From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andre Przywara <andre.przywara@arm.com>
Subject: Re: [PATCH v2 01/15] KVM: arm/arm64: VGIC: don't track used LRs in
 the distributor
Date: Fri, 2 Oct 2015 13:49:17 +0100
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Cc: Marc Zyngier <Marc.Zyngier@arm.com>,
	"christoffer.dall@linaro.org" <christoffer.dall@linaro.org>,
	"eric.auger@linaro.org" <eric.auger@linaro.org>,
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To: Pavel Fedin <p.fedin@samsung.com>,
	"kvmarm@lists.cs.columbia.edu" <kvmarm@lists.cs.columbia.edu>
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Hi Pavel,

On 02/10/15 13:39, Pavel Fedin wrote:
>  Hello!
> 
>> Can't you use the ELRSR bitmap instead? The idea of lr_used sounds like
>> a moot optimization to me.
> 
>  This perfectly works on 4.2, but will break HW interrupt forwarding on 4.3. If you look at 4.3
> __kvm_vgic_sync_hwstate(), you'll notice that for HW interrupts lr_used and elrsr_ptr will diverge
> at this point, and this function actually brings them into sync. And it relies on lr_used for the
> loop to operate correctly (no idea why we use "for" loop here with extra check instead of
> "for_each_set_bit(lr, vgic_cpu->lr_used, vgic->nr_lr)", looks stupid to me).

I know, because I have reworked my patch lately to work on top of 4.3-rc
and Christoffer's timer rework series. I have something which "works
now"(TM), but wanted to wait for Christoffer's respin to send out.
I will send you this new version this as a sneak preview in private,
maybe that helps.

Cheers,
Andre.