]> err.no Git - linux-2.6/blobdiff - arch/x86/kernel/amd_iommu.c
Merge branch 'release' of git://git.kernel.org/pub/scm/linux/kernel/git/aegl/linux-2.6
[linux-2.6] / arch / x86 / kernel / amd_iommu.c
index 90392c7b253b6ad33113b3088612b44e3e179bd2..c25210e6ac888e94224b460e6eb82f3c556d7616 100644 (file)
 #include <linux/scatterlist.h>
 #include <linux/iommu-helper.h>
 #include <asm/proto.h>
-#include <asm/gart.h>
+#include <asm/iommu.h>
 #include <asm/amd_iommu_types.h>
+#include <asm/amd_iommu.h>
 
 #define CMD_SET_TYPE(cmd, t) ((cmd)->data[1] |= ((t) << 28))
 
 #define to_pages(addr, size) \
         (round_up(((addr) & ~PAGE_MASK) + (size), PAGE_SIZE) >> PAGE_SHIFT)
 
+#define EXIT_LOOP_COUNT 10000000
+
 static DEFINE_RWLOCK(amd_iommu_devtable_lock);
 
-struct command {
+/*
+ * general struct to manage commands send to an IOMMU
+ */
+struct iommu_cmd {
        u32 data[4];
 };
 
+static int dma_ops_unity_map(struct dma_ops_domain *dma_dom,
+                            struct unity_map_entry *e);
+
+/* returns !0 if the IOMMU is caching non-present entries in its TLB */
+static int iommu_has_npcache(struct amd_iommu *iommu)
+{
+       return iommu->cap & IOMMU_CAP_NPCACHE;
+}
+
+/****************************************************************************
+ *
+ * IOMMU command queuing functions
+ *
+ ****************************************************************************/
+
+/*
+ * Writes the command to the IOMMUs command buffer and informs the
+ * hardware about the new command. Must be called with iommu->lock held.
+ */
+static int __iommu_queue_command(struct amd_iommu *iommu, struct iommu_cmd *cmd)
+{
+       u32 tail, head;
+       u8 *target;
+
+       tail = readl(iommu->mmio_base + MMIO_CMD_TAIL_OFFSET);
+       target = (iommu->cmd_buf + tail);
+       memcpy_toio(target, cmd, sizeof(*cmd));
+       tail = (tail + sizeof(*cmd)) % iommu->cmd_buf_size;
+       head = readl(iommu->mmio_base + MMIO_CMD_HEAD_OFFSET);
+       if (tail == head)
+               return -ENOMEM;
+       writel(tail, iommu->mmio_base + MMIO_CMD_TAIL_OFFSET);
+
+       return 0;
+}
+
+/*
+ * General queuing function for commands. Takes iommu->lock and calls
+ * __iommu_queue_command().
+ */
+static int iommu_queue_command(struct amd_iommu *iommu, struct iommu_cmd *cmd)
+{
+       unsigned long flags;
+       int ret;
+
+       spin_lock_irqsave(&iommu->lock, flags);
+       ret = __iommu_queue_command(iommu, cmd);
+       spin_unlock_irqrestore(&iommu->lock, flags);
+
+       return ret;
+}
+
+/*
+ * This function is called whenever we need to ensure that the IOMMU has
+ * completed execution of all commands we sent. It sends a
+ * COMPLETION_WAIT command and waits for it to finish. The IOMMU informs
+ * us about that by writing a value to a physical address we pass with
+ * the command.
