Re: [PATCH v8 7/9] KVM: arm/arm64: Provide a get_input_level for the arch timer

From: Marc Zyngier <marc.zyngier@arm.com>
To: Christoffer Dall <christoffer.dall@linaro.org>
Cc: Andre Przywara <andre.przywara@arm.com>,
	kvmarm@lists.cs.columbia.edu,
	linux-arm-kernel@lists.infradead.org, kvm@vger.kernel.org
Subject: Re: [PATCH v8 7/9] KVM: arm/arm64: Provide a get_input_level for the arch timer
Date: Wed, 13 Dec 2017 19:45:51 +0000	[thread overview]
Message-ID: <86h8suwgwg.wl-marc.zyngier@arm.com> (raw)
In-Reply-To: <20171213104602.16383-8-christoffer.dall@linaro.org>

On Wed, 13 Dec 2017 10:46:00 +0000,
Christoffer Dall wrote:
> 
> The VGIC can now support the life-cycle of mapped level-triggered
> interrupts, and we no longer have to read back the timer state on every
> exit from the VM if we had an asserted timer interrupt signal, because
> the VGIC already knows if we hit the unlikely case where the guest
> disables the timer without ACKing the virtual timer interrupt.
> 
> This means we rework a bit of the code to factor out the functionality
> to snapshot the timer state from vtimer_save_state(), and we can reuse
> this functionality in the sync path when we have an irqchip in
> userspace, and also to support our implementation of the
> get_input_level() function for the timer.
> 
> This change also means that we can no longer rely on the timer's view of
> the interrupt line to set the active state, because we no longer
> maintain this state for mapped interrupts when exiting from the guest.
> Instead, we only set the active state if the virtual interrupt is
> active, and otherwise we simply let the timer fire again and raise the
> virtual interrupt from the ISR.
> 
> Reviewed-by: Eric Auger <eric.auger@redhat.com>
> Signed-off-by: Christoffer Dall <christoffer.dall@linaro.org>

Reviewed-by: Marc Zyngier <marc.zyngier@arm.com>

	M.