RE: [PATCH v8 10/10] iommu/vt-d: Add iotlb flush for nested domain

Tian, Kevin
2023-12-28T07:11:53Z

> From: Liu, Yi L <yi.l.liu@intel.com>
> Sent: Thursday, December 28, 2023 12:14 AM
>
>
> +static void nested_flush_pasid_iotlb(struct intel_iommu *iommu,
> + struct dmar_domain *domain, u64 addr,
> + unsigned long npages, bool ih)
> +{
> + u16 did = domain_id_iommu(domain, iommu);
> + unsigned long flags;
> +
> + spin_lock_irqsave(&domain->lock, flags);
> + if (!list_empty(&domain->devices))
> + qi_flush_piotlb(iommu, did, IOMMU_NO_PASID, addr,
> + npages, ih, NULL);

Not sure the check of domain->devices makes sense here. The outer
loop is xa_for_each(&domain->iommu_array, i, info) which, if found,
then implies certain devices behind this iommu must be attached to
this domain.

I wonder whether it's clearer to remove this function and just call
qi_flush_piotlb() from intel_nested_flush_cache().

> +
> + /*
> + * Invalidation queue error (i.e. IQE) will not be reported to user
> + * as it's caused only by driver internal bug.
> + */

here lack of:

*error = 0;

> + if (fault & DMA_FSTS_ICE)
> + *error |= IOMMU_HWPT_INVALIDATE_VTD_S1_ICE;
> + if (fault & DMA_FSTS_ITE)
> + *error |= IOMMU_HWPT_INVALIDATE_VTD_S1_ITE;
> +}
> +