rust: fix --enable-debug-mutex

--feature is an option for cargo but not for rustc.

Reported-by: Bernhard Beschow <shentey@gmail.com>
Reviewed-by: Bernhard Beschow <shentey@gmail.com>
Signed-off-by:

rust: fix --enable-debug-mutex

--feature is an option for cargo but not for rustc.

Reported-by: Bernhard Beschow <shentey@gmail.com>
Reviewed-by: Bernhard Beschow <shentey@gmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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rust: pl011: fix migration stream

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 alre

rust: pl011: fix migration stream

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>

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rust: qemu-api: add a module to wrap functions and zero-sized closures

One recurring issue when writing Rust bindings is how to convert a Rust
function ("fn" or "impl Fn") to a C function, and how t

rust: qemu-api: add a module to wrap functions and zero-sized closures

One recurring issue when writing Rust bindings is how to convert a Rust
function ("fn" or "impl Fn") to a C function, and how to pass around
"self" to a C function that only takes a void*.

An easy solution would be to store on the heap a pair consisting of
a pointer to the Rust function and the pointer to "self", but it is
possible to do better. If an "Fn" has zero size (that is, if it is a
zero-capture closures or a function pointer---which in turn includes all
methods), it is possible to build a generic Rust function that calls it
even if you only have the type; you don't need either the pointer to the
function itself (because the address of the code is part of the type)
or any closure data (because it has size zero).

Introduce a wrapper that provides the functionality of calling the
function given only its type.

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

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rust: qom: add initial subset of methods on Object

Add an example of implementing instance methods and converting the
result back to a Rust type. In this case the returned types are a
string (actua

rust: qom: add initial subset of methods on Object

Add an example of implementing instance methods and converting the
result back to a Rust type. In this case the returned types are a
string (actually a Cow<str>; but that's transparent as long as it derefs
to &str) and a QOM class.

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

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rust: qom: add casting functionality

Add traits that let client cast typecast safely between object types.
In particular, an upcast is compile-time guaranteed to succeed, and a
YOLO C-style downcast

rust: qom: add casting functionality

Add traits that let client cast typecast safely between object types.
In particular, an upcast is compile-time guaranteed to succeed, and a
YOLO C-style downcast must be marked as unsafe.

The traits are based on an IsA<> trait that declares what
is a subclass of what, which is an idea taken from glib-rs
(https://docs.rs/glib/latest/glib/object/trait.IsA.html).
The four primitives are also taken from there
(https://docs.rs/glib/latest/glib/object/trait.Cast.html). However,
the implementation of casting itself is a bit different and uses the
Deref trait.

This removes some pointer arithmetic from the pl011 device; it is also a
prerequisite for the definition of methods, so that they can be invoked
on all subclass structs. This will use the IsA<> trait to detect the
structs that support the methods.

glib also has a "monadic" casting trait which could be implemented on
Option (as in https://docs.rs/glib/latest/glib/object/trait.CastNone.html)
and perhaps even Result. For now I'm leaving it out, as the patch is
already big enough and the benefit seems debatable.

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

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rust: tests: allow writing more than one test

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

bql: add a "mock" BQL for Rust unit tests

Right now, the stub BQL in stubs/iothread-lock.c always reports itself as
unlocked. However, Rust would like to run its tests in an environment where
the B

bql: add a "mock" BQL for Rust unit tests

Right now, the stub BQL in stubs/iothread-lock.c always reports itself as
unlocked. However, Rust would like to run its tests in an environment where
the BQL *is* locked. Provide an extremely dirty function that flips the
return value of bql_is_locked() to true.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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rust: re-export C types from qemu-api submodules

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.

Rev

rust: re-export C types from qemu-api submodules

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>

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rust: rename qemu-api modules to follow C code a bit more

A full match would mean calling them qom::object and hw::core::qdev. For now,
keep the names shorter but still a bit easier to find.

Revie

rust: rename qemu-api modules to follow C code a bit more

A full match would mean calling them qom::object and hw::core::qdev. For now,
keep the names shorter but still a bit easier to find.

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

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rust: qom: add possibility of overriding unparent

Add a blanket definition of ClassInitImpl<ObjectClass> that thunks
ObjectImpl::UNPARENT and overrides it in ObjectClass if it is not
None.

