linux-kernel - Re: [PART1 RFC v3 07/12] svm: Add interrupt injection via AVIC

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Date:	Tue, 5 Apr 2016 22:56:39 +0700
From:	Suravee Suthikulpanit <Suravee.Suthikulpanit@....com>
To:	Paolo Bonzini <pbonzini@...hat.com>, <rkrcmar@...hat.com>,
	<joro@...tes.org>, <bp@...en8.de>, <gleb@...nel.org>,
	<alex.williamson@...hat.com>
CC:	<kvm@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
	<wei@...hat.com>, <sherry.hurwitz@....com>
Subject: Re: [PART1 RFC v3 07/12] svm: Add interrupt injection via AVIC

Hi Paolo,

On 4/5/16 20:26, Suravee Suthikulpanit wrote:
>>> @@ -2877,8 +2895,10 @@ static int clgi_interception(struct vcpu_svm
>>> *svm)
>>>       disable_gif(svm);
>>>
>>>       /* After a CLGI no interrupts should come */
>>> -    svm_clear_vintr(svm);
>>> -    svm->vmcb->control.int_ctl &= ~V_IRQ_MASK;
>>> +    if (!svm_vcpu_avic_enabled(svm)) {
>>> +        svm_clear_vintr(svm);
>>> +        svm->vmcb->control.int_ctl &= ~V_IRQ_MASK;
>>> +    }
>>
>> This is for nested virtualization.  Unless you support nested AVIC, the
>> L2 guest should run without AVIC (i.e. IsRunning should be false) and
>> use the old VINTR mechanism.
>
> I see. I am not planning to supported nested AVIC at the L2 level for
> the moment. If it is alright, I would like to get the basic AVIC and
> IOMMU in first (unless you have a different opinion).
>
> In that case, I think I should also make sure to not expose AVIC CPUID
> to the guest VM.

Actually, it should have already not set the AVIC CPUID in the L1 guest.

Thanks,
Suravee