rust: move rust.bindgen to qemu-api crate

Once qemu-api is split in multiple crates, each of them will have
its own invocation of bindgen.  There cannot be only one, because
there are occasional "impl" blocks for the bindgen-generated
structs (e.g. VMStateFlags or QOM classes) that have to
reside in the same crate as the bindgen-generated code.

For now, prepare for this new organization by invoking bindgen
within the qemu-api crate's build definitions; it's also a
much better place to list enums that need specific treatment
from bindgen.

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

rust/qemu-api/build.rs

@@ -14,7 +14,7 @@ fn main() -> Result<()> {
     let path = env::var("MESON_BUILD_ROOT")
         .unwrap_or_else(|_| format!("{}/src", env!("CARGO_MANIFEST_DIR")));
 
-    let file = format!("{path}/bindings.inc.rs");
+    let file = format!("{path}/rust/qemu-api/bindings.inc.rs");
     let file = Path::new(&file);
     if !Path::new(&file).exists() {
         panic!(concat!(

rust/qemu-api/meson.build

@@ -7,6 +7,47 @@ if get_option('debug_mutex')
   _qemu_api_cfg += ['--cfg', 'feature="debug_cell"']
 endif
 
+c_enums = [
+  'DeviceCategory',
+  'GpioPolarity',
+  'MachineInitPhase',
+  'MemoryDeviceInfoKind',
+  'MigrationPolicy',
+  'MigrationPriority',
+  'QEMUChrEvent',
+  'QEMUClockType',
+  'ResetType',
+  'device_endian',
+  'module_init_type',
+]
+_qemu_api_bindgen_args = []
+foreach enum : c_enums
+  _qemu_api_bindgen_args += ['--rustified-enum', enum]
+endforeach
+c_bitfields = [
+  'ClockEvent',
+  'VMStateFlags',
+]
+foreach enum : c_bitfields
+  _qemu_api_bindgen_args += ['--bitfield-enum', enum]
+endforeach
+
+# TODO: Remove this comment when the clang/libclang mismatch issue is solved.
+#
+# Rust bindings generation with `bindgen` might fail in some cases where the
+# detected `libclang` does not match the expected `clang` version/target. In
+# this case you must pass the path to `clang` and `libclang` to your build
+# command invocation using the environment variables CLANG_PATH and
+# LIBCLANG_PATH
+_qemu_api_bindings_inc_rs = rust.bindgen(
+  input: 'wrapper.h',
+  dependencies: common_ss.all_dependencies(),
+  output: 'bindings.inc.rs',
+  include_directories: bindings_incdir,
+  bindgen_version: ['>=0.60.0'],
+  args: bindgen_args_common + _qemu_api_bindgen_args,
+  )
+
 _qemu_api_rs = static_library(
   'qemu_api',
   structured_sources(

rust/qemu-api/wrapper.h

@@ -0,0 +1,69 @@
+/*
+ * QEMU System Emulator
+ *
+ * Copyright (c) 2024 Linaro Ltd.
+ *
+ * Authors: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a copy
+ * of this software and associated documentation files (the "Software"), to deal
+ * in the Software without restriction, including without limitation the rights
+ * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+ * copies of the Software, and to permit persons to whom the Software is
+ * furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice shall be included in
+ * all copies or substantial portions of the Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+ * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+ * THE SOFTWARE.
+ */
+
+
+/*
+ * This header file is meant to be used as input to the `bindgen` application
+ * in order to generate C FFI compatible Rust bindings.
+ */
+
+#ifndef __CLANG_STDATOMIC_H
+#define __CLANG_STDATOMIC_H
+/*
+ * Fix potential missing stdatomic.h error in case bindgen does not insert the
+ * correct libclang header paths on its own. We do not use stdatomic.h symbols
+ * in QEMU code, so it's fine to declare dummy types instead.
+ */
+typedef enum memory_order {
+  memory_order_relaxed,
+  memory_order_consume,
+  memory_order_acquire,
+  memory_order_release,
+  memory_order_acq_rel,
+  memory_order_seq_cst,
+} memory_order;
+#endif /* __CLANG_STDATOMIC_H */
+
+#include "qemu/osdep.h"
+#include "qemu/module.h"
+#include "qemu-io.h"
+#include "system/system.h"
+#include "hw/sysbus.h"
+#include "system/memory.h"
+#include "chardev/char-fe.h"
+#include "hw/clock.h"
+#include "hw/qdev-clock.h"
+#include "hw/qdev-properties.h"
+#include "hw/qdev-properties-system.h"
+#include "hw/irq.h"
+#include "qapi/error.h"
+#include "qapi/error-internal.h"
+#include "migration/vmstate.h"
+#include "chardev/char-serial.h"
+#include "exec/memattrs.h"
+#include "qemu/timer.h"
+#include "system/address-spaces.h"
+#include "hw/char/pl011.h"