+ */
+static int iommu_completion_wait(struct amd_iommu *iommu)
+{
+       int ret;
+       struct iommu_cmd cmd;
+       volatile u64 ready = 0;
+       unsigned long ready_phys = virt_to_phys(&ready);
+       unsigned long i = 0;
+
+       memset(&cmd, 0, sizeof(cmd));
+       cmd.data[0] = LOW_U32(ready_phys) | CMD_COMPL_WAIT_STORE_MASK;
+       cmd.data[1] = upper_32_bits(ready_phys);
+       cmd.data[2] = 1; /* value written to 'ready' */
+       CMD_SET_TYPE(&cmd, CMD_COMPL_WAIT);
+
+       iommu->need_sync = 0;
+
+       ret = iommu_queue_command(iommu, &cmd);
+
+       if (ret)
+               return ret;
+
+       while (!ready && (i < EXIT_LOOP_COUNT)) {
+               ++i;
+               cpu_relax();
+       }
+
+       if (unlikely((i == EXIT_LOOP_COUNT) && printk_ratelimit()))
+               printk(KERN_WARNING "AMD IOMMU: Completion wait loop failed\n");
+
+       return 0;
+}
+
+/*
+ * Command send function for invalidating a device table entry
+ */
+static int iommu_queue_inv_dev_entry(struct amd_iommu *iommu, u16 devid)
+{
+       struct iommu_cmd cmd;
+
+       BUG_ON(iommu == NULL);
+
+       memset(&cmd, 0, sizeof(cmd));
+       CMD_SET_TYPE(&cmd, CMD_INV_DEV_ENTRY);
+       cmd.data[0] = devid;
+
+       iommu->need_sync = 1;
+
+       return iommu_queue_command(iommu, &cmd);
+}
+
+/*
+ * Generic command send function for invalidaing TLB entries
+ */
+static int iommu_queue_inv_iommu_pages(struct amd_iommu *iommu,
+               u64 address, u16 domid, int pde, int s)
+{
+       struct iommu_cmd cmd;
+
+       memset(&cmd, 0, sizeof(cmd));
+       address &= PAGE_MASK;
+       CMD_SET_TYPE(&cmd, CMD_INV_IOMMU_PAGES);
+       cmd.data[1] |= domid;
+       cmd.data[2] = LOW_U32(address);
+       cmd.data[3] = upper_32_bits(address);
+       if (s) /* size bit - we flush more than one 4kb page */
+               cmd.data[2] |= CMD_INV_IOMMU_PAGES_SIZE_MASK;
+       if (pde) /* PDE bit - we wan't flush everything not only the PTEs */
+               cmd.data[2] |= CMD_INV_IOMMU_PAGES_PDE_MASK;
+
+       iommu->need_sync = 1;
+
+       return iommu_queue_command(iommu, &cmd);
+}
+
+/*
+ * TLB invalidation function which is called from the mapping functions.
+ * It invalidates a single PTE if the range to flush is within a single
+ * page. Otherwise it flushes the whole TLB of the IOMMU.
+ */
+static int iommu_flush_pages(struct amd_iommu *iommu, u16 domid,
+               u64 address, size_t size)
+{
+       int s = 0;
+       unsigned pages = to_pages(address, size);
+
+       address &= PAGE_MASK;
+
+       if (pages > 1) {
+               /*
+                * If we have to flush more than one page, flush all
+                * TLB entries for this domain
+                */
+               address = CMD_INV_IOMMU_ALL_PAGES_ADDRESS;
+               s = 1;
+       }
+
+       iommu_queue_inv_iommu_pages(iommu, address, domid, 0, s);
+
+       return 0;
+}
+
+/****************************************************************************
+ *
+ * The functions below are used the create the page table mappings for
+ * unity mapped regions.
+ *
+ ****************************************************************************/
+
+/*
+ * Generic mapping functions. It maps a physical address into a DMA
+ * address space. It allocates the page table pages if necessary.
+ * In the future it can be extended to a generic mapping function
+ * supporting all features of AMD IOMMU page tables like level skipping
+ * and full 64 bit address spaces.
+ */
+static int iommu_map(struct protection_domain *dom,
+                    unsigned long bus_addr,
+                    unsigned long phys_addr,
+                    int prot)
+{
+       u64 __pte, *pte, *page;
+
+       bus_addr  = PAGE_ALIGN(bus_addr);
+       phys_addr = PAGE_ALIGN(bus_addr);
+
+       /* only support 512GB address spaces for now */
+       if (bus_addr > IOMMU_MAP_SIZE_L3 || !(prot & IOMMU_PROT_MASK))
+               return -EINVAL;
+
+       pte = &dom->pt_root[IOMMU_PTE_L2_INDEX(bus_addr)];
+
+       if (!IOMMU_PTE_PRESENT(*pte)) {
+               page = (u64 *)get_zeroed_page(GFP_KERNEL);
+               if (!page)
+                       return -ENOMEM;
+               *pte = IOMMU_L2_PDE(virt_to_phys(page));
+       }
+
+       pte = IOMMU_PTE_PAGE(*pte);
+       pte = &pte[IOMMU_PTE_L1_INDEX(bus_addr)];
+
+       if (!IOMMU_PTE_PRESENT(*pte)) {
+               page = (u64 *)get_zeroed_page(GFP_KERNEL);
+               if (!page)
+                       return -ENOMEM;
+               *pte = IOMMU_L1_PDE(virt_to_phys(page));
+       }
+
+       pte = IOMMU_PTE_PAGE(*pte);
+       pte = &pte[IOMMU_PTE_L0_INDEX(bus_addr)];
+
+       if (IOMMU_PTE_PRESENT(*pte))
+               return -EBUSY;
+
+       __pte = phys_addr | IOMMU_PTE_P;
+       if (prot & IOMMU_PROT_IR)
+               __pte |= IOMMU_PTE_IR;
+       if (prot & IOMMU_PROT_IW)
+               __pte |= IOMMU_PTE_IW;
+
+       *pte = __pte;
+
+       return 0;
+}
+
+/*
+ * This function checks if a specific unity mapping entry is needed for
+ * this specific IOMMU.
