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SubjectRe: [RFC 02/13] iommu: Introduce tlb_invalidate API
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On 23/08/18 13:17, Eric Auger wrote:
> +/**
> + * Translation cache invalidation information, contains generic IOMMU
> + * data which can be parsed based on model ID by model specific drivers.
> + * Since the invalidation of second level page tables are included in the
> + * unmap operation, this info is only applicable to the first level
> + * translation caches, i.e. DMA request with PASID.
> + *
> + * @granularity: requested invalidation granularity, type dependent
> + * @size: 2^size of 4K pages, 0 for 4k, 9 for 2MB, etc.
> + * @nr_pages: number of pages to invalidate
> + * @pasid: processor address space ID value per PCI spec.
> + * @addr: page address to be invalidated
> + * @flags IOMMU_INVALIDATE_ADDR_LEAF: leaf paging entries
> + * IOMMU_INVALIDATE_GLOBAL_PAGE: global pages
> + *
> + */
> +struct iommu_tlb_invalidate_info {
> + struct iommu_tlb_invalidate_hdr hdr;
> + enum iommu_inv_granularity granularity;
> + __u32 flags;
> +#define IOMMU_INVALIDATE_ADDR_LEAF (1 << 0)
> +#define IOMMU_INVALIDATE_GLOBAL_PAGE (1 << 1)
> + __u8 size;
> + __u64 nr_pages;
> + __u32 pasid;
> + __u64 addr;
> +};
> #endif /* _UAPI_IOMMU_H */

Since the ioctl will be used to combine invalidations (invalidate both
ATC and TLB with a single call), we need an additional ASID field for
the SMMU - ATC is invalidated by PASID, TLB by ASID. I used to call it
"tag", but I'm leaning towards "arch_id" now
(http://www.linux-arm.org/git?p=linux-jpb.git;a=commitdiff;h=40fdef74816dd8d8d113100b9e0162fab4cec28d)

Thanks,
Jean

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