diff options
Diffstat (limited to 'rust/qemu-api/src/vmstate.rs')
| -rw-r--r-- | rust/qemu-api/src/vmstate.rs | 242 |
1 files changed, 234 insertions, 8 deletions
diff --git a/rust/qemu-api/src/vmstate.rs b/rust/qemu-api/src/vmstate.rs index 8515e38213..f5f1ea5590 100644 --- a/rust/qemu-api/src/vmstate.rs +++ b/rust/qemu-api/src/vmstate.rs @@ -24,12 +24,24 @@ //! `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}; -use std::ffi::{c_int, c_void}; +pub use std::convert::Infallible; +use std::{ + error::Error, + ffi::{c_int, c_void, CStr}, + fmt, io, + marker::PhantomData, + mem, + ptr::NonNull, +}; -pub use crate::bindings::{VMStateDescription, VMStateField}; +pub use crate::bindings::{MigrationPriority, VMStateField}; use crate::{ - bindings::VMStateFlags, callbacks::FnCall, prelude::*, qom::Owned, zeroable::Zeroable, + bindings::{self, VMStateFlags}, + callbacks::FnCall, + errno::{into_neg_errno, Errno}, + prelude::*, + qom::Owned, + zeroable::Zeroable, }; /// This macro is used to call a function with a generic argument bound @@ -440,7 +452,7 @@ pub extern "C" fn rust_vms_test_field_exists<T, F: for<'a> FnCall<(&'a T, u8), b opaque: *mut c_void, version_id: c_int, ) -> bool { - // SAFETY: the opaque was passed as a reference to `T`. + // SAFETY: assumes vmstate_struct! is used correctly let owner: &T = unsafe { &*(opaque.cast::<T>()) }; let version: u8 = version_id.try_into().unwrap(); F::call((owner, version)) @@ -490,7 +502,7 @@ macro_rules! vmstate_struct { }, size: ::core::mem::size_of::<$type>(), flags: $crate::bindings::VMStateFlags::VMS_STRUCT, - vmsd: $vmsd, + vmsd: $vmsd.as_ref(), $(field_exists: $crate::vmstate_exist_fn!($struct_name, $test_fn),)? ..$crate::zeroable::Zeroable::ZERO } $(.with_varray_flag_unchecked( @@ -594,11 +606,225 @@ macro_rules! vmstate_subsections { ($($subsection:expr),*$(,)*) => {{ static _SUBSECTIONS: $crate::vmstate::VMStateSubsectionsWrapper = $crate::vmstate::VMStateSubsectionsWrapper(&[ $({ - static _SUBSECTION: $crate::bindings::VMStateDescription = $subsection; + static _SUBSECTION: $crate::bindings::VMStateDescription = $subsection.get(); ::core::ptr::addr_of!(_SUBSECTION) }),*, ::core::ptr::null() ]); - _SUBSECTIONS.0.as_ptr() + &_SUBSECTIONS }} } + +pub struct VMStateDescription<T>(bindings::VMStateDescription, PhantomData<fn(&T)>); + +// SAFETY: When a *const T is passed to the callbacks, the call itself +// is done in a thread-safe manner. The invocation is okay as long as +// T itself is `Sync`. +unsafe impl<T: Sync> Sync for VMStateDescription<T> {} + +#[derive(Clone)] +pub struct VMStateDescriptionBuilder<T>(bindings::VMStateDescription, PhantomData<fn(&T)>); + +#[derive(Debug)] +pub struct InvalidError; + +impl Error for InvalidError {} + +impl std::fmt::Display for InvalidError { + fn fmt(&self, f: &mut fmt::Formatter<'_>) -> fmt::Result { + write!(f, "invalid migration data") + } +} + +impl From<InvalidError> for Errno { + fn from(_value: InvalidError) -> Errno { + io::ErrorKind::InvalidInput.into() + } +} + +unsafe extern "C" fn vmstate_no_version_cb< + T, + F: for<'a> FnCall<(&'a T,), Result<(), impl Into<Errno>>>, +>( + opaque: *mut c_void, +) -> c_int { + // SAFETY: assumes vmstate_struct! is used correctly + let result = F::call((unsafe { &*(opaque.cast::<T>()) },)); + into_neg_errno(result) +} + +unsafe extern "C" fn vmstate_post_load_cb< + T, + F: for<'a> FnCall<(&'a T, u8), Result<(), impl Into<Errno>>>, +>( + opaque: *mut c_void, + version_id: c_int, +) -> c_int { + // SAFETY: assumes vmstate_struct! is used correctly + let owner: &T = unsafe { &*(opaque.cast::<T>()) }; + let