Hi Christoffer,
On 07/12/17 11:54, Christoffer Dall wrote:
> The GIC sometimes need to sample the physical line of a mapped
> interrupt. As we know this to be notoriously slow, provide a callback
> function for devices (such as the timer) which can do this much faster
> than talking to the distributor, for example by comparing a few
> in-memory values. Fall back to the good old method of poking the
> physical GIC if no callback is provided.
>
> Reviewed-by: Marc Zyngier <marc.zyngier@xxxxxxx>
> Signed-off-by: Christoffer Dall <christoffer.dall@xxxxxxxxxx>
> ---
> include/kvm/arm_vgic.h | 13 ++++++++++++-
> virt/kvm/arm/arch_timer.c | 3 ++-
> virt/kvm/arm/vgic/vgic.c | 12 +++++++++---
> 3 files changed, 23 insertions(+), 5 deletions(-)
>
> diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
> index 8c896540a72c..cdbd142ca7f2 100644
> --- a/include/kvm/arm_vgic.h
> +++ b/include/kvm/arm_vgic.h
> @@ -130,6 +130,17 @@ struct vgic_irq {
> u8 priority;
> enum vgic_irq_config config; /* Level or edge */
>
> + /*
> + * Callback function pointer to in-kernel devices that can tell us the
> + * state of the input level of mapped level-triggered IRQ faster than
> + * peaking into the physical GIC.
> + *
> + * Always called in non-preemptible section and the functions can use
> + * kvm_arm_get_running_vcpu() to get the vcpu pointer for private
> + * IRQs.
> + */
> + bool (*get_input_level)(int vintid);
> +
> void *owner; /* Opaque pointer to reserve an interrupt
> for in-kernel devices. */
> };
> @@ -331,7 +342,7 @@ void kvm_vgic_init_cpu_hardware(void);
> int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid,
> bool level, void *owner);
> int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, unsigned int host_irq,
> - u32 vintid);
> + u32 vintid, bool (*get_input_level)(int vindid));
> int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int vintid);
> bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, unsigned int vintid);
>
> diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c
> index dd5aca05c500..e78ba5e20f74 100644
> --- a/virt/kvm/arm/arch_timer.c
> +++ b/virt/kvm/arm/arch_timer.c
> @@ -840,7 +840,8 @@ int kvm_timer_enable(struct kvm_vcpu *vcpu)
> return -EINVAL;
> }
>
> - ret = kvm_vgic_map_phys_irq(vcpu, host_vtimer_irq, vtimer->irq.irq);
> + ret = kvm_vgic_map_phys_irq(vcpu, host_vtimer_irq, vtimer->irq.irq,
> + NULL);
> if (ret)
> return ret;
>
> diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c
> index 607cbbc27a1c..eadabb249d2a 100644
> --- a/virt/kvm/arm/vgic/vgic.c
> +++ b/virt/kvm/arm/vgic/vgic.c
Nit: the comment "Get the input level of a mapped IRQ directly from the
physical GIC" is not strictly correct anymore
> @@ -151,6 +151,9 @@ bool vgic_get_phys_line_level(struct vgic_irq *irq)
>
> BUG_ON(!irq->hw);
>
> + if (irq->get_input_level)
> + return irq->get_input_level(irq->intid);
> +
> WARN_ON(irq_get_irqchip_state(irq->host_irq,
> IRQCHIP_STATE_PENDING,
> &line_level));
> @@ -436,7 +439,8 @@ int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid,
>
> /* @irq->irq_lock must be held */
> static int kvm_vgic_map_irq(struct kvm_vcpu *vcpu, struct vgic_irq *irq,
> - unsigned int host_irq)
> + unsigned int host_irq,
> + bool (*get_input_level)(int vindid))
> {
> struct irq_desc *desc;
> struct irq_data *data;
> @@ -456,6 +460,7 @@ static int kvm_vgic_map_irq(struct kvm_vcpu *vcpu, struct vgic_irq *irq,
> irq->hw = true;
> irq->host_irq = host_irq;
> irq->hwintid = data->hwirq;
> + irq->get_input_level = get_input_level;
> return 0;
> }
>
> @@ -464,10 +469,11 @@ static inline void kvm_vgic_unmap_irq(struct vgic_irq *irq)
> {
> irq->hw = false;
> irq->hwintid = 0;
> + irq->get_input_level = NULL;
> }
>
> int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, unsigned int host_irq,
> - u32 vintid)
> + u32 vintid, bool (*get_input_level)(int vindid))
> {
> struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, vintid);
> unsigned long flags;
> @@ -476,7 +482,7 @@ int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, unsigned int host_irq,
> BUG_ON(!irq);
>
> spin_lock_irqsave(&irq->irq_lock, flags);
> - ret = kvm_vgic_map_irq(vcpu, irq, host_irq);
> + ret = kvm_vgic_map_irq(vcpu, irq, host_irq, get_input_level);
> spin_unlock_irqrestore(&irq->irq_lock, flags);
> vgic_put_irq(vcpu->kvm, irq);
>
>
Reviewed-by: Eric Auger <eric.auger@xxxxxxxxxx>
Thanks
Eric