+ */
+static int iommu_for_unity_map(struct amd_iommu *iommu,
+                              struct unity_map_entry *entry)
+{
+       u16 bdf, i;
+
+       for (i = entry->devid_start; i <= entry->devid_end; ++i) {
+               bdf = amd_iommu_alias_table[i];
+               if (amd_iommu_rlookup_table[bdf] == iommu)
+                       return 1;
+       }
+
+       return 0;
+}
+
+/*
+ * Init the unity mappings for a specific IOMMU in the system
+ *
+ * Basically iterates over all unity mapping entries and applies them to
+ * the default domain DMA of that IOMMU if necessary.
+ */
+static int iommu_init_unity_mappings(struct amd_iommu *iommu)
+{
+       struct unity_map_entry *entry;
+       int ret;
+
+       list_for_each_entry(entry, &amd_iommu_unity_map, list) {
+               if (!iommu_for_unity_map(iommu, entry))
+                       continue;
+               ret = dma_ops_unity_map(iommu->default_dom, entry);
+               if (ret)
+                       return ret;
+       }
+
+       return 0;
+}
+
+/*
+ * This function actually applies the mapping to the page table of the
+ * dma_ops domain.
+ */
+static int dma_ops_unity_map(struct dma_ops_domain *dma_dom,
+                            struct unity_map_entry *e)
+{
+       u64 addr;
+       int ret;
+
+       for (addr = e->address_start; addr < e->address_end;
+            addr += PAGE_SIZE) {
+               ret = iommu_map(&dma_dom->domain, addr, addr, e->prot);
+               if (ret)
+                       return ret;
+               /*
+                * if unity mapping is in aperture range mark the page
+                * as allocated in the aperture
+                */
+               if (addr < dma_dom->aperture_size)
+                       __set_bit(addr >> PAGE_SHIFT, dma_dom->bitmap);
+       }
+
+       return 0;
+}
+
+/*
+ * Inits the unity mappings required for a specific device
+ */
+static int init_unity_mappings_for_device(struct dma_ops_domain *dma_dom,
+                                         u16 devid)
+{
+       struct unity_map_entry *e;
+       int ret;
+
+       list_for_each_entry(e, &amd_iommu_unity_map, list) {
+               if (!(devid >= e->devid_start && devid <= e->devid_end))
+                       continue;
+               ret = dma_ops_unity_map(dma_dom, e);
+               if (ret)
+                       return ret;
+       }
+
+       return 0;
+}
+
+/****************************************************************************
+ *
+ * The next functions belong to the address allocator for the dma_ops
+ * interface functions. They work like the allocators in the other IOMMU
+ * drivers. Its basically a bitmap which marks the allocated pages in
+ * the aperture. Maybe it could be enhanced in the future to a more
+ * efficient allocator.
+ *
+ ****************************************************************************/
+static unsigned long dma_mask_to_pages(unsigned long mask)
+{
+       return (mask >> PAGE_SHIFT) +
+               (PAGE_ALIGN(mask & ~PAGE_MASK) >> PAGE_SHIFT);
+}
+
+/*
+ * The address allocator core function.
+ *
+ * called with domain->lock held
+ */
+static unsigned long dma_ops_alloc_addresses(struct device *dev,
+                                            struct dma_ops_domain *dom,
+                                            unsigned int pages)
+{
+       unsigned long limit = dma_mask_to_pages(*dev->dma_mask);
+       unsigned long address;
+       unsigned long size = dom->aperture_size >> PAGE_SHIFT;
+       unsigned long boundary_size;
+
+       boundary_size = ALIGN(dma_get_seg_boundary(dev) + 1,
+                       PAGE_SIZE) >> PAGE_SHIFT;
+       limit = limit < size ? limit : size;
+
+       if (dom->next_bit >= limit)
+               dom->next_bit = 0;
+
+       address = iommu_area_alloc(dom->bitmap, limit, dom->next_bit, pages,
+                       0 , boundary_size, 0);
+       if (address == -1)
+               address = iommu_area_alloc(dom->bitmap, limit, 0, pages,
+                               0, boundary_size, 0);
+
+       if (likely(address != -1)) {
+               dom->next_bit = address + pages;
+               address <<= PAGE_SHIFT;
+       } else
+               address = bad_dma_address;
+
+       WARN_ON((address + (PAGE_SIZE*pages)) > dom->aperture_size);
+
+       return address;
+}
+
+/*
+ * The address free function.
+ *
+ * called with domain->lock held
+ */
+static void dma_ops_free_addresses(struct dma_ops_domain *dom,
+                                  unsigned long address,
+                                  unsigned int pages)
+{
+       address >>= PAGE_SHIFT;
+       iommu_area_free(dom->bitmap, address, pages);
+}
+
+/****************************************************************************
+ *
+ * The next functions belong to the domain allocation. A domain is
+ * allocated for every IOMMU as the default domain. If device isolation
+ * is enabled, every device get its own domain. The most important thing
+ * about domains is the page table mapping the DMA address space they
+ * contain.
