[PATCH 12/12] rust/hpet: Drop BqlCell wrapper for num_timers

[Paolo Bonzini <pbonzini@redhat.com>]

From: Zhao Liu <zhao1.liu@intel.com>

Now that the num_timers field is initialized as a property, someone may
change its default value using qdev_prop_set_uint8(), but the value is
fixed after the Rust code sees it first.  Since there is no need to modify
it after realize(), it is not to be necessary to have a BqlCell wrapper.

Signed-off-by: Zhao Liu <zhao1.liu@intel.com>
Link: https://lore.kernel.org/r/20250520152750.2542612-4-zhao1.liu@intel.com
[Remove .into() as well. - Paolo]
Signed-off-by: Paolo Bonzini <pbonzini@redhat.com>
---
 rust/hw/timer/hpet/src/hpet.rs | 27 +++++++++++----------------
 1 file changed, 11 insertions(+), 16 deletions(-)

diff --git a/rust/hw/timer/hpet/src/hpet.rs b/rust/hw/timer/hpet/src/hpet.rs
index b298938e4d5..3c5c65ff47d 100644
--- a/rust/hw/timer/hpet/src/hpet.rs
+++ b/rust/hw/timer/hpet/src/hpet.rs
@@ -562,7 +562,7 @@ pub struct HPETState {
     /// HPET timer array managed by this timer block.
     #[doc(alias = "timer")]
     timers: [BqlRefCell<HPETTimer>; HPET_MAX_TIMERS],
-    num_timers: BqlCell<usize>,
+    num_timers: usize,
     num_timers_save: BqlCell<u8>,
 
     /// Instance id (HPET timer block ID).
@@ -570,11 +570,6 @@ pub struct HPETState {
 }
 
 impl HPETState {
-    // Get num_timers with `usize` type, which is useful to play with array index.
-    fn get_num_timers(&self) -> usize {
-        self.num_timers.get()
-    }
-
     const fn has_msi_flag(&self) -> bool {
         self.flags & (1 << HPET_FLAG_MSI_SUPPORT_SHIFT) != 0
     }
@@ -636,7 +631,7 @@ fn set_cfg_reg(&self, shift: u32, len: u32, val: u64) {
             self.hpet_offset
                 .set(ticks_to_ns(self.counter.get()) - CLOCK_VIRTUAL.get_ns());
 
-            for timer in self.timers.iter().take(self.get_num_timers()) {
+            for timer in self.timers.iter().take(self.num_timers) {
                 let mut t = timer.borrow_mut();
 
                 if t.is_int_enabled() && t.is_int_active() {
@@ -648,7 +643,7 @@ fn set_cfg_reg(&self, shift: u32, len: u32, val: u64) {
             // Halt main counter and disable interrupt generation.
             self.counter.set(self.get_ticks());
 
-            for timer in self.timers.iter().take(self.get_num_timers()) {
+            for timer in self.timers.iter().take(self.num_timers) {
                 timer.borrow_mut().del_timer();
             }
         }
@@ -671,7 +666,7 @@ fn set_int_status_reg(&self, shift: u32, _len: u32, val: u64) {
         let new_val = val << shift;
         let cleared = new_val & self.int_status.get();
 
-        for (index, timer) in self.timers.iter().take(self.get_num_timers()).enumerate() {
+        for (index, timer) in self.timers.iter().take(self.num_timers).enumerate() {
             if cleared & (1 << index) != 0 {
                 timer.borrow_mut().update_irq(false);
             }
@@ -725,7 +720,7 @@ fn post_init(&self) {
     }
 
     fn realize(&self) -> qemu_api::Result<()> {
-        if self.num_timers.get() < HPET_MIN_TIMERS || self.num_timers.get() > HPET_MAX_TIMERS {
+        if self.num_timers < HPET_MIN_TIMERS || self.num_timers > HPET_MAX_TIMERS {
             Err(format!(
                 "hpet.num_timers must be between {HPET_MIN_TIMERS} and {HPET_MAX_TIMERS}"
             ))?;
@@ -743,7 +738,7 @@ fn realize(&self) -> qemu_api::Result<()> {
             1 << HPET_CAP_COUNT_SIZE_CAP_SHIFT |
             1 << HPET_CAP_LEG_RT_CAP_SHIFT |
             HPET_CAP_VENDER_ID_VALUE << HPET_CAP_VENDER_ID_SHIFT |
-            ((self.get_num_timers() - 1) as u64) << HPET_CAP_NUM_TIM_SHIFT | // indicate the last timer
+            ((self.num_timers - 1) as u64) << HPET_CAP_NUM_TIM_SHIFT | // indicate the last timer
             (HPET_CLK_PERIOD * FS_PER_NS) << HPET_CAP_CNT_CLK_PERIOD_SHIFT, // 10 ns
         );
 
@@ -753,7 +748,7 @@ fn realize(&self) -> qemu_api::Result<()> {
     }
 
     fn reset_hold(&self, _type: ResetType) {
-        for timer in self.timers.iter().take(self.get_num_timers()) {
+        for timer in self.timers.iter().take(self.num_timers) {
             timer.borrow_mut().reset();
         }
 
@@ -781,7 +776,7 @@ fn decode(&self, mut addr: hwaddr, size: u32) -> HPETAddrDecode {
             GlobalRegister::try_from(addr).map(HPETRegister::Global)
         } else {
             let timer_id: usize = ((addr - 0x100) / 0x20) as usize;
-            if timer_id <= self.get_num_timers() {
+            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))
@@ -852,12 +847,12 @@ fn pre_save(&self) -> i32 {
          * also added to the migration stream.  Check that it matches the value
          * that was configured.
          */
-        self.num_timers_save.set(self.num_timers.get() as u8);
+        self.num_timers_save.set(self.num_timers as u8);
         0
     }
 
     fn post_load(&self, _version_id: u8) -> i32 {
-        for timer in self.timers.iter().take(self.get_num_timers()) {
+        for timer in self.timers.iter().take(self.num_timers) {
             let mut t = timer.borrow_mut();
 
             t.cmp64 = t.calculate_cmp64(t.get_state().counter.get(), t.cmp);
@@ -882,7 +877,7 @@ fn is_offset_needed(&self) -> bool {
     }
 
     fn validate_num_timers(&self, _version_id: u8) -> bool {
-        self.num_timers.get() == self.num_timers_save.get().into()
+        self.num_timers == self.num_timers_save.get().into()
     }
 }
 
-- 
2.49.0