Re: [RFC PATCH v5 3/4] x86/acrn: Use HYPERVISOR_CALLBACK_VECTOR for ACRN guest upcall vector

["Zhao, Yakui" <yakui.zhao@intel.com>]

On 2019年04月26日 03:45, Ingo Molnar wrote:
> 
> * Zhao, Yakui <yakui.zhao@intel.com> wrote:
> 
>>>> +	alloc_intr_gate(HYPERVISOR_CALLBACK_VECTOR,
>>>> +			acrn_hv_callback_vector);
>>>
>>> Why is this on two lines, not a single line?
>>
>> At first it used the long function name for acrn_hv_callback_vector.
>> As it exceeds 80 columns, it is split into two lines.
> 
> No, it doesn't exceed 80 columns - the last character of that line is on
> column 71.

Thanks for the helps.
It will be fixed.
> 
>>> Does the hypervisor model the APIC EOI command, i.e. does it require the
>>> APIC to be acked? I.e. would not acking the APIC create an IRQ storm?
>>
>> The hypervisor requires that the APIC EOI should be acked. If the EOI APIC
>> is not acked, the APIC ISR bit for the HYPERVISOR_CALLBACK_VECTOR will not
>> be cleared and then it will block the interrupt whose vector is lower than
>> HYPERVISOR_CALLBACK_VECTOR.
> 
> Ok!
> 

I will add some comments for calling entering_ack_irq in 
acrn_hv_callback_handler. Is this ok to you?

> Thanks,
> 
> 	Ingo
>