Hi Vitaly:
     Thanks for your review.

On 3/24/2020 11:49 PM, Vitaly Kuznetsov wrote:

Yubo Xie [off-list ref] writes:

quoted

sched clock callback should return time with nano second as unit
but current hv callback returns time with 100ns. Fix it.

Cc: stable@vger.kernel.org
Signed-off-by: Yubo Xie <redacted>
Signed-off-by: Tianyu Lan <redacted>
Fixes: adb87ff4f96c ("clocksource/drivers/hyperv: Allocate Hyper-V TSC page statically")

I don't think this is the right commit to reference,

commit bd00cd52d5be655a2f217e2ed74b91a71cb2b14f
Author: Tianyu Lan [off-list ref]
Date:   Wed Aug 14 20:32:16 2019 +0800

     clocksource/drivers/hyperv: Add Hyper-V specific sched clock function

looks like the one.

Sorry. You are right. Will update in the next version.

quoted

---
  drivers/clocksource/hyperv_timer.c | 6 ++++--
  1 file changed, 4 insertions(+), 2 deletions(-)

diff --git a/drivers/clocksource/hyperv_timer.c b/drivers/clocksource/hyperv_timer.c
index 9d808d595ca8..662ed978fa24 100644
--- a/drivers/clocksource/hyperv_timer.c
+++ b/drivers/clocksource/hyperv_timer.c

@@ -343,7 +343,8 @@ static u64 notrace read_hv_clock_tsc_cs(struct clocksource *arg)
  
  static u64 read_hv_sched_clock_tsc(void)
  {
-	return read_hv_clock_tsc() - hv_sched_clock_offset;
+	return (read_hv_clock_tsc() - hv_sched_clock_offset)
+		* (NSEC_PER_SEC / HV_CLOCK_HZ);
  }
  
  static void suspend_hv_clock_tsc(struct clocksource *arg)

@@ -398,7 +399,8 @@ static u64 notrace read_hv_clock_msr_cs(struct clocksource *arg)
  
  static u64 read_hv_sched_clock_msr(void)
  {
-	return read_hv_clock_msr() - hv_sched_clock_offset;
+	return (read_hv_clock_msr() - hv_sched_clock_offset)
+		* (NSEC_PER_SEC / HV_CLOCK_HZ);
  }

kvmclock seems to have the same (pre-patch) code ...

kvm sched clock gets time from pvclock_clocksource_read() and
the time unit is nanosecond. So there is such issue in KVM code.

quoted

  
  static struct clocksource hyperv_cs_msr = {