Merge tag 'tracing-pull-request' of https://gitlab.com/stefanha/qemu into staging

Pull request

Tanish Desai and Paolo Bonzini's tracing Rust support.

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# gpg: Signature made Wed 01 Oct 2025 08:30:42 AM PDT
# gpg:                using RSA key 8695A8BFD3F97CDAAC35775A9CA4ABB381AB73C8
# gpg: Good signature from "Stefan Hajnoczi <stefanha@redhat.com>" [unknown]
# gpg:                 aka "Stefan Hajnoczi <stefanha@gmail.com>" [unknown]
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# gpg:          There is no indication that the signature belongs to the owner.
# Primary key fingerprint: 8695 A8BF D3F9 7CDA AC35  775A 9CA4 ABB3 81AB 73C8

* tag 'tracing-pull-request' of https://gitlab.com/stefanha/qemu:
  tracetool/syslog: add Rust support
  tracetool/ftrace: add Rust support
  tracetool/log: add Rust support
  log: change qemu_loglevel to unsigned
  tracetool/simple: add Rust support
  rust: pl011: add tracepoints
  rust: qdev: add minimal clock bindings
  rust: add trace crate
  tracetool: Add Rust format support
  tracetool/backend: remove redundant trace event checks
  tracetool: add CHECK_TRACE_EVENT_GET_STATE
  trace/ftrace: move snprintf+write from tracepoints to ftrace.c
  tracetool: add SPDX headers
  treewide: remove unnessary "coding" header
  tracetool: remove dead code
  tracetool: fix usage of try_import()

Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

docs/conf.py

@@ -1,5 +1,3 @@
-# -*- coding: utf-8 -*-
-#
 # QEMU documentation build configuration file, created by
 # sphinx-quickstart on Thu Jan 31 16:40:14 2019.
 #

docs/sphinx-static/theme_overrides.css

@@ -1,5 +1,4 @@
-/* -*- coding: utf-8; mode: css -*-
- *
+/*
  * Sphinx HTML theme customization: read the doc
  * Based on Linux Documentation/sphinx-static/theme_overrides.css
  */

hw/char/trace-events

@@ -58,15 +58,15 @@ imx_serial_write(const char *chrname, uint64_t addr, uint64_t value) "%s:[0x%03"
 imx_serial_put_data(const char *chrname, uint32_t value) "%s: 0x%" PRIx32
 
 # pl011.c
-pl011_irq_state(int level) "irq state %d"
-pl011_read(uint32_t addr, uint32_t value, const char *regname) "addr 0x%03x value 0x%08x reg %s"
-pl011_read_fifo(unsigned rx_fifo_used, size_t rx_fifo_depth) "RX FIFO read, used %u/%zu"
-pl011_write(uint32_t addr, uint32_t value, const char *regname) "addr 0x%03x value 0x%08x reg %s"
-pl011_can_receive(uint32_t lcr, unsigned rx_fifo_used, size_t rx_fifo_depth, unsigned rx_fifo_available) "LCR 0x%02x, RX FIFO used %u/%zu, can_receive %u chars"
-pl011_fifo_rx_put(uint32_t c, unsigned read_count, size_t rx_fifo_depth) "RX FIFO push char [0x%02x] %d/%zu depth used"
+pl011_irq_state(bool level) "irq state %d"
+pl011_read(uint64_t addr, uint32_t value, const char *regname) "addr 0x%03" PRIx64 " value 0x%08x reg %s"
+pl011_read_fifo(unsigned rx_fifo_used, unsigned rx_fifo_depth) "RX FIFO read, used %u/%u"
+pl011_write(uint64_t addr, uint32_t value, const char *regname) "addr 0x%03" PRIx64 " value 0x%08x reg %s"
+pl011_can_receive(uint32_t lcr, unsigned rx_fifo_used, unsigned rx_fifo_depth, unsigned rx_fifo_available) "LCR 0x%02x, RX FIFO used %u/%u, can_receive %u chars"
+pl011_fifo_rx_put(uint32_t c, unsigned read_count, unsigned rx_fifo_depth) "RX FIFO push char [0x%02x] %d/%u depth used"
 pl011_fifo_rx_full(void) "RX FIFO now full, RXFF set"
 pl011_baudrate_change(unsigned int baudrate, uint64_t clock, uint32_t ibrd, uint32_t fbrd) "new baudrate %u (clk: %" PRIu64 "hz, ibrd: %" PRIu32 ", fbrd: %" PRIu32 ")"
-pl011_receive(int size) "recv %d chars"
+pl011_receive(size_t size) "recv %zd chars"
 
