Move raw FFI bindings generation to separate crates. This makes it
possible to reuse bindgen declarations for a header file in its
dependencies (this was not the case before this change), while keeping
multiple -sys crates to avoid rebuilding all the code whenever
something changes.
Because the -sys crates are generated in dependency order, this also
enforces that the crates are organized in something that resembles
the dependencies between C headers.
The meson.build for rust-safe crates becomes simpler, and it should be
possible in the future to let Meson's cargo support handle most of it.
Signed-off-by: Marc-André Lureau <marcandre.lureau@redhat.com>
[General cleanup and Python script. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Implement DTrace/SystemTap SDT by emitting the following:
- The probe crate's probe!() macro is used to emit a DTrace/SystemTap
SDT probe.
- Every trace event gets a corresponding trace_<name>_enabled() -> bool
generated function that Rust code can use to avoid expensive
computation when a trace event is disabled. This API works for other
trace backends too.
`#[allow(dead_code)]` additions are necessary for QEMU's dstate in
generated trace-<dir>.rs files since they are unused by the dtrace
backend. `./configure --enable-trace-backends=` can enable multiple
backends, so keep it simple and just silence the warning instead of
trying to detect the condition when generating the dstate code can be
skipped.
The tracetool tests are updated. Take a look at
tests/tracetool/dtrace.rs to see what the new generated code looks like.
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Link: https://lore.kernel.org/r/20251119205200.173170-5-stefanha@redhat.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Add a macro that recursively builds the "migrated" version
of a struct.
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The high-level wrapper Migratable<T> will contain a BqlCell,
which would introduce a circular dependency betwen the bql and
migration crates. Move the implementation of VMState for cells
to "migration", together with the implementation for std types.
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
The syslog backend needs the syslog function from libc and the LOG_INFO enum
value; they are re-exported as "::trace::syslog" and "::trace::LOG_INFO"
so that device crates do not all have to add the libc dependency, but
otherwise there is nothing special.
Signed-off-by: Tanish Desai <tanishdesai37@gmail.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20250929154938.594389-17-pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
The trace crate is a minimal container for dependencies of tracepoints
(so that they do not have to be imported in all the crates that use
tracepoints); it also contains a macro called "include_trace!" that is
able to find the right include file from the trace/ directory.
[Write commit message, add #[allow()]. - Paolo]
Signed-off-by: Tanish Desai <tanishdesai37@gmail.com>
Reviewed-by: Stefan Hajnoczi <stefanha@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Message-ID: <20250929154938.594389-10-pbonzini@redhat.com>
Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
Since we are going to add more attribute parsing for high-level migration
state macros, use the attrs crate instead of a handwritten parser for
device properties as well.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Provide an implementation of std::error::Error that bridges the Rust
anyhow::Error and std::panic::Location types with QEMU's Error*.
It also has several utility methods, analogous to error_propagate(),
that convert a Result into a return value + Error** pair. One important
difference is that these propagation methods *panic* if *errp is NULL,
unlike error_propagate() which eats subsequent errors[1]. The reason
for this is that in C you have an error_set*() call at the site where
the error is created, and calls to error_propagate() are relatively rare.
In Rust instead, even though these functions do "propagate" a
qemu_api::Error into a C Error**, there is no error_setg() anywhere that
could check for non-NULL errp and call abort(). error_propagate()'s
behavior of ignoring subsequent errors is generally considered weird,
and there would be a bigger risk of triggering it from Rust code.
[1] This is actually a violation of the preconditions of error_propagate(),
so it should not happen. But you never know...
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
One common thing that device emulation does is manipulate bitmasks, for example
to check whether two bitmaps have common bits. One example in the pl011 crate
is the checks for pending interrupts, where an interrupt cause corresponds to
at least one interrupt source from a fixed set.
Unfortunately, this is one case where Rust *can* provide some kind of
abstraction but it does so with a rather Perl-ish There Is More Way To
Do It. It is not something where a crate like "bilge" helps, because
it only covers the packing of bits in a structure; operations like "are
all bits of Y set in X" almost never make sense for bit-packed structs;
you need something else, there are several crates that do it and of course
we're going to roll our own.
In particular I examined three:
- bitmask (https://docs.rs/bitmask/0.5.0/bitmask/) does not support const
at all. This is a showstopper because one of the ugly things in the
current pl011 code is the ugliness of code that defines interrupt masks
at compile time:
pub const E: Self = Self(Self::OE.0 | Self::BE.0 | Self::PE.0 | Self::FE.0);
or even worse:
const IRQMASK: [u32; 6] = [
Interrupt::E.0 | Interrupt::MS.0 | Interrupt::RT.0 | Interrupt::TX.0 | Interrupt::RX.0,
...
}
You would have to use roughly the same code---"bitmask" only helps with
defining the struct.
- bitmask_enum (https://docs.rs/bitmask-enum/2.2.5/bitmask_enum/) does not
have a good separation of "valid" and "invalid" bits, so for example "!x"
will invert all 16 bits if you choose u16 as the representation -- even if
you only defined 10 bits. This makes it easier to introduce subtle bugs
in comparisons.
- bitflags (https://docs.rs/bitflags/2.6.0/bitflags/) is generally the most
used such crate and is the one that I took most inspiration from with
respect to the syntax. It's a pretty sophisticated implementation,
with a lot of bells and whistles such as an implementation of "Iter"
that returns the bits one at a time.
The main thing that all of them lack, however, is a way to simplify the
ugly definitions like the above. "bitflags" includes const methods that
perform AND/OR/XOR of masks (these are necessary because Rust operator
overloading does not support const yet, and therefore overloaded operators
cannot be used in the definition of a "static" variable), but they become
even more verbose and unmanageable, like
Interrupt::E.union(Interrupt::MS).union(Interrupt::RT).union(Interrupt::TX).union(Interrupt::RX)
This was the main reason to create "bits", which allows something like
bits!(Interrupt: E | MS | RT | TX | RX)
and expands it 1) add "Interrupt::" in front of all identifiers 2) convert
operators to the wordy const functions like "union". It supports boolean
operators "&", "|", "^", "!" and parentheses, with a relatively simple
recursive descent parser that's implemented in qemu_api_macros.
Since I don't remember exactly how the macro was developed, I cannot exclude
that it contains code from "bitflags". Therefore, I am conservatively leaving
in the MIT and Apache 2.0 licenses from bitflags. In fact, I think there
would be a benefit in being able to push code back to "bitflags" anyway
whenever applicable, so that the two libraries do not diverge too much,
so that's another reason to use this.
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Define HPETFwEntry structure with the same memory layout as
hpet_fw_entry in C.
Further, define the global hpet_cfg variable in Rust which is the
same as the C version. This hpet_cfg variable in Rust will replace
the C version one and allows both Rust code and C code to access it.
The Rust version of hpet_cfg is self-contained, avoiding unsafe
access to C code.
Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
Link: https://lore.kernel.org/r/20250210030051.2562726-8-zhao1.liu@intel.com
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
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>
Workspaces allows tracking dependencies for multiple crates at once,
by having a single Cargo.lock file at the top of the rust/ tree.
Because QEMU's Cargo.lock files have to be synchronized with the versions
of crates in subprojects/, using a workspace avoids the need to copy
over the Cargo.lock file when adding a new device (and thus a new crate)
under rust/hw/.
In addition, workspaces let cargo download and build dependencies just
once. While right now we have one leaf crate (hw/char/pl011), this
will not be the case once more devices are added.
Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
