On Fri, Oct 06, 2017 at 04:33:44PM +0100, Marc Zyngier wrote:
> Let's use the irq bypass mechanism introduced for platform device
> interrupts to intercept the virtual PCIe endpoint configuration
> and establish our LPI->VLPI mapping.
> 
> Signed-off-by: Marc Zyngier <[email protected]>

Reviewed-by: Christoffer Dall <[email protected]>

> ---
>  include/kvm/arm_vgic.h      |   8 ++++
>  virt/kvm/arm/arm.c          |   6 ++-
>  virt/kvm/arm/vgic/vgic-v4.c | 104 
> ++++++++++++++++++++++++++++++++++++++++++++
>  3 files changed, 116 insertions(+), 2 deletions(-)
> 
> diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
> index 7eeb6c2a2f9c..2f750c770bf2 100644
> --- a/include/kvm/arm_vgic.h
> +++ b/include/kvm/arm_vgic.h
> @@ -373,4 +373,12 @@ int kvm_vgic_setup_default_irq_routing(struct kvm *kvm);
>  
>  int kvm_vgic_set_owner(struct kvm_vcpu *vcpu, unsigned int intid, void 
> *owner);
>  
> +struct kvm_kernel_irq_routing_entry;
> +
> +int kvm_vgic_v4_set_forwarding(struct kvm *kvm, int irq,
> +                            struct kvm_kernel_irq_routing_entry *irq_entry);
> +
> +int kvm_vgic_v4_unset_forwarding(struct kvm *kvm, int irq,
> +                              struct kvm_kernel_irq_routing_entry 
> *irq_entry);
> +
>  #endif /* __KVM_ARM_VGIC_H */
> diff --git a/virt/kvm/arm/arm.c b/virt/kvm/arm/arm.c
> index 5d5218ecd547..8388c1cc23f6 100644
> --- a/virt/kvm/arm/arm.c
> +++ b/virt/kvm/arm/arm.c
> @@ -1462,7 +1462,8 @@ int kvm_arch_irq_bypass_add_producer(struct 
> irq_bypass_consumer *cons,
>       struct kvm_kernel_irqfd *irqfd =
>               container_of(cons, struct kvm_kernel_irqfd, consumer);
>  
> -     return 0;
> +     return kvm_vgic_v4_set_forwarding(irqfd->kvm, prod->irq,
> +                                       &irqfd->irq_entry);
>  }
>  void kvm_arch_irq_bypass_del_producer(struct irq_bypass_consumer *cons,
>                                     struct irq_bypass_producer *prod)
> @@ -1470,7 +1471,8 @@ void kvm_arch_irq_bypass_del_producer(struct 
> irq_bypass_consumer *cons,
>       struct kvm_kernel_irqfd *irqfd =
>               container_of(cons, struct kvm_kernel_irqfd, consumer);
>  
> -     return;
> +     kvm_vgic_v4_unset_forwarding(irqfd->kvm, prod->irq,
> +                                  &irqfd->irq_entry);
>  }
>  
>  void kvm_arch_irq_bypass_stop(struct irq_bypass_consumer *cons)
> diff --git a/virt/kvm/arm/vgic/vgic-v4.c b/virt/kvm/arm/vgic/vgic-v4.c
> index c794f0cef09e..ba1dd3162eba 100644
> --- a/virt/kvm/arm/vgic/vgic-v4.c
> +++ b/virt/kvm/arm/vgic/vgic-v4.c
> @@ -81,3 +81,107 @@ void vgic_v4_teardown(struct kvm *kvm)
>       its_vm->nr_vpes = 0;
>       its_vm->vpes = NULL;
>  }
> +
> +static struct vgic_its *vgic_get_its(struct kvm *kvm,
> +                                  struct kvm_kernel_irq_routing_entry 
> *irq_entry)
> +{
> +     struct kvm_msi msi  = (struct kvm_msi) {
> +             .address_lo     = irq_entry->msi.address_lo,
> +             .address_hi     = irq_entry->msi.address_hi,
> +             .data           = irq_entry->msi.data,
> +             .flags          = irq_entry->msi.flags,
> +             .devid          = irq_entry->msi.devid,
> +     };
> +
> +     /*
> +      * Get a reference on the LPI. If NULL, this is not a valid
> +      * translation for any of our vITSs.
> +      */
> +     return vgic_msi_to_its(kvm, &msi);
> +}
> +
> +int kvm_vgic_v4_set_forwarding(struct kvm *kvm, int virq,
> +                            struct kvm_kernel_irq_routing_entry *irq_entry)
> +{
> +     struct vgic_its *its;
> +     struct vgic_irq *irq;
> +     struct its_vlpi_map map;
> +     int ret;
> +
> +     if (!vgic_supports_direct_msis(kvm))
> +             return 0;
> +
> +     /*
> +      * Get the ITS, and escape early on error (not a valid
> +      * doorbell for any of our vITSs).
> +      */
> +     its = vgic_get_its(kvm, irq_entry);
> +     if (IS_ERR(its))
> +             return 0;
> +
> +     mutex_lock(&its->its_lock);
> +
> +     /* Perform then actual DevID/EventID -> LPI translation. */
> +     ret = vgic_its_resolve_lpi(kvm, its, irq_entry->msi.devid,
> +                                irq_entry->msi.data, &irq);
> +     if (ret)
> +             goto out;
> +
> +     /*
> +      * Emit the mapping request. If it fails, the ITS probably
> +      * isn't v4 compatible, so let's silently bail out. Holding
> +      * the ITS lock should ensure that nothing can modify the
> +      * target vcpu.
> +      */
> +     map = (struct its_vlpi_map) {
> +             .vm             = &kvm->arch.vgic.its_vm,
> +             .vpe            = 
> &irq->target_vcpu->arch.vgic_cpu.vgic_v3.its_vpe,
> +             .vintid         = irq->intid,
> +             .db_enabled     = true,
> +     };
> +
> +     ret = its_map_vlpi(virq, &map);
> +     if (ret)
> +             goto out;
> +
> +     irq->hw         = true;
> +     irq->host_irq   = virq;
> +
> +out:
> +     mutex_unlock(&its->its_lock);
> +     return ret;
> +}
> +
> +int kvm_vgic_v4_unset_forwarding(struct kvm *kvm, int virq,
> +                              struct kvm_kernel_irq_routing_entry *irq_entry)
> +{
> +     struct vgic_its *its;
> +     struct vgic_irq *irq;
> +     int ret;
> +
> +     if (!vgic_supports_direct_msis(kvm))
> +             return 0;
> +
> +     /*
> +      * Get the ITS, and escape early on error (not a valid
> +      * doorbell for any of our vITSs).
> +      */
> +     its = vgic_get_its(kvm, irq_entry);
> +     if (IS_ERR(its))
> +             return 0;
> +
> +     mutex_lock(&its->its_lock);
> +
> +     ret = vgic_its_resolve_lpi(kvm, its, irq_entry->msi.devid,
> +                                irq_entry->msi.data, &irq);
> +     if (ret)
> +             goto out;
> +
> +     WARN_ON(!(irq->hw && irq->host_irq == virq));
> +     irq->hw = false;
> +     ret = its_unmap_vlpi(virq);
> +
> +out:
> +     mutex_unlock(&its->its_lock);
> +     return ret;
> +}
> -- 
> 2.14.1
> 
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