 # cmsdk-apb-uart.c
 cmsdk_apb_uart_read(uint64_t offset, uint64_t data, unsigned size) "CMSDK APB UART read: offset 0x%" PRIx64 " data 0x%" PRIx64 " size %u"

include/qemu/log-for-trace.h

@@ -19,9 +19,9 @@
 #define QEMU_LOG_FOR_TRACE_H
 
 /* Private global variable, don't use */
-extern int qemu_loglevel;
+extern unsigned qemu_loglevel;
 
-#define LOG_TRACE          (1 << 15)
+#define LOG_TRACE          (1u << 15)
 
 /* Returns true if a bit is set in the current loglevel mask */
 static inline bool qemu_loglevel_mask(int mask)

include/qemu/log.h

@@ -14,30 +14,30 @@ bool qemu_log_enabled(void);
 /* Returns true if qemu_log() will write somewhere other than stderr. */
 bool qemu_log_separate(void);
 
-#define CPU_LOG_TB_OUT_ASM (1 << 0)
-#define CPU_LOG_TB_IN_ASM  (1 << 1)
-#define CPU_LOG_TB_OP      (1 << 2)
-#define CPU_LOG_TB_OP_OPT  (1 << 3)
-#define CPU_LOG_INT        (1 << 4)
-#define CPU_LOG_EXEC       (1 << 5)
-#define CPU_LOG_PCALL      (1 << 6)
-#define CPU_LOG_TB_CPU     (1 << 8)
-#define CPU_LOG_RESET      (1 << 9)
-#define LOG_UNIMP          (1 << 10)
-#define LOG_GUEST_ERROR    (1 << 11)
-#define CPU_LOG_MMU        (1 << 12)
-#define CPU_LOG_TB_NOCHAIN (1 << 13)
-#define CPU_LOG_PAGE       (1 << 14)
+#define CPU_LOG_TB_OUT_ASM (1u << 0)
+#define CPU_LOG_TB_IN_ASM  (1u << 1)
+#define CPU_LOG_TB_OP      (1u << 2)
+#define CPU_LOG_TB_OP_OPT  (1u << 3)
+#define CPU_LOG_INT        (1u << 4)
+#define CPU_LOG_EXEC       (1u << 5)
+#define CPU_LOG_PCALL      (1u << 6)
+#define CPU_LOG_TB_CPU     (1u << 8)
+#define CPU_LOG_RESET      (1u << 9)
+#define LOG_UNIMP          (1u << 10)
+#define LOG_GUEST_ERROR    (1u << 11)
+#define CPU_LOG_MMU        (1u << 12)
+#define CPU_LOG_TB_NOCHAIN (1u << 13)
+#define CPU_LOG_PAGE       (1u << 14)
 /* LOG_TRACE (1 << 15) is defined in log-for-trace.h */
-#define CPU_LOG_TB_OP_IND  (1 << 16)
-#define CPU_LOG_TB_FPU     (1 << 17)
-#define CPU_LOG_PLUGIN     (1 << 18)
+#define CPU_LOG_TB_OP_IND  (1u << 16)
+#define CPU_LOG_TB_FPU     (1u << 17)
+#define CPU_LOG_PLUGIN     (1u << 18)
 /* LOG_STRACE is used for user-mode strace logging. */
-#define LOG_STRACE         (1 << 19)
-#define LOG_PER_THREAD     (1 << 20)
-#define CPU_LOG_TB_VPU     (1 << 21)
-#define LOG_TB_OP_PLUGIN   (1 << 22)
-#define LOG_INVALID_MEM    (1 << 23)
+#define LOG_STRACE         (1u << 19)
+#define LOG_PER_THREAD     (1u << 20)
+#define CPU_LOG_TB_VPU     (1u << 21)
+#define LOG_TB_OP_PLUGIN   (1u << 22)
+#define LOG_INVALID_MEM    (1u << 23)
 
 /* Lock/unlock output. */
 

rust/Cargo.lock

@@ -159,6 +159,7 @@ dependencies = [
  "migration",
  "qom",
  "system",
+ "trace",
  "util",
 ]
 
