iommu/amd: Correctly encode huge pages in iommu page tables

commit d4b03664 upstream.

When a default page-size for given level should be mapped,
the level encoding must be 0 rather than 7. This fixes an
issue seen on IOMMUv2 hardware, where this encoding is
enforced.
Tested-by: Suravee Suthikulpanit <Suravee.Suthikulpanit@amd.com>
Signed-off-by: Joerg Roedel <jroedel@suse.de>
Signed-off-by: Jiri Slaby <jslaby@suse.cz>

drivers/iommu/amd_iommu.c

@@ -1444,19 +1444,20 @@ static int iommu_map_page(struct protection_domain *dom,
 	u64 __pte, *pte;
 	int i, count;
 
+	BUG_ON(!IS_ALIGNED(bus_addr, page_size));
+	BUG_ON(!IS_ALIGNED(phys_addr, page_size));
+
 	if (!(prot & IOMMU_PROT_MASK))
 		return -EINVAL;
 
-	bus_addr  = PAGE_ALIGN(bus_addr);
-	phys_addr = PAGE_ALIGN(phys_addr);
-	count     = PAGE_SIZE_PTE_COUNT(page_size);
-	pte       = alloc_pte(dom, bus_addr, page_size, NULL, GFP_KERNEL);
+	count = PAGE_SIZE_PTE_COUNT(page_size);
+	pte   = alloc_pte(dom, bus_addr, page_size, NULL, GFP_KERNEL);
 
 	for (i = 0; i < count; ++i)
 		if (IOMMU_PTE_PRESENT(pte[i]))
 			return -EBUSY;
 
-	if (page_size > PAGE_SIZE) {
+	if (count > 1) {
 		__pte = PAGE_SIZE_PTE(phys_addr, page_size);
 		__pte |= PM_LEVEL_ENC(7) | IOMMU_PTE_P | IOMMU_PTE_FC;
 	} else