On 22/07/2016 15:56, Radim Krčmář wrote:
> 2016-07-22 15:52+0200, Auger Eric:
>> 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
>
> No problem. Give me half an hour for a review, please. :)
Sure
Eric
>
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