![allow(unused_variables)] |
| 75 | const fn phantom__<T>(_: &T) -> ::core::marker::PhantomData<T> { ::core::marker::PhantomData } |
| 76 | // Unreachable code is exempt from checks on uninitialized values. |
| 77 | // Use that trick to infer the type of this PhantomData. |
| 78 | break ::core::marker::PhantomData; |
| 79 | break phantom__(&{ let value__: $typ; value__.$($field).+ }); |
| 80 | }) |
| 81 | }; |
| 82 | } |
| 83 | |
| 84 | /// A trait for types that can be included in a device's migration stream. It |
| 85 | /// provides the base contents of a `VMStateField` (minus the name and offset). |
| 86 | /// |
| 87 | /// # Safety |
| 88 | /// |
| 89 | /// The contents of this trait go straight into structs that are parsed by C |
| 90 | /// code and used to introspect into other structs. Generally, you don't need |
| 91 | /// to implement it except via macros that do it for you, such as |
| 92 | /// `impl_vmstate_forward!`. |
| 93 | pub unsafe trait VMState { |
| 94 | /// The base contents of a `VMStateField` (minus the name and offset) for |
| 95 | /// the type that is implementing the trait. |
| 96 | const BASE: VMStateField; |
| 97 | |
| 98 | /// A flag that is added to another field's `VMStateField` to specify the |
| 99 | /// length's type in a variable-sized array. If this is not a supported |
| 100 | /// type for the length (i.e. if it is not `u8`, `u16`, `u32`), using it |
| 101 | /// in a call to [`vmstate_of!`](crate::vmstate_of) will cause a |
| 102 | /// compile-time error. |
| 103 | #[doc(hidden)] // https://github.com/rust-lang/rust/issues/149635 |
| 104 | const VARRAY_FLAG: VMStateFlags = { |
| 105 | panic!("invalid type for variable-sized array"); |
| 106 | }; |
| 107 | } |
| 108 | |
| 109 | /// Internal utility function to retrieve a type's `VMStateField`; |
| 110 | /// used by [`vmstate_of!`](crate::vmstate_of). |
| 111 | pub const fn vmstate_base<T: VMState>(_: PhantomData<T>) -> VMStateField { |
| 112 | T::BASE |
| 113 | } |
| 114 | |
| 115 | /// Internal utility function to retrieve a type's `VMStateFlags` when it |
| 116 | /// is used as the element count of a `VMSTATE_VARRAY`; used by |
| 117 | /// [`vmstate_of!`](crate::vmstate_of). |
| 118 | pub const fn vmstate_varray_flag<T: VMState>(_: PhantomData<T>) -> VMStateFlags { |
| 119 | T::VARRAY_FLAG |
| 120 | } |
| 121 | |
| 122 | pub const OPAQUE: &[u8; 1048576] = &[0; 1048576]; |
| 123 | |
| 124 | pub const fn size_of_ptr_type<T>(_: *const T) -> usize { |
| 125 | ::core::mem::size_of::<T>() |
| 126 | } |
| 127 | |
| 128 | #[macro_export] |
| 129 | macro_rules! size_of_field_type { |
| 130 | ($struct_name:ty, $($field_name:ident).+) => { |
| 131 | $crate::vmstate::size_of_ptr_type(unsafe { |
| 132 | ::core::ptr::addr_of!( |
| 133 | (*$crate::vmstate::OPAQUE.as_ptr().cast::<$struct_name>()).$($field_name).+ |
| 134 | ) |
| 135 | }) |
| 136 | }; |
| 137 | } |
| 138 | |
