Re: [PATCH 4/5] KVM: arm/arm64: vgic-v3: Do not use Active+Pending state for a HW interrupt

Christoffer Dall
2017-05-02T20:56:45Z

On Tue, May 02, 2017 at 02:30:40PM +0100, Marc Zyngier wrote:
> When an interrupt is injected with the HW bit set (indicating that
> deactivation should be propagated to the physical distributor),
> special care must be taken so that we never mark the corresponding
> LR with the Active+Pending state (as the pending state is kept in
> the physycal distributor).
>
> Cc: stable@vger.kernel.org
> Fixes: 59529f69f504 ("KVM: arm/arm64: vgic-new: Add GICv3 world switch backend")
> Signed-off-by: Marc Zyngier <marc.zyngier@arm.com>

Reviewed-by: Christoffer Dall <cdall@linaro.org>

> ---
> virt/kvm/arm/vgic/vgic-v3.c | 7 +++++++
> 1 file changed, 7 insertions(+)
>
> diff --git a/virt/kvm/arm/vgic/vgic-v3.c b/virt/kvm/arm/vgic/vgic-v3.c
> index df1503650300..393779ebe87c 100644
> --- a/virt/kvm/arm/vgic/vgic-v3.c
> +++ b/virt/kvm/arm/vgic/vgic-v3.c
> @@ -127,6 +127,13 @@ void vgic_v3_populate_lr(struct kvm_vcpu *vcpu, struct vgic_irq *irq, int lr)
> if (irq->hw) {
> val |= ICH_LR_HW;
> val |= ((u64)irq->hwintid) << ICH_LR_PHYS_ID_SHIFT;
> + /*
> + * Never set pending+active on a HW interrupt, as the
> + * pending state is kept at the physical distributor
> + * level.
> + */
> + if (irq->active && irq_is_pending(irq))
> + val &= ~ICH_LR_PENDING_BIT;
> } else {
> if (irq->config == VGIC_CONFIG_LEVEL)
> val |= ICH_LR_EOI;
> --
> 2.11.0
>