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Date:   Thu, 25 Apr 2019 21:45:27 +0200
From:   Ingo Molnar <mingo@kernel.org>
To:     "Zhao, Yakui" <yakui.zhao@intel.com>
Cc:     linux-kernel@vger.kernel.org, x86@kernel.org, tglx@linutronix.de,
        bp@alien8.de, Jason Chen CJ <jason.cj.chen@intel.com>
Subject: Re: [RFC PATCH v5 3/4] x86/acrn: Use HYPERVISOR_CALLBACK_VECTOR for
 ACRN guest upcall vector
Message-ID: <20190425194527.GA52659@gmail.com>
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* 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.

> > 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!

Thanks,

	Ingo