[PATCH 0/2] rust/hpet: add trace events

[PATCH 0/2] rust/hpet: add trace events

[Stefan Hajnoczi]

The Rust hpet device implementation has todo comments where the trace events
belong. This patch series implements the missing trace events.

Stefan Hajnoczi (2):
  hpet: remove unused trace events
  rust/hpet: add trace events

 hw/timer/trace-events            |  2 --
 rust/hw/timer/hpet/Cargo.toml    |  1 +
 rust/hw/timer/hpet/meson.build   |  1 +
 rust/hw/timer/hpet/src/device.rs | 45 +++++++++++++++++++-------------
 4 files changed, 29 insertions(+), 20 deletions(-)

-- 
2.51.1

[PATCH 1/2] hpet: remove unused trace events

[Stefan Hajnoczi]

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 hw/timer/trace-events | 2 --
 1 file changed, 2 deletions(-)

diff --git a/hw/timer/trace-events b/hw/timer/trace-events
index 2bb51f95ea..f3fca6fc9b 100644
--- a/hw/timer/trace-events
+++ b/hw/timer/trace-events
@@ -112,7 +112,6 @@ sh_timer_write(uint64_t offset, uint64_t value) "tmu012_write 0x%" PRIx64 " 0x%0
 
 # hpet.c
 hpet_timer_id_out_of_range(uint8_t timer_id) "timer id out of range: 0x%" PRIx8
-hpet_invalid_hpet_cfg(uint8_t reg_off) "invalid HPET_CFG + %u" PRIx8
 hpet_ram_read(uint64_t addr) "enter hpet_ram_readl at 0x%" PRIx64
 hpet_ram_read_reading_counter(uint8_t reg_off, uint64_t cur_tick) "reading counter + %" PRIu8 " = 0x%" PRIx64
 hpet_ram_read_invalid(void) "invalid hpet_ram_readl"
@@ -123,4 +122,3 @@ hpet_ram_write_tn_cmp(uint8_t reg_off) "hpet_ram_writel HPET_TN_CMP + %" PRIu8
 hpet_ram_write_invalid_tn_cmp(void) "invalid HPET_TN_CMP + 4 write"
 hpet_ram_write_invalid(void) "invalid hpet_ram_writel"
 hpet_ram_write_counter_write_while_enabled(void) "Writing counter while HPET enabled!"
-hpet_ram_write_counter_written(uint8_t reg_off, uint64_t value, uint64_t counter) "HPET counter + %" PRIu8 "written. crt = 0x%" PRIx64 " -> 0x%" PRIx64
-- 
2.51.1

[PATCH 2/2] rust/hpet: add trace events

[Stefan Hajnoczi]

Implement the same trace events as the C implementation.

Notes:
- Keep order of hpet_ram_write_invalid_tn_cmp and hpet_ram_write_tn_cmp
  the same as the C implementation.
- Put hpet_ram_write_timer_id in HPETTimer::write() instead of
  HPETState::decode() so that reads can be excluded.

Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
---
 rust/hw/timer/hpet/Cargo.toml    |  1 +
 rust/hw/timer/hpet/meson.build   |  1 +
 rust/hw/timer/hpet/src/device.rs | 45 +++++++++++++++++++-------------
 3 files changed, 29 insertions(+), 18 deletions(-)

diff --git a/rust/hw/timer/hpet/Cargo.toml b/rust/hw/timer/hpet/Cargo.toml
index f781b28d8b..5567eefda4 100644
--- a/rust/hw/timer/hpet/Cargo.toml
+++ b/rust/hw/timer/hpet/Cargo.toml
@@ -18,6 +18,7 @@ bql = { path = "../../../bql" }
 qom = { path = "../../../qom" }
 system = { path = "../../../system" }
 hwcore = { path = "../../../hw/core" }
+trace = { path = "../../../trace" }
 
 [lints]
 workspace = true
diff --git a/rust/hw/timer/hpet/meson.build b/rust/hw/timer/hpet/meson.build
index bb64b96672..465995bb5a 100644
--- a/rust/hw/timer/hpet/meson.build
+++ b/rust/hw/timer/hpet/meson.build
@@ -11,6 +11,7 @@ _libhpet_rs = static_library(
     qom_rs,
     system_rs,
     hwcore_rs,
+    trace_rs
   ],
 )
 
diff --git a/rust/hw/timer/hpet/src/device.rs b/rust/hw/timer/hpet/src/device.rs
index 3564aa79c6..90b0ae927c 100644
--- a/rust/hw/timer/hpet/src/device.rs
+++ b/rust/hw/timer/hpet/src/device.rs
@@ -32,6 +32,8 @@
 
 use crate::fw_cfg::HPETFwConfig;
 
