Re: [RFC] nmi watchdog in kvm

[Avi Kivity <avi-atKUWr5tajBWk0Htik3J/w@public.gmane.org>]

Balaji Rao wrote:
> On Wednesday 30 January 2008 04:13:58 pm Avi Kivity wrote:
>   
>>> @@ -790,6 +795,18 @@ static int apic_mmio_range(struct kvm_io_device
>>> *this, gpa_t addr) return ret;
>>>  }
>>>
>>> +static int nmi_notify(struct notifier_block *self,unsigned long val,
>>> void *data) { +
>>> +        struct kvm *kvm;
>>> +        kvm  = list_entry(vm_list.next, struct kvm, vm_list);
>>> +	kvm_x86_ops->inject_nmi(kvm->vcpus[0]);
>>> +        return NOTIFY_STOP;
>>> +}
>>>       
>> You're not guaranteed to be in vcpu context here, that's what's causing
>> the vmwrite errors.
>>
>>     
> I intended to do this here. Looks like its not the right way to check for 
> presence in vcpu context. How do i do it ? please explain.
>
> +static void vmx_inject_nmi(struct kvm_vcpu *vcpu) {
> +
> +       struct vcpu_vmx * vmx = to_vmx(vcpu);
> +               if (vmx->launched)
> +               vmcs_write32(VM_ENTRY_INTR_INFO_FIELD,
> +                       2 | INTR_TYPE_NMI | INTR_INFO_VALID_MASK);
> +}
>
>   

No, this is the wrong place.  If you have a vcpu, you'd better be in 
vcpu context.

The way to do it is to set a bit in vcpu->requests and force an IPI to 
vcpu->cpu.  You can look at kvm_flush_remote_tlbs() for an example 
(another example is in the lapic IPI code, actually a better one since 
it also wakes the cpu up if it is in hlt state).

-- 
error compiling committee.c: too many arguments to function


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