Re: [Qemu-devel] [PATCH qemu] RFC: spapr/iommu: Enable in-kernel TCE acceleration via VFIO KVM device

[Paolo Bonzini]

On 20/12/2017 15:13, Alexey Kardashevskiy wrote:
> On 20/12/17 20:04, Paolo Bonzini wrote:
>> On 20/12/2017 02:47, Alexey Kardashevskiy wrote:
>>>> - if we foresee having more IOMMU devices in KVM, let's rename
>>>> KVM_DEV_VFIO_GROUP_SET_SPAPR_TCE to KVM_DEV_VFIO_GROUP_ATTACH_IOMMU and
>>>> add a new function
>>>>
>>>>      int iommu_memory_region_get_kvm_fd(IOMMUMemoryRegion *iommu);
>>>>
>>>> that requires no object-type check in VFIO.
>>>
>>> This is how it started and the comment was that this KVM fd needs to have a
>>> well defined semantic which I struggle to provide.
>>
>> I don't think the definition should be anything more than "it can be
>> passed to KVM_DEV_VFIO_GROUP_ATTACH_IOMMU".  I'll discuss it with Alex
>> later today.
> 
> That was more David's concern :)

The get_attr API is okay, just remove the unused set_attr and follow the
other review comments from Alex.

Paolo