RE: [PATCH v7 9/9] iommu/vt-d: Add iotlb flush for nested domain

[Tian, Kevin]

> From: Liu, Yi L <yi.l.liu@xxxxxxxxx>
> Sent: Thursday, December 21, 2023 11:40 PM
> 
> +
> +static void intel_nested_flush_cache(struct dmar_domain *domain, u64
> addr,
> +				     unsigned long npages, u32 *error)
> +{
> +	struct iommu_domain_info *info;
> +	unsigned long i;
> +	unsigned mask;
> +	u32 fault = 0;
> +
> +	if (npages == U64_MAX)
> +		mask = 64 - VTD_PAGE_SHIFT;
> +	else
> +		mask = ilog2(__roundup_pow_of_two(npages));
> +
> +	xa_for_each(&domain->iommu_array, i, info) {
> +		nested_flush_pasid_iotlb(info->iommu, domain, addr,
> npages, 0);

so IOMMU_VTD_INV_FLAGS_LEAF is defined but ignored?

> +
> +		if (domain->has_iotlb_device)
> +			continue;
> +
> +		nested_flush_dev_iotlb(domain, addr, mask, &fault);
> +		if (fault & (DMA_FSTS_ITE | DMA_FSTS_ICE))
> +			break;

here you may add a note that we don't plan to forward invalidation 
queue error (i.e. IQE) to the caller as it's caused only by driver
internal bug.

> +
> +		if (!IS_ALIGNED(inv_entry.addr, VTD_PAGE_SIZE) ||
> +		    ((inv_entry.npages == U64_MAX) && inv_entry.addr)) {
> +			ret = -EINVAL;
> +			break;
> +		}
> +

why is [non-zero-addr, U64_MAX] an error? Is it explicitly stated to
be not supported by underlying helpers?