[PATCH 2/2] xen/cpu: round up cpu_khz calculations

[Roger Pau Monne <roger.pau@xxxxxxxxxx>]

All arches truncate the cpu_khz without taking into account the less
significant digits.  Instead use DIV_ROUND_UP() when scaling from Hz to kHz
to get as more accurate kHz value.

Signed-off-by: Roger Pau Monné <roger.pau@xxxxxxxxxx>
---
While the possibly more accurate value is nice, I'm not sure it's actually
fixing any functional bug, and hence the lack of "Fixes:" tag.
---
 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 a12912a106a0..9e0c485c77db 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_UP(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_UP(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 7efa76fdbcb1..faca7b70e13a 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_UP(rate, 1000);
 }
 
 int reprogram_timer(s_time_t timeout)
diff --git a/xen/arch/x86/time.c b/xen/arch/x86/time.c
index 244277c0a921..b84414f00d05 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_UP(tmp, 1000);
     printk("Detected %lu.%03lu MHz processor.\n", 
            cpu_khz / 1000, cpu_khz % 1000);
 
-- 
2.53.0