RE: [PATCH v4 09/12] iommu/vt-d: Add iotlb flush for nested domain

From: Liu, Yi L yi.l.liu@intel.com Sent: Monday, July 24, 2023 7:14 PM

+static int intel_nested_cache_invalidate_user(struct iommu_domain *domain,

• 			      void *user_data)
  

+{

• struct iommu_hwpt_vtd_s1_invalidate_desc *req = user_data;
• struct iommu_hwpt_vtd_s1_invalidate *inv_info = user_data;
• struct dmar_domain *dmar_domain = to_dmar_domain(domain);
• unsigned int entry_size = inv_info->entry_size;
• u64 uptr = inv_info->inv_data_uptr;
• u64 nr_uptr = inv_info->entry_nr_uptr;
• struct device_domain_info *info;
• u32 entry_nr, index;
• unsigned long flags;
• int ret = 0;
• if (get_user(entry_nr, (uint32_t __user *)u64_to_user_ptr(nr_uptr)))

• return -EFAULT;
  

• for (index = 0; index < entry_nr; index++) {

• ret = copy_struct_from_user(req, sizeof(*req),
  

• 			    u64_to_user_ptr(uptr + index *
  

entry_size),

• 			    entry_size);
  

If continuing this direction then the driver should also check minsz etc. for struct iommu_hwpt_vtd_s1_invalidate and iommu_hwpt_vtd_s1_invalidate_desc since they are uAPI and subject to change.

• if (ret) {
  

• 	pr_err_ratelimited("Failed to fetch invalidation
  

request\n");

• 	break;
  

• }
  

• if (req->__reserved || (req->flags &
  

~IOMMU_VTD_QI_FLAGS_LEAF) ||

•     !IS_ALIGNED(req->addr, VTD_PAGE_SIZE)) {
  

• 	ret = -EINVAL;
  

• 	break;
  

• }
  

• spin_lock_irqsave(&dmar_domain->lock, flags);
  

• list_for_each_entry(info, &dmar_domain->devices, link)
  

• 	intel_nested_invalidate(info->dev, dmar_domain,
  

• 				req->addr, req->npages);
  

• spin_unlock_irqrestore(&dmar_domain->lock, flags);
  

Disabling interrupt while invalidating iotlb is certainly unacceptable.

Actually there is no need to walk devices. Under dmar_domain there is already a list of attached iommu's.