| 139 | /// Return the `VMStateField` for a field of a struct. The field must be |
| 140 | /// visible in the current scope. |
| 141 | /// |
| 142 | /// Only a limited set of types is supported out of the box: |
| 143 | /// * scalar types (integer and `bool`) |
| 144 | /// * the C struct `QEMUTimer` |
| 145 | /// * a transparent wrapper for any of the above (`Cell`, `UnsafeCell`, |
| 146 | /// [`BqlCell`], [`BqlRefCell`]) |
| 147 | /// * a raw pointer to any of the above |
| 148 | /// * a `NonNull` pointer, a `Box` or an [`Owned`] for any of the above |
| 149 | /// * an array of any of the above |
| 150 | /// |
| 151 | /// In order to support other types, the trait `VMState` must be implemented |
| 152 | /// for them. The macros [`impl_vmstate_forward`](crate::impl_vmstate_forward) |
| 153 | /// and [`impl_vmstate_struct`](crate::impl_vmstate_struct) help with this. |
| 154 | /// |
| 155 | /// [`BqlCell`]: ../../bql/cell/struct.BqlCell.html |
| 156 | /// [`BqlRefCell`]: ../../bql/cell/struct.BqlRefCell.html |
| 157 | /// [`Owned`]: ../../qom/qom/struct.Owned.html |
| 158 | #[macro_export] |
| 159 | macro_rules! vmstate_of { |
| 160 | ($struct_name:ty, $($field_name:ident).+ $([0 .. $($num:ident).+ $(* $factor:expr)?])? $(, $test_fn:expr)? $(,)?) => { |
| 161 | $crate::bindings::VMStateField { |
| 162 | name: ::core::concat!(::core::stringify!($($field_name).+), "\0") |
| 163 | .as_bytes() |
| 164 | .as_ptr().cast::<::std::os::raw::c_char>(), |
| 165 | offset: ::std::mem::offset_of!($struct_name, $($field_name).+), |
| 166 | $(num_indirect: $crate::vmstate::VMStateStructMember { |
| 167 | offset: ::std::mem::offset_of!($struct_name, $($num).+) as u32, |
| 168 | size: $crate::size_of_field_type!($struct_name, $($num).+) as u8, |
| 169 | },)? |
| 170 | $(field_exists: $crate::vmstate_exist_fn!($struct_name, $test_fn),)? |
| 171 | // The calls to `call_func_with_field!` are the magic that |
| 172 | // computes most of the VMStateField from the type of the field. |
| 173 | ..$crate::call_func_with_field!( |
| 174 | $crate::vmstate::vmstate_base, |
| 175 | $struct_name, |
| 176 | $($field_name).+ |
| 177 | )$(.with_varray_flag($crate::call_func_with_field!( |
| 178 | $crate::vmstate::vmstate_varray_flag, |
| 179 | $struct_name, |
| 180 | $($num).+)))? |
| 181 | } |
| 182 | }; |
| 183 | } |
| 184 | |
| 185 | /// This macro can be used (by just passing it a type) to forward the `VMState` |
| 186 | /// trait to the first field of a tuple. This is a workaround for lack of |
| 187 | /// support of nested [`offset_of`](core::mem::offset_of) until Rust 1.82.0. |
| 188 | /// |
| 189 | /// # Examples |
| 190 | /// |
| 191 | /// ``` |
| 192 | /// # use migration::impl_vmstate_forward; |
| 193 | /// pub struct Fifo([u8; 16]); |
| 194 | /// impl_vmstate_forward!(Fifo); |
| 195 | /// ``` |
| 196 | #[macro_export] |
| 197 | macro_rules! impl_vmstate_forward { |
