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

Marc Zyngier
2017-12-13T19:42:25Z

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.