linux-kernel - Re: [PATCH v5 12/26] KVM: arm/arm64: GICv4: Unmap VLPI when freeing an LPI

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Date:   Wed, 8 Nov 2017 15:14:03 +0100
From:   Auger Eric <eric.auger@...hat.com>
To:     Marc Zyngier <marc.zyngier@....com>,
        linux-arm-kernel@...ts.infradead.org, kvmarm@...ts.cs.columbia.edu,
        kvm@...r.kernel.org, linux-kernel@...r.kernel.org
Cc:     Christoffer Dall <christoffer.dall@...aro.org>,
        Shanker Donthineni <shankerd@...eaurora.org>,
        Mark Rutland <mark.rutland@....com>,
        Shameerali Kolothum Thodi 
        <shameerali.kolothum.thodi@...wei.com>,
        Andre Przywara <Andre.Przywara@....com>,
        Christoffer Dall <cdall@...aro.org>
Subject: Re: [PATCH v5 12/26] KVM: arm/arm64: GICv4: Unmap VLPI when freeing
 an LPI

Hi,

On 08/11/2017 12:52, Marc Zyngier wrote:
> On 07/11/17 20:28, Auger Eric wrote:
>> Hi Marc,
>>
>> On 27/10/2017 16:28, Marc Zyngier wrote:
>>> When freeing an LPI (on a DISCARD command, for example), we need
>>> to unmap the VLPI down to the physical ITS level.
>>>
>>> Acked-by: Christoffer Dall <cdall@...aro.org>
>>> Signed-off-by: Marc Zyngier <marc.zyngier@....com>
>>> ---
>>>  virt/kvm/arm/vgic/vgic-its.c | 6 +++++-
>>>  1 file changed, 5 insertions(+), 1 deletion(-)
>>>
>>> diff --git a/virt/kvm/arm/vgic/vgic-its.c b/virt/kvm/arm/vgic/vgic-its.c
>>> index b2a678d131d0..c9b1c0967426 100644
>>> --- a/virt/kvm/arm/vgic/vgic-its.c
>>> +++ b/virt/kvm/arm/vgic/vgic-its.c
>>> @@ -628,8 +628,12 @@ static void its_free_ite(struct kvm *kvm, struct its_ite *ite)
>>>  	list_del(&ite->ite_list);
>>>  
>>>  	/* This put matches the get in vgic_add_lpi. */
>>> -	if (ite->irq)
>>> +	if (ite->irq) {
>>> +		if (ite->irq->hw)
>>> +			WARN_ON(its_unmap_vlpi(ite->irq->host_irq));
>>> +
>>>  		vgic_put_irq(kvm, ite->irq);
>> You could have put the its_unmap_vlpi() directly in vgic_put_irq which
>> is meant to decr the ref/release the LPI irq.
> 
> Do you see this as an issue?

not really. I just thought it would be nicer in vgic_put_irq but that's
a detail.

Thanks

Eric
> 
> I'm trying hard to keep the GICv4 changes local to the ITS code, and not
> spread it everywhere in the vgic, but I'll happily change it if you spot
> something that seems wrong.
> 
> Thanks,
> 
> 	M.
>