Message ID | 20241231002336.25931-3-pbonzini@redhat.com (mailing list archive) |
---|---|
State | New, archived |
Headers | show |
Series | rust: (mostly) type safe VMState | expand |
On Tue, Dec 31, 2024 at 01:23:29AM +0100, Paolo Bonzini wrote: > Date: Tue, 31 Dec 2024 01:23:29 +0100 > From: Paolo Bonzini <pbonzini@redhat.com> > Subject: [RFC PATCH 2/9] rust: vmstate: implement VMState for non-leaf types > X-Mailer: git-send-email 2.47.1 > > 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> > --- > rust/qemu-api/src/vmstate.rs | 66 +++++++++++++++++++++++++++++++++++- > 1 file changed, 65 insertions(+), 1 deletion(-) > > diff --git a/rust/qemu-api/src/vmstate.rs b/rust/qemu-api/src/vmstate.rs > index bfcf06e8f1d..e20f27b172b 100644 > --- a/rust/qemu-api/src/vmstate.rs > +++ b/rust/qemu-api/src/vmstate.rs > @@ -19,8 +19,9 @@ > //! `include/migration/vmstate.h`. These are not type-safe and should not be > //! used if the equivalent functionality is available with `vmstate_of!`. > > -use core::marker::PhantomData; > +use core::{marker::PhantomData, mem, ptr::NonNull}; > > +use crate::bindings::VMStateFlags; > pub use crate::bindings::{VMStateDescription, VMStateField}; > > /// This macro is used to call a function with a generic argument bound > @@ -108,6 +109,69 @@ pub const fn with_version_id(mut self, version_id: i32) -> Self { > self.version_id = version_id; > self > } > + > + #[must_use] > + pub const fn with_array_flag(mut self, num: usize) -> Self { > + assert!(num <= 0x7FFF_FFFFusize); I see, this is the similar case to check overflow like your comment for patch 1. I think we can use i32::MAX to avoid such magic number. > + assert!((self.flags.0 & VMStateFlags::VMS_ARRAY.0) == 0); Do we need to also check varray flags? e.g., But the doc (in vmstate.h) of VMS_ARRAY said "May not be combined with VMS_VARRAY*", I understand VMS_ARRAY shouldn't be combined with VMS_VARRAY*, am I right? If so, we can add a simple const variable that combines all VARRY flags, e.g, const VMS_VARRAY_FLAGS: VMStateFlags = VMStateFlags( VMStateFlags::VMS_VARRAY_INT32.0 | VMStateFlags::VMS_VARRAY_UINT8.0 | VMStateFlags::VMS_VARRAY_UINT16.0 | VMStateFlags::VMS_VARRAY_UINT32.0 ); ... assert!((self.flags.0 & VMS_VARRAY_FLAGS.0) == 0); > + if (self.flags.0 & VMStateFlags::VMS_POINTER.0) != 0 { > + self.flags = VMStateFlags(self.flags.0 & !VMStateFlags::VMS_POINTER.0); > + self.flags = VMStateFlags(self.flags.0 | VMStateFlags::VMS_ARRAY_OF_POINTER.0); > + } > + self.flags = VMStateFlags(self.flags.0 & !VMStateFlags::VMS_SINGLE.0); > + self.flags = VMStateFlags(self.flags.0 | VMStateFlags::VMS_ARRAY.0); > + self.num = num as i32; > + self > + } > + > + #[must_use] > + pub const fn with_pointer_flag(mut self) -> Self { > + assert!((self.flags.0 & VMStateFlags::VMS_POINTER.0) == 0); Maybe VMS_ARRAY_OF_POINTER should be checked here as well? > + self.flags = VMStateFlags(self.flags.0 | VMStateFlags::VMS_POINTER.0); > + self > + } > +} > + > +// Transparent wrappers: just use the internal type > + > +macro_rules! impl_vmstate_transparent { > + ($type:ty where $base:tt: VMState $($where:tt)*) => { > + unsafe impl<$base> VMState for $type where $base: VMState $($where)* { > + const BASE: VMStateField = VMStateField { > + size: mem::size_of::<$type>(), > + ..<$base as VMState>::BASE > + }; > + } > + }; > +} > + > +impl_vmstate_transparent!(std::cell::Cell<T> where T: VMState); > +impl_vmstate_transparent!(std::cell::UnsafeCell<T> where T: VMState); > +impl_vmstate_transparent!(crate::cell::BqlCell<T> where T: VMState); > +impl_vmstate_transparent!(crate::cell::BqlRefCell<T> where T: VMState); > + > +// Pointer types using the underlying type's VMState plus VMS_POINTER > + > +macro_rules! impl_vmstate_pointer { > + ($type:ty where $base:tt: VMState $($where:tt)*) => { > + unsafe impl<$base> VMState for $type where $base: VMState $($where)* { > + const SCALAR_TYPE: VMStateFieldType = <T as VMState>::SCALAR_TYPE; Rebase issue: SCALAR_TYPE is introduced in patch 5. > + const BASE: VMStateField = <$base as VMState>::BASE.with_pointer_flag(); > + } > + }; > +} > + > +impl_vmstate_pointer!