Re: [PATCH v4 08/22] iommu: Introduce attach/detach_pasid_table API

[Jean-Philippe Brucker]

On 24/06/2019 16:06, Auger Eric wrote:
> Hi,
> 
> On 6/18/19 5:41 PM, Jonathan Cameron wrote:
>> On Sun, 9 Jun 2019 06:44:08 -0700
>> Jacob Pan <jacob.jun.pan@xxxxxxxxxxxxxxx> wrote:
>>
>>> In virtualization use case, when a guest is assigned
>>> a PCI host device, protected by a virtual IOMMU on the guest,
>>> the physical IOMMU must be programmed to be consistent with
>>> the guest mappings. If the physical IOMMU supports two
>>> translation stages it makes sense to program guest mappings
>>> onto the first stage/level (ARM/Intel terminology) while the host
>>> owns the stage/level 2.
>>>
>>> In that case, it is mandated to trap on guest configuration
>>> settings and pass those to the physical iommu driver.
>>>
>>> This patch adds a new API to the iommu subsystem that allows
>>> to set/unset the pasid table information.
>>>
>>> A generic iommu_pasid_table_config struct is introduced in
>>> a new iommu.h uapi header. This is going to be used by the VFIO
>>> user API.
>>
>> Another case where strictly speaking stuff is introduced that this series
>> doesn't use.  I don't know what the plans are to merge the various
>> related series though so this might make sense in general. Right now
>> it just bloats this series a bit..
> 
> I am now the only user of this API in
> [PATCH v8 00/29] SMMUv3 Nested Stage Setup
> (https://patchwork.kernel.org/cover/10961733/).
> 
> This can live in this series or Jean-Philippe do you intend to keep on
> maintaining it in your api branch?

No, I think it makes sense to keep it within your series

Thanks,
Jean