iommu/amd: Fix memory leak in free_pagetable

The IOMMU pagetables can have up to 6 levels, but the code
in free_pagetable() only releases the first 3 levels. Fix
this leak by releasing all levels.
Reported-by: Alex Williamson <alex.williamson@redhat.com>
Signed-off-by: Joerg Roedel <joro@8bytes.org>
Reviewed-by: Alex Williamson <alex.williamson@redhat.com>

drivers/iommu/amd_iommu.c

@@ -1893,34 +1893,59 @@ static void domain_id_free(int id)
 	write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
 }
 
+#define DEFINE_FREE_PT_FN(LVL, FN)				\
+static void free_pt_##LVL (unsigned long __pt)			\
+{								\
+	unsigned long p;					\
+	u64 *pt;						\
+	int i;							\
+								\
+	pt = (u64 *)__pt;					\
+								\
+	for (i = 0; i < 512; ++i) {				\
+		if (!IOMMU_PTE_PRESENT(pt[i]))			\
+			continue;				\
+								\
+		p = (unsigned long)IOMMU_PTE_PAGE(pt[i]);	\
+		FN(p);						\
+	}							\
+	free_page((unsigned long)pt);				\
+}
+
+DEFINE_FREE_PT_FN(l2, free_page)
+DEFINE_FREE_PT_FN(l3, free_pt_l2)
+DEFINE_FREE_PT_FN(l4, free_pt_l3)
+DEFINE_FREE_PT_FN(l5, free_pt_l4)
+DEFINE_FREE_PT_FN(l6, free_pt_l5)
+
 static void free_pagetable(struct protection_domain *domain)
 {
-	int i, j;
-	u64 *p1, *p2, *p3;
-
-	p1 = domain->pt_root;
-
-	if (!p1)
-		return;
+	unsigned long root = (unsigned long)domain->pt_root;
 
-	for (i = 0; i < 512; ++i) {
-		if (!IOMMU_PTE_PRESENT(p1[i]))
-			continue;
-
-		p2 = IOMMU_PTE_PAGE(p1[i]);
-		for (j = 0; j < 512; ++j) {
-			if (!IOMMU_PTE_PRESENT(p2[j]))
-				continue;
-			p3 = IOMMU_PTE_PAGE(p2[j]);
-			free_page((unsigned long)p3);
-		}
-
-		free_page((unsigned long)p2);
+	switch (domain->mode) {
+	case PAGE_MODE_NONE:
+		break;
+	case PAGE_MODE_1_LEVEL:
+		free_page(root);
+		break;
+	case PAGE_MODE_2_LEVEL:
+		free_pt_l2(root);
+		break;
+	case PAGE_MODE_3_LEVEL:
+		free_pt_l3(root);
+		break;
+	case PAGE_MODE_4_LEVEL:
+		free_pt_l4(root);
+		break;
+	case PAGE_MODE_5_LEVEL:
+		free_pt_l5(root);
+		break;
+	case PAGE_MODE_6_LEVEL:
+		free_pt_l6(root);
+		break;
+	default:
+		BUG();
 	}
-
-	free_page((unsigned long)p1);
-
-	domain->pt_root = NULL;
 }
 
 static void free_gcr3_tbl_level1(u64 *tbl)