[xenial][PATCH v2 1/8] UBUNTU: SAUCE: hv: make clocksource available for PTP device supporting

[Marcelo Cerri]

Good catch. I will prepare a v3 with that fixed.

-- 
Regards,
Marcelo

On Mon, Jul 03, 2017 at 12:29:47PM +0200, Kleber Souza wrote:
> 
> 
> On 06/30/17 21:21, Marcelo Henrique Cerri wrote:
> > BugLink: http://bugs.launchpad.net/bugs/1676635
> > 
> > Make the MSR and TSC clock sources available during the hv_init() and
> > export them via hyperv_cs in a similar way as the following upstream
> > commit does:
> > 
> > commit dee863b571b0 ("hv: export current Hyper-V clocksource")
> > 
> > Signed-off-by: Marcelo Henrique Cerri <marcelo.cerri at canonical.com>
> > ---
> >  arch/x86/kernel/cpu/mshyperv.c | 23 -----------------------
> >  drivers/hv/hv.c                | 36 +++++++++++++++++++++++++++++++++++-
> >  drivers/hv/hyperv_vmbus.h      |  3 +++
> >  3 files changed, 38 insertions(+), 24 deletions(-)
> > 
> > diff --git a/arch/x86/kernel/cpu/mshyperv.c b/arch/x86/kernel/cpu/mshyperv.c
> > index 668df428f8ad..8ffd894d4b8e 100644
> > --- a/arch/x86/kernel/cpu/mshyperv.c
> > +++ b/arch/x86/kernel/cpu/mshyperv.c
> > @@ -134,26 +134,6 @@ static uint32_t  __init ms_hyperv_platform(void)
> >  	return 0;
> >  }
> >  
> > -static cycle_t read_hv_clock(struct clocksource *arg)
> > -{
> > -	cycle_t current_tick;
> > -	/*
> > -	 * Read the partition counter to get the current tick count. This count
> > -	 * is set to 0 when the partition is created and is incremented in
> > -	 * 100 nanosecond units.
> > -	 */
> > -	rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
> > -	return current_tick;
> > -}
> > -
> > -static struct clocksource hyperv_cs = {
> > -	.name		= "hyperv_clocksource",
> > -	.rating		= 400, /* use this when running on Hyperv*/
> > -	.read		= read_hv_clock,
> > -	.mask		= CLOCKSOURCE_MASK(64),
> > -	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
> > -};
> > -
> >  static unsigned char hv_get_nmi_reason(void)
> >  {
> >  	return 0;
> > @@ -209,9 +189,6 @@ static void __init ms_hyperv_init_platform(void)
> >  			     "hv_nmi_unknown");
> >  #endif
> >  
> > -	if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE)
> > -		clocksource_register_hz(&hyperv_cs, NSEC_PER_SEC/100);
> > -
> >  #ifdef CONFIG_X86_IO_APIC
> >  	no_timer_check = 1;
> >  #endif
> > diff --git a/drivers/hv/hv.c b/drivers/hv/hv.c
> > index 176ee7d4c243..92fb168a6633 100644
> > --- a/drivers/hv/hv.c
> > +++ b/drivers/hv/hv.c
> > @@ -191,6 +191,28 @@ static struct clocksource hyperv_cs_tsc = {
> >  };
> >  #endif
> >  
> > +static cycle_t read_hv_clock_msr(struct clocksource *arg)
> > +{
> > +	cycle_t current_tick;
> > +	/*
> > +	 * Read the partition counter to get the current tick count. This count
> > +	 * is set to 0 when the partition is created and is incremented in
> > +	 * 100 nanosecond units.
> > +	 */
> > +	rdmsrl(HV_X64_MSR_TIME_REF_COUNT, current_tick);
> > +	return current_tick;
> > +}
> > +
> > +static struct clocksource hyperv_cs_msr = {
> > +	.name		= "hyperv_clocksource_msr",
> > +	.rating		= 400, /* use this when running on Hyperv*/
> > +	.read		= read_hv_clock_msr,
> > +	.mask		= CLOCKSOURCE_MASK(64),
> > +	.flags		= CLOCK_SOURCE_IS_CONTINUOUS,
> > +};
> > +
> > +struct clocksource *hyperv_cs;
> > +EXPORT_SYMBOL_GPL(hyperv_cs);
> >  
> >  /*
> >   * hv_init - Main initialization routine.
> > @@ -254,9 +276,11 @@ int hv_init(void)
> >  
> >  		va_tsc = __vmalloc(PAGE_SIZE, GFP_KERNEL, PAGE_KERNEL);
> >  		if (!va_tsc)
> > -			goto cleanup;
> > +			goto register_msr_cs;
> >  		hv_context.tsc_page = va_tsc;
> >  
> > +		hyperv_cs = &hyperv_cs_tsc;
> > +
> >  		rdmsrl(HV_X64_MSR_REFERENCE_TSC, tsc_msr.as_uint64);
> >  
> >  		tsc_msr.enable = 1;
> > @@ -266,6 +290,16 @@ int hv_init(void)
> >  		clocksource_register_hz(&hyperv_cs_tsc, NSEC_PER_SEC/100);
> >  	}
> >  #endif
> > +	/*
> > +	 * For 32 bit guests just use the MSR based mechanism for reading
> > +	 * the partition counter.
> > +	 */
> > +
> > +register_msr_cs:
> > +	hyperv_cs = &hyperv_cs_msr;
> > +	if (ms_hyperv.features & HV_X64_MSR_TIME_REF_COUNT_AVAILABLE)
> > +		clocksource_register_hz(&hyperv_cs_msr, NSEC_PER_SEC/100);
> > +
> >  	return 0;
> 
> As in commit dee863b571b0 ("hv: export current Hyper-V clocksource")
> upstream, the label could be placed inside the ifdef to void the
> following warning on archs other than X86_64:
> 
> /tmp/kernel-kleber-3902cd9-oxu2/build/drivers/hv/hv.c: In function
> 'hv_init':
> /tmp/kernel-kleber-3902cd9-oxu2/build/drivers/hv/hv.c:298:1: warning:
> label 'register_msr_cs' defined but not used [-Wunused-label]
>  register_msr_cs:
>  ^
> 
> >  
> >  cleanup:
> > diff --git a/drivers/hv/hyperv_vmbus.h b/drivers/hv/hyperv_vmbus.h
> > index 8d7f865c1133..f75729b5aed6 100644
> > --- a/drivers/hv/hyperv_vmbus.h
> > +++ b/drivers/hv/hyperv_vmbus.h
> > @@ -29,6 +29,7 @@
> >  #include <asm/sync_bitops.h>
> >  #include <linux/atomic.h>
> >  #include <linux/hyperv.h>
> > +#include <linux/clocksource.h>
> >  
> >  /*
> >   * Timeout for services such as KVP and fcopy.
> > @@ -719,4 +720,6 @@ enum hvutil_device_state {
> >  	HVUTIL_DEVICE_DYING,     /* driver unload is in progress */
> >  };
> >  
> > +extern struct clocksource *hyperv_cs;
> > +
> >  #endif /* _HYPERV_VMBUS_H */
> > 
> 
> 
> -- 
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