Commit graph

12 commits

Author SHA1 Message Date
Paolo Bonzini
1de82059aa rust: build: restrict --cfg generation to only required symbols
Parse the Cargo.toml file, looking for the unexpected_cfgs
configuration.  When generating --cfg options from the
config-host.h file, only use those that are included in the
configuration.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-12-10 18:44:06 +01:00
Paolo Bonzini
f3a6e9bc47 rust: build: move rustc_args.py invocation to qemu-api crate
Only qemu-api needs access to the symbols in config-host.h.  Remove
the temptation to use them elsewhere by limiting the --cfg arguments to
the qemu-api crate.

Per-crate invocation of the script will also be needed to add --check-cfg
options for each crate's features (when more complex, build-time
configurable devices are added in the future).

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-12-10 18:44:06 +01:00
Paolo Bonzini
cb7ada5409 rust: allow using build-root bindings.rs from cargo
Right now, using cargo with QEMU requires copying by hand the bindings.rs to the
source tree.  Instead, we can use an include file to escape the cage of cargo's
mandated source directory structure.

By running cargo within meson's "devenv" and adding a MESON_BUILD_ROOT
environment variable, it is easy for build.rs to find the file.  However, the
file must be symlinked into cargo's output directory for rust-analyzer to find
it.

Suggested-by: Junjie Mao <junjie.mao@hotmail.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-12-10 18:44:06 +01:00
Paolo Bonzini
8c28667503 rust: apply --cfg MESON to all crates
We might have more uses for --cfg MESON, even though right now it's only
qemu-api that has generated files.  Since we're going to add more flags
to the add_project_arguments calls for Rust, it makes sense to also add
--cfg MESON everywhere.

Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-12-10 18:44:06 +01:00
Junjie Mao
f351840088 rust: introduce alternative implementation of offset_of!
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>
2024-11-05 14:18:16 +01:00
Paolo Bonzini
718e255f0a rust: introduce a c_str macro
This allows CStr constants to be defined easily on Rust 1.63.0, while
checking that there are no embedded NULs.  c"" literals were only
stabilized in Rust 1.77.0.

Reviewed-by: Zhao Liu <zhao1.liu@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-11-05 14:18:16 +01:00
Manos Pitsidianakis
0a65e4124a rust: add definitions for vmstate
Add a new qemu_api module, `vmstate`. Declare a bunch of Rust
macros declared that are equivalent in spirit to the C macros in
include/migration/vmstate.h.

For example the Rust of equivalent of the C macro:

  VMSTATE_UINT32(field_name, struct_name)

is:

  vmstate_uint32!(field_name, StructName)

This breathtaking development will allow us to reach feature parity between
the Rust and C pl011 implementations.

Extracted from a patch by Manos Pitsidianakis
(https://lore.kernel.org/qemu-devel/20241024-rust-round-2-v1-4-051e7a25b978@linaro.org/).

Signed-off-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-11-05 14:18:16 +01:00
Paolo Bonzini
6e50bde1e1 rust: provide safe wrapper for MaybeUninit::zeroed()
MaybeUninit::zeroed() is handy, but it introduces unsafe (and has a
pretty heavy syntax in general).  Introduce a trait that provides the
same functionality while staying within safe Rust.

In addition, MaybeUninit::zeroed() is not available as a "const"
function until Rust 1.75.0, so this also prepares for having handwritten
implementations of the trait until we can assume that version.

Reviewed-by: Junjie Mao <junjie.mao@hotmail.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-11-05 14:18:16 +01:00
Paolo Bonzini
cde3c425d1 rust: build integration test for the qemu_api crate
Adjust the integration test to compile with a subset of QEMU object
files, and make it actually create an object of the class it defines.

Follow the Rust filesystem conventions, where tests go in tests/ if
they use the library in the same way any other code would.

Reviewed-by: Junjie Mao <junjie.mao@hotmail.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-11-05 14:18:15 +01:00
Paolo Bonzini
7b72c7dd0d meson: pass rustc_args when building all crates
rustc_args is needed to smooth the difference in warnings between the various
versions of rustc.  Always include those arguments.

Reviewed-by: Junjie Mao <junjie.mao@hotmail.com>
Reviewed-by: Kevin Wolf <kwolf@redhat.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-11-05 14:18:15 +01:00
Manos Pitsidianakis
2b74dd9180 rust: add utility procedural macro crate
This commit adds a helper crate library, qemu-api-macros for derive (and
other procedural) macros to be used along qemu-api.

It needs to be a separate library because in Rust, procedural macros, or
macros that can generate arbitrary code, need to be special separate
compilation units.

Only one macro is introduced in this patch, #[derive(Object)]. It
generates a constructor to register a QOM TypeInfo on init and it must
be used on types that implement qemu_api::definitions::ObjectImpl trait.

Reviewed-by: Junjie Mao <junjie.mao@hotmail.com>
Signed-off-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
Link: https://lore.kernel.org/r/dd645642406a6dc2060c6f3f17db2bc77ed67b59.1727961605.git.manos.pitsidianakis@linaro.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-10-11 12:32:17 +02:00
Manos Pitsidianakis
5a5110d290 rust: add crate to expose bindings and interfaces
Add rust/qemu-api, which exposes rust-bindgen generated FFI bindings and
provides some declaration macros for symbols visible to the rest of
QEMU.

Co-authored-by: Junjie Mao <junjie.mao@intel.com>
Co-authored-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Junjie Mao <junjie.mao@intel.com>
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
Signed-off-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
Link: https://lore.kernel.org/r/0fb23fbe211761b263aacec03deaf85c0cc39995.1727961605.git.manos.pitsidianakis@linaro.org
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
2024-10-11 12:32:17 +02:00