Re: [v3][PATCH 1/1] xen:vtd: missing RMRR mapping while share EPT

["Chen, Tiejun" <tiejun.chen@intel.com>]

> So I think it would be prudent to at least try to detect a clash here
> and return an error.

Could we check if this pte already present like this?

@@ -1870,6 +1872,16 @@ static int rmrr_identity_mapping(struct domain *d,
          if ( iommu_use_hap_pt(d) )
          {
              ASSERT(!iommu_passthrough || !is_hardware_domain(d));
+            /* get last level pte */
+            pg_maddr = addr_to_dma_page_maddr(d, ((paddr_t)gfn << 
PAGE_SHIFT_4K), 0);
+            page = (struct dma_pte *)map_vtd_domain_page(pg_maddr);
+            pte = page + address_level_offset(addr, 1);
+            if ( dma_pte_present(*pte) )
+            {
+                printk(XENLOG_ERR VTDPREFIX
+                       "Overlapping RMRRs at %"PRIx64".\n", 
(paddr_t)base_gfn);
+                return -1;
+            }
              if ( set_mmio_p2m_entry(d, base_pfn, _mfn(base_pfn)) )
                  return -1;
          }

Thanks
Tiejun