| 198 | // This is similar to impl_vmstate_transparent below, but it |
| 199 | // uses the same trick as vmstate_of! to obtain the type of |
| 200 | // the first field of the tuple |
| 201 | ($tuple:ty) => { |
| 202 | unsafe impl $crate::vmstate::VMState for $tuple { |
| 203 | const BASE: $crate::bindings::VMStateField = |
| 204 | $crate::call_func_with_field!($crate::vmstate::vmstate_base, $tuple, 0); |
| 205 | } |
| 206 | }; |
| 207 | } |
| 208 | |
| 209 | // Transparent wrappers: just use the internal type |
| 210 | |
| 211 | #[macro_export] |
| 212 | macro_rules! impl_vmstate_transparent { |
| 213 | ($type:ty where $base:tt: VMState $($where:tt)*) => { |
| 214 | unsafe impl<$base> $crate::vmstate::VMState for $type where $base: $crate::vmstate::VMState $($where)* { |
| 215 | const BASE: $crate::vmstate::VMStateField = $crate::vmstate::VMStateField { |
| 216 | size: ::core::mem::size_of::<$type>(), |
| 217 | ..<$base as $crate::vmstate::VMState>::BASE |
| 218 | }; |
| 219 | const VARRAY_FLAG: $crate::bindings::VMStateFlags = <$base as $crate::vmstate::VMState>::VARRAY_FLAG; |
| 220 | } |
| 221 | }; |
| 222 | } |
| 223 | |
| 224 | impl_vmstate_transparent!(bql::BqlCell<T> where T: VMState); |
| 225 | impl_vmstate_transparent!(bql::BqlRefCell<T> where T: VMState); |
| 226 | impl_vmstate_transparent!(std::cell::Cell<T> where T: VMState); |
| 227 | impl_vmstate_transparent!(std::cell::UnsafeCell<T> where T: VMState); |
| 228 | impl_vmstate_transparent!(std::pin::Pin<T> where T: VMState); |
| 229 | impl_vmstate_transparent!(common::Opaque<T> where T: VMState); |
| 230 | impl_vmstate_transparent!(std::mem::ManuallyDrop<T> where T: VMState); |
| 231 | |
| 232 | // Scalar types using predefined VMStateInfos |
| 233 | |
| 234 | macro_rules! impl_vmstate_scalar { |
| 235 | ($info:ident, $type:ty$(, $varray_flag:ident)?) => { |
| 236 | unsafe impl $crate::vmstate::VMState for $type { |
| 237 | const BASE: $crate::vmstate::VMStateField = $crate::vmstate::VMStateField { |
| 238 | info: addr_of!(bindings::$info), |
| 239 | size: mem::size_of::<$type>(), |
| 240 | flags: $crate::vmstate::VMStateFlags::VMS_SINGLE, |
| 241 | ..::common::zeroable::Zeroable::ZERO |
| 242 | }; |
| 243 | $(const VARRAY_FLAG: VMStateFlags = VMStateFlags::$varray_flag;)? |
| 244 | } |
| 245 | }; |
| 246 | } |
| 247 | |
| 248 | impl_vmstate_scalar!(vmstate_info_bool, bool); |
| 249 | impl_vmstate_scalar!(vmstate_info_int8, i8); |
| 250 | impl_vmstate_scalar!(vmstate_info_int16, i16); |
| 251 | impl_vmstate_scalar!(vmstate_info_int32, i32); |
| 252 | impl_vmstate_scalar!(vmstate_info_int64, i64); |
| 253 | impl_vmstate_scalar!(vmstate_info_uint8, u8, VMS_VARRAY); |
| 254 | impl_vmstate_scalar!(vmstate_info_uint16, u16, VMS_VARRAY); |
| 255 | impl_vmstate_scalar!(vmstate_info_uint32, u32, VMS_VARRAY); |
| 256 | impl_vmstate_scalar!(vmstate_info_uint64, u64); |
| 257 | impl_vmstate_scalar!(vmstate_info_timer, util::timer::Timer); |