+ *
+ ****************************************************************************/
+
+static u16 domain_id_alloc(void)
+{
+       unsigned long flags;
+       int id;
+
+       write_lock_irqsave(&amd_iommu_devtable_lock, flags);
+       id = find_first_zero_bit(amd_iommu_pd_alloc_bitmap, MAX_DOMAIN_ID);
+       BUG_ON(id == 0);
+       if (id > 0 && id < MAX_DOMAIN_ID)
+               __set_bit(id, amd_iommu_pd_alloc_bitmap);
+       else
+               id = 0;
+       write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
+
+       return id;
+}
+
+/*
+ * Used to reserve address ranges in the aperture (e.g. for exclusion
+ * ranges.
+ */
+static void dma_ops_reserve_addresses(struct dma_ops_domain *dom,
+                                     unsigned long start_page,
+                                     unsigned int pages)
+{
+       unsigned int last_page = dom->aperture_size >> PAGE_SHIFT;
+
+       if (start_page + pages > last_page)
+               pages = last_page - start_page;
+
+       set_bit_string(dom->bitmap, start_page, pages);
+}
+
+static void dma_ops_free_pagetable(struct dma_ops_domain *dma_dom)
+{
+       int i, j;
+       u64 *p1, *p2, *p3;
+
+       p1 = dma_dom->domain.pt_root;
+
+       if (!p1)
+               return;
+
+       for (i = 0; i < 512; ++i) {
+               if (!IOMMU_PTE_PRESENT(p1[i]))
+                       continue;
+
+               p2 = IOMMU_PTE_PAGE(p1[i]);
+               for (j = 0; j < 512; ++i) {
+                       if (!IOMMU_PTE_PRESENT(p2[j]))
+                               continue;
+                       p3 = IOMMU_PTE_PAGE(p2[j]);
+                       free_page((unsigned long)p3);
+               }
+
+               free_page((unsigned long)p2);
+       }
+
+       free_page((unsigned long)p1);
+}
+
+/*
+ * Free a domain, only used if something went wrong in the
+ * allocation path and we need to free an already allocated page table
+ */
+static void dma_ops_domain_free(struct dma_ops_domain *dom)
+{
+       if (!dom)
+               return;
+
+       dma_ops_free_pagetable(dom);
+
+       kfree(dom->pte_pages);
+
+       kfree(dom->bitmap);
+
+       kfree(dom);
+}
+
+/*
+ * Allocates a new protection domain usable for the dma_ops functions.
+ * It also intializes the page table and the address allocator data
+ * structures required for the dma_ops interface
+ */
+static struct dma_ops_domain *dma_ops_domain_alloc(struct amd_iommu *iommu,
+                                                  unsigned order)
+{
+       struct dma_ops_domain *dma_dom;
+       unsigned i, num_pte_pages;
+       u64 *l2_pde;
+       u64 address;
+
+       /*
+        * Currently the DMA aperture must be between 32 MB and 1GB in size
+        */
+       if ((order < 25) || (order > 30))
+               return NULL;
+
+       dma_dom = kzalloc(sizeof(struct dma_ops_domain), GFP_KERNEL);
+       if (!dma_dom)
+               return NULL;
+
+       spin_lock_init(&dma_dom->domain.lock);
+
+       dma_dom->domain.id = domain_id_alloc();
+       if (dma_dom->domain.id == 0)
+               goto free_dma_dom;
+       dma_dom->domain.mode = PAGE_MODE_3_LEVEL;
+       dma_dom->domain.pt_root = (void *)get_zeroed_page(GFP_KERNEL);
+       dma_dom->domain.priv = dma_dom;
+       if (!dma_dom->domain.pt_root)
+               goto free_dma_dom;
+       dma_dom->aperture_size = (1ULL << order);
+       dma_dom->bitmap = kzalloc(dma_dom->aperture_size / (PAGE_SIZE * 8),
+                                 GFP_KERNEL);
+       if (!dma_dom->bitmap)
+               goto free_dma_dom;
+       /*
+        * mark the first page as allocated so we never return 0 as
+        * a valid dma-address. So we can use 0 as error value
+        */
+       dma_dom->bitmap[0] = 1;
+       dma_dom->next_bit = 0;
+
+       /* Intialize the exclusion range if necessary */
+       if (iommu->exclusion_start &&
+           iommu->exclusion_start < dma_dom->aperture_size) {
+               unsigned long startpage = iommu->exclusion_start >> PAGE_SHIFT;
+               int pages = to_pages(iommu->exclusion_start,
+                               iommu->exclusion_length);
+               dma_ops_reserve_addresses(dma_dom, startpage, pages);
+       }
+
+       /*
+        * At the last step, build the page tables so we don't need to
+        * allocate page table pages in the dma_ops mapping/unmapping
+        * path.
