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

[Joerg Roedel]

This reverts commit 7a5dbf3ab2f04905cf8468c66fcdbfb643068bcb.

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@xxxxxxx>
---
 drivers/iommu/amd_iommu.c | 80 +++++++++++++++++++++++++++++++++++++----------
 1 file changed, 63 insertions(+), 17 deletions(-)

diff --git a/drivers/iommu/amd_iommu.c b/drivers/iommu/amd_iommu.c
index bc98de5fa867..23c1a7eebb06 100644
--- a/drivers/iommu/amd_iommu.c
+++ b/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));
 }
-- 
2.16.4