AMD IOMMU: add domain address lookup function for IOMMU API

Impact: add a generic function to lockup addresses in protection domains
Signed-off-by: Joerg Roedel <joerg.roedel@amd.com>

arch/x86/kernel/amd_iommu.c

@@ -1788,4 +1788,35 @@ static void amd_iommu_unmap_range(struct iommu_domain *dom,
 	iommu_flush_domain(domain->id);
 }
 
+static phys_addr_t amd_iommu_iova_to_phys(struct iommu_domain *dom,
+					  unsigned long iova)
+{
+	struct protection_domain *domain = dom->priv;
+	unsigned long offset = iova & ~PAGE_MASK;
+	phys_addr_t paddr;
+	u64 *pte;
+
+	pte = &domain->pt_root[IOMMU_PTE_L2_INDEX(iova)];
+
+	if (!IOMMU_PTE_PRESENT(*pte))
+		return 0;
+
+	pte = IOMMU_PTE_PAGE(*pte);
+	pte = &pte[IOMMU_PTE_L1_INDEX(iova)];
+
+	if (!IOMMU_PTE_PRESENT(*pte))
+		return 0;
+
+	pte = IOMMU_PTE_PAGE(*pte);
+	pte = &pte[IOMMU_PTE_L0_INDEX(iova)];
+
+	if (!IOMMU_PTE_PRESENT(*pte))
+		return 0;
+
+	paddr  = *pte & IOMMU_PAGE_MASK;
+	paddr |= offset;
+
+	return paddr;
+}
+
 #endif