| 258 | |
| 259 | #[macro_export] |
| 260 | macro_rules! impl_vmstate_c_struct { |
| 261 | ($type:ty, $vmsd:expr) => { |
| 262 | unsafe impl $crate::vmstate::VMState for $type { |
| 263 | const BASE: $crate::bindings::VMStateField = $crate::bindings::VMStateField { |
| 264 | vmsd: ::std::ptr::addr_of!($vmsd), |
| 265 | size: ::std::mem::size_of::<$type>(), |
| 266 | flags: $crate::bindings::VMStateFlags::VMS_STRUCT, |
| 267 | ..::common::zeroable::Zeroable::ZERO |
| 268 | }; |
| 269 | } |
| 270 | }; |
| 271 | } |
| 272 | |
| 273 | // Pointer types using the underlying type's VMState plus VMS_POINTER |
| 274 | // Note that references are not supported, though references to cells |
| 275 | // could be allowed. |
| 276 | |
| 277 | #[macro_export] |
| 278 | macro_rules! impl_vmstate_pointer { |
| 279 | ($type:ty where $base:tt: VMState $($where:tt)*) => { |
| 280 | unsafe impl<$base> $crate::vmstate::VMState for $type where $base: $crate::vmstate::VMState $($where)* { |
| 281 | const BASE: $crate::vmstate::VMStateField = <$base as $crate::vmstate::VMState>::BASE.with_pointer_flag(); |
| 282 | } |
| 283 | }; |
| 284 | } |
| 285 | |
| 286 | impl_vmstate_pointer!(*const T where T: VMState); |
| 287 | impl_vmstate_pointer!(*mut T where T: VMState); |
| 288 | impl_vmstate_pointer!(NonNull<T> where T: VMState); |
| 289 | |
| 290 | // Unlike C pointers, Box is always non-null therefore there is no need |
| 291 | // to specify VMS_ALLOC. |
| 292 | impl_vmstate_pointer!(Box<T> where T: VMState); |
| 293 | |
| 294 | // Arrays using the underlying type's VMState plus |
| 295 | // VMS_ARRAY/VMS_ARRAY_OF_POINTER |
| 296 | |
| 297 | unsafe impl<T: VMState, const N: usize> VMState for [T; N] { |
| 298 | const BASE: VMStateField = <T as VMState>::BASE.with_array_flag(N); |
| 299 | } |
| 300 | |
| 301 | #[doc(alias = "VMSTATE_UNUSED")] |
| 302 | #[macro_export] |
| 303 | macro_rules! vmstate_unused { |
| 304 | ($size:expr) => {{ |
| 305 | $crate::bindings::VMStateField { |
| 306 | name: c"unused".as_ptr(), |
| 307 | size: $size, |
| 308 | info: unsafe { ::core::ptr::addr_of!($crate::bindings::vmstate_info_unused_buffer) }, |
| 309 | flags: $crate::bindings::VMStateFlags::VMS_BUFFER, |
| 310 | ..::common::Zeroable::ZERO |
| 311 | } |
| 312 | }}; |
| 313 | } |
| 314 | |
| 315 | pub extern "C" fn rust_vms_test_field_exists<T, F: for<'a> FnCall<(&'a T, u8), bool>>( |
| 316 | opaque: *mut c_void, |
| 317 | version_id: c_int, |
| 318 | ) -> bool { |
| 319 | // SAFETY: the function is used in T's implementation of VMState |
| 320 | let owner: &T = unsafe { &*(opaque.cast::<T>()) }; |
| 321 | let version: u8 = version_id.try_into().unwrap(); |
| 322 | F::call((owner, version)) |
| 323 | } |
| 324 | |
| 325 | pub type VMSFieldExistCb = unsafe extern "C" fn( |
| 326 | opaque: *mut std::os::raw::c_void, |
| 327 | version_id: std::os::raw::c_int, |
| 328 | ) -> bool; |
| 329 | |
| 330 | #[macro_export] |
