Also tick_to_ns() is implemeted as it is used in get_s_time().

Signed-off-by: Oleksii Kurochko <oleksii.kurochko@gmail.com>
---
 xen/arch/riscv/include/asm/time.h | 6 ++++++
 xen/arch/riscv/stubs.c            | 5 -----
 xen/arch/riscv/time.c             | 7 +++++++
 3 files changed, 13 insertions(+), 5 deletions(-)

diff --git a/xen/arch/riscv/include/asm/time.h b/xen/arch/riscv/include/asm/time.h
index e8d9ffec57..0f6aa99ab1 100644
--- a/xen/arch/riscv/include/asm/time.h
+++ b/xen/arch/riscv/include/asm/time.h
@@ -3,6 +3,7 @@
 #define ASM__RISCV__TIME_H
 
 #include <xen/bug.h>
+#include <xen/lib.h>
 #include <xen/types.h>
 #include <asm/csr.h>
 
@@ -23,6 +24,11 @@ static inline cycles_t get_cycles(void)
     return csr_read(CSR_TIME);
 }
 
+static inline s_time_t ticks_to_ns(uint64_t ticks)
+{
+    return muldiv64(ticks, SECONDS(1), 1000 * cpu_khz);
+}
+
 void preinit_xen_time(void);
 
 #endif /* ASM__RISCV__TIME_H */
diff --git a/xen/arch/riscv/stubs.c b/xen/arch/riscv/stubs.c
index a1d64534cd..83416d3350 100644
--- a/xen/arch/riscv/stubs.c
+++ b/xen/arch/riscv/stubs.c
@@ -27,11 +27,6 @@ nodemask_t __read_mostly node_online_map = { { [0] = 1UL } };
 
 /* time.c */
 
-s_time_t get_s_time(void)
-{
-    BUG_ON("unimplemented");
-}
-
 int reprogram_timer(s_time_t timeout)
 {
     BUG_ON("unimplemented");
diff --git a/xen/arch/riscv/time.c b/xen/arch/riscv/time.c
index 905bb13eb4..81e06781f8 100644
--- a/xen/arch/riscv/time.c
+++ b/xen/arch/riscv/time.c
@@ -4,10 +4,17 @@
 #include <xen/init.h>
 #include <xen/lib.h>
 #include <xen/sections.h>
+#include <xen/types.h>
 
 unsigned long __ro_after_init cpu_khz; /* CPU clock frequency in kHz. */
 uint64_t __ro_after_init boot_clock_cycles;
 
+s_time_t get_s_time(void)
+{
+    uint64_t ticks = get_cycles() - boot_clock_cycles;
+    return ticks_to_ns(ticks);
+}
+
 /* Set up the timer on the boot CPU (early init function) */
 static void __init preinit_dt_xen_time(void)
 {
-- 
2.49.0

On 08.04.2025 17:57, Oleksii Kurochko wrote:
> @@ -23,6 +24,11 @@ static inline cycles_t get_cycles(void)
>      return csr_read(CSR_TIME);
>  }
>  
> +static inline s_time_t ticks_to_ns(uint64_t ticks)
> +{
> +    return muldiv64(ticks, SECONDS(1), 1000 * cpu_khz);
> +}

Why the extra multiplication by 1000? I.e. why not
"muldiv64(ticks, MILLISECONDS(1), cpu_khz)", getting away with just one
multiplication and a reduced risk of encountering intermediate overflow
(affecting only hypothetical above 4THz CPUs then)?

> --- a/xen/arch/riscv/time.c
> +++ b/xen/arch/riscv/time.c
> @@ -4,10 +4,17 @@
>  #include <xen/init.h>
>  #include <xen/lib.h>
>  #include <xen/sections.h>
> +#include <xen/types.h>
>  
>  unsigned long __ro_after_init cpu_khz; /* CPU clock frequency in kHz. */
>  uint64_t __ro_after_init boot_clock_cycles;
>  
> +s_time_t get_s_time(void)
> +{
> +    uint64_t ticks = get_cycles() - boot_clock_cycles;
> +    return ticks_to_ns(ticks);

Nit: Blank line between declaration(s) and statement(s) please, as well as
ahead of the main "return" of a function.

Happy to make both adjustments upon committing, so long as you agree; then:
Reviewed-by: Jan Beulich <jbeulich@suse.com>

Jan

On 4/10/25 2:52 PM, Jan Beulich wrote:
> On 08.04.2025 17:57, Oleksii Kurochko wrote:
>> @@ -23,6 +24,11 @@ static inline cycles_t get_cycles(void)
>>       return csr_read(CSR_TIME);
>>   }
>>   
>> +static inline s_time_t ticks_to_ns(uint64_t ticks)
>> +{
>> +    return muldiv64(ticks, SECONDS(1), 1000 * cpu_khz);
>> +}
> Why the extra multiplication by 1000? I.e. why not
> "muldiv64(ticks, MILLISECONDS(1), cpu_khz)", getting away with just one
> multiplication and a reduced risk of encountering intermediate overflow
> (affecting only hypothetical above 4THz CPUs then)?

Multiplication by 1000 was needed to convert khz to hz, but yes, your option
would be better.

>
>> --- a/xen/arch/riscv/time.c
>> +++ b/xen/arch/riscv/time.c
>> @@ -4,10 +4,17 @@
>>   #include <xen/init.h>
>>   #include <xen/lib.h>
>>   #include <xen/sections.h>
>> +#include <xen/types.h>
>>   
>>   unsigned long __ro_after_init cpu_khz; /* CPU clock frequency in kHz. */
>>   uint64_t __ro_after_init boot_clock_cycles;
>>   
>> +s_time_t get_s_time(void)
>> +{
>> +    uint64_t ticks = get_cycles() - boot_clock_cycles;
>> +    return ticks_to_ns(ticks);
> Nit: Blank line between declaration(s) and statement(s) please, as well as
> ahead of the main "return" of a function.
>
> Happy to make both adjustments upon committing, so long as you agree; then:
> Reviewed-by: Jan Beulich<jbeulich@suse.com>

I'll be happy with that.

Thank you very much.

~ Oleksii