Hi Marc,
On 06/08/2015 07:04 PM, Marc Zyngier wrote:
> So far, the only use of the HW interrupt facility is the timer,
> implying that the active state is context-switched for each vcpu,
> as the device is is shared across all vcpus.
s/is//
>
> This does not work for a device that has been assigned to a VM,
> as the guest is entierely in control of that device (the HW is
entirely?
> not shared). In that case, it makes sense to bypass the whole
> active state srtwitchint, and only track the deactivation of the
switching
> interrupt.
>
> Signed-off-by: Marc Zyngier <marc.zyng...@arm.com>
> ---
> include/kvm/arm_vgic.h | 5 +++--
> virt/kvm/arm/arch_timer.c | 2 +-
> virt/kvm/arm/vgic.c | 37 ++++++++++++++++++++++++-------------
> 3 files changed, 28 insertions(+), 16 deletions(-)
>
> diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
> index 1c653c1..5d47d60 100644
> --- a/include/kvm/arm_vgic.h
> +++ b/include/kvm/arm_vgic.h
> @@ -164,7 +164,8 @@ struct irq_phys_map {
> u32 virt_irq;
> u32 phys_irq;
> u32 irq;
> - bool active;
> + bool shared;
> + bool active; /* Only valid if shared */
> };
>
> struct vgic_dist {
> @@ -347,7 +348,7 @@ void vgic_v3_dispatch_sgi(struct kvm_vcpu *vcpu, u64 reg);
> int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu);
> int kvm_vgic_vcpu_active_irq(struct kvm_vcpu *vcpu);
> struct irq_phys_map *vgic_map_phys_irq(struct kvm_vcpu *vcpu,
> - int virt_irq, int irq);
> + int virt_irq, int irq, bool shared);
> int vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, struct irq_phys_map *map);
> bool vgic_get_phys_irq_active(struct irq_phys_map *map);
> void vgic_set_phys_irq_active(struct irq_phys_map *map, bool active);
> diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c
> index b9fff78..9544d79 100644
> --- a/virt/kvm/arm/arch_timer.c
> +++ b/virt/kvm/arm/arch_timer.c
> @@ -202,7 +202,7 @@ void kvm_timer_vcpu_reset(struct kvm_vcpu *vcpu,
> * Tell the VGIC that the virtual interrupt is tied to a
> * physical interrupt. We do that once per VCPU.
> */
> - timer->map = vgic_map_phys_irq(vcpu, irq->irq, host_vtimer_irq);
> + timer->map = vgic_map_phys_irq(vcpu, irq->irq, host_vtimer_irq, true);
> WARN_ON(!timer->map);
> }
>
> diff --git a/virt/kvm/arm/vgic.c b/virt/kvm/arm/vgic.c
> index f376b56..4223166 100644
> --- a/virt/kvm/arm/vgic.c
> +++ b/virt/kvm/arm/vgic.c
> @@ -1125,18 +1125,21 @@ static void vgic_queue_irq_to_lr(struct kvm_vcpu
> *vcpu, int irq,
> map = vgic_irq_map_search(vcpu, irq);
>
> if (map) {
> - int ret;
> -
> - BUG_ON(!map->active);
> vlr.hwirq = map->phys_irq;
> vlr.state |= LR_HW;
> vlr.state &= ~LR_EOI_INT;
>
> - ret = irq_set_irqchip_state(map->irq,
> - IRQCHIP_STATE_ACTIVE,
> - true);
> vgic_irq_set_queued(vcpu, irq);
the queued state is set again in vgic_queue_hwirq for level_sensitive
IRQs although not harmful.
> - WARN_ON(ret);
> +
> + if (map->shared) {
> + int ret;
> +
> + BUG_ON(!map->active);
> + ret = irq_set_irqchip_state(map->irq,
> +
> IRQCHIP_STATE_ACTIVE,
> + true);
> + WARN_ON(ret);
> + }
> }
> }
>
> @@ -1368,21 +1371,28 @@ static bool vgic_process_maintenance(struct kvm_vcpu
> *vcpu)
> static int vgic_sync_hwirq(struct kvm_vcpu *vcpu, struct vgic_lr vlr)
> {
> struct irq_phys_map *map;
> + bool active;
> int ret;
>
> if (!(vlr.state & LR_HW))
> return 0;
>
> map = vgic_irq_map_search(vcpu, vlr.irq);
> - BUG_ON(!map || !map->active);
> + BUG_ON(!map);
> + BUG_ON(map->shared && !map->active);
>
> ret = irq_get_irqchip_state(map->irq,
> IRQCHIP_STATE_ACTIVE,
> - &map->active);
> + &active);
>
In case of non shared and EOIMode = 1 - I know this is not your current
interest here though ;-) - , once the guest EOIs its virtual IRQ and GIC
deactivates the physical one, a new phys IRQ can hit immediatly, the
physical handler can be entered and the state is seen as active here.
The queued state is never reset in such a case and the system gets stuck
since the can_sample fails I think. What I mean here is sounds the state
machine as is does not work for my VFIO case. So some adaptations still
are needed I think. Do you share my diagnosis?
Eric
>
> - if (map->active) {
> + if (!map->shared)
> + return !active;
> +
> + map->active = active;
> +
> + if (active) {
> ret = irq_set_irqchip_state(map->irq,
> IRQCHIP_STATE_ACTIVE,
> false);
> @@ -1663,7 +1673,7 @@ static struct rb_root *vgic_get_irq_phys_map(struct
> kvm_vcpu *vcpu,
> }
>
> struct irq_phys_map *vgic_map_phys_irq(struct kvm_vcpu *vcpu,
> - int virt_irq, int irq)
> + int virt_irq, int irq, bool shared)
> {
> struct vgic_dist *dist = &vcpu->kvm->arch.vgic;
> struct rb_root *root = vgic_get_irq_phys_map(vcpu, virt_irq);
> @@ -1710,6 +1720,7 @@ struct irq_phys_map *vgic_map_phys_irq(struct kvm_vcpu
> *vcpu,
> new_map->virt_irq = virt_irq;
> new_map->phys_irq = phys_irq;
> new_map->irq = irq;
> + new_map->shared = shared;
>
> rb_link_node(&new_map->node, parent, new);
> rb_insert_color(&new_map->node, root);
> @@ -1746,13 +1757,13 @@ static struct irq_phys_map
> *vgic_irq_map_search(struct kvm_vcpu *vcpu,
>
> bool vgic_get_phys_irq_active(struct irq_phys_map *map)
> {
> - BUG_ON(!map);
> + BUG_ON(!map || !map->shared);
> return map->active;
> }
>
> void vgic_set_phys_irq_active(struct irq_phys_map *map, bool active)
> {
> - BUG_ON(!map);
> + BUG_ON(!map || !map->shared);
> map->active = active;
> }
>
>
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