version: u8 = version_id.try_into().unwrap(); + let result = F::call((owner, version)); + into_neg_errno(result) +} + +unsafe extern "C" fn vmstate_needed_cb<T, F: for<'a> FnCall<(&'a T,), bool>>( + opaque: *mut c_void, +) -> bool { + // SAFETY: assumes vmstate_struct! is used correctly + F::call((unsafe { &*(opaque.cast::<T>()) },)) +} + +unsafe extern "C" fn vmstate_dev_unplug_pending_cb<T, F: for<'a> FnCall<(&'a T,), bool>>( + opaque: *mut c_void, +) -> bool { + // SAFETY: assumes vmstate_struct! is used correctly + F::call((unsafe { &*(opaque.cast::<T>()) },)) +} + +impl<T> VMStateDescriptionBuilder<T> { + #[must_use] + pub const fn name(mut self, name_str: &CStr) -> Self { + self.0.name = ::std::ffi::CStr::as_ptr(name_str); + self + } + + #[must_use] + pub const fn unmigratable(mut self) -> Self { + self.0.unmigratable = true; + self + } + + #[must_use] + pub const fn early_setup(mut self) -> Self { + self.0.early_setup = true; + self + } + + #[must_use] + pub const fn version_id(mut self, version: u8) -> Self { + self.0.version_id = version as c_int; + self + } + + #[must_use] + pub const fn minimum_version_id(mut self, min_version: u8) -> Self { + self.0.minimum_version_id = min_version as c_int; + self + } + + #[must_use] + pub const fn priority(mut self, priority: MigrationPriority) -> Self { + self.0.priority = priority; + self + } + + #[must_use] + pub const fn pre_load<F: for<'a> FnCall<(&'a T,), Result<(), impl Into<Errno>>>>( + mut self, + _f: &F, + ) -> Self { + self.0.pre_load = if F::IS_SOME { + Some(vmstate_no_version_cb::<T, F>) + } else { + None + }; + self + } + + #[must_use] + pub const fn post_load<F: for<'a> FnCall<(&'a T, u8), Result<(), impl Into<Errno>>>>( + mut self, + _f: &F, + ) -> Self { + self.0.post_load = if F::IS_SOME { + Some(vmstate_post_load_cb::<T, F>) + } else { + None + }; + self + } + + #[must_use] + pub const fn pre_save<F: for<'a> FnCall<(&'a T,), Result<(), impl Into<Errno>>>>( + mut self, + _f: &F, + ) -> Self { + self.0.pre_save = if F::IS_SOME { + Some(vmstate_no_version_cb::<T, F>) + } else { + None + }; + self + } + + #[must_use] + pub const fn post_save<F: for<'a> FnCall<(&'a T,), Result<(), impl Into<Errno>>>>( + mut self, + _f: &F, + ) -> Self { + self.0.post_save = if F::IS_SOME { + Some(vmstate_no_version_cb::<T, F>) + } else { + None + }; + self + } + + #[must_use] + pub const fn needed<F: for<'a> FnCall<(&'a T,), bool>>(mut self, _f: &F) -> Self { + self.0.needed = if F::IS_SOME { + Some(vmstate_needed_cb::<T, F>) + } else { + None + }; + self + } + + #[must_use] + pub const fn unplug_pending<F: for<'a> FnCall<(&'a T,), bool>>(mut self, _f: &F) -> Self { + self.0.dev_unplug_pending = if F::IS_SOME { + Some(vmstate_dev_unplug_pending_cb::<T, F>) + } else { + None + }; + self + } + + #[must_use] + pub const fn fields(mut self, fields: *const VMStateField) -> Self { + self.0.fields = fields; + self + } + + #[must_use] + pub const fn subsections(mut self, subs: &'static VMStateSubsectionsWrapper) -> Self { + self.0.subsections = subs.0.as_ptr(); + self + } + + #[must_use] + pub const fn build(self) -> VMStateDescription<T> { + VMStateDescription::<T>(self.0, PhantomData) + } + + #[must_use] + pub const fn new() -> Self { + Self(bindings::VMStateDescription::ZERO, PhantomData) + } +} + +impl<T> Default for VMStateDescriptionBuilder<T> { + fn default() -> Self { + Self::new() + } +} + +impl<T> VMStateDescription<T> { + pub const fn get(&self) -> bindings::VMStateDescription { + self.0 + } + + pub const fn as_ref(&self) -> &bindings::VMStateDescription { + &self.0 + } +} |