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

[Tian, Kevin]

> From: Liu, Yi L <yi.l.liu@xxxxxxxxx>
> 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;
> +}
> +