(*const T where T: VMState); > +impl_vmstate_pointer!(*mut T where T: VMState); > +impl_vmstate_pointer!(NonNull<T> where T: VMState); > +impl_vmstate_pointer!(Option<NonNull<T>> where T: VMState); > + > +// Arrays using the underlying type's VMState plus > +// VMS_ARRAY/VMS_ARRAY_OF_POINTER > + > +unsafe impl<T: VMState, const N: usize> VMState for [T; N] { > + const SCALAR_TYPE: VMStateFieldType = <T as VMState>::SCALAR_TYPE; Ditto. > + const BASE: VMStateField = <T as VMState>::BASE.with_array_flag(N); > } > > #[doc(alias = "VMSTATE_UNUSED_BUFFER")] > -- > 2.47.1 > Overall, I think this patch handles the array/pointer/cell cases very well. So (with some nits fixed :-)), Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
diff --git a/rust/qemu-api/src/vmstate.rs b/rust/qemu-api/src/vmstate.rs index bfcf06e8f1d..e20f27b172b 100644 --- a/rust/qemu-api/src/vmstate.rs +++ b/rust/qemu-api/src/vmstate.rs @@ -19,8 +19,9 @@ //! `include/migration/vmstate.h`. These are not type-safe and should not be //! used if the equivalent functionality is available with `vmstate_of!`. -use core::marker::PhantomData; +use core::{marker::PhantomData, mem, ptr::NonNull}; +use crate::bindings::VMStateFlags; pub use crate::bindings::{VMStateDescription, VMStateField}; /// This macro is used to call a function with a generic argument bound @@ -108,6 +109,69 @@ pub const fn with_version_id(mut self, version_id: i32) -> Self { self.version_id = version_id; self } + + #[must_use] + pub const fn with_array_flag(mut self, num: usize) -> Self { + assert!(num <= 0x7FFF_FFFFusize); + assert!((self.flags.0 & VMStateFlags::VMS_ARRAY.0) == 0); + if (self.flags.0 & VMStateFlags::VMS_POINTER.0) != 0 { + self.flags = VMStateFlags(self.flags.0 & !VMStateFlags::VMS_POINTER.0); + self.flags = VMStateFlags(self.flags.0 | VMStateFlags::VMS_ARRAY_OF_POINTER.0); + } + self.flags = VMStateFlags(self.flags.0 & !VMStateFlags::VMS_SINGLE.0); + self.flags = VMStateFlags(self.flags.0 | VMStateFlags::VMS_ARRAY.0); + self.num = num as i32; + self + } + + #[must_use] + pub const fn with_pointer_flag(mut self) -> Self { + assert!((self.flags.0 & VMStateFlags::VMS_POINTER.0) == 0); + self.flags = VMStateFlags(self.flags.0 | VMStateFlags::VMS_POINTER.0); + self + } +} + +// Transparent wrappers: just use the internal type + +macro_rules! impl_vmstate_transparent { + ($type:ty where $base:tt: VMState $($where:tt)*) => { + unsafe impl<$base> VMState for $type where $base: VMState $($where)* { + const BASE: VMStateField = VMStateField { + size: mem::size_of::<$type>(), + ..<$base as VMState>::BASE + }; + } + }; +} + +impl_vmstate_transparent!(std::cell::Cell<T> where T: VMState); +impl_vmstate_transparent!(std::cell::UnsafeCell<T> where T: VMState); +impl_vmstate_transparent!(crate::cell::BqlCell<T> where T: VMState); +impl_vmstate_transparent!(crate::cell::BqlRefCell<T> where T: VMState); + +// Pointer types using the underlying type's VMState plus VMS_POINTER + +macro_rules! impl_vmstate_pointer { + ($type:ty where $base:tt: VMState $($where:tt)*) => { + unsafe impl<$base> VMState for $type where $base: VMState $($where)* { + const SCALAR_TYPE: VMStateFieldType = <T as VMState>::SCALAR_TYPE; + const BASE: VMStateField = <$base as VMState>::BASE.with_pointer_flag(); + } + }; +} + +impl_vmstate_pointer!(*const T where T: VMState); +impl_vmstate_pointer!(*mut T where T: VMState); +impl_vmstate_pointer!(NonNull<T> where T: VMState); +impl_vmstate_pointer!(Option<NonNull<T>> where T: VMState); + +// Arrays using the underlying type's VMState plus +// VMS_ARRAY/VMS_ARRAY_OF_POINTER + +unsafe impl<T: VMState, const N: usize> VMState for [T; N] { + const SCALAR_TYPE: VMStateFieldType = <T as VMState>::SCALAR_TYPE; + const BASE: VMStateField = <T as VMState>::BASE.with_array_flag(N); } #[doc(alias = "VMSTATE_UNUSED_BUFFER")]
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> --- rust/qemu-api/src/vmstate.rs | 66 +++++++++++++++++++++++++++++++++++- 1 file changed, 65 insertions(+), 1 deletion(-)