| 331 | macro_rules! vmstate_exist_fn { |
| 332 | ($struct_name:ty, $test_fn:expr) => {{ |
| 333 | const fn test_cb_builder__<T, F: for<'a> ::common::FnCall<(&'a T, u8), bool>>( |
| 334 | _phantom: ::core::marker::PhantomData<F>, |
| 335 | ) -> $crate::vmstate::VMSFieldExistCb { |
| 336 | const { assert!(F::IS_SOME) }; |
| 337 | $crate::vmstate::rust_vms_test_field_exists::<T, F> |
| 338 | } |
| 339 | |
| 340 | const fn phantom__<T>(_: &T) -> ::core::marker::PhantomData<T> { |
| 341 | ::core::marker::PhantomData |
| 342 | } |
| 343 | Some(test_cb_builder__::<$struct_name, _>(phantom__(&$test_fn))) |
| 344 | }}; |
| 345 | } |
| 346 | |
| 347 | /// Add a terminator to the fields in the arguments, and return |
| 348 | /// a reference to the resulting array of values. |
| 349 | #[macro_export] |
| 350 | macro_rules! vmstate_fields_ref { |
| 351 | ($($field:expr),*$(,)*) => { |
| 352 | &[ |
| 353 | $($field),*, |
| 354 | $crate::bindings::VMStateField { |
| 355 | flags: $crate::bindings::VMStateFlags::VMS_END, |
| 356 | ..::common::zeroable::Zeroable::ZERO |
| 357 | } |
| 358 | ] |
| 359 | } |
| 360 | } |
| 361 | |
| 362 | /// Helper macro to declare a list of |
| 363 | /// ([`VMStateField`](`crate::bindings::VMStateField`)) into a static and return |
| 364 | /// a pointer to the array of values it created. |
| 365 | #[macro_export] |
| 366 | macro_rules! vmstate_fields { |
| 367 | ($($field:expr),*$(,)*) => {{ |
| 368 | static _FIELDS: &[$crate::bindings::VMStateField] = $crate::vmstate_fields_ref!( |
| 369 | $($field),*, |
| 370 | ); |
| 371 | _FIELDS |
| 372 | }} |
| 373 | } |
| 374 | |
| 375 | #[doc(alias = "VMSTATE_VALIDATE")] |
| 376 | #[macro_export] |
| 377 | macro_rules! vmstate_validate { |
| 378 | ($struct_name:ty, $test_name:expr, $test_fn:expr $(,)?) => { |
| 379 | $crate::bindings::VMStateField { |
| 380 | name: ::std::ffi::CStr::as_ptr($test_name), |
| 381 | field_exists: $crate::vmstate_exist_fn!($struct_name, $test_fn), |
| 382 | flags: $crate::bindings::VMStateFlags( |
| 383 | $crate::bindings::VMStateFlags::VMS_MUST_EXIST.0 |
| 384 | | $crate::bindings::VMStateFlags::VMS_NO_STATE.0, |
| 385 | ), |
| 386 | num: 0, // 0 elements: no data, only run test_fn callback |
| 387 | ..::common::zeroable::Zeroable::ZERO |
| 388 | } |
| 389 | }; |
| 390 | } |
| 391 | |
| 392 | /// Helper macro to allow using a struct in [`vmstate_of!`] |
| 393 | /// |
| 394 | /// # Safety |
| 395 | /// |
| 396 | /// The [`VMStateDescription`] constant `$vmsd` must be an accurate |
| 397 | /// description of the struct. |
| 398 | #[macro_export] |
| 399 | macro_rules! impl_vmstate_struct { |
| 400 | ($type:ty, $vmsd:expr) => { |
| 401 | unsafe impl $crate::vmstate::VMState for $type { |
| 402 | const BASE: $crate::bindings::VMStateField = { |
| 403 | static VMSD: &$crate::bindings::VMStateDescription = $vmsd.as_ref(); |
| 404 | |
| 405 | $crate::bindings::VMStateField { |
