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[xen master] xen/cpu: round cpu_khz calculations



commit 986707b461eb56d75f55581dd1c8e2633f814795
Author:     Roger Pau Monne <roger.pau@xxxxxxxxxx>
AuthorDate: Tue Apr 14 09:38:55 2026 +0200
Commit:     Roger Pau Monne <roger.pau@xxxxxxxxxx>
CommitDate: Thu Apr 16 15:28:32 2026 +0200

    xen/cpu: round cpu_khz calculations
    
    All arches truncate the cpu_khz without taking into account the less
    significant digits.  Instead use DIV_ROUND() when scaling from Hz to kHz
    to get as more accurate kHz value.
    
    Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
    Reviewed-by: Jan Beulich <jbeulich@xxxxxxxx>
---
 xen/arch/arm/time.c   | 4 ++--
 xen/arch/riscv/time.c | 2 +-
 xen/arch/x86/time.c   | 2 +-
 3 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/xen/arch/arm/time.c b/xen/arch/arm/time.c
index a12912a106..6955b2788f 100644
--- a/xen/arch/arm/time.c
+++ b/xen/arch/arm/time.c
@@ -118,7 +118,7 @@ static void __init preinit_dt_xen_time(void)
     res = dt_property_read_u32(timer, "clock-frequency", &rate);
     if ( res )
     {
-        cpu_khz = rate / 1000;
+        cpu_khz = DIV_ROUND(rate, 1000);
         validate_timer_frequency();
         timer_dt_clock_frequency = rate;
     }
@@ -136,7 +136,7 @@ void __init preinit_xen_time(void)
 
     if ( !cpu_khz )
     {
-        cpu_khz = (READ_SYSREG(CNTFRQ_EL0) & CNTFRQ_MASK) / 1000;
+        cpu_khz = DIV_ROUND(READ_SYSREG(CNTFRQ_EL0) & CNTFRQ_MASK, 1000);
         validate_timer_frequency();
     }
 
diff --git a/xen/arch/riscv/time.c b/xen/arch/riscv/time.c
index 7efa76fdbc..698ab49d12 100644
--- a/xen/arch/riscv/time.c
+++ b/xen/arch/riscv/time.c
@@ -40,7 +40,7 @@ static void __init preinit_dt_xen_time(void)
     if ( !dt_property_read_u32(timer, "timebase-frequency", &rate) )
         panic("Unable to find clock frequency\n");
 
-    cpu_khz = rate / 1000;
+    cpu_khz = DIV_ROUND(rate, 1000);
 }
 
 int reprogram_timer(s_time_t timeout)
diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c
index 244277c0a9..008d9e97d9 100644
--- a/xen/arch/x86/time.c
+++ b/xen/arch/x86/time.c
@@ -2642,7 +2642,7 @@ void __init early_time_init(void)
     set_time_scale(&t->tsc_scale, tmp);
     t->stamp.local_tsc = boot_tsc_stamp;
 
-    cpu_khz = tmp / 1000;
+    cpu_khz = DIV_ROUND(tmp, 1000);
     printk("Detected %lu.%03lu MHz processor.\n", 
            cpu_khz / 1000, cpu_khz % 1000);
 
--
generated by git-patchbot for /home/xen/git/xen.git#master



 


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