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SubjectRe: [PATCH v2 03/16] iommu: introduce iommu invalidate API function
On Thu, Oct 05, 2017 at 04:03:31PM -0700, Jacob Pan wrote:
> +int iommu_invalidate(struct iommu_domain *domain,
> + struct device *dev, struct tlb_invalidate_info *inv_info)

This name is way too generic, it should at least be called
iommu_svm_invalidate() or something like that. With the name above it is
easily confused with the other TLB invalidation functions of the
IOMMU-API.

> +enum iommu_inv_granularity {
> + IOMMU_INV_GRANU_GLOBAL, /* all TLBs invalidated */

Is that needed? We certainly don't want to give userspace/guests that
fine-grained control about IOMMU cache invalidations.

In the end a guest issues flush-global command does not translate to a
flush-global on the host, but to separate flushes for the domains the
guest uses.

> + IOMMU_INV_GRANU_DOMAIN, /* all TLBs associated with a domain */
> + IOMMU_INV_GRANU_DEVICE, /* caching structure associated with a
> + * device ID

What is the difference between a DOMAIN and a DEVICE flush?

> + IOMMU_INV_GRANU_DOMAN_PAGE, /* address range with a domain */
> + IOMMU_INV_GRANU_ALL_PASID, /* cache of a given PASID */
> + IOMMU_INV_GRANU_PASID_SEL, /* only invalidate specified PASID */
> +
> + IOMMU_INV_GRANU_NG_ALL_PASID, /* non-global within all PASIDs */
> + IOMMU_INV_GRANU_NG_PASID, /* non-global within a PASIDs */
> + IOMMU_INV_GRANU_PAGE_PASID, /* page-selective within a PASID */
> + IOMMU_INV_NR_GRANU,
> +};
> +
> +enum iommu_inv_type {
> + IOMMU_INV_TYPE_DTLB, /* device IOTLB */
> + IOMMU_INV_TYPE_TLB, /* IOMMU paging structure cache */
> + IOMMU_INV_TYPE_PASID, /* PASID cache */
> + IOMMU_INV_TYPE_CONTEXT, /* device context entry cache */

Is that really needed? When the guest updates it context-entry
equivalent it translates to bind_pasid_table/unbind_pasid_table calls,
no?

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