Hi,
On 10/17/2015 10:30 PM, Christoffer Dall wrote:
> When a guest reboots or offlines/onlines CPUs, it is not uncommon for it
> to clear the pending and active states of an interrupt through the
> emulated VGIC distributor. However, since we emulate an edge-triggered
> based on a level-triggered device,
I do not get this sentence.
Besides that
Reviewed-by: Eric Auger <eric.auger@xxxxxxxxxx>
Best Regards
Eric
the guest expects the timer interrupt
> to hit even after clearing the pending state.
>
> We currently do not signal the VGIC when the map->active field is true,
> because it indicates that the guest has already been signalled of the
> interrupt as required. Normally this field is set to false when the
> guest deactivates the virtual interrupt through the sync path.
>
> We also need to catch the case where the guest deactivates the interrupt
> through the emulated distributor, again allowing guests to boot even if
> the original virtual timer signal hit before the guest's GIC
> initialization sequence is run.
>
> Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
> ---
> virt/kvm/arm/vgic.c | 32 +++++++++++++++++++++++++++++++-
> 1 file changed, 31 insertions(+), 1 deletion(-)
>
> diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
> index ea21bc2..58b1256 100644
> --- a/virt/kvm/arm/vgic.c
> +++ b/virt/kvm/arm/vgic.c
> @@ -531,6 +531,34 @@ bool vgic_handle_set_pending_reg(struct kvm *kvm,
> return false;
> }
>
> +/*
> + * If a mapped interrupt's state has been modified by the guest such that it
> + * is no longer active or pending, without it have gone through the sync path,
> + * then the map->active field must be cleared so the interrupt can be taken
> + * again.
> + */
> +static void vgic_handle_clear_mapped_irq(struct kvm_vcpu *vcpu)
> +{
> + struct vgic_cpu *vgic_cpu = &vcpu->arch.vgic_cpu;
> + struct list_head *root;
> + struct irq_phys_map_entry *entry;
> + struct irq_phys_map *map;
> +
> + rcu_read_lock();
> +
> + /* Check for PPIs */
> + root = &vgic_cpu->irq_phys_map_list;
> + list_for_each_entry_rcu(entry, root, entry) {
> + map = &entry->map;
> +
> + if (!vgic_dist_irq_is_pending(vcpu, map->virt_irq) &&
> + !vgic_irq_is_active(vcpu, map->virt_irq))
> + map->active = false;
> + }
> +
> + rcu_read_unlock();
> +}
> +
> bool vgic_handle_clear_pending_reg(struct kvm *kvm,
> struct kvm_exit_mmio *mmio,
> phys_addr_t offset, int vcpu_id)
> @@ -561,6 +589,7 @@ bool vgic_handle_clear_pending_reg(struct kvm *kvm,
> vcpu_id, offset);
> vgic_reg_access(mmio, reg, offset, mode);
>
> + vgic_handle_clear_mapped_irq(kvm_get_vcpu(kvm, vcpu_id));
> vgic_update_state(kvm);
> return true;
> }
> @@ -598,6 +627,7 @@ bool vgic_handle_clear_active_reg(struct kvm *kvm,
> ACCESS_READ_VALUE | ACCESS_WRITE_CLEARBIT);
>
> if (mmio->is_write) {
> + vgic_handle_clear_mapped_irq(kvm_get_vcpu(kvm, vcpu_id));
> vgic_update_state(kvm);
> return true;
> }
> @@ -1406,7 +1436,7 @@ static int vgic_sync_hwirq(struct kvm_vcpu *vcpu, struct vgic_lr vlr)
> return 0;
>
> map = vgic_irq_map_search(vcpu, vlr.irq);
> - BUG_ON(!map || !map->active);
> + BUG_ON(!map);
>
> ret = irq_get_irqchip_state(map->irq,
> IRQCHIP_STATE_ACTIVE,
>
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