Re: [PATCH v5 10/11] iommu/vt-d: Add nested domain allocation

[Yi Liu <yi.l.liu@intel.com>]

On 2023/9/27 14:56, Tian, Kevin wrote:
>> From: Liu, Yi L <yi.l.liu@intel.com>
>> Sent: Thursday, September 21, 2023 3:55 PM
>>
>>
>> +	if (hwpt_type != IOMMU_HWPT_TYPE_DEFAULT &&
>> +	    hwpt_type != IOMMU_HWPT_TYPE_VTD_S1)
>> +		return ERR_PTR(-EINVAL);
>> +
>> +	if ((hwpt_type == IOMMU_HWPT_TYPE_DEFAULT) == !!parent)
>> +		return ERR_PTR(-EINVAL);
> 
> this is probably too strict. What about intel-iommu driver supports a
> IOMMU_HWPT_TYPE_VTD_S2 later for some tweak w/o nesting?

in that case, this check needs to be updated

> let's make the parent match specific to VTD_S1 type.

ok. how about below?

if ((data_type == IOMMU_HWPT_ALLOC_DATA_VTD_S1) && !parent)

>> +
>> +	if (parent && request_nest_parent)
>> +		return ERR_PTR(-EINVAL);
> 
> this check should be moved to iommufd?
> 

oops, maybe no need, iommufd_hwpt_alloc() has below check.

if (cmd->flags & IOMMU_HWPT_ALLOC_NEST_PARENT &&
     cmd->data_type != IOMMU_HWPT_ALLOC_DATA_NONE)
         return -EINVAL;

-- 
Regards,
Yi Liu