| 406 | vmsd: ::core::ptr::addr_of!(*VMSD), |
| 407 | size: ::core::mem::size_of::<$type>(), |
| 408 | flags: $crate::bindings::VMStateFlags::VMS_STRUCT, |
| 409 | ..common::Zeroable::ZERO |
| 410 | } |
| 411 | }; |
| 412 | } |
| 413 | }; |
| 414 | } |
| 415 | |
| 416 | /// The type returned by [`vmstate_subsections!`](crate::vmstate_subsections). |
| 417 | pub type VMStateSubsections = &'static [Option<&'static crate::bindings::VMStateDescription>]; |
| 418 | |
| 419 | /// Helper macro to declare a list of subsections ([`VMStateDescription`]) |
| 420 | /// into a static and return a pointer to the array of pointers it created. |
| 421 | #[macro_export] |
| 422 | macro_rules! vmstate_subsections { |
| 423 | ($($subsection:expr),*$(,)*) => {{ |
| 424 | static _SUBSECTIONS: $crate::vmstate::VMStateSubsections = &[ |
| 425 | $({ |
| 426 | static _SUBSECTION: $crate::bindings::VMStateDescription = $subsection.get(); |
| 427 | Some(&_SUBSECTION) |
| 428 | }),*, |
| 429 | None, |
| 430 | ]; |
| 431 | &_SUBSECTIONS |
| 432 | }} |
| 433 | } |
| 434 | |
| 435 | pub struct VMStateDescription<T>(bindings::VMStateDescription, PhantomData<fn(&T)>); |
| 436 | |
| 437 | // SAFETY: When a *const T is passed to the callbacks, the call itself |
| 438 | // is done in a thread-safe manner. The invocation is okay as long as |
| 439 | // T itself is `Sync`. |
| 440 | unsafe impl<T: Sync> Sync for VMStateDescription<T> {} |
| 441 | |
| 442 | #[derive(Clone)] |
| 443 | pub struct VMStateDescriptionBuilder<T>( |
| 444 | bindings::VMStateDescription, |
| 445 | Option<*const std::os::raw::c_char>, // the name of VMStateDescription |
| 446 | PhantomData<fn(&T)>, |
| 447 | ); |
| 448 | |
| 449 | #[derive(Debug)] |
| 450 | pub struct InvalidError; |
| 451 | |
| 452 | impl Error for InvalidError {} |
| 453 | |
| 454 | impl std::fmt::Display for InvalidError { |
| 455 | fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { |
| 456 | write!(f, "invalid migration data") |
| 457 | } |
| 458 | } |
| 459 | |
| 460 | impl From<InvalidError> for Errno { |
| 461 | fn from(_value: InvalidError) -> Errno { |
| 462 | io::ErrorKind::InvalidInput.into() |
| 463 | } |
| 464 | } |
| 465 | |
| 466 | unsafe extern "C" fn vmstate_no_version_cb< |
| 467 | T, |
| 468 | F: for<'a> FnCall<(&'a T,), Result<(), impl Into<Errno>>>, |
| 469 | >( |
| 470 | opaque: *mut c_void, |
| 471 | ) -> c_int { |
| 472 | // SAFETY: the function is used in T's implementation of VMState |
| 473 | let result = F::call((unsafe { &*(opaque.cast::<T>()) },)); |
| 474 | into_neg_errno(result) |
| 475 | } |
| 476 | |
| 477 | unsafe extern "C" fn vmstate_post_save_cb<T, F: for<'a> FnCall<(&'a T,), ()>>(opaque: *mut c_void) { |
| 478 | // SAFETY: the function is used in T's implementation of VMState. |
| 479 | F::call((unsafe { &*(opaque.cast::<T>()) },)); |
| 480 | } |
| 481 | |
| 482 | unsafe extern "C" fn vmstate_post_load_cb< |