+::trace::include_trace!("hw_timer");
+
 /// Register space for each timer block (`HPET_BASE` is defined in hpet.h).
 const HPET_REG_SPACE_LEN: u64 = 0x400; // 1024 bytes
 
@@ -402,7 +404,8 @@ fn del_timer(&mut self) {
 
     /// Configuration and Capability Register
     fn set_tn_cfg_reg(&mut self, shift: u32, len: u32, val: u64) {
-        // TODO: Add trace point - trace_hpet_ram_write_tn_cfg(addr & 4)
+        trace::trace_hpet_ram_write_tn_cfg((shift / 8).try_into().unwrap());
+
         let old_val: u64 = self.config;
         let mut new_val: u64 = old_val.deposit(shift, len, val);
         new_val = hpet_fixup_reg(new_val, old_val, HPET_TN_CFG_WRITE_MASK);
@@ -435,17 +438,18 @@ fn set_tn_cmp_reg(&mut self, shift: u32, len: u32, val: u64) {
         let mut length = len;
         let mut value = val;
 
-        // TODO: Add trace point - trace_hpet_ram_write_tn_cmp(addr & 4)
         if self.is_32bit_mod() {
             // High 32-bits are zero, leave them untouched.
             if shift != 0 {
-                // TODO: Add trace point - trace_hpet_ram_write_invalid_tn_cmp()
+                trace::trace_hpet_ram_write_invalid_tn_cmp();
                 return;
             }
             length = 64;
             value = u64::from(value as u32); // truncate!
         }
 
+        trace::trace_hpet_ram_write_tn_cmp((shift / 8).try_into().unwrap());
+
         if !self.is_periodic() || self.is_valset_enabled() {
             self.cmp = self.cmp.deposit(shift, length, value);
         }
@@ -512,6 +516,9 @@ const fn read(&self, reg: TimerRegister) -> u64 {
 
     fn write(&mut self, reg: TimerRegister, value: u64, shift: u32, len: u32) {
         use TimerRegister::*;
+
+        trace::trace_hpet_ram_write_timer_id(self.index as u64);
+
         match reg {
             CFG => self.set_tn_cfg_reg(shift, len, value),
             CMP => self.set_tn_cmp_reg(shift, len, value),
@@ -689,15 +696,13 @@ fn set_int_status_reg(&self, shift: u32, _len: u32, val: u64) {
     /// Main Counter Value Register
     fn set_counter_reg(&self, shift: u32, len: u32, val: u64) {
         if self.is_hpet_enabled() {
-            // TODO: Add trace point -
-            // trace_hpet_ram_write_counter_write_while_enabled()
-            //
             // HPET spec says that writes to this register should only be
             // done while the counter is halted. So this is an undefined
             // behavior. There's no need to forbid it, but when HPET is
             // enabled, the changed counter value will not affect the
             // tick count (i.e., the previously calculated offset will
             // not be changed as well).
+            trace::trace_hpet_ram_write_counter_write_while_enabled();
         }
         self.counter
             .set(self.counter.get().deposit(shift, len, val));
@@ -787,11 +792,10 @@ fn decode(&self, mut addr: hwaddr, size: u32) -> HPETAddrDecode<'_> {
         } else {
             let timer_id: usize = ((addr - 0x100) / 0x20) as usize;
             if timer_id < self.num_timers {
-                // TODO: Add trace point - trace_hpet_ram_[read|write]_timer_id(timer_id)
                 TimerRegister::try_from(addr & 0x18)
                     .map(|reg| HPETRegister::Timer(&self.timers[timer_id], reg))
             } else {
-                // TODO: Add trace point -  trace_hpet_timer_id_out_of_range(timer_id)
+                trace::trace_hpet_timer_id_out_of_range(timer_id.try_into().unwrap());
                 Err(addr)
             }
         };
@@ -803,7 +807,8 @@ fn decode(&self, mut addr: hwaddr, size: u32) -> HPETAddrDecode<'_> {
     }
 
     fn read(&self, addr: hwaddr, size: u32) -> u64 {
-        // TODO: Add trace point - trace_hpet_ram_read(addr)
+        trace::trace_hpet_ram_read(addr);
+
         let HPETAddrDecode { shift, reg, .. } = self.decode(addr, size);
 