+        */
+       num_pte_pages = dma_dom->aperture_size / (PAGE_SIZE * 512);
+       dma_dom->pte_pages = kzalloc(num_pte_pages * sizeof(void *),
+                       GFP_KERNEL);
+       if (!dma_dom->pte_pages)
+               goto free_dma_dom;
+
+       l2_pde = (u64 *)get_zeroed_page(GFP_KERNEL);
+       if (l2_pde == NULL)
+               goto free_dma_dom;
+
+       dma_dom->domain.pt_root[0] = IOMMU_L2_PDE(virt_to_phys(l2_pde));
+
+       for (i = 0; i < num_pte_pages; ++i) {
+               dma_dom->pte_pages[i] = (u64 *)get_zeroed_page(GFP_KERNEL);
+               if (!dma_dom->pte_pages[i])
+                       goto free_dma_dom;
+               address = virt_to_phys(dma_dom->pte_pages[i]);
+               l2_pde[i] = IOMMU_L1_PDE(address);
+       }
+
+       return dma_dom;
+
+free_dma_dom:
+       dma_ops_domain_free(dma_dom);
+
+       return NULL;
+}
+
+/*
+ * Find out the protection domain structure for a given PCI device. This
+ * will give us the pointer to the page table root for example.
+ */
+static struct protection_domain *domain_for_device(u16 devid)
+{
+       struct protection_domain *dom;
+       unsigned long flags;
+
+       read_lock_irqsave(&amd_iommu_devtable_lock, flags);
+       dom = amd_iommu_pd_table[devid];
+       read_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
+
+       return dom;
+}
+
+/*
+ * If a device is not yet associated with a domain, this function does
+ * assigns it visible for the hardware
+ */
+static void set_device_domain(struct amd_iommu *iommu,
+                             struct protection_domain *domain,
+                             u16 devid)
+{
+       unsigned long flags;
+
+       u64 pte_root = virt_to_phys(domain->pt_root);
+
+       pte_root |= (domain->mode & 0x07) << 9;
+       pte_root |= IOMMU_PTE_IR | IOMMU_PTE_IW | IOMMU_PTE_P | 2;
+
+       write_lock_irqsave(&amd_iommu_devtable_lock, flags);
+       amd_iommu_dev_table[devid].data[0] = pte_root;
+       amd_iommu_dev_table[devid].data[1] = pte_root >> 32;
+       amd_iommu_dev_table[devid].data[2] = domain->id;
+
+       amd_iommu_pd_table[devid] = domain;
+       write_unlock_irqrestore(&amd_iommu_devtable_lock, flags);
+
+       iommu_queue_inv_dev_entry(iommu, devid);
+
+       iommu->need_sync = 1;
+}
+
+/*****************************************************************************
+ *
+ * The next functions belong to the dma_ops mapping/unmapping code.
+ *
+ *****************************************************************************/
+
+/*
+ * In the dma_ops path we only have the struct device. This function
+ * finds the corresponding IOMMU, the protection domain and the
+ * requestor id for a given device.
+ * If the device is not yet associated with a domain this is also done
+ * in this function.
+ */
+static int get_device_resources(struct device *dev,
+                               struct amd_iommu **iommu,
+                               struct protection_domain **domain,
+                               u16 *bdf)
+{
+       struct dma_ops_domain *dma_dom;
+       struct pci_dev *pcidev;
+       u16 _bdf;
+
+       BUG_ON(!dev || dev->bus != &pci_bus_type || !dev->dma_mask);
+
+       pcidev = to_pci_dev(dev);
+       _bdf = calc_devid(pcidev->bus->number, pcidev->devfn);
+
+       /* device not translated by any IOMMU in the system? */
+       if (_bdf >= amd_iommu_last_bdf) {
+               *iommu = NULL;
+               *domain = NULL;
+               *bdf = 0xffff;
+               return 0;
+       }
+
+       *bdf = amd_iommu_alias_table[_bdf];
+
+       *iommu = amd_iommu_rlookup_table[*bdf];
+       if (*iommu == NULL)
+               return 0;
+       dma_dom = (*iommu)->default_dom;
+       *domain = domain_for_device(*bdf);
+       if (*domain == NULL) {
+               *domain = &dma_dom->domain;
+               set_device_domain(*iommu, *domain, *bdf);
+               printk(KERN_INFO "AMD IOMMU: Using protection domain %d for "
+                               "device ", (*domain)->id);
+               print_devid(_bdf, 1);
+       }
+
+       return 1;
+}
+
+/*
+ * This is the generic map function. It maps one 4kb page at paddr to
+ * the given address in the DMA address space for the domain.
