Re: [PATCH v4 6/7] KVM: arm/arm64: enable MSI routing

[Christoffer Dall <christoffer.dall@linaro.org>]

On Mon, Apr 04, 2016 at 10:47:36AM +0200, Eric Auger wrote:
> Up to now, only irqchip routing entries could be set. This patch
> adds the capability to insert MSI routing entries.
> 
> For ARM64, let's also increase KVM_MAX_IRQ_ROUTES to 4096: this
> include SPI irqchip routes plus MSI routes. In the future this
> might be extended.
> 
> Signed-off-by: Eric Auger <eric.auger@linaro.org>
> 
> ---
> v2 -> v3:
> - remove any reference to KVM_IRQ_ROUTING_EXTENDED_MSI type
> - unconditionnaly uapi flags and devid downto the kernel
>   routing entry struct
> - handle KVM_MSI_VALID_DEVID flag in kvm_set_irq_routing
> - note about KVM_CAP_MSI_DEVID moved in the first patch file
>   of the series
> 
> v1 -> v2:
> - adapt to new routing entry types
> 
> RFC -> PATCH:
> - move api MSI routing updates into that patch file
> - use new devid field of user api struct
> ---
>  Documentation/virtual/kvm/api.txt | 5 +++++
>  include/linux/kvm_host.h          | 2 ++
>  virt/kvm/arm/vgic/vgic_irqfd.c    | 8 ++++++++
>  virt/kvm/irqchip.c                | 2 +-
>  4 files changed, 16 insertions(+), 1 deletion(-)
> 
> diff --git a/Documentation/virtual/kvm/api.txt b/Documentation/virtual/kvm/api.txt
> index 61f8f27..217b460 100644
> --- a/Documentation/virtual/kvm/api.txt
> +++ b/Documentation/virtual/kvm/api.txt
> @@ -2368,6 +2368,11 @@ On arm/arm64, gsi routing being supported, the following can happen:
>  - in case no routing entry is associated to this gsi, injection fails
>  - in case the gsi is associated to an irqchip routing entry,
>    irqchip.pin + 32 corresponds to the injected SPI ID.
> +- in case the gsi is associated to an MSI routing entry,
> +  * without GICv3 ITS in-kernel emulation, MSI data matches the SPI ID
> +    of the injected SPI

can we be more specific here and perhaps express this in the positive?
For example, if the user creates a KVM_DEV_TYPE_ARM_VGIC_V2, then...

> +  * with GICv3 ITS in-kernel emulation, the MSI message and device ID
> +    are translated into an LPI.
>  
>  4.76 KVM_PPC_ALLOCATE_HTAB
>  
> diff --git a/include/linux/kvm_host.h b/include/linux/kvm_host.h
> index 461e480..f25613d 100644
> --- a/include/linux/kvm_host.h
> +++ b/include/linux/kvm_host.h
> @@ -1021,6 +1021,8 @@ static inline int mmu_notifier_retry(struct kvm *kvm, unsigned long mmu_seq)
>  
>  #ifdef CONFIG_S390
>  #define KVM_MAX_IRQ_ROUTES 4096 //FIXME: we can have more than that...
> +#elif defined(CONFIG_ARM64)
> +#define KVM_MAX_IRQ_ROUTES 4096
>  #else
>  #define KVM_MAX_IRQ_ROUTES 1024
>  #endif
> diff --git a/virt/kvm/arm/vgic/vgic_irqfd.c b/virt/kvm/arm/vgic/vgic_irqfd.c
> index a76994f..a3a7f02 100644
> --- a/virt/kvm/arm/vgic/vgic_irqfd.c
> +++ b/virt/kvm/arm/vgic/vgic_irqfd.c
> @@ -64,6 +64,14 @@ int kvm_set_routing_entry(struct kvm_kernel_irq_routing_entry *e,
>  		    (e->irqchip.irqchip >= KVM_NR_IRQCHIPS))
>  			goto out;
>  		break;
> +	case KVM_IRQ_ROUTING_MSI:
> +		e->set = kvm_set_msi;
> +		e->msi.address_lo = ue->u.msi.address_lo;
> +		e->msi.address_hi = ue->u.msi.address_hi;
> +		e->msi.data = ue->u.msi.data;
> +		e->flags = ue->flags;
> +		e->devid = ue->u.msi.devid;
> +		break;
>  	default:
>  		goto out;
>  	}
> diff --git a/virt/kvm/irqchip.c b/virt/kvm/irqchip.c
> index b4222d6..269d949 100644
> --- a/virt/kvm/irqchip.c
> +++ b/virt/kvm/irqchip.c
> @@ -211,7 +211,7 @@ int kvm_set_irq_routing(struct kvm *kvm,
>  			goto out;
>  
>  		r = -EINVAL;
> -		if (ue->flags) {
> +		if (ue->flags & ~KVM_MSI_VALID_DEVID) {
>  			kfree(e);
>  			goto out;
>  		}
> -- 
> 1.9.1
>