linux-kernel - Re: [PATCH V2] x86/Hyper-V: Fix hv sched clock function return wrong time unit

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Message-ID: <20200330102201.qs2ty22zxx2n53h3@debian>
Date:   Mon, 30 Mar 2020 11:22:01 +0100
From:   Wei Liu <wei.liu@...nel.org>
To:     Vitaly Kuznetsov <vkuznets@...hat.com>
Cc:     Tianyu Lan <ltykernel@...il.com>,
        Tianyu Lan <Tianyu.Lan@...rosoft.com>,
        linux-hyperv@...r.kernel.org, linux-kernel@...r.kernel.org,
        stable@...r.kernel.org, Yubo Xie <yuboxie@...rosoft.com>,
        kys@...rosoft.com, haiyangz@...rosoft.com, sthemmin@...rosoft.com,
        liuwe@...rosoft.com, daniel.lezcano@...aro.org, tglx@...utronix.de,
        michael.h.kelley@...rosoft.com, Wei Liu <wei.liu@...nel.org>
Subject: Re: [PATCH V2] x86/Hyper-V: Fix hv sched clock function return wrong
 time unit

On Mon, Mar 30, 2020 at 11:05:02AM +0100, Wei Liu wrote:
> On Fri, Mar 27, 2020 at 09:53:39AM +0100, Vitaly Kuznetsov wrote:
> > Tianyu Lan <ltykernel@...il.com> writes:
> > 
> > > From: Yubo Xie <yuboxie@...rosoft.com>
> > >
> > > sched clock callback should return time with nano second as unit
> > > but current hv callback returns time with 100ns. Fix it.
> > >
> > > Cc: stable@...r.kernel.org
> > > Signed-off-by: Yubo Xie <yuboxie@...rosoft.com>
> > > Signed-off-by: Tianyu Lan <Tianyu.Lan@...rosoft.com>
> > > Fixes: bd00cd52d5be ("clocksource/drivers/hyperv: Add Hyper-V specific sched clock function")
> > > ---
> > > Change since v1:
> > > 	Update fix commit number in change log. 
> > > ---
> > >  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);
> > >  }
> > >  
> > >  static struct clocksource hyperv_cs_msr = {
> > 
> > Reviewed-by: Vitaly Kuznetsov <vkuznets@...hat.com>
> 
> Queued for hyperv-fixes. Thank you both.

It appears Thomas already sent this to Linus, so I will drop this from
my branch.

Wei.

> 
> Wei.