+ */
+static dma_addr_t dma_ops_domain_map(struct amd_iommu *iommu,
+                                    struct dma_ops_domain *dom,
+                                    unsigned long address,
+                                    phys_addr_t paddr,
+                                    int direction)
+{
+       u64 *pte, __pte;
+
+       WARN_ON(address > dom->aperture_size);
+
+       paddr &= PAGE_MASK;
+
+       pte  = dom->pte_pages[IOMMU_PTE_L1_INDEX(address)];
+       pte += IOMMU_PTE_L0_INDEX(address);
+
+       __pte = paddr | IOMMU_PTE_P | IOMMU_PTE_FC;
+
+       if (direction == DMA_TO_DEVICE)
+               __pte |= IOMMU_PTE_IR;
+       else if (direction == DMA_FROM_DEVICE)
+               __pte |= IOMMU_PTE_IW;
+       else if (direction == DMA_BIDIRECTIONAL)
+               __pte |= IOMMU_PTE_IR | IOMMU_PTE_IW;
+
+       WARN_ON(*pte);
+
+       *pte = __pte;
+
+       return (dma_addr_t)address;
+}
+
+/*
+ * The generic unmapping function for on page in the DMA address space.
+ */
+static void dma_ops_domain_unmap(struct amd_iommu *iommu,
+                                struct dma_ops_domain *dom,
+                                unsigned long address)
+{
+       u64 *pte;
+
+       if (address >= dom->aperture_size)
+               return;
+
+       WARN_ON(address & 0xfffULL || address > dom->aperture_size);
+
+       pte  = dom->pte_pages[IOMMU_PTE_L1_INDEX(address)];
+       pte += IOMMU_PTE_L0_INDEX(address);
+
+       WARN_ON(!*pte);
+
+       *pte = 0ULL;
+}
+
+/*
+ * This function contains common code for mapping of a physically
+ * contiguous memory region into DMA address space. It is uses by all
+ * mapping functions provided by this IOMMU driver.
+ * Must be called with the domain lock held.
+ */
+static dma_addr_t __map_single(struct device *dev,
+                              struct amd_iommu *iommu,
+                              struct dma_ops_domain *dma_dom,
+                              phys_addr_t paddr,
+                              size_t size,
+                              int dir)
+{
+       dma_addr_t offset = paddr & ~PAGE_MASK;
+       dma_addr_t address, start;
+       unsigned int pages;
+       int i;
+
+       pages = to_pages(paddr, size);
+       paddr &= PAGE_MASK;
+
+       address = dma_ops_alloc_addresses(dev, dma_dom, pages);
+       if (unlikely(address == bad_dma_address))
+               goto out;
+
+       start = address;
+       for (i = 0; i < pages; ++i) {
+               dma_ops_domain_map(iommu, dma_dom, start, paddr, dir);
+               paddr += PAGE_SIZE;
+               start += PAGE_SIZE;
+       }
+       address += offset;
+
+out:
+       return address;
+}
+
+/*
+ * Does the reverse of the __map_single function. Must be called with
+ * the domain lock held too
+ */
+static void __unmap_single(struct amd_iommu *iommu,
+                          struct dma_ops_domain *dma_dom,
+                          dma_addr_t dma_addr,
+                          size_t size,
+                          int dir)
+{
+       dma_addr_t i, start;
+       unsigned int pages;
+
+       if ((dma_addr == 0) || (dma_addr + size > dma_dom->aperture_size))
+               return;
+
+       pages = to_pages(dma_addr, size);
+       dma_addr &= PAGE_MASK;
+       start = dma_addr;
+
+       for (i = 0; i < pages; ++i) {
+               dma_ops_domain_unmap(iommu, dma_dom, start);
+               start += PAGE_SIZE;
+       }
+
+       dma_ops_free_addresses(dma_dom, dma_addr, pages);
+}
+
+/*
+ * The exported map_single function for dma_ops.
+ */
+static dma_addr_t map_single(struct device *dev, phys_addr_t paddr,
+                            size_t size, int dir)
+{
+       unsigned long flags;
+       struct amd_iommu *iommu;
+       struct protection_domain *domain;
+       u16 devid;
+       dma_addr_t addr;
+
+       get_device_resources(dev, &iommu, &domain, &devid);
+
+       if (iommu == NULL || domain == NULL)
+               /* device not handled by any AMD IOMMU */
+               return (dma_addr_t)paddr;
+
+       spin_lock_irqsave(&domain->lock, flags);
+       addr = __map_single(dev, iommu, domain->priv, paddr, size, dir);
+       if (addr == bad_dma_address)
+               goto out;
+
+       if (iommu_has_npcache(iommu))
+               iommu_flush_pages(iommu, domain->id, addr, size);
+
+       if (iommu->need_sync)
+               iommu_completion_wait(iommu);
+
+out:
+       spin_unlock_irqrestore(&domain->lock, flags);
+
+       return addr;
+}
+
+/*
+ * The exported unmap_single function for dma_ops.