         use GlobalRegister::*;
@@ -814,16 +819,21 @@ fn read(&self, addr: hwaddr, size: u32) -> u64 {
             Global(CFG) => self.config.get(),
             Global(INT_STATUS) => self.int_status.get(),
             Global(COUNTER) => {
-                // TODO: Add trace point
-                // trace_hpet_ram_read_reading_counter(addr & 4, cur_tick)
-                if self.is_hpet_enabled() {
+                let cur_tick = if self.is_hpet_enabled() {
                     self.get_ticks()
                 } else {
                     self.counter.get()
-                }
+                };
+
+                trace::trace_hpet_ram_read_reading_counter(
+                    (addr & 4) as u8,
+                    cur_tick
+                );
+
+                cur_tick
             }
             Unknown(_) => {
-                // TODO: Add trace point- trace_hpet_ram_read_invalid()
+                trace::trace_hpet_ram_read_invalid();
                 0
             }
         }) >> shift
@@ -832,7 +842,8 @@ fn read(&self, addr: hwaddr, size: u32) -> u64 {
     fn write(&self, addr: hwaddr, value: u64, size: u32) {
         let HPETAddrDecode { shift, len, reg } = self.decode(addr, size);
 
-        // TODO: Add trace point - trace_hpet_ram_write(addr, value)
+        trace::trace_hpet_ram_write(addr, value);
+
         use GlobalRegister::*;
         use HPETRegister::*;
         match reg {
@@ -841,9 +852,7 @@ fn write(&self, addr: hwaddr, value: u64, size: u32) {
             Global(CFG) => self.set_cfg_reg(shift, len, value),
             Global(INT_STATUS) => self.set_int_status_reg(shift, len, value),
             Global(COUNTER) => self.set_counter_reg(shift, len, value),
-            Unknown(_) => {
-                // TODO: Add trace point - trace_hpet_ram_write_invalid()
-            }
+            Unknown(_) => trace::trace_hpet_ram_write_invalid(),
         }
     }
 
-- 
2.51.1

Re: [PATCH 1/2] hpet: remove unused trace events

[Manos Pitsidianakis]

On Sun, Nov 9, 2025 at 3:57 PM Stefan Hajnoczi <stefanha@redhat.com> wrote:
>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---

Reviewed-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>

>  hw/timer/trace-events | 2 --
>  1 file changed, 2 deletions(-)
>
> diff --git a/hw/timer/trace-events b/hw/timer/trace-events
> index 2bb51f95ea..f3fca6fc9b 100644
> --- a/hw/timer/trace-events
> +++ b/hw/timer/trace-events
> @@ -112,7 +112,6 @@ sh_timer_write(uint64_t offset, uint64_t value) "tmu012_write 0x%" PRIx64 " 0x%0
>
>  # hpet.c
>  hpet_timer_id_out_of_range(uint8_t timer_id) "timer id out of range: 0x%" PRIx8
> -hpet_invalid_hpet_cfg(uint8_t reg_off) "invalid HPET_CFG + %u" PRIx8
>  hpet_ram_read(uint64_t addr) "enter hpet_ram_readl at 0x%" PRIx64
>  hpet_ram_read_reading_counter(uint8_t reg_off, uint64_t cur_tick) "reading counter + %" PRIu8 " = 0x%" PRIx64
>  hpet_ram_read_invalid(void) "invalid hpet_ram_readl"
> @@ -123,4 +122,3 @@ hpet_ram_write_tn_cmp(uint8_t reg_off) "hpet_ram_writel HPET_TN_CMP + %" PRIu8
>  hpet_ram_write_invalid_tn_cmp(void) "invalid HPET_TN_CMP + 4 write"
>  hpet_ram_write_invalid(void) "invalid hpet_ram_writel"
>  hpet_ram_write_counter_write_while_enabled(void) "Writing counter while HPET enabled!"
> -hpet_ram_write_counter_written(uint8_t reg_off, uint64_t value, uint64_t counter) "HPET counter + %" PRIu8 "written. crt = 0x%" PRIx64 " -> 0x%" PRIx64
> --
> 2.51.1
>

Re: [PATCH 2/2] rust/hpet: add trace events

[Manos Pitsidianakis]

On Sun, Nov 9, 2025 at 3:57 PM Stefan Hajnoczi <stefanha@redhat.com> wrote:
>
> Implement the same trace events as the C implementation.
>
> Notes:
> - Keep order of hpet_ram_write_invalid_tn_cmp and hpet_ram_write_tn_cmp
>   the same as the C implementation.
> - Put hpet_ram_write_timer_id in HPETTimer::write() instead of
>   HPETState::decode() so that reads can be excluded.
>
> Signed-off-by: Stefan Hajnoczi <stefanha@redhat.com>
> ---

LGTM but let's see what Zhao has to say also.