| 483 | T, |
| 484 | F: for<'a> FnCall<(&'a T, u8), Result<(), impl Into<Errno>>>, |
| 485 | >( |
| 486 | opaque: *mut c_void, |
| 487 | version_id: c_int, |
| 488 | ) -> c_int { |
| 489 | // SAFETY: the function is used in T's implementation of VMState |
| 490 | let owner: &T = unsafe { &*(opaque.cast::<T>()) }; |
| 491 | let version: u8 = version_id.try_into().unwrap(); |
| 492 | let result = F::call((owner, version)); |
| 493 | into_neg_errno(result) |
| 494 | } |
| 495 | |
| 496 | unsafe extern "C" fn vmstate_needed_cb<T, F: for<'a> FnCall<(&'a T,), bool>>( |
| 497 | opaque: *mut c_void, |
| 498 | ) -> bool { |
| 499 | // SAFETY: the function is used in T's implementation of VMState |
| 500 | F::call((unsafe { &*(opaque.cast::<T>()) },)) |
| 501 | } |
| 502 | |
| 503 | unsafe extern "C" fn vmstate_dev_unplug_pending_cb<T, F: for<'a> FnCall<(&'a T,), bool>>( |
| 504 | opaque: *mut c_void, |
| 505 | ) -> bool { |
| 506 | // SAFETY: the function is used in T's implementation of VMState |
| 507 | F::call((unsafe { &*(opaque.cast::<T>()) },)) |
| 508 | } |
| 509 | |
| 510 | impl<T> VMStateDescriptionBuilder<T> { |
| 511 | #[must_use] |
| 512 | pub const fn name(mut self, name_str: &CStr) -> Self { |
| 513 | self.1 = Some(::std::ffi::CStr::as_ptr(name_str)); |
| 514 | self |
| 515 | } |
| 516 | |
| 517 | #[must_use] |
| 518 | pub const fn unmigratable(mut self) -> Self { |
| 519 | self.0.unmigratable = true; |
| 520 | self |
| 521 | } |
| 522 | |
| 523 | #[must_use] |
| 524 | pub const fn early_setup(mut self) -> Self { |
| 525 | self.0.early_setup = true; |
| 526 | self |
| 527 | } |
| 528 | |
| 529 | #[must_use] |
| 530 | pub const fn version_id(mut self, version: u8) -> Self { |
| 531 | self.0.version_id = version as c_int; |
| 532 | self |
| 533 | } |
| 534 | |
| 535 | #[must_use] |
| 536 | pub const fn minimum_version_id(mut self, min_version: u8) -> Self { |
| 537 | self.0.minimum_version_id = min_version as c_int; |
| 538 | self |
| 539 | } |
| 540 | |
| 541 | #[must_use] |
| 542 | pub const fn priority(mut self, priority: MigrationPriority) -> Self { |
| 543 | self.0.priority = priority; |
| 544 | self |
| 545 | } |
| 546 | |
| 547 | #[must_use] |
| 548 | pub const fn pre_load<F: for<'a> FnCall<(&'a T,), Result<(), impl Into<Errno>>>>( |
| 549 | mut self, |
| 550 | _f: &F, |
| 551 | ) -> Self { |
| 552 | self.0.pre_load = if F::IS_SOME { |
| 553 | Some(vmstate_no_version_cb::<T, F>) |
| 554 | } else { |
| 555 | None |
| 556 | }; |
| 557 | self |
| 558 | } |
| 559 | |
| 560 | #[must_use] |
| 561 | pub const fn post_load<F: for<'a> FnCall<(&'a T, u8), Result<(), impl Into<Errno>>>>( |
| 562 | mut self, |
| 563 | _f: &F, |
| 564 | ) -> Self { |
| 565 | self.0.post_load = if F::IS_SOME { |
| 566 | Some(vmstate_post_load_cb::<T, F>) |
| 567 | } else { |
| 568 | None |
| 569 | }; |
| 570 | self |
| 571 | } |
| 572 | |
| 573 | #[must_use] |
