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

[Eric Auger <eric.auger@linaro.org>]

Hi Pavel,
On 07/02/2015 09:53 AM, Pavel Fedin wrote:
>  Hello!
> 
>> -----Original Message-----
>> From: kvm-owner@vger.kernel.org [mailto:kvm-owner@vger.kernel.org] On Behalf Of Eric Auger
>> Sent: Monday, June 29, 2015 6:37 PM
>> To: eric.auger@st.com; eric.auger@linaro.org; linux-arm-kernel@lists.infradead.org;
>> marc.zyngier@arm.com; christoffer.dall@linaro.org; andre.przywara@arm.com;
>> kvmarm@lists.cs.columbia.edu; kvm@vger.kernel.org
>> Cc: linux-kernel@vger.kernel.org; patches@linaro.org; p.fedin@samsung.com; pbonzini@redhat.com
>> Subject: [PATCH 7/7] KVM: arm: implement kvm_set_msi by gsi direct mapping
>>
>> 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>
>> ---
>>  arch/arm/kvm/Kconfig | 1 +
>>  virt/kvm/arm/vgic.c  | 5 +++++
>>  2 files changed, 6 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
>>  	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.c b/virt/kvm/arm/vgic.c
>> index 0b4c48c..b3c10dc 100644
>> --- a/virt/kvm/arm/vgic.c
>> +++ b/virt/kvm/arm/vgic.c
>> @@ -2314,6 +2314,11 @@ int kvm_set_msi(struct kvm_kernel_irq_routing_entry *e,
>>  			return kvm->arch.vgic.vm_ops.inject_msi(kvm, &msi);
>>  		else
>>  			return -ENODEV;
>> +	case KVM_IRQ_ROUTING_MSI:
>> +		if (kvm->arch.vgic.vm_ops.inject_msi)
>> +			return -EINVAL;
>> +		else
>> +			return kvm_vgic_inject_irq(kvm, 0, e->msi.data, level);
> 
>  Given API change i suggest (using KVM_MSI_VALID_DEVID flag), we could get rid of all these if()'s
> here. Just forward all parameters to vGIC implementation code and let it do its checks.
I don't understand this comment. Here this is the kernel struct that is
used (struct kvm_kernel_irq_routing_entry) and not the user one
(kvm_irq_routing_entry). The kernel struct does not have the flag field.
Another reason I think to keep using the type for homogeneity. To be
noted that in the kernel struct, the devid is passed in
kvm_extended_msi, as you suggested for the user-space struct.

Thanks

Eric
> 
>>  	default:
>>  		return -EINVAL;
>>  	}
>> --
>> 1.9.1
>>
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> 
> Kind regards,
> Pavel Fedin
> Expert Engineer
> Samsung Electronics Research center Russia
> 
>