Reviewed-by: Manos Pitsidianakis <manos.pitsidianakis@linaro.org>

>  rust/hw/timer/hpet/Cargo.toml    |  1 +
>  rust/hw/timer/hpet/meson.build   |  1 +
>  rust/hw/timer/hpet/src/device.rs | 45 +++++++++++++++++++-------------
>  3 files changed, 29 insertions(+), 18 deletions(-)
>
> diff --git a/rust/hw/timer/hpet/Cargo.toml b/rust/hw/timer/hpet/Cargo.toml
> index f781b28d8b..5567eefda4 100644
> --- a/rust/hw/timer/hpet/Cargo.toml
> +++ b/rust/hw/timer/hpet/Cargo.toml
> @@ -18,6 +18,7 @@ bql = { path = "../../../bql" }
>  qom = { path = "../../../qom" }
>  system = { path = "../../../system" }
>  hwcore = { path = "../../../hw/core" }
> +trace = { path = "../../../trace" }
>
>  [lints]
>  workspace = true
> diff --git a/rust/hw/timer/hpet/meson.build b/rust/hw/timer/hpet/meson.build
> index bb64b96672..465995bb5a 100644
> --- a/rust/hw/timer/hpet/meson.build
> +++ b/rust/hw/timer/hpet/meson.build
> @@ -11,6 +11,7 @@ _libhpet_rs = static_library(
>      qom_rs,
>      system_rs,
>      hwcore_rs,
> +    trace_rs
>    ],
>  )
>
> diff --git a/rust/hw/timer/hpet/src/device.rs b/rust/hw/timer/hpet/src/device.rs
> index 3564aa79c6..90b0ae927c 100644
> --- a/rust/hw/timer/hpet/src/device.rs
> +++ b/rust/hw/timer/hpet/src/device.rs
> @@ -32,6 +32,8 @@
>
>  use crate::fw_cfg::HPETFwConfig;
>
> +::trace::include_trace!("hw_timer");
> +
>  /// Register space for each timer block (`HPET_BASE` is defined in hpet.h).
>  const HPET_REG_SPACE_LEN: u64 = 0x400; // 1024 bytes
>
> @@ -402,7 +404,8 @@ fn del_timer(&mut self) {
>
>      /// Configuration and Capability Register
>      fn set_tn_cfg_reg(&mut self, shift: u32, len: u32, val: u64) {
> -        // TODO: Add trace point - trace_hpet_ram_write_tn_cfg(addr & 4)
> +        trace::trace_hpet_ram_write_tn_cfg((shift / 8).try_into().unwrap());
> +
>          let old_val: u64 = self.config;
>          let mut new_val: u64 = old_val.deposit(shift, len, val);
>          new_val = hpet_fixup_reg(new_val, old_val, HPET_TN_CFG_WRITE_MASK);
> @@ -435,17 +438,18 @@ fn set_tn_cmp_reg(&mut self, shift: u32, len: u32, val: u64) {
>          let mut length = len;
>          let mut value = val;
>
> -        // TODO: Add trace point - trace_hpet_ram_write_tn_cmp(addr & 4)
>          if self.is_32bit_mod() {
>              // High 32-bits are zero, leave them untouched.
>              if shift != 0 {
> -                // TODO: Add trace point - trace_hpet_ram_write_invalid_tn_cmp()
> +                trace::trace_hpet_ram_write_invalid_tn_cmp();
>                  return;
>              }
>              length = 64;
>              value = u64::from(value as u32); // truncate!
>          }
>
> +        trace::trace_hpet_ram_write_tn_cmp((shift / 8).try_into().unwrap());
> +
>          if !self.is_periodic() || self.is_valset_enabled() {
>              self.cmp = self.cmp.deposit(shift, length, value);
>          }
> @@ -512,6 +516,9 @@ const fn read(&self, reg: TimerRegister) -> u64 {
>
>      fn write(&mut self, reg: TimerRegister, value: u64, shift: u32, len: u32) {
>          use TimerRegister::*;
> +
> +        trace::trace_hpet_ram_write_timer_id(self.index as u64);
> +
>          match reg {
>              CFG => self.set_tn_cfg_reg(shift, len, value),
>              CMP => self.set_tn_cmp_reg(shift, len, value),
> @@ -689,15 +696,13 @@ fn set_int_status_reg(&self, shift: u32, _len: u32, val: u64) {
>      /// Main Counter Value Register
>      fn set_counter_reg(&self, shift: u32, len: u32, val: u64) {
>          if self.is_hpet_enabled() {
> -            // TODO: Add trace point -
> -            // trace_hpet_ram_write_counter_write_while_enabled()
> -            //
>              // HPET spec says that writes to this register should only be