+ */
+static void unmap_single(struct device *dev, dma_addr_t dma_addr,
+                        size_t size, int dir)
+{
+       unsigned long flags;
+       struct amd_iommu *iommu;
+       struct protection_domain *domain;
+       u16 devid;
+
+       if (!get_device_resources(dev, &iommu, &domain, &devid))
+               /* device not handled by any AMD IOMMU */
+               return;
+
+       spin_lock_irqsave(&domain->lock, flags);
+
+       __unmap_single(iommu, domain->priv, dma_addr, size, dir);
+
+       iommu_flush_pages(iommu, domain->id, dma_addr, size);
+
+       if (iommu->need_sync)
+               iommu_completion_wait(iommu);
+
+       spin_unlock_irqrestore(&domain->lock, flags);
+}
+
+/*
+ * This is a special map_sg function which is used if we should map a
+ * device which is not handled by an AMD IOMMU in the system.
+ */
+static int map_sg_no_iommu(struct device *dev, struct scatterlist *sglist,
+                          int nelems, int dir)
+{
+       struct scatterlist *s;
+       int i;
+
+       for_each_sg(sglist, s, nelems, i) {
+               s->dma_address = (dma_addr_t)sg_phys(s);
+               s->dma_length  = s->length;
+       }
+
+       return nelems;
+}
+
+/*
+ * The exported map_sg function for dma_ops (handles scatter-gather
+ * lists).
+ */
+static int map_sg(struct device *dev, struct scatterlist *sglist,
+                 int nelems, int dir)
+{
+       unsigned long flags;
+       struct amd_iommu *iommu;
+       struct protection_domain *domain;
+       u16 devid;
+       int i;
+       struct scatterlist *s;
+       phys_addr_t paddr;
+       int mapped_elems = 0;
+
+       get_device_resources(dev, &iommu, &domain, &devid);
+
+       if (!iommu || !domain)
+               return map_sg_no_iommu(dev, sglist, nelems, dir);
+
+       spin_lock_irqsave(&domain->lock, flags);
+
+       for_each_sg(sglist, s, nelems, i) {
+               paddr = sg_phys(s);
+
+               s->dma_address = __map_single(dev, iommu, domain->priv,
+                                             paddr, s->length, dir);
+
+               if (s->dma_address) {
+                       s->dma_length = s->length;
+                       mapped_elems++;
+               } else
+                       goto unmap;
+               if (iommu_has_npcache(iommu))
+                       iommu_flush_pages(iommu, domain->id, s->dma_address,
+                                         s->dma_length);
+       }
+
+       if (iommu->need_sync)
+               iommu_completion_wait(iommu);
+
+out:
+       spin_unlock_irqrestore(&domain->lock, flags);
+
+       return mapped_elems;
+unmap:
+       for_each_sg(sglist, s, mapped_elems, i) {
+               if (s->dma_address)
+                       __unmap_single(iommu, domain->priv, s->dma_address,
+                                      s->dma_length, dir);
+               s->dma_address = s->dma_length = 0;
+       }
+
+       mapped_elems = 0;
+
+       goto out;
+}
+
+/*
+ * The exported map_sg function for dma_ops (handles scatter-gather
+ * lists).
+ */
+static void unmap_sg(struct device *dev, struct scatterlist *sglist,
+                    int nelems, int dir)
+{
+       unsigned long flags;
+       struct amd_iommu *iommu;
+       struct protection_domain *domain;
+       struct scatterlist *s;
+       u16 devid;
+       int i;
+
+       if (!get_device_resources(dev, &iommu, &domain, &devid))
+               return;
+
+       spin_lock_irqsave(&domain->lock, flags);
+
+       for_each_sg(sglist, s, nelems, i) {
+               __unmap_single(iommu, domain->priv, s->dma_address,
+                              s->dma_length, dir);
+               iommu_flush_pages(iommu, domain->id, s->dma_address,
+                                 s->dma_length);
+               s->dma_address = s->dma_length = 0;
+       }
+
+       if (iommu->need_sync)
+               iommu_completion_wait(iommu);
+
+       spin_unlock_irqrestore(&domain->lock, flags);
+}
+
+/*
+ * The exported alloc_coherent function for dma_ops.
+ */
+static void *alloc_coherent(struct device *dev, size_t size,
+                           dma_addr_t *dma_addr, gfp_t flag)
+{
+       unsigned long flags;
+       void *virt_addr;
+       struct amd_iommu *iommu;
+       struct protection_domain *domain;
+       u16 devid;
+       phys_addr_t paddr;
+
+       virt_addr = (void *)__get_free_pages(flag, get_order(size));
+       if (!virt_addr)
+               return 0;
+
+       memset(virt_addr, 0, size);
+       paddr = virt_to_phys(virt_addr);
+
+       get_device_resources(dev, &iommu, &domain, &devid);
+
+       if (!iommu || !domain) {
+               *dma_addr = (dma_addr_t)paddr;
+               return virt_addr;
+       }
+
+       spin_lock_irqsave(&domain->lock, flags);
+
+       *dma_addr = __map_single(dev, iommu, domain->priv, paddr,
+                                size, DMA_BIDIRECTIONAL);
+
+       if (*dma_addr == bad_dma_address) {
+               free_pages((unsigned long)virt_addr, get_order(size));
+               virt_addr = NULL;
+               goto out;
+       }
+
+       if (iommu_has_npcache(iommu))
+               iommu_flush_pages(iommu, domain->id, *dma_addr, size);
+
+       if (iommu->need_sync)
+               iommu_completion_wait(iommu);
+
+out:
+       spin_unlock_irqrestore(&domain->lock, flags);
+
+       return virt_addr;
+}
+
+/*
+ * The exported free_coherent function for dma_ops.
