Re: [PATCH v7 1/9] iommu: Add cache_invalidate_user op

Yi Liu
2023-12-26T02:21:44Z

On 2023/12/22 10:30, Tian, Kevin wrote:
>> From: Liu, Yi L <yi.l.liu@intel.com>
>> Sent: Thursday, December 21, 2023 11:40 PM
>>
>> From: Lu Baolu <baolu.lu@linux.intel.com>
>>
>> The updates of the PTEs in the nested page table will be propagated to the
>> hardware caches on both IOMMU (IOTLB) and devices (DevTLB/ATC).
>
> this is incorrect. the scope of this cmd is driver specific.

yes. May just say the hardware caches.

>
>>
>> Add a new domain op cache_invalidate_user for the userspace to flush the
>> hardware caches for a nested domain through iommufd. No wrapper for it,
>> as it's only supposed to be used by iommufd. Then, pass in invalidation
>> requests in form of a user data array conatining a number of invalidation
>> data entries.
>>
>> Signed-off-by: Lu Baolu <baolu.lu@linux.intel.com>
>> Reviewed-by: Kevin Tian <kevin.tian@intel.com>
>> Signed-off-by: Nicolin Chen <nicolinc@nvidia.com>
>> Signed-off-by: Yi Liu <yi.l.liu@intel.com>
>> ---
>> include/linux/iommu.h | 27 +++++++++++++++++++++++++++
>> 1 file changed, 27 insertions(+)
>>
>> diff --git a/include/linux/iommu.h b/include/linux/iommu.h
>> index 6291aa7b079b..5c4a17f13761 100644
>> --- a/include/linux/iommu.h
>> +++ b/include/linux/iommu.h
>> @@ -284,6 +284,24 @@ struct iommu_user_data {
>> size_t len;
>> };
>>
>> +/**
>> + * struct iommu_user_data_array - iommu driver specific user space data
>> array
>> + * @type: The data type of all the entries in the user buffer array
>> + * @uptr: Pointer to the user buffer array for copy_from_user()
>
> remove 'for copy_from_user();
>
>> + * @entry_len: The fixed-width length of a entry in the array, in bytes
>
> s/a/an/
>
>> + * @entry_num: The number of total entries in the array
>> + *
>> + * A array having a @entry_num number of @entry_len sized entries, each
>
> the first sentence is redundant.
>
>> entry is
>> + * user space data, an uAPI defined in include/uapi/linux/iommufd.h where
>> @type
>> + * is also defined as enum iommu_xyz_data_type.
>
> I'd just say:
>
> "The user buffer includes an array of requests with format defined
> in include/uapi/linux/iommufd.h"

sure.

--
Regards,
Yi Liu