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Subject: Re: [RFC PATCH v5 3/4] x86/acrn: Use HYPERVISOR_CALLBACK_VECTOR for
 ACRN guest upcall vector
To:     Ingo Molnar <mingo@kernel.org>
Cc:     linux-kernel@vger.kernel.org, x86@kernel.org, tglx@linutronix.de,
        bp@alien8.de, Jason Chen CJ <jason.cj.chen@intel.com>
References: <1556067260-9128-1-git-send-email-yakui.zhao@intel.com>
 <1556067260-9128-4-git-send-email-yakui.zhao@intel.com>
 <20190425071700.GB57256@gmail.com>
 <a206d93b-9c9e-3cfd-d34f-b9d373edb09e@intel.com>
 <20190425194527.GA52659@gmail.com>
From:   "Zhao, Yakui" <yakui.zhao@intel.com>
Message-ID: <12c00f28-a1a8-8642-6912-ec9b706b589e@intel.com>
Date:   Fri, 26 Apr 2019 09:46:50 +0800
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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
>