@@ -258,6 +259,13 @@ dependencies = [
  "util",
 ]
 
+[[package]]
+name = "trace"
+version = "0.1.0"
+dependencies = [
+ "libc",
+]
+
 [[package]]
 name = "unicode-ident"
 version = "1.0.12"

rust/Cargo.toml

@@ -11,6 +11,7 @@ members = [
     "hw/core",
     "hw/char/pl011",
     "hw/timer/hpet",
+    "trace",
     "util",
     "tests",
 ]

rust/hw/char/pl011/Cargo.toml

@@ -24,6 +24,7 @@ qom = { path = "../../../qom" }
 chardev = { path = "../../../chardev" }
 system = { path = "../../../system" }
 hwcore = { path = "../../../hw/core" }
+trace = { path = "../../../trace" }
 
 [lints]
 workspace = true

rust/hw/char/pl011/meson.build

@@ -40,6 +40,7 @@ _libpl011_rs = static_library(
     chardev_rs,
     system_rs,
     hwcore_rs,
+    trace_rs
   ],
 )
 

rust/hw/char/pl011/src/device.rs

@@ -21,6 +21,8 @@ use util::{log::Log, log_mask_ln};
 
 use crate::registers::{self, Interrupt, RegisterOffset};
 
+::trace::include_trace!("hw_char");
+
 // TODO: You must disable the UART before any of the control registers are
 // reprogrammed. When the UART is disabled in the middle of transmission or
 // reception, it completes the current character before stopping
@@ -208,13 +210,7 @@ impl PL011Registers {
         (update, result)
     }
 
-    pub(self) fn write(
-        &mut self,
-        offset: RegisterOffset,
-        value: u32,
-        char_backend: &CharBackend,
-    ) -> bool {
-        // eprintln!("write offset {offset} value {value}");
+    pub(self) fn write(&mut self, offset: RegisterOffset, value: u32, device: &PL011State) -> bool {
         use RegisterOffset::*;
         match offset {
             DR => return self.write_data_register(value),
@@ -229,9 +225,11 @@ impl PL011Registers {
             }
             IBRD => {
                 self.ibrd = value;
+                device.trace_baudrate_change(self.ibrd, self.fbrd);
             }
             FBRD => {
                 self.fbrd = value;
+                device.trace_baudrate_change(self.ibrd, self.fbrd);
             }
             LCR_H => {
                 let new_val: registers::LineControl = value.into();
@@ -242,7 +240,7 @@ impl PL011Registers {
                 }
                 let update = (self.line_control.send_break() != new_val.send_break()) && {
                     let break_enable = new_val.send_break();
-                    let _ = char_backend.send_break(break_enable);
+                    let _ = device.char_backend.send_break(break_enable);
                     self.loopback_break(break_enable)
                 };
                 self.line_control = new_val;
@@ -279,12 +277,13 @@ impl PL011Registers {
     }
 
     fn read_data_register(&mut self, update: &mut bool) -> u32 {
+        let depth = self.fifo_depth();
         self.flags.set_receive_fifo_full(false);
         let c = self.read_fifo[self.read_pos];
 
         if self.read_count > 0 {
             self.read_count -= 1;
-            self.read_pos = (self.read_pos + 1) & (self.fifo_depth() - 1);
+            self.read_pos = (self.read_pos + 1) & (depth - 1);
         }
         if self.read_count == 0 {
             self.flags.set_receive_fifo_empty(true);
@@ -292,6 +291,7 @@ impl PL011Registers {
         if self.read_count + 1 == self.read_trigger {
             self.int_level &= !Interrupt::RX;
         }
+        trace::trace_pl011_read_fifo(self.read_count, depth);
         self.receive_status_error_clear.set_from_data(c);
         *update = true;
         u32::from(c)
@@ -447,7 +447,9 @@ impl PL011Registers {
         self.read_fifo[slot] = value;
         self.read_count += 1;
         self.flags.set_receive_fifo_empty(false);
+        trace::trace_pl011_fifo_rx_put(value.into(), self.read_count, depth);
         if self.read_count == depth {
+            trace::trace_pl011_fifo_rx_full();
             self.flags.set_receive_fifo_full(true);
         }
 
@@ -516,8 +518,21 @@ impl PL011State {
         uninit_field_mut!(*this, clock).write(clock);
     }
 
