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

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;
  

+}