From: Marc-André Lureau <marcandre.lur...@redhat.com> Hi,
Among the QEMU developers, there is a desire to use Rust. (see previous thread from Stefan "Why QEMU should move from C to Rust", the rust-vmm related projects and other experiments). Thanks to our QAPI type system and the associate code generator, it is possible to create Rust bindings for the generated C types (also called FFI binding) and functions (rust-bindgen could probably do a similar job, but it is unnecessary given the FFI generator is quite straightforward). More interesting (but more complicated) is to expose a Rust API, and provide convenient conversions FFI<->Rust. Taking inspiration from glib-rs binding, I implemented a simplified version of the FromGlib/ToGlib traits, with simpler ownership model, sufficient for QAPI needs. The usage is as such: - from_qemu_none(ptr: *const sys::P) -> T Return a Rust type T for a const ffi pointer P. - from_qemu_full(ptr: *mut sys::P) -> T Return a Rust type T for a ffi pointer P, taking ownership. - T::to_qemu_none() -> Stash<P> Returns a borrowed ffi pointer P (using a Stash to destroy "glue" storage data, if any). - T::to_qemu_full() -> P Returns a ffi pointer P. (P resources are leaked/passed to C/ffi) With the Rust QAPI bindings, we can implement QMP callbacks in idiomatic Rust. With the translation traits, we can also bind manually more types and implement other functions (QOM is my next target). Since Rust doesn't cover all the platforms QEMU supports (see first patch and https://doc.rust-lang.org/nightly/rustc/platform-support.html), the Rust code should be optional. Nevertheless, it is desirable to write sensitive code in Rust first, and a C version if the code/feature is not optional and not specific to a platform where Rust is Tier-1 or 2. v3 (RFC): - rebased (was waiting for qapi 'if' conditions to be merged) - now covers the various QEMU QAPI schemas (QEMU schema is left out of this series, but test schema is the complete) - numerous improvements, patch reorgnisation, cleanups etc v2 (PoC): - split the original patch in smaller patches and more digestable form - dropped the DBus interface experiment from this series - various build-sys improvements, new configure options --with-rust(-target) - various attempts at better meson integration, finally satisfied enough with the current solution, which handles getting link flags from Rust sanely. (more meson stuff to come to handle config-host/features mapping etc). - rebased, QGA QMP now uses unions, added support for it. - start a common crate (which re-surfaced issues with foreign types and traits, worked around with a NewPtr wrapper) - explicit errors when ifcond are presents (after various unsucessful attempts, I will try to tackle it in v3) - mingw cross compilation support - some attempts to add it to CI - actually implement {get,set}-vcpus - vendor the external crates Marc-André Lureau (32): RFC: docs: add supported host CPUs section build-sys: add HAVE_IPPROTO_MPTCP scripts/qapi: teach c_param_type() to return const argument type glib-compat: add G_SIZEOF_MEMBER scripts/qapi: add QAPISchemaVisitor.visit_module_end scripts/qapi: add a CABI module scripts/qapi: generate CABI dump for C types tests: build qapi-cabi (C ABI dump) build-sys: add i686 cpu target build-sys: add --with-rust{-target} & basic build infrastructure build-sys: add a cargo-wrapper script rust: provide a common crate for QEMU rust: use vendored-sources scripts/qapi: add QAPISchemaIfCond.rsgen() scripts/qapi: strip trailing whitespaces scripts/qapi: add Rust FFI bindings generation scripts/qapi: learn to generate ABI dump for Rust FFI tests: generate Rust bindings tests: check Rust and C CABI diffs scripts/qapi: generate high-level Rust bindings tests/rust: build a common library, checking bindings compile qga: build qapi-cabi binary (ABI from C) qga/rust: build and link an empty static library qga/rust: generate QGA QAPI types FFI bindings qga/rust: build a qga-cabi-rs executable (ABI from Rust) qga/rust: check the Rust C binding qga/rust: build high-level Rust QAPI types qga/rust: implement get-host-name in Rust (example) qga/rust: implement {get,set}-vcpus in Rust (example) tests/vm: add Rust to FreeBSD VM tests/vm: bump fedora VM to f32 tests/vm: add Rust to Fedora docs/about/build-platforms.rst | 28 + configure | 32 +- meson.build | 49 +- qapi/sockets.json | 2 +- include/glib-compat.h | 7 + include/qemu/osdep.h | 10 - io/dns-resolver.c | 2 +- qga/commands-posix.c | 152 ------ qga/commands-win32.c | 71 --- qga/commands.c | 34 +- qga/qapi-cabi.c | 9 + tests/qapi-cabi.c | 9 + tests/unit/test-qga.c | 4 + util/oslib-posix.c | 35 -- util/oslib-win32.c | 13 - util/qemu-sockets.c | 6 +- .cargo/config.toml.in | 5 + .cargo/meson.build | 5 + .gitignore | 1 + .gitmodules | 4 + Cargo.lock | 119 ++++ Cargo.toml | 6 + meson_options.txt | 5 + qga/Cargo.toml | 24 + qga/lib.rs | 5 + qga/meson.build | 64 ++- qga/qapi-cabi.rs | 6 + qga/qapi.rs | 6 + qga/qapi_ffi.rs | 8 + qga/qmp/hostname.rs | 9 + qga/qmp/mod.rs | 28 + qga/qmp/vcpus.rs | 161 ++++++ rust/common/Cargo.toml | 11 + rust/common/src/error.rs | 113 ++++ rust/common/src/ffi.rs | 93 ++++ rust/common/src/lib.rs | 21 + rust/common/src/qemu.rs | 101 ++++ rust/common/src/qmp.rs | 0 rust/common/src/translate.rs | 482 ++++++++++++++++ rust/vendored | 1 + scripts/archive-source.sh | 2 +- scripts/cargo_wrapper.py | 183 +++++++ scripts/configh_to_cfg.py | 44 ++ scripts/diff_commands.py | 40 ++ scripts/qapi/cabi.py | 187 +++++++ scripts/qapi/common.py | 16 + scripts/qapi/gen.py | 6 +- scripts/qapi/main.py | 25 +- scripts/qapi/rs.py | 262 +++++++++ scripts/qapi/rs_ffi.py | 446 +++++++++++++++ scripts/qapi/rs_types.py | 966 +++++++++++++++++++++++++++++++++ scripts/qapi/schema.py | 23 +- scripts/qapi/types.py | 58 +- tests/Cargo.toml | 17 + tests/lib.rs | 2 + tests/meson.build | 72 ++- tests/qapi-cabi.rs | 5 + tests/qapi.rs | 11 + tests/qapi_ffi.rs | 8 + tests/vm/fedora | 12 +- tests/vm/freebsd | 1 + 61 files changed, 3794 insertions(+), 333 deletions(-) create mode 100644 qga/qapi-cabi.c create mode 100644 tests/qapi-cabi.c create mode 100644 .cargo/config.toml.in create mode 100644 .cargo/meson.build create mode 100644 Cargo.lock create mode 100644 Cargo.toml create mode 100644 qga/Cargo.toml create mode 100644 qga/lib.rs create mode 100644 qga/qapi-cabi.rs create mode 100644 qga/qapi.rs create mode 100644 qga/qapi_ffi.rs create mode 100644 qga/qmp/hostname.rs create mode 100644 qga/qmp/mod.rs create mode 100644 qga/qmp/vcpus.rs create mode 100644 rust/common/Cargo.toml create mode 100644 rust/common/src/error.rs create mode 100644 rust/common/src/ffi.rs create mode 100644 rust/common/src/lib.rs create mode 100644 rust/common/src/qemu.rs create mode 100644 rust/common/src/qmp.rs create mode 100644 rust/common/src/translate.rs create mode 160000 rust/vendored create mode 100644 scripts/cargo_wrapper.py create mode 100644 scripts/configh_to_cfg.py create mode 100644 scripts/diff_commands.py create mode 100644 scripts/qapi/cabi.py create mode 100644 scripts/qapi/rs.py create mode 100644 scripts/qapi/rs_ffi.py create mode 100644 scripts/qapi/rs_types.py create mode 100644 tests/Cargo.toml create mode 100644 tests/lib.rs create mode 100644 tests/qapi-cabi.rs create mode 100644 tests/qapi.rs create mode 100644 tests/qapi_ffi.rs -- 2.33.0.113.g6c40894d24