-    const fn clock_update(&self, _event: ClockEvent) {
-        /* pl011_trace_baudrate_change(s); */
+    pub fn trace_baudrate_change(&self, ibrd: u32, fbrd: u32) {
+        let divider = 4.0 / f64::from(ibrd * (FBRD_MASK + 1) + fbrd);
+        let hz = self.clock.hz();
+        let rate = if ibrd == 0 {
+            0
+        } else {
+            ((hz as f64) * divider) as u32
+        };
+        trace::trace_pl011_baudrate_change(rate, hz, ibrd, fbrd);
+    }
+
+    fn clock_update(&self, _event: ClockEvent) {
+        let regs = self.regs.borrow();
+        let (ibrd, fbrd) = (regs.ibrd, regs.fbrd);
+        self.trace_baudrate_change(ibrd, fbrd)
     }
 
     pub fn clock_needed(&self) -> bool {
@@ -543,6 +558,7 @@ impl PL011State {
             }
             Ok(field) => {
                 let (update_irq, result) = self.regs.borrow_mut().read(field);
+                trace::trace_pl011_read(offset, result, c"");
                 if update_irq {
                     self.update();
                     self.char_backend.accept_input();
@@ -557,6 +573,7 @@ impl PL011State {
         if let Ok(field) = RegisterOffset::try_from(offset) {
             // qemu_chr_fe_write_all() calls into the can_receive
             // callback, so handle writes before entering PL011Registers.
+            trace::trace_pl011_write(offset, value as u32, c"");
             if field == RegisterOffset::DR {
                 // ??? Check if transmitter is enabled.
                 let ch: [u8; 1] = [value as u8];
@@ -565,10 +582,7 @@ impl PL011State {
                 let _ = self.char_backend.write_all(&ch);
             }
 
-            update_irq = self
-                .regs
-                .borrow_mut()
-                .write(field, value as u32, &self.char_backend);
+            update_irq = self.regs.borrow_mut().write(field, value as u32, self);
         } else {
             log_mask_ln!(
                 Log::GuestError,
@@ -582,11 +596,19 @@ impl PL011State {
 
     fn can_receive(&self) -> u32 {
         let regs = self.regs.borrow();
-        // trace_pl011_can_receive(s->lcr, s->read_count, r);
-        regs.fifo_depth() - regs.read_count
+        let fifo_available = regs.fifo_depth() - regs.read_count;
+        trace::trace_pl011_can_receive(
+            regs.line_control.into(),
+            regs.read_count,
+            regs.fifo_depth(),
+            fifo_available,
+        );
+        fifo_available
     }
 
     fn receive(&self, buf: &[u8]) {
+        trace::trace_pl011_receive(buf.len());
+
         let mut regs = self.regs.borrow_mut();
         if regs.loopback_enabled() {
             // In loopback mode, the RX input signal is internally disconnected
@@ -635,6 +657,7 @@ impl PL011State {
     fn update(&self) {
         let regs = self.regs.borrow();
         let flags = regs.int_level & regs.int_enabled;
+        trace::trace_pl011_irq_state(flags != 0);
         for (irq, i) in self.interrupts.iter().zip(IRQMASK) {
             irq.set(flags.any_set(i));
         }

rust/hw/core/src/qdev.rs

@@ -411,6 +411,39 @@ where
 
 impl<R: ObjectDeref> DeviceMethods for R where R::Target: IsA<DeviceState> {}
 
+impl Clock {
+    pub const PERIOD_1SEC: u64 = bindings::CLOCK_PERIOD_1SEC;
+
+    pub const fn period_from_ns(ns: u64) -> u64 {
+        ns * Self::PERIOD_1SEC / 1_000_000_000
+    }
+
+    pub const fn period_from_hz(hz: u64) -> u64 {
+        if hz == 0 {
+            0
+        } else {
+            Self::PERIOD_1SEC / hz
+        }
+    }
+
+    pub const fn period_to_hz(period: u64) -> u64 {
+        if period == 0 {
+            0
+        } else {
+            Self::PERIOD_1SEC / period
+        }
+    }
+
+    pub const fn period(&self) -> u64 {
+        // SAFETY: Clock is returned by init_clock_in with zero value for period
+        unsafe { &*self.0.as_ptr() }.period
+    }
+
+    pub const fn hz(&self) -> u64 {
+        Self::period_to_hz(self.period())
+    }
+}
+
 unsafe impl ObjectType for Clock {
     type Class = ObjectClass;
     const TYPE_NAME: &'static CStr =