| 574 | pub const fn pre_save<F: for<'a> FnCall<(&'a T,), Result<(), impl Into<Errno>>>>( |
| 575 | mut self, |
| 576 | _f: &F, |
| 577 | ) -> Self { |
| 578 | self.0.pre_save = if F::IS_SOME { |
| 579 | Some(vmstate_no_version_cb::<T, F>) |
| 580 | } else { |
| 581 | None |
| 582 | }; |
| 583 | self |
| 584 | } |
| 585 | |
| 586 | #[must_use] |
| 587 | pub const fn post_save<F: for<'a> FnCall<(&'a T,), ()>>(mut self, _f: &F) -> Self { |
| 588 | self.0.post_save = if F::IS_SOME { |
| 589 | Some(vmstate_post_save_cb::<T, F>) |
| 590 | } else { |
| 591 | None |
| 592 | }; |
| 593 | self |
| 594 | } |
| 595 | |
| 596 | #[must_use] |
| 597 | pub const fn needed<F: for<'a> FnCall<(&'a T,), bool>>(mut self, _f: &F) -> Self { |
| 598 | self.0.needed = if F::IS_SOME { |
| 599 | Some(vmstate_needed_cb::<T, F>) |
| 600 | } else { |
| 601 | None |
| 602 | }; |
| 603 | self |
| 604 | } |
| 605 | |
| 606 | #[must_use] |
| 607 | pub const fn unplug_pending<F: for<'a> FnCall<(&'a T,), bool>>(mut self, _f: &F) -> Self { |
| 608 | self.0.dev_unplug_pending = if F::IS_SOME { |
| 609 | Some(vmstate_dev_unplug_pending_cb::<T, F>) |
| 610 | } else { |
| 611 | None |
| 612 | }; |
| 613 | self |
| 614 | } |
| 615 | |
| 616 | #[must_use] |
| 617 | pub const fn fields(mut self, fields: &'static [VMStateField]) -> Self { |
| 618 | if fields[fields.len() - 1].flags.0 != VMStateFlags::VMS_END.0 { |
| 619 | panic!("fields are not terminated, use vmstate_fields!"); |
| 620 | } |
| 621 | self.0.fields = fields.as_ptr(); |
| 622 | self |
| 623 | } |
| 624 | |
| 625 | #[must_use] |
| 626 | pub const fn subsections(mut self, subs: &'static VMStateSubsections) -> Self { |
| 627 | if subs[subs.len() - 1].is_some() { |
| 628 | panic!("subsections are not terminated, use vmstate_subsections!"); |
| 629 | } |
| 630 | let subs: *const Option<&bindings::VMStateDescription> = subs.as_ptr(); |
| 631 | self.0.subsections = subs.cast::<*const bindings::VMStateDescription>(); |
| 632 | self |
| 633 | } |
| 634 | |
| 635 | #[must_use] |
| 636 | pub const fn build(mut self) -> VMStateDescription<T> { |
| 637 | // FIXME: is_null()/as_ref() become const since v1.84. |
| 638 | assert!(self.1.is_some(), "VMStateDescription requires name field!"); |
| 639 | self.0.name = self.1.unwrap(); |
| 640 | VMStateDescription::<T>(self.0, PhantomData) |
| 641 | } |
| 642 | |
| 643 | #[must_use] |
| 644 | pub const fn new() -> Self { |
| 645 | Self(bindings::VMStateDescription::ZERO, None, PhantomData) |
| 646 | } |
| 647 | } |
| 648 | |
| 649 | impl<T> Default for VMStateDescriptionBuilder<T> { |
| 650 | fn default() -> Self { |
| 651 | Self::new() |
| 652 | } |
| 653 | } |
| 654 | |
| 655 | impl<T> VMStateDescription<T> { |
| 656 | pub const fn get(&self) -> bindings::VMStateDescription { |
| 657 | self.0 |
| 658 | } |
| 659 | |
| 660 | pub const fn as_ref(&self) -> &bindings::VMStateDescription { |
| 661 | &self.0 |
| 662 | } |
| 663 | } |