From mboxrd@z Thu Jan  1 00:00:00 1970
From: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Subject: Re: [PART1 V5 08/13] svm: Add interrupt injection via AVIC
Date: Tue, 31 May 2016 23:02:22 -0500
Message-ID: <574E5E4E.2040200@amd.com>
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 <20160510091956.GB16752@pd.tnic> <5731F518.9000205@redhat.com>
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Cc: <rkrcmar@redhat.com>, <joro@8bytes.org>, <gleb@kernel.org>,
	<alex.williamson@redhat.com>, <kvm@vger.kernel.org>,
	<linux-kernel@vger.kernel.org>, <wei@redhat.com>,
	<sherry.hurwitz@amd.com>
To: Paolo Bonzini <pbonzini@redhat.com>, Borislav Petkov <bp@alien8.de>
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Hi,

Sorry for late response on this.

On 5/10/16 09:50, Paolo Bonzini wrote:
>
>
> On 10/05/2016 11:19, Borislav Petkov wrote:
>>>> This patch introduces a new mechanism to inject interrupt using AV=
IC.
>>>> Since VINTR is not supported when enable AVIC, we need to inject
>> 	"... is not supported when AVIC is enabled ..."
>>
>> VINTR?
>
> The ability to request a vmexit as soon as an interrupt can be inject=
ed
> (IF=3DGIF=3D1, no interrupt window, etc.).  It's called the "VINTR in=
tercept".
>
>> Please write those things out in the commit message for maximum
>> information transfer to the reader. :)
>
> More important, where does the APM document that VINTR is not support=
ed
> when AVIC is enabled?  It is certainly pointless and inefficient, but
> I'm not sure where it says that it doesn't work.
>
> Paolo
>

Basically, from the APM vol2 here:

   http://developer.amd.com/wordpress/media/2012/10/24593_APM_v21.pdf

On page 115, section AVIC Enable=E2=80=94Virtual Interrupt Control, Bit=
 31:

   "... Enabling AVIC implicitly disables the V_IRQ, V_INTR_PRIO,
    V_IGN_TPR, and V_INTR_VECTOR fields in the VMCB Control Word."

Thanks,
Suravee