rust/meson.build

@@ -34,7 +34,7 @@ subdir('system')
 subdir('chardev')
 subdir('hw/core')
 subdir('tests')
-
+subdir('trace')
 subdir('hw')
 
 cargo = find_program('cargo', required: false)

rust/trace/Cargo.toml

@@ -0,0 +1,19 @@
+[package]
+name = "trace"
+version = "0.1.0"
+authors = ["Tanish Desai <tanishdesai37@gmail.com>"]
+description = "QEMU tracing infrastructure support"
+resolver = "2"
+publish = false
+
+edition.workspace = true
+homepage.workspace = true
+license.workspace = true
+repository.workspace = true
+rust-version.workspace = true
+
+[dependencies]
+libc = { workspace = true }
+
+[lints]
+workspace = true

rust/trace/meson.build

@@ -0,0 +1,19 @@
+rust = import('rust')
+
+lib_rs = configure_file(
+  input: 'src/lib.rs',
+  output: 'lib.rs',
+  configuration: {
+    'MESON_BUILD_ROOT': meson.project_build_root(),
+  })
+
+_trace_rs = static_library(
+  'trace',             # Library name,
+  lib_rs,
+  trace_rs_targets,         # List of generated `.rs` custom targets
+  override_options: ['rust_std=2021', 'build.rust_std=2021'],
+  dependencies: [libc_rs],
+  rust_abi: 'rust',
+)
+
+trace_rs = declare_dependency(link_with: _trace_rs)

rust/trace/src/lib.rs

@@ -0,0 +1,39 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+
+//! This crate provides macros that aid in using QEMU's tracepoint
+//! functionality.
+
+#[doc(hidden)]
+/// Re-exported item to avoid adding libc as a dependency everywhere.
+pub use libc::{syslog, LOG_INFO};
+
+#[macro_export]
+/// Define the trace-points from the named directory (which should have slashes
+/// replaced by underscore characters) as functions in a module called `trace`.
+///
+/// ```ignore
+/// ::trace::include_trace!("hw_char");
+/// // ...
+/// trace::trace_pl011_read_fifo_rx_full();
+/// ```
+macro_rules! include_trace {
+    ($name:literal) => {
+        #[allow(
+            clippy::ptr_as_ptr,
+            clippy::cast_lossless,
+            clippy::used_underscore_binding
+        )]
+        mod trace {
+            #[cfg(not(MESON))]
+            include!(concat!(
+                env!("MESON_BUILD_ROOT"),
+                "/trace/trace-",
+                $name,
+                ".rs"
+            ));
+
+            #[cfg(MESON)]
+            include!(concat!("@MESON_BUILD_ROOT@/trace/trace-", $name, ".rs"));
+        }
+    };
+}

rust/util/src/log.rs

@@ -142,7 +142,7 @@ macro_rules! log_mask_ln {
         let _: $crate::log::Log = $mask;
 
         if unsafe {
-            ($crate::bindings::qemu_loglevel & ($mask as std::os::raw::c_int)) != 0
+            ($crate::bindings::qemu_loglevel & ($mask as std::os::raw::c_uint)) != 0
         } {
             _ = $crate::log::LogGuard::log_fmt(
                 format_args!("{}\n", format_args!($fmt $($args)*)));

scripts/analyse-locks-simpletrace.py

@@ -1,5 +1,4 @@
 #!/usr/bin/env python3
-# -*- coding: utf-8 -*-
 #
 # Analyse lock events and compute statistics
 #

scripts/modinfo-collect.py

@@ -1,5 +1,4 @@
 #!/usr/bin/env python3
-# -*- coding: utf-8 -*-
 
 import os
 import sys

scripts/modinfo-generate.py

@@ -1,5 +1,4 @@
 #!/usr/bin/env python3
-# -*- coding: utf-8 -*-
 
 import os
 import sys

scripts/oss-fuzz/minimize_qtest_trace.py

@@ -1,5 +1,4 @@
 #!/usr/bin/env python3
-# -*- coding: utf-8 -*-
 
 """
 This takes a crashing qtest trace and tries to remove superfluous operations