A log_mask!() macro is provided which expects similar arguments as the
C version. However, the formatting works as one would expect from Rust.
To maximize code reuse the macro is just a thin wrapper around
qemu_log(). Also, just the bare minimum of logging masks is provided
which should suffice for the current use case of Rust in QEMU.
Signed-off-by: Bernhard Beschow <shen...@gmail.com>
---
docs/devel/rust.rst | 1 +
rust/wrapper.h | 2 ++
rust/qemu-api/meson.build | 1 +
rust/qemu-api/src/lib.rs | 1 +
rust/qemu-api/src/log.rs | 76 +++++++++++++++++++++++++++++++++++++++
5 files changed, 81 insertions(+)
create mode 100644 rust/qemu-api/src/log.rs
diff --git a/docs/devel/rust.rst b/docs/devel/rust.rst
index 47e9677fcb..dc8c44109e 100644
--- a/docs/devel/rust.rst
+++ b/docs/devel/rust.rst
@@ -162,6 +162,7 @@ module status
``errno`` complete
``error`` stable
``irq`` complete
+``log`` proof of concept
``memory`` stable
``module`` complete
``qdev`` stable
diff --git a/rust/wrapper.h b/rust/wrapper.h
index 6060d3ba1a..15a1b19847 100644
--- a/rust/wrapper.h
+++ b/rust/wrapper.h
@@ -48,6 +48,8 @@ typedef enum memory_order {
#endif /* __CLANG_STDATOMIC_H */
#include "qemu/osdep.h"
+#include "qemu/log.h"
+#include "qemu/log-for-trace.h"
#include "qemu/module.h"
#include "qemu-io.h"
#include "system/system.h"
diff --git a/rust/qemu-api/meson.build b/rust/qemu-api/meson.build
index cac8595a14..33caee3c4f 100644
--- a/rust/qemu-api/meson.build
+++ b/rust/qemu-api/meson.build
@@ -21,6 +21,7 @@ _qemu_api_rs = static_library(
'src/errno.rs',
'src/error.rs',
'src/irq.rs',
+ 'src/log.rs',
'src/memory.rs',
'src/module.rs',
'src/prelude.rs',
diff --git a/rust/qemu-api/src/lib.rs b/rust/qemu-api/src/lib.rs
index 93902fc94b..e20be35460 100644
--- a/rust/qemu-api/src/lib.rs
+++ b/rust/qemu-api/src/lib.rs
@@ -21,6 +21,7 @@
pub mod errno;
pub mod error;
pub mod irq;
+pub mod log;
pub mod memory;
pub mod module;
pub mod qdev;
diff --git a/rust/qemu-api/src/log.rs b/rust/qemu-api/src/log.rs
new file mode 100644
index 0000000000..9e3c61b8b7
--- /dev/null
+++ b/rust/qemu-api/src/log.rs
@@ -0,0 +1,76 @@
+// Copyright 2025 Bernhard Beschow <shen...@gmail.com>
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+#[repr(u32)]
+/// Represents specific error categories within QEMU's logging system.
+///
+/// The `Log` enum provides a Rust abstraction for logging errors,
corresponding
+/// to a subset of the error categories defined in the C implementation.
+pub enum Log {
+ /// Log an invalid access caused by the guest.
+ /// Corresponds to `LOG_GUEST_ERROR` in the C implementation.
+ GuestError = crate::bindings::LOG_GUEST_ERROR,
+
+ /// Log guest access of unimplemented functionality.
+ /// Corresponds to `LOG_UNIMP` in the C implementation.
+ Unimp = crate::bindings::LOG_UNIMP,
+}
+
+/// A macro to log messages conditionally based on a provided mask.
+///
+/// The `log_mask` macro checks whether the given mask matches the current log
+/// level and, if so, formats and logs the message. It is the Rust counterpart
+/// of the qemu_log_mask() macro in the C implementation.
+///
+/// # Parameters
+///
+/// - `$mask`: A log level mask. This should be a variant of the `Log` enum.
+/// - `$fmt`: A format string following the syntax and rules of the `format!`
+/// macro. It specifies the structure of the log message.
+/// - `$args`: Optional arguments to be interpolated into the format string.
+///
+/// # Example
+///
+/// ```
+/// use qemu_api::log::Log;
+/// use qemu_api::log_mask;
+///
+/// let error_address = 0xbad;
+/// log_mask!(
+/// Log::GuestError,
+/// "Address 0x{error_address:x} out of range\n"
+/// );
+/// ```
+///
+/// It is also possible to use printf-style formatting, as well as having a
+/// trailing `,`:
+///
+/// ```
+/// use qemu_api::log::Log;
+/// use qemu_api::log_mask;
+///
+/// let error_address = 0xbad;
+/// log_mask!(
+/// Log::GuestError,
+/// "Address 0x{:x} out of range\n",
+/// error_address,
+/// );
+/// ```
+#[macro_export]
+macro_rules! log_mask {
+ ($mask:expr, $fmt:tt $($args:tt)*) => {{
+ // Type assertion to enforce type `Log` for $mask
+ let _: Log = $mask;
+
+ if unsafe {
+ (::qemu_api::bindings::qemu_loglevel & ($mask as
std::os::raw::c_int)) != 0
+ } {
+ let formatted_string = format!($fmt $($args)*);
+ let c_string = std::ffi::CString::new(formatted_string).unwrap();
+
+ unsafe {
+ ::qemu_api::bindings::qemu_log(c_string.as_ptr());
+ }
+ }
+ }};
+}
--
2.49.0
