Re: [PATCH v2 4/8] KVM: arm/arm64: vgic: restructure kvm_vgic_(un)map_phys_irq

[Christoffer Dall <cdall@linaro.org>]

On Thu, Jun 15, 2017 at 02:52:36PM +0200, Eric Auger wrote:
> We want to reuse the core of the map/unmap functions for IRQ
> forwarding. Let's move the computation of the hwirq in
> kvm_vgic_map_phys_irq and pass the linux IRQ as parameter.
> the host_irq is added to struct vgic_irq.
> 
> We introduce kvm_vgic_map/unmap_irq which take a struct vgic_irq
> handle as a parameter.

So this is to avoid the linux-to-hardware irq number translation in
other callers?

I am sort of guessing that we need to store the host_irq number so that
we can probe into the physical GIC in later patches?  That may be good
to note in this commit message if you respin.

Thanks,
-Christoffer

> 
> Signed-off-by: Eric Auger <eric.auger@redhat.com>
> ---
>  include/kvm/arm_vgic.h    |  8 ++++---
>  virt/kvm/arm/arch_timer.c | 24 +------------------
>  virt/kvm/arm/vgic/vgic.c  | 60 +++++++++++++++++++++++++++++++++++------------
>  3 files changed, 51 insertions(+), 41 deletions(-)
> 
> diff --git a/include/kvm/arm_vgic.h b/include/kvm/arm_vgic.h
> index ef71858..cceb31d 100644
> --- a/include/kvm/arm_vgic.h
> +++ b/include/kvm/arm_vgic.h
> @@ -112,6 +112,7 @@ struct vgic_irq {
>  	bool hw;			/* Tied to HW IRQ */
>  	struct kref refcount;		/* Used for LPIs */
>  	u32 hwintid;			/* HW INTID number */
> +	unsigned int host_irq;		/* linux irq corresponding to hwintid */
>  	union {
>  		u8 targets;			/* GICv2 target VCPUs mask */
>  		u32 mpidr;			/* GICv3 target VCPU */
> @@ -301,9 +302,10 @@ int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid,
>  			bool level);
>  int kvm_vgic_inject_mapped_irq(struct kvm *kvm, int cpuid, unsigned int intid,
>  			       bool level);
> -int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, u32 virt_irq, u32 phys_irq);
> -int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int virt_irq);
> -bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, unsigned int virt_irq);
> +int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, unsigned int host_irq,
> +			  u32 vintid);
> +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);
>  
>  int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu);
>  
> diff --git a/virt/kvm/arm/arch_timer.c b/virt/kvm/arm/arch_timer.c
> index 5976609..57a30ab 100644
> --- a/virt/kvm/arm/arch_timer.c
> +++ b/virt/kvm/arm/arch_timer.c
> @@ -617,9 +617,6 @@ int kvm_timer_enable(struct kvm_vcpu *vcpu)
>  {
>  	struct arch_timer_cpu *timer = &vcpu->arch.timer_cpu;
>  	struct arch_timer_context *vtimer = vcpu_vtimer(vcpu);
> -	struct irq_desc *desc;
> -	struct irq_data *data;
> -	int phys_irq;
>  	int ret;
>  
>  	if (timer->enabled)
> @@ -632,26 +629,7 @@ int kvm_timer_enable(struct kvm_vcpu *vcpu)
>  	if (!vgic_initialized(vcpu->kvm))
>  		return -ENODEV;
>  
> -	/*
> -	 * Find the physical IRQ number corresponding to the host_vtimer_irq
> -	 */
> -	desc = irq_to_desc(host_vtimer_irq);
> -	if (!desc) {
> -		kvm_err("%s: no interrupt descriptor\n", __func__);
> -		return -EINVAL;
> -	}
> -
> -	data = irq_desc_get_irq_data(desc);
> -	while (data->parent_data)
> -		data = data->parent_data;
> -
> -	phys_irq = data->hwirq;
