x86: make GART to respect device's dma_mask about virtual mappings

Currently, GART IOMMU ingores device's dma_mask when it does virtual
mappings. So it could give a device a virtual address that the device
can't access to.

This patch fixes the above problem.

Signed-off-by: FUJITA Tomonori <fujita.tomonori@lab.ntt.co.jp>
Signed-off-by: Ingo Molnar <mingo@elte.hu>

arch/x86/kernel/pci-gart_64.c

@@ -83,23 +83,34 @@ static unsigned long next_bit;  /* protected by iommu_bitmap_lock */
 static int need_flush;		/* global flush state. set for each gart wrap */
 
 static unsigned long alloc_iommu(struct device *dev, int size,
-				 unsigned long align_mask)
+				 unsigned long align_mask, u64 dma_mask)
 {
 	unsigned long offset, flags;
 	unsigned long boundary_size;
 	unsigned long base_index;
+	unsigned long limit;
 
 	base_index = ALIGN(iommu_bus_base & dma_get_seg_boundary(dev),
 			   PAGE_SIZE) >> PAGE_SHIFT;
 	boundary_size = ALIGN((unsigned long long)dma_get_seg_boundary(dev) + 1,
 			      PAGE_SIZE) >> PAGE_SHIFT;
 
+	limit = iommu_device_max_index(iommu_pages,
+				       DIV_ROUND_UP(iommu_bus_base, PAGE_SIZE),
+				       dma_mask >> PAGE_SHIFT);
+
 	spin_lock_irqsave(&iommu_bitmap_lock, flags);
-	offset = iommu_area_alloc(iommu_gart_bitmap, iommu_pages, next_bit,
-				  size, base_index, boundary_size, align_mask);
-	if (offset == -1) {
+
+	if (limit <= next_bit) {
 		need_flush = 1;
-		offset = iommu_area_alloc(iommu_gart_bitmap, iommu_pages, 0,
+		next_bit = 0;
+	}
+
+	offset = iommu_area_alloc(iommu_gart_bitmap, limit, next_bit,
+				  size, base_index, boundary_size, align_mask);
+	if (offset == -1 && next_bit) {
+		need_flush = 1;
+		offset = iommu_area_alloc(iommu_gart_bitmap, limit, 0,
 					  size, base_index, boundary_size,
 					  align_mask);
 	}
@@ -228,12 +239,14 @@ nonforced_iommu(struct device *dev, unsigned long addr, size_t size)
  * Caller needs to check if the iommu is needed and flush.
  */
 static dma_addr_t dma_map_area(struct device *dev, dma_addr_t phys_mem,
-				size_t size, int dir, unsigned long align_mask)
+			       size_t size, int dir, unsigned long align_mask,
+			       u64 dma_mask)
 {
 	unsigned long npages = iommu_num_pages(phys_mem, size);
-	unsigned long iommu_page = alloc_iommu(dev, npages, align_mask);
+	unsigned long iommu_page;
 	int i;
 
+	iommu_page = alloc_iommu(dev, npages, align_mask, dma_mask);
 	if (iommu_page == -1) {
 		if (!nonforced_iommu(dev, phys_mem, size))
 			return phys_mem;
@@ -263,7 +276,7 @@ gart_map_single(struct device *dev, phys_addr_t paddr, size_t size, int dir)
 	if (!need_iommu(dev, paddr, size))
 		return paddr;
 
-	bus = dma_map_area(dev, paddr, size, dir, 0);
+	bus = dma_map_area(dev, paddr, size, dir, 0, dma_get_mask(dev));
 	flush_gart();
 
 	return bus;
@@ -314,6 +327,7 @@ static int dma_map_sg_nonforce(struct device *dev, struct scatterlist *sg,
 {
 	struct scatterlist *s;
 	int i;
+	u64 dma_mask = dma_get_mask(dev);
 
 #ifdef CONFIG_IOMMU_DEBUG
 	printk(KERN_DEBUG "dma_map_sg overflow\n");
@@ -323,7 +337,8 @@ static int dma_map_sg_nonforce(struct device *dev, struct scatterlist *sg,
 		unsigned long addr = sg_phys(s);
 
 		if (nonforced_iommu(dev, addr, s->length)) {
-			addr = dma_map_area(dev, addr, s->length, dir, 0);
+			addr = dma_map_area(dev, addr, s->length, dir, 0,
+					    dma_mask);
 			if (addr == bad_dma_address) {
 				if (i > 0)
 					gart_unmap_sg(dev, sg, i, dir);
@@ -345,14 +360,16 @@ static int __dma_map_cont(struct device *dev, struct scatterlist *start,
 			  int nelems, struct scatterlist *sout,
 			  unsigned long pages)
 {
-	unsigned long iommu_start = alloc_iommu(dev, pages, 0);
-	unsigned long iommu_page = iommu_start;
+	unsigned long iommu_start;
+	unsigned long iommu_page;
 	struct scatterlist *s;
 	int i;
 
+	iommu_start = alloc_iommu(dev, pages, 0, dma_get_mask(dev));
 	if (iommu_start == -1)
 		return -1;
 
+	iommu_page = iommu_start;
 	for_each_sg(start, s, nelems, i) {
 		unsigned long pages, addr;
 		unsigned long phys_addr = s->dma_address;
@@ -497,7 +514,7 @@ gart_alloc_coherent(struct device *dev, size_t size, dma_addr_t *dma_addr,
 	align_mask = (1UL << get_order(size)) - 1;
 
 	*dma_addr = dma_map_area(dev, __pa(vaddr), size, DMA_BIDIRECTIONAL,
-				 align_mask);
+				 align_mask, dma_mask);
 	flush_gart();
 
 	if (*dma_addr != bad_dma_address)