Re: [PATCH 2/4 V16] Add functions to check if the host has stoppedthe vm

[Eric B Munson]

On Wed, 14 Mar 2012 11:12:35 +0100, Jan Kiszka wrote:
> On 2012-03-10 20:37, Eric B Munson wrote:
> > When a host stops or suspends a VM it will set a flag to show this.  
> > The
> > watchdog will use these functions to determine if a softlockup is 
> > real, or the
> > result of a suspended VM.
>
> ...
>
> > diff --git a/arch/x86/kernel/kvmclock.c b/arch/x86/kernel/kvmclock.c
> > index f8492da..4ba090c 100644
> > --- a/arch/x86/kernel/kvmclock.c
> > +++ b/arch/x86/kernel/kvmclock.c
> > @@ -22,6 +22,7 @@
> >  #include <asm/msr.h>
> >  #include <asm/apic.h>
> >  #include <linux/percpu.h>
> > +#include <linux/hardirq.h>
> >
> >  #include <asm/x86_init.h>
> >  #include <asm/reboot.h>
> > @@ -114,6 +115,26 @@ static void kvm_get_preset_lpj(void)
> >  	preset_lpj = lpj;
> >  }
> >
> > +bool kvm_check_and_clear_guest_paused(void)
> > +{
> > +	bool ret = false;
> > +	struct pvclock_vcpu_time_info *src;
> > +
> > +	/*
> > +	 * per_cpu() is safe here because this function is only called 
> > from
> > +	 * timer functions where preemption is already disabled.
> > +	 */
> > +	WARN_ON(!in_atomic());
> > +	src = &__get_cpu_var(hv_clock);
> > +	if ((src->flags & PVCLOCK_GUEST_STOPPED) != 0) {
> > +		__this_cpu_and(hv_clock.flags, ~PVCLOCK_GUEST_STOPPED);
> > +		ret = true;
> > +	}
> > +
> > +	return ret;
> > +}
> > +EXPORT_SYMBOL_GPL(kvm_check_and_clear_guest_paused);
>
> Which module is going to use this? I failed to find it, but I may 
> have
> missed something.
>
> The actual reason for this reply: this patches causes a compiler 
> warning
> here, likely due to lacking include for EXPORT_SYMBOL_GPL:
>
>   CC      arch/x86/kernel/kvmclock.o
> /data/linux-kvm/arch/x86/kernel/kvmclock.c:136:1: warning: data
> definition has no type or storage class
> /data/linux-kvm/arch/x86/kernel/kvmclock.c:136:1: warning: type 
> defaults
> to âintâ in declaration of âEXPORT_SYMBOL_GPLâ
> /data/linux-kvm/arch/x86/kernel/kvmclock.c:136:1: warning: parameter
> names (without types) in function declaration
>
> Jan


I will have a look at these this evening.

Eric
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