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Message-ID: <232a8580f7a6c54d0efa1a74df3e5353@mgebm.net>
Date: Thu, 15 Mar 2012 09:17:55 -0400
From: Eric B Munson <emunson@...bm.net>
To: Jan Kiszka <jan.kiszka@...mens.com>
Cc: <avi@...hat.com>, <mingo@...hat.com>, <hpa@...or.com>,
<ryanh@...ux.vnet.ibm.com>, <aliguori@...ibm.com>,
<mtosatti@...hat.com>, <kvm@...r.kernel.org>,
<linux-arch@...r.kernel.org>, <x86@...nel.org>,
<linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 2/4 V16] Add functions to check if the host has stopped
the vm
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 ‘int’ in declaration of ‘EXPORT_SYMBOL_GPL’
> /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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