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@citrix.com>
Reviewed-by: Jan Beulich <jbeulich@suse.com>
master commit: 986707b461
master date: 2026-04-16 15:28:32 +0200

xen/arch/arm/time.c

@@ -128,7 +128,7 @@ 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;
     }
@@ -146,7 +146,7 @@ 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();
     }
 

xen/arch/riscv/time.c

@@ -36,7 +36,7 @@ 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);
 }
 
 void __init preinit_xen_time(void)

xen/arch/x86/time.c

@@ -2634,7 +2634,7 @@ 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);