> -
> -	/*
> -	 * Tell the VGIC that the virtual interrupt is tied to a
> -	 * physical interrupt. We do that once per VCPU.
> -	 */
> -	ret = kvm_vgic_map_phys_irq(vcpu, vtimer->irq.irq, phys_irq);
> +	ret = kvm_vgic_map_phys_irq(vcpu, host_vtimer_irq, vtimer->irq.irq);
>  	if (ret)
>  		return ret;
>  
> diff --git a/virt/kvm/arm/vgic/vgic.c b/virt/kvm/arm/vgic/vgic.c
> index 83b24d2..075f073 100644
> --- a/virt/kvm/arm/vgic/vgic.c
> +++ b/virt/kvm/arm/vgic/vgic.c
> @@ -17,6 +17,8 @@
>  #include <linux/kvm.h>
>  #include <linux/kvm_host.h>
>  #include <linux/list_sort.h>
> +#include <linux/interrupt.h>
> +#include <linux/irq.h>
>  
>  #include "vgic.h"
>  
> @@ -392,38 +394,66 @@ int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int intid,
>  	return 0;
>  }
>  
> -int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, u32 virt_irq, u32 phys_irq)
> +/* @irq->irq_lock must be held */
> +static int kvm_vgic_map_irq(struct kvm_vcpu *vcpu, struct vgic_irq *irq,
> +			    unsigned int host_irq)
>  {
> -	struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, virt_irq);
> +	struct irq_desc *desc;
> +	struct irq_data *data;
>  
> -	BUG_ON(!irq);
> -
> -	spin_lock(&irq->irq_lock);
> +	/*
> +	 * Find the physical IRQ number corresponding to @host_irq
> +	 */
> +	desc = irq_to_desc(host_irq);
> +	if (!desc) {
> +		kvm_err("%s: no interrupt descriptor\n", __func__);
> +		return -EINVAL;
> +	}
> +	data = irq_desc_get_irq_data(desc);
> +	while (data->parent_data)
> +		data = data->parent_data;
>  
>  	irq->hw = true;
> -	irq->hwintid = phys_irq;
> +	irq->host_irq = host_irq;
> +	irq->hwintid = data->hwirq;
> +	return 0;
> +}
> +
> +/* @irq->irq_lock must be held */
> +static inline void kvm_vgic_unmap_irq(struct vgic_irq *irq)
> +{
> +	irq->hw = false;
> +	irq->hwintid = 0;
> +}
> +
> +int kvm_vgic_map_phys_irq(struct kvm_vcpu *vcpu, unsigned int host_irq,
> +			  u32 vintid)
> +{
> +	struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, vintid);
> +	int ret;
>  
> +	BUG_ON(!irq);
> +
> +	spin_lock(&irq->irq_lock);
> +	ret = kvm_vgic_map_irq(vcpu, irq, host_irq);
>  	spin_unlock(&irq->irq_lock);
>  	vgic_put_irq(vcpu->kvm, irq);
>  
> -	return 0;
> +	return ret;
>  }
>  
> -int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int virt_irq)
> +int kvm_vgic_unmap_phys_irq(struct kvm_vcpu *vcpu, unsigned int vintid)
>  {
>  	struct vgic_irq *irq;
>  
>  	if (!vgic_initialized(vcpu->kvm))
>  		return -EAGAIN;
>  
> -	irq = vgic_get_irq(vcpu->kvm, vcpu, virt_irq);
> +	irq = vgic_get_irq(vcpu->kvm, vcpu, vintid);
>  	BUG_ON(!irq);
>  
>  	spin_lock(&irq->irq_lock);
> -
> -	irq->hw = false;
> -	irq->hwintid = 0;
> -
> +	kvm_vgic_unmap_irq(irq);
>  	spin_unlock(&irq->irq_lock);
>  	vgic_put_irq(vcpu->kvm, irq);
>  
> @@ -726,9 +756,9 @@ void vgic_kick_vcpus(struct kvm *kvm)
>  	}
>  }
>  
> -bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, unsigned int virt_irq)
> +bool kvm_vgic_map_is_active(struct kvm_vcpu *vcpu, unsigned int vintid)
>  {
> -	struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, virt_irq);
> +	struct vgic_irq *irq = vgic_get_irq(vcpu->kvm, vcpu, vintid);
>  	bool map_is_active;
>  
>  	spin_lock(&irq->irq_lock);
> -- 
> 2.5.5
>