>              // done while the counter is halted. So this is an undefined
>              // behavior. There's no need to forbid it, but when HPET is
>              // enabled, the changed counter value will not affect the
>              // tick count (i.e., the previously calculated offset will
>              // not be changed as well).
> +            trace::trace_hpet_ram_write_counter_write_while_enabled();
>          }
>          self.counter
>              .set(self.counter.get().deposit(shift, len, val));
> @@ -787,11 +792,10 @@ fn decode(&self, mut addr: hwaddr, size: u32) -> HPETAddrDecode<'_> {
>          } else {
>              let timer_id: usize = ((addr - 0x100) / 0x20) as usize;
>              if timer_id < self.num_timers {
> -                // TODO: Add trace point - trace_hpet_ram_[read|write]_timer_id(timer_id)
>                  TimerRegister::try_from(addr & 0x18)
>                      .map(|reg| HPETRegister::Timer(&self.timers[timer_id], reg))
>              } else {
> -                // TODO: Add trace point -  trace_hpet_timer_id_out_of_range(timer_id)
> +                trace::trace_hpet_timer_id_out_of_range(timer_id.try_into().unwrap());
>                  Err(addr)
>              }
>          };
> @@ -803,7 +807,8 @@ fn decode(&self, mut addr: hwaddr, size: u32) -> HPETAddrDecode<'_> {
>      }
>
>      fn read(&self, addr: hwaddr, size: u32) -> u64 {
> -        // TODO: Add trace point - trace_hpet_ram_read(addr)
> +        trace::trace_hpet_ram_read(addr);
> +
>          let HPETAddrDecode { shift, reg, .. } = self.decode(addr, size);
>
>          use GlobalRegister::*;
> @@ -814,16 +819,21 @@ fn read(&self, addr: hwaddr, size: u32) -> u64 {
>              Global(CFG) => self.config.get(),
>              Global(INT_STATUS) => self.int_status.get(),
>              Global(COUNTER) => {
> -                // TODO: Add trace point
> -                // trace_hpet_ram_read_reading_counter(addr & 4, cur_tick)
> -                if self.is_hpet_enabled() {
> +                let cur_tick = if self.is_hpet_enabled() {
>                      self.get_ticks()
>                  } else {
>                      self.counter.get()
> -                }
> +                };
> +
> +                trace::trace_hpet_ram_read_reading_counter(
> +                    (addr & 4) as u8,
> +                    cur_tick
> +                );
> +
> +                cur_tick
>              }
>              Unknown(_) => {
> -                // TODO: Add trace point- trace_hpet_ram_read_invalid()
> +                trace::trace_hpet_ram_read_invalid();
>                  0
>              }
>          }) >> shift
> @@ -832,7 +842,8 @@ fn read(&self, addr: hwaddr, size: u32) -> u64 {
>      fn write(&self, addr: hwaddr, value: u64, size: u32) {
>          let HPETAddrDecode { shift, len, reg } = self.decode(addr, size);
>
> -        // TODO: Add trace point - trace_hpet_ram_write(addr, value)
> +        trace::trace_hpet_ram_write(addr, value);
> +
>          use GlobalRegister::*;
>          use HPETRegister::*;
>          match reg {
> @@ -841,9 +852,7 @@ fn write(&self, addr: hwaddr, value: u64, size: u32) {
>              Global(CFG) => self.set_cfg_reg(shift, len, value),
>              Global(INT_STATUS) => self.set_int_status_reg(shift, len, value),
>              Global(COUNTER) => self.set_counter_reg(shift, len, value),
> -            Unknown(_) => {
> -                // TODO: Add trace point - trace_hpet_ram_write_invalid()
> -            }
> +            Unknown(_) => trace::trace_hpet_ram_write_invalid(),
>          }
>      }
>
> --
> 2.51.1
>

Re: [PATCH 0/2] rust/hpet: add trace events

[Paolo Bonzini]

Queued, thanks.

Paolo