Revert "iommu/amd: Remove the leftover of bypass support"

This reverts commit 7a5dbf3a.

This commit not only removes the leftovers of bypass
support, it also mostly removes the checking of the return
value of the get_domain() function. This can lead to silent
data corruption bugs when a device is not attached to its
dma_ops domain and a DMA-API function is called for that
device.
Signed-off-by: Joerg Roedel <jroedel@suse.de>

drivers/iommu/amd_iommu.c

@@ -2459,10 +2459,20 @@ static dma_addr_t map_page(struct device *dev, struct page *page,
 			   unsigned long attrs)
 {
 	phys_addr_t paddr = page_to_phys(page) + offset;
-	struct protection_domain *domain = get_domain(dev);
-	struct dma_ops_domain *dma_dom = to_dma_ops_domain(domain);
+	struct protection_domain *domain;
+	struct dma_ops_domain *dma_dom;
+	u64 dma_mask;
+
+	domain = get_domain(dev);
+	if (PTR_ERR(domain) == -EINVAL)
+		return (dma_addr_t)paddr;
+	else if (IS_ERR(domain))
+		return DMA_MAPPING_ERROR;
+
+	dma_mask = *dev->dma_mask;
+	dma_dom = to_dma_ops_domain(domain);
 
-	return __map_single(dev, dma_dom, paddr, size, dir, *dev->dma_mask);
+	return __map_single(dev, dma_dom, paddr, size, dir, dma_mask);
 }
 
 /*
@@ -2471,8 +2481,14 @@ static dma_addr_t map_page(struct device *dev, struct page *page,
 static void unmap_page(struct device *dev, dma_addr_t dma_addr, size_t size,
 		       enum dma_data_direction dir, unsigned long attrs)
 {
-	struct protection_domain *domain = get_domain(dev);
-	struct dma_ops_domain *dma_dom = to_dma_ops_domain(domain);
+	struct protection_domain *domain;
+	struct dma_ops_domain *dma_dom;
+
+	domain = get_domain(dev);
+	if (IS_ERR(domain))
+		return;
+
+	dma_dom = to_dma_ops_domain(domain);
 
 	__unmap_single(dma_dom, dma_addr, size, dir);
 }
@@ -2512,13 +2528,20 @@ static int map_sg(struct device *dev, struct scatterlist *sglist,
 		  unsigned long attrs)
 {
 	int mapped_pages = 0, npages = 0, prot = 0, i;
-	struct protection_domain *domain = get_domain(dev);
-	struct dma_ops_domain *dma_dom = to_dma_ops_domain(domain);
+	struct protection_domain *domain;
+	struct dma_ops_domain *dma_dom;
 	struct scatterlist *s;
 	unsigned long address;
-	u64 dma_mask = *dev->dma_mask;
+	u64 dma_mask;
 	int ret;
 
+	domain = get_domain(dev);
+	if (IS_ERR(domain))
+		return 0;
+
+	dma_dom  = to_dma_ops_domain(domain);
+	dma_mask = *dev->dma_mask;
+
 	npages = sg_num_pages(dev, sglist, nelems);
 
 	address = dma_ops_alloc_iova(dev, dma_dom, npages, dma_mask);
@@ -2592,11 +2615,20 @@ static void unmap_sg(struct device *dev, struct scatterlist *sglist,
 		     int nelems, enum dma_data_direction dir,
 		     unsigned long attrs)
 {
-	struct protection_domain *domain = get_domain(dev);
-	struct dma_ops_domain *dma_dom = to_dma_ops_domain(domain);
+	struct protection_domain *domain;
+	struct dma_ops_domain *dma_dom;
+	unsigned long startaddr;
+	int npages = 2;
+
+	domain = get_domain(dev);
+	if (IS_ERR(domain))
+		return;
+
+	startaddr = sg_dma_address(sglist) & PAGE_MASK;
+	dma_dom   = to_dma_ops_domain(domain);
+	npages    = sg_num_pages(dev, sglist, nelems);
 
-	__unmap_single(dma_dom, sg_dma_address(sglist) & PAGE_MASK,
-			sg_num_pages(dev, sglist, nelems) << PAGE_SHIFT, dir);
+	__unmap_single(dma_dom, startaddr, npages << PAGE_SHIFT, dir);
 }
 
 /*
@@ -2607,11 +2639,16 @@ static void *alloc_coherent(struct device *dev, size_t size,
 			    unsigned long attrs)
 {
 	u64 dma_mask = dev->coherent_dma_mask;
-	struct protection_domain *domain = get_domain(dev);
+	struct protection_domain *domain;
 	struct dma_ops_domain *dma_dom;
 	struct page *page;
 
-	if (IS_ERR(domain))
+	domain = get_domain(dev);
+	if (PTR_ERR(domain) == -EINVAL) {
+		page = alloc_pages(flag, get_order(size));
+		*dma_addr = page_to_phys(page);
+		return page_address(page);
+	} else if (IS_ERR(domain))
 		return NULL;
 
 	dma_dom   = to_dma_ops_domain(domain);
@@ -2657,13 +2694,22 @@ static void free_coherent(struct device *dev, size_t size,
 			  void *virt_addr, dma_addr_t dma_addr,
 			  unsigned long attrs)
 {
-	struct protection_domain *domain = get_domain(dev);
-	struct dma_ops_domain *dma_dom = to_dma_ops_domain(domain);
-	struct page *page = virt_to_page(virt_addr);
+	struct protection_domain *domain;
+	struct dma_ops_domain *dma_dom;
+	struct page *page;
 
+	page = virt_to_page(virt_addr);
 	size = PAGE_ALIGN(size);
 
+	domain = get_domain(dev);
+	if (IS_ERR(domain))
+		goto free_mem;
+
+	dma_dom = to_dma_ops_domain(domain);
+
 	__unmap_single(dma_dom, dma_addr, size, DMA_BIDIRECTIONAL);
+
+free_mem:
 	if (!dma_release_from_contiguous(dev, page, size >> PAGE_SHIFT))
 		__free_pages(page, get_order(size));
 }