ClassIni

rust: qom: add possibility of overriding unparent

Add a blanket definition of ClassInitImpl<ObjectClass> that thunks
ObjectImpl::UNPARENT and overrides it in ObjectClass if it is not
None.

ClassInitImpl<DeviceClass> can now call its superclass's ClassInitImpl,
so that the C and Rust hierarchies match more closely.

This is mostly done as an example of implementing the metaclass
hierarchy under ClassInitImpl.

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

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rust: qom: put class_init together from multiple ClassInitImpl<>

Parameterize the implementation of ClassInitImpl so that it is
possible to call up the chain of implementations, one superclass at
a

rust: qom: put class_init together from multiple ClassInitImpl<>

Parameterize the implementation of ClassInitImpl so that it is
possible to call up the chain of implementations, one superclass at
a time starting at ClassInitImpl<Self::Class>.

In order to avoid having to implement (for example)
ClassInitImpl<PL011Class>, also remove the dummy PL011Class and
PL011LuminaryClass structs and specify the same ObjectType::Class as
the superclass. In the future this default behavior can be handled by
a procedural macro, by looking at the first field in the struct.

Note that the new trait is safe: the calls are started by
rust_class_init<>(), which is not public and can convert the class
pointer to a Rust reference.

Since CLASS_BASE_INIT applies to the type that is being defined,
and only to it, move it to ObjectImpl.

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

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rust/qemu-api: Use device_class_set_props_n

This means we can update declare_properties to drop the
zero terminator at the end of the array as well.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>

rust/qemu-api: Use device_class_set_props_n

This means we can update declare_properties to drop the
zero terminator at the end of the array as well.

Reviewed-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>
Tested-by: Lei Yang <leiyang@redhat.com>
Link: https://lore.kernel.org/r/20241218134251.4724-18-richard.henderson@linaro.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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rust: qom: change the parent type to an associated type

Avoid duplicated code to retrieve the QOM type strings from the
Rust type.

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

rust: qom: change the parent type to an associated type

Avoid duplicated code to retrieve the QOM type strings from the
Rust type.

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

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rust: qom: split ObjectType from ObjectImpl trait

Define a separate trait for fields that also applies to classes that are
defined by C code. This makes it possible to add metadata to core classes,

rust: qom: split ObjectType from ObjectImpl trait

Define a separate trait for fields that also applies to classes that are
defined by C code. This makes it possible to add metadata to core classes,
which has multiple uses:

- it makes it possible to access the parent struct's TYPE_* for types
that are defined in Rust code, and to avoid repeating it in every subclass

- implementors of ObjectType will be allowed to implement the IsA<> trait and
therefore to perform typesafe casts from one class to another.

- in the future, an ObjectType could be created with Foo::new() in a type-safe
manner, without having to pass a TYPE_* constant.

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

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rust: qom: move bridge for TypeInfo functions out of pl011

Allow the ObjectImpl trait to expose Rust functions that avoid raw
pointers (though INSTANCE_INIT for example is still unsafe).
ObjectImpl:

rust: qom: move bridge for TypeInfo functions out of pl011

Allow the ObjectImpl trait to expose Rust functions that avoid raw
pointers (though INSTANCE_INIT for example is still unsafe).
ObjectImpl::TYPE_INFO adds thunks around the functions in
ObjectImpl.

While at it, document `TypeInfo`.

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

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rust: qdev: move bridge for realize and reset functions out of pl011

Allow the DeviceImpl trait to expose safe Rust functions.
rust_device_class_init<> adds thunks around the functions
in DeviceImpl

rust: qdev: move bridge for realize and reset functions out of pl011

Allow the DeviceImpl trait to expose safe Rust functions.
rust_device_class_init<> adds thunks around the functions
in DeviceImpl.

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

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rust: qdev: move device_class_init! body to generic function, ClassInitImpl implementation to macro

Use a trait to access the former parameters to device_class_init!.
This allows hiding the details

rust: qdev: move device_class_init! body to generic function, ClassInitImpl implementation to macro

Use a trait to access the former parameters to device_class_init!.
This allows hiding the details of the class_init implementation behind
a generic function and makes higher-level functionality available from
qemu_api.