+ * FIXME: fix the generic x86 DMA layer so that it actually calls that
+ *        function.
+ */
+static void free_coherent(struct device *dev, size_t size,
+                         void *virt_addr, dma_addr_t dma_addr)
+{
+       unsigned long flags;
+       struct amd_iommu *iommu;
+       struct protection_domain *domain;
+       u16 devid;
+
+       get_device_resources(dev, &iommu, &domain, &devid);
+
+       if (!iommu || !domain)
+               goto free_mem;
+
+       spin_lock_irqsave(&domain->lock, flags);
+
+       __unmap_single(iommu, domain->priv, dma_addr, size, DMA_BIDIRECTIONAL);
+       iommu_flush_pages(iommu, domain->id, dma_addr, size);
+
+       if (iommu->need_sync)
+               iommu_completion_wait(iommu);
+
+       spin_unlock_irqrestore(&domain->lock, flags);
+
+free_mem:
+       free_pages((unsigned long)virt_addr, get_order(size));
+}
+
+/*
+ * The function for pre-allocating protection domains.
+ *
+ * If the driver core informs the DMA layer if a driver grabs a device
+ * we don't need to preallocate the protection domains anymore.
+ * For now we have to.
+ */
+void prealloc_protection_domains(void)
+{
+       struct pci_dev *dev = NULL;
+       struct dma_ops_domain *dma_dom;
+       struct amd_iommu *iommu;
+       int order = amd_iommu_aperture_order;
+       u16 devid;
+
+       while ((dev = pci_get_device(PCI_ANY_ID, PCI_ANY_ID, dev)) != NULL) {
+               devid = (dev->bus->number << 8) | dev->devfn;
+               if (devid >= amd_iommu_last_bdf)
+                       continue;
+               devid = amd_iommu_alias_table[devid];
+               if (domain_for_device(devid))
+                       continue;
+               iommu = amd_iommu_rlookup_table[devid];
+               if (!iommu)
+                       continue;
+               dma_dom = dma_ops_domain_alloc(iommu, order);
+               if (!dma_dom)
+                       continue;
+               init_unity_mappings_for_device(dma_dom, devid);
+               set_device_domain(iommu, &dma_dom->domain, devid);
+               printk(KERN_INFO "AMD IOMMU: Allocated domain %d for device ",
+                      dma_dom->domain.id);
+               print_devid(devid, 1);
+       }
+}
+
+static struct dma_mapping_ops amd_iommu_dma_ops = {
+       .alloc_coherent = alloc_coherent,
+       .free_coherent = free_coherent,
+       .map_single = map_single,
+       .unmap_single = unmap_single,
+       .map_sg = map_sg,
+       .unmap_sg = unmap_sg,
+};
+
+/*
+ * The function which clues the AMD IOMMU driver into dma_ops.
+ */
+int __init amd_iommu_init_dma_ops(void)
+{
+       struct amd_iommu *iommu;
+       int order = amd_iommu_aperture_order;
+       int ret;
+
+       /*
+        * first allocate a default protection domain for every IOMMU we
+        * found in the system. Devices not assigned to any other
+        * protection domain will be assigned to the default one.
+        */
+       list_for_each_entry(iommu, &amd_iommu_list, list) {
+               iommu->default_dom = dma_ops_domain_alloc(iommu, order);
+               if (iommu->default_dom == NULL)
+                       return -ENOMEM;
+               ret = iommu_init_unity_mappings(iommu);
+               if (ret)
+                       goto free_domains;
+       }
+
+       /*
+        * If device isolation is enabled, pre-allocate the protection
+        * domains for each device.
+        */
+       if (amd_iommu_isolate)
+               prealloc_protection_domains();
+
+       iommu_detected = 1;
+       force_iommu = 1;
+       bad_dma_address = 0;
+#ifdef CONFIG_GART_IOMMU
+       gart_iommu_aperture_disabled = 1;
+       gart_iommu_aperture = 0;
+#endif
+
+       /* Make the driver finally visible to the drivers */
+       dma_ops = &amd_iommu_dma_ops;
+
+       return 0;
+
+free_domains:
+
+       list_for_each_entry(iommu, &amd_iommu_list, list) {
+               if (iommu->default_dom)
+                       dma_ops_domain_free(iommu->default_dom);
+       }
 
+       return ret;
+}