Re: [PATCH v5 05/22] iommu: Introduce cache_invalidate API

Auger Eric
2019-03-18T12:44:08Z

Hi Jean,

On 3/18/19 12:01 PM, Jean-Philippe Brucker wrote:
> On 17/03/2019 16:43, Auger Eric wrote:
>>>> diff --git a/include/uapi/linux/iommu.h b/include/uapi/linux/iommu.h
>>>> index 532a64075f23..e4c6a447e85a 100644
>>>> --- a/include/uapi/linux/iommu.h
>>>> +++ b/include/uapi/linux/iommu.h
>>>> @@ -159,4 +159,75 @@ struct iommu_pasid_table_config {
>>>> };
>>>> };
>>>>
>>>> +/* defines the granularity of the invalidation */
>>>> +enum iommu_inv_granularity {
>>>> + IOMMU_INV_GRANU_DOMAIN, /* domain-selective
>>>> invalidation */
>>>> + IOMMU_INV_GRANU_PASID, /* pasid-selective
>>>> invalidation */
>>>> + IOMMU_INV_GRANU_ADDR, /* page-selective invalidation
>>>> */ +};
>>>> +
>>>> +/**
>>>> + * Address Selective Invalidation Structure
>>>> + *
>>>> + * @flags indicates the granularity of the address-selective
>>>> invalidation
>>>> + * - if PASID bit is set, @pasid field is populated and the
>>>> invalidation
>>>> + * relates to cache entries tagged with this PASID and matching the
>>>> + * address range.
>>>> + * - if ARCHID bit is set, @archid is populated and the invalidation
>>>> relates
>>>> + * to cache entries tagged with this architecture specific id and
>>>> matching
>>>> + * the address range.
>>>> + * - Both PASID and ARCHID can be set as they may tag different
>>>> caches.
>>>> + * - if neither PASID or ARCHID is set, global addr invalidation
>>>> applies
>>>> + * - LEAF flag indicates whether only the leaf PTE caching needs to
>>>> be
>>>> + * invalidated and other paging structure caches can be preserved.
>>>> + * @pasid: process address space id
>>>> + * @archid: architecture-specific id
>>>> + * @addr: first stage/level input address
>>>> + * @granule_size: page/block size of the mapping in bytes
>>>> + * @nb_granules: number of contiguous granules to be invalidated
>>>> + */
>>>> +struct iommu_inv_addr_info {
>>>> +#define IOMMU_INV_ADDR_FLAGS_PASID (1 << 0)
>>>> +#define IOMMU_INV_ADDR_FLAGS_ARCHID (1 << 1)
>>>> +#define IOMMU_INV_ADDR_FLAGS_LEAF (1 << 2)
>>>> + __u32 flags;
>>>> + __u32 archid;
>>>> + __u64 pasid;
>>>> + __u64 addr;
>>>> + __u64 granule_size;
>>>> + __u64 nb_granules;
>>>> +};
>>>> +
>>>> +/**
>>>> + * First level/stage invalidation information
>>>> + * @cache: bitfield that allows to select which caches to invalidate
>>>> + * @granularity: defines the lowest granularity used for the
>>>> invalidation:
>>>> + * domain > pasid > addr
>>>> + *
>>>> + * Not all the combinations of cache/granularity make sense:
>>>> + *
>>>> + * type | DEV_IOTLB | IOTLB | PASID |
>>>> + * granularity | | |
>>>> cache |
>>>> + * -------------+---------------+---------------+---------------+
>>>> + * DOMAIN | N/A | Y |
>>>> Y |
>>>> + * PASID | Y | Y |
>>>> Y |
>>>> + * ADDR | Y | Y |
>>>> N/A |
>>>> + */
>>>> +struct iommu_cache_invalidate_info {
>>>> +#define IOMMU_CACHE_INVALIDATE_INFO_VERSION_1 1
>>>> + __u32 version;
>>>> +/* IOMMU paging structure cache */
>>>> +#define IOMMU_CACHE_INV_TYPE_IOTLB (1 << 0) /* IOMMU IOTLB */
>>>> +#define IOMMU_CACHE_INV_TYPE_DEV_IOTLB (1 << 1) /* Device
>>>> IOTLB */ +#define IOMMU_CACHE_INV_TYPE_PASID (1 << 2) /* PASID
>>>> cache */
>>>> + __u8 cache;
>>>> + __u8 granularity;
>>>> + __u8 padding[2];
>>>> + union {
>>>> + __u64 pasid;
>>> just realized there is already a pasid field in the addr_info, do we
>>> still need this?
>> I think so. Either you do a PASID based invalidation and you directly
>> use the pasid field or you do an address based invalidation and you use
>> the addr_info where the pasid may or not be passed.
>
> I guess a comment would be useful?
>
> - Invalidations by %IOMMU_INV_GRANU_ADDR use field @addr_info.
> - Invalidations by %IOMMU_INV_GRANU_PASID use field @pasid.
> - Invalidations by %IOMMU_INV_GRANU_DOMAIN don't take an argument.

OK. I will add those comments in v7.

Thanks

Eric
>
> Thanks,
> Jean
>
>>
>> Thanks
>>
>> Eric
>>>> + struct iommu_inv_addr_info addr_info;
>>>> + };
>>>> +};
>>>> +
>>>> +
>>>> #endif /* _UAPI_IOMMU_H */
>>>
>>> [Jacob Pan]
>>>
>