The implementation of ClassInitImpl is then the same for all devices and
is easily macroized. Later on, we can remove the need to implement
ClassInitImpl by hand for all device types, and stop making
rust_device_class_init<>() public.

While at it, document the members of DeviceImpl.

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

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rust: qom: move ClassInitImpl to the instance side

Put all traits on the instance struct, which makes it possible to reuse
class structs if no new virtual methods or class fields are added.
This is

rust: qom: move ClassInitImpl to the instance side

Put all traits on the instance struct, which makes it possible to reuse
class structs if no new virtual methods or class fields are added.
This is almost always the case for devices (because they are leaf
classes), which is the primary use case for Rust.

This is also simpler: soon we will find the implemented methods without
macros, and this removes the need to go from the class struct to the
instance struct to find the implementation of the *Impl traits.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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rust: qom: convert type_info! macro to an associated const

type_info! is only used in the definition of ObjectImpl::TYPE_INFO, and
in fact in all of them. Pull type_info!'s definition into the Obje

rust: qom: convert type_info! macro to an associated const

type_info! is only used in the definition of ObjectImpl::TYPE_INFO, and
in fact in all of them. Pull type_info!'s definition into the ObjectImpl
trait, thus simplifying the external interface of qemu_api::definitions.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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rust: qom: rename Class trait to ClassInitImpl

While at it, document it.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

rust: qom: add default definitions for ObjectImpl

Remove a bunch of duplicate const definitions.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

rust: add a bit operation module

The bindgen supports `static inline` function binding since v0.64.0 as
an experimental feature (`--wrap-static-fns`), and stabilizes it after
v0.70.0.

But the oldes

rust: add a bit operation module

The bindgen supports `static inline` function binding since v0.64.0 as
an experimental feature (`--wrap-static-fns`), and stabilizes it after
v0.70.0.

But the oldest version of bindgen supported by QEMU is v0.60.1, so
there's no way to generate the binding for deposit64() which is `static
inline` (in include/qemu/bitops.h).

Instead, implement it by hand in Rust and make it available for all
unsigned types through an IntegerExt trait. Since it only involves bit
operations, the Rust version of the code is almost identical to the
original C version, but it applies to more types than just u64.

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

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rust: add bindings for interrupt sources

The InterruptSource bindings let us call qemu_set_irq() and sysbus_init_irq()
as safe code.

Interrupt sources, qemu_irq in C code, are pointers to IRQState

rust: add bindings for interrupt sources

The InterruptSource bindings let us call qemu_set_irq() and sysbus_init_irq()
as safe code.

Interrupt sources, qemu_irq in C code, are pointers to IRQState objects.
They are QOM link properties and can be written to outside the control
of the device (i.e. from a shared reference); therefore they must be
interior-mutable in Rust. Since thread-safety is provided by the BQL,
what we want here is the newly-introduced BqlCell. A pointer to the
contents of the BqlCell (an IRQState**, or equivalently qemu_irq*)
is then passed to the C sysbus_init_irq function.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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rust: define prelude

Add a module that will contain frequently used traits and
occasionally structs. They can be included quickly with
"use qemu_api::prelude::*".

Signed-off-by: Paolo Bonzini <pbo

rust: define prelude

Add a module that will contain frequently used traits and
occasionally structs. They can be included quickly with
"use qemu_api::prelude::*".

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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rust: cell: add BQL-enforcing RefCell variant

Similar to the existing BqlCell, introduce a custom interior mutability
primitive that resembles RefCell but accounts for QEMU's threading model.
Borrow

rust: cell: add BQL-enforcing RefCell variant

Similar to the existing BqlCell, introduce a custom interior mutability
primitive that resembles RefCell but accounts for QEMU's threading model.
Borrowing the RefCell requires proving that the BQL is held, and
attempting to access without the BQL is a runtime panic.

Almost all of the code was taken from Rust's standard library, while
removing unstable features and probably-unnecessary functionality that
amounts to 60% of the original code. A lot of what's left is documentation,
as well as unit tests in the form of doctests. These are not yet integrated
in "make check" but can be run with "cargo test --doc".

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>

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