[PATCH v4 09/13] ARM: KVM: VGIC interrupt injection

[Will Deacon]

On Sat, Nov 10, 2012 at 03:45:18PM +0000, Christoffer Dall wrote:
> From: Marc Zyngier <marc.zyngier at arm.com>
> 
> Plug the interrupt injection code. Interrupts can now be generated
> from user space.
> 
> Signed-off-by: Marc Zyngier <marc.zyngier at arm.com>
> Signed-off-by: Christoffer Dall <c.dall at virtualopensystems.com>
> ---
>  arch/arm/include/asm/kvm_vgic.h |    8 +++
>  arch/arm/kvm/arm.c              |   29 +++++++++++++
>  arch/arm/kvm/vgic.c             |   90 +++++++++++++++++++++++++++++++++++++++
>  3 files changed, 127 insertions(+)
> 
> diff --git a/arch/arm/include/asm/kvm_vgic.h b/arch/arm/include/asm/kvm_vgic.h
> index 7229324..6e3d303 100644
> --- a/arch/arm/include/asm/kvm_vgic.h
> +++ b/arch/arm/include/asm/kvm_vgic.h
> @@ -241,6 +241,8 @@ struct kvm_exit_mmio;
>  int kvm_vgic_set_addr(struct kvm *kvm, unsigned long type, u64 addr);
>  void kvm_vgic_sync_to_cpu(struct kvm_vcpu *vcpu);
>  void kvm_vgic_sync_from_cpu(struct kvm_vcpu *vcpu);
> +int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid, unsigned int irq_num,
> +			bool level);
>  int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu);
>  bool vgic_handle_mmio(struct kvm_vcpu *vcpu, struct kvm_run *run,
>  		      struct kvm_exit_mmio *mmio);
> @@ -271,6 +273,12 @@ static inline void kvm_vgic_vcpu_init(struct kvm_vcpu *vcpu) {}
>  static inline void kvm_vgic_sync_to_cpu(struct kvm_vcpu *vcpu) {}
>  static inline void kvm_vgic_sync_from_cpu(struct kvm_vcpu *vcpu) {}
>  
> +static inline int kvm_vgic_inject_irq(struct kvm *kvm, int cpuid,
> +				      const struct kvm_irq_level *irq)
> +{
> +	return 0;
> +}
> +
>  static inline int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu)
>  {
>  	return 0;
> diff --git a/arch/arm/kvm/arm.c b/arch/arm/kvm/arm.c
> index 3ac1aab..f43da01 100644
> --- a/arch/arm/kvm/arm.c
> +++ b/arch/arm/kvm/arm.c
> @@ -764,10 +764,31 @@ int kvm_vm_ioctl_irq_line(struct kvm *kvm, struct kvm_irq_level *irq_level)
>  
>  	switch (irq_type) {
>  	case KVM_ARM_IRQ_TYPE_CPU:
> +		if (irqchip_in_kernel(kvm))
> +			return -ENXIO;
> +
>  		if (irq_num > KVM_ARM_IRQ_CPU_FIQ)
>  			return -EINVAL;
>  
>  		return vcpu_interrupt_line(vcpu, irq_num, level);
> +#ifdef CONFIG_KVM_ARM_VGIC
> +	case KVM_ARM_IRQ_TYPE_PPI:
> +		if (!irqchip_in_kernel(kvm))
> +			return -ENXIO;
> +
> +		if (irq_num < 16 || irq_num > 31)
> +			return -EINVAL;

It's our favourite two numbers again! :)

> +
> +		return kvm_vgic_inject_irq(kvm, vcpu->vcpu_id, irq_num, level);
> +	case KVM_ARM_IRQ_TYPE_SPI:
> +		if (!irqchip_in_kernel(kvm))
> +			return -ENXIO;
> +
> +		if (irq_num < 32 || irq_num > KVM_ARM_IRQ_GIC_MAX)
> +			return -EINVAL;
> +
> +		return kvm_vgic_inject_irq(kvm, 0, irq_num, level);
> +#endif
>  	}
>  
>  	return -EINVAL;
> @@ -849,6 +870,14 @@ long kvm_arch_vm_ioctl(struct file *filp,
>  	void __user *argp = (void __user *)arg;
>  
>  	switch (ioctl) {
> +#ifdef CONFIG_KVM_ARM_VGIC
> +	case KVM_CREATE_IRQCHIP: {
> +		if (vgic_present)
> +			return kvm_vgic_create(kvm);
> +		else
> +			return -EINVAL;

ENXIO? At least, that's what you use when setting the GIC addresses.

> +	}
> +#endif
>  	case KVM_SET_DEVICE_ADDRESS: {
>  		struct kvm_device_address dev_addr;
>  
> diff --git a/arch/arm/kvm/vgic.c b/arch/arm/kvm/vgic.c
> index dda5623..70040bb 100644
> --- a/arch/arm/kvm/vgic.c
> +++ b/arch/arm/kvm/vgic.c
> @@ -75,6 +75,7 @@
>  #define ACCESS_WRITE_MASK(x)	((x) & (3 << 1))
>  
>  static void vgic_update_state(struct kvm *kvm);
> +static void vgic_kick_vcpus(struct kvm *kvm);
>  static void vgic_dispatch_sgi(struct kvm_vcpu *vcpu, u32 reg);
>  
>  static inline int vgic_irq_is_edge(struct vgic_dist *dist, int irq)
> @@ -542,6 +543,9 @@ bool vgic_handle_mmio(struct kvm_vcpu *vcpu, struct kvm_run *run, struct kvm_exi
>  	kvm_prepare_mmio(run, mmio);
>  	kvm_handle_mmio_return(vcpu, run);
>  
> +	if (updated_state)
> +		vgic_kick_vcpus(vcpu->kvm);
> +
>  	return true;
>  }
>  
> @@ -867,6 +871,92 @@ int kvm_vgic_vcpu_pending_irq(struct kvm_vcpu *vcpu)
>  	return test_bit(vcpu->vcpu_id, &dist->irq_pending_on_cpu);
>  }
>  
> +static void vgic_kick_vcpus(struct kvm *kvm)
> +{
> +	struct kvm_vcpu *vcpu;
> +	int c;
> +
> +	/*
> +	 * We've injected an interrupt, time to find out who deserves
> +	 * a good kick...
> +	 */
> +	kvm_for_each_vcpu(c, vcpu, kvm) {
> +		if (kvm_vgic_vcpu_pending_irq(vcpu))
> +			kvm_vcpu_kick(vcpu);
> +	}
> +}
> +
> +static bool vgic_update_irq_state(struct kvm *kvm, int cpuid,
> +				  unsigned int irq_num, bool level)
> +{
> +	struct vgic_dist *dist = &kvm->arch.vgic;
> +	struct kvm_vcpu *vcpu;
> +	int is_edge, is_level, state;
> +	int enabled;
> +	bool ret = true;
> +
> +	spin_lock(&dist->lock);
> +
> +	is_edge = vgic_irq_is_edge(dist, irq_num);
> +	is_level = !is_edge;
> +	state = vgic_bitmap_get_irq_val(&dist->irq_state, cpuid, irq_num);
> +
> +	/*
> +	 * Only inject an interrupt if:
> +	 * - level triggered and we change level
> +	 * - edge triggered and we have a rising edge
> +	 */
> +	if ((is_level && !(state ^ level)) || (is_edge && (state || !level))) {
> +		ret = false;
> +		goto out;
> +	}

Eek, more of the edge/level combo. Can this be be restructured so that we
have vgic_update_{edge,level}_irq_state, which are called from here
appropriately?

Will