Hi Radim,
On 22/07/2016 15:39, Radim Krčmář wrote:
> 2016-07-21 23:10+0200, Auger Eric:
>> On 21/07/2016 18:33, Radim Krčmář wrote:
>>> 2016-07-18 13:25+0000, Eric Auger:
>>>> 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 and MSI
>>>> routing for arm too.
>>>>
>>>> Signed-off-by: Eric Auger <eric.auger@xxxxxxxxxx>
>>>>
>>>> ---
>>>> diff --git a/virt/kvm/arm/vgic/vgic-irqfd.c b/virt/kvm/arm/vgic/vgic-irqfd.c
>>>> +static int vgic_v2m_inject_msi(struct kvm *kvm, struct kvm_msi *msi)
>>>> +{
>>>> + if (msi->flags & KVM_MSI_VALID_DEVID)
>>>> + return -EINVAL;
>>>> + if (!vgic_valid_spi(kvm, msi->data))
>>>> + return -EINVAL;
>>>> +
>>>> + return kvm_vgic_inject_irq(kvm, 0, msi->data, 1);
>>>
>>> Hm, this isn't very MSI related ...
>>>
>>> arm already has KVM_IRQ_LINE/kvm_vm_ioctl_irq_line with
>>> KVM_ARM_IRQ_TYPE_SPI that does
>>> kvm_vgic_inject_irq(kvm, 0, irq_num, level)
>>>
>>> Is that interface lacking?
>>
>> You mean KVM_SIGNAL_MSI? Well at QEMU level, for ARM/ARM64 is doesn't.
>
> No, I meant KVM_IRQ_LINE, the one that is used to deliver SPI today.
> Or isn't it?
>
>> For kvm-tools I guess, Andre manages without.
>>
>> My first feeling was it is part of the KVM API and we can implement it
>> easily for GICv2M, as we do for GICv3 ITS . This can avoid a user app to
>> do what QEMU implements as "kvm_gsi_direct_mapping" and manage the
>> translation into the semantic of the ARM GSI.
>
> I think that reusing KVM_SIGNAL_MSI and KVM_IRQ_ROUTING_MSI for SPI is
> unfortunate.
>
> SPI only uses msi.data, which makes remaining fields in the msi struct
> arbitrary and [5/7] defined KVM_IRQ_ROUTING_IRQCHIP for SPI, so two
> route types now do the same, but only sometimes (without ITS), which
> makes the situation even less understandable ...
>
> Delivering SPI as KVM_IRQ_ROUTING_IRQCHIP seems more sensible and if we
> wanted ad-hoc delivery of KVM_IRQ_ROUTING_IRQCHIP, then I would prefer a
> new interface to two different meanings for KVM_SIGNAL_MSI:
> KVM_SIGNAL_MSI was created because we didn't have anything that could
> inject an interrupt without setting up a route with KVM_SET_GSI_ROUTING
> and we are still missing a generic interface to do that.
>
>> But Well, if you prefer we do not implement it for GICv2M, since
>> considered as far fetched I can remove this patch.
>
> I do, thanks. Documentation in [6/7] was ahead and needs changing then.
Argh just saw your reply after sending v8. Will respin immediatly.
Sorry for the confusion
Thanks
Eric
>
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