Re: [PATCH v2 7/7] KVM: arm: implement kvm_set_msi by gsi direct mapping

[Andre Przywara <andre.przywara@arm.com>]

On 09/07/15 09:22, Eric Auger wrote:
> If the ITS modality is not available, let's simply support MSI
> injection by transforming the MSI.data into an SPI ID.
> 
> This becomes possible to use KVM_SIGNAL_MSI ioctl for arm too.
> 
> Signed-off-by: Eric Auger <eric.auger@linaro.org>
> 
> ---
> 
> v1 -> v2:
> - introduce vgic_v2m_inject_msi in vgic-v2-emul.c following Andre's
>   advice
> ---
>  arch/arm/kvm/Kconfig        |  1 +
>  virt/kvm/arm/vgic-v2-emul.c | 12 ++++++++++++
>  2 files changed, 13 insertions(+)
> 
> diff --git a/arch/arm/kvm/Kconfig b/arch/arm/kvm/Kconfig
> index 151e710..0f58baf 100644
> --- a/arch/arm/kvm/Kconfig
> +++ b/arch/arm/kvm/Kconfig
> @@ -31,6 +31,7 @@ config KVM
>  	select KVM_VFIO
>  	select HAVE_KVM_EVENTFD
>  	select HAVE_KVM_IRQFD
> +	select HAVE_KVM_MSI

I wonder if this requires some more code to only advertise
KVM_CAP_SIGNAL_MSI if userland actually sets up a GICv2M?
Otherwise userland could get the idea of being able to inectj MSIs
without the guest actually being prepared for that (because the GICv2M
driver did not initialize).

Cheers,
Andre.

>  	select HAVE_KVM_IRQCHIP
>  	select HAVE_KVM_IRQ_ROUTING
>  	depends on ARM_VIRT_EXT && ARM_LPAE && ARM_ARCH_TIMER
> diff --git a/virt/kvm/arm/vgic-v2-emul.c b/virt/kvm/arm/vgic-v2-emul.c
> index 1390797..43013cc 100644
> --- a/virt/kvm/arm/vgic-v2-emul.c
> +++ b/virt/kvm/arm/vgic-v2-emul.c
> @@ -478,6 +478,17 @@ static bool vgic_v2_queue_sgi(struct kvm_vcpu *vcpu, int irq)
>  }
>  
>  /**
> + * Emulates GICv2M MSI injection by injecting the SPI ID matching
> + * the msi data
> + * @kvm: pointer to the kvm struct
> + * @msi: the msi struct handle
> + */
> +static int vgic_v2m_inject_msi(struct kvm *kvm, struct kvm_msi *msi)
> +{
> +	return kvm_vgic_inject_irq(kvm, 0, msi->data, 1);
> +}
> +
> +/**
>   * kvm_vgic_map_resources - Configure global VGIC state before running any VCPUs
>   * @kvm: pointer to the kvm struct
>   *
> @@ -566,6 +577,7 @@ void vgic_v2_init_emulation(struct kvm *kvm)
>  	dist->vm_ops.add_sgi_source = vgic_v2_add_sgi_source;
>  	dist->vm_ops.init_model = vgic_v2_init_model;
>  	dist->vm_ops.map_resources = vgic_v2_map_resources;
> +	dist->vm_ops.inject_msi = vgic_v2m_inject_msi;
>  
>  	kvm->arch.max_vcpus = VGIC_V2_MAX_CPUS;
>  }
>