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

Jean-Philippe Brucker
2019-03-18T11:01:21Z

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.

Thanks,
Jean

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