/*
 * Copyright (c) 2006, Intel Corporation.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope it will be useful, but WITHOUT
 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 * more details.
 *
 * You should have received a copy of the GNU General Public License along with
 * this program; if not, write to the Free Software Foundation, Inc., 59 Temple
 * Place - Suite 330, Boston, MA 02111-1307 USA.
 *
 * Copyright (C) 2006-2008 Intel Corporation
 * Author: Ashok Raj <ashok.raj@intel.com>
 * Author: Shaohua Li <shaohua.li@intel.com>
 * Author: Anil S Keshavamurthy <anil.s.keshavamurthy@intel.com>
 * Author: Fenghua Yu <fenghua.yu@intel.com>
 */

#include <linux/init.h>
#include <linux/bitmap.h>
#include <linux/debugfs.h>
#include <linux/export.h>
#include <linux/slab.h>
#include <linux/irq.h>
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/pci.h>
#include <linux/dmar.h>
#include <linux/dma-mapping.h>
#include <linux/mempool.h>
#include <linux/timer.h>
#include <linux/iova.h>
#include <linux/iommu.h>
#include <linux/intel-iommu.h>
#include <linux/syscore_ops.h>
#include <linux/tboot.h>
#include <linux/dmi.h>
#include <linux/pci-ats.h>
#include <linux/memblock.h>
#include <asm/irq_remapping.h>
#include <asm/cacheflush.h>
#include <asm/iommu.h>

#define ROOT_SIZE               VTD_PAGE_SIZE
#define CONTEXT_SIZE            VTD_PAGE_SIZE

#define IS_GFX_DEVICE(pdev) ((pdev->class >> 16) == PCI_BASE_CLASS_DISPLAY)
#define IS_ISA_DEVICE(pdev) ((pdev->class >> 8) == PCI_CLASS_BRIDGE_ISA)
#define IS_AZALIA(pdev) ((pdev)->vendor == 0x8086 && (pdev)->device == 0x3a3e)

#define IOAPIC_RANGE_START      (0xfee00000)
#define IOAPIC_RANGE_END        (0xfeefffff)
#define IOVA_START_ADDR         (0x1000)

#define DEFAULT_DOMAIN_ADDRESS_WIDTH 48

#define MAX_AGAW_WIDTH 64

#define __DOMAIN_MAX_PFN(gaw)  ((((uint64_t)1) << (gaw-VTD_PAGE_SHIFT)) - 1)
#define __DOMAIN_MAX_ADDR(gaw) ((((uint64_t)1) << gaw) - 1)

/* We limit DOMAIN_MAX_PFN to fit in an unsigned long, and DOMAIN_MAX_ADDR
   to match. That way, we can use 'unsigned long' for PFNs with impunity. */
#define DOMAIN_MAX_PFN(gaw)     ((unsigned long) min_t(uint64_t, \
                                __DOMAIN_MAX_PFN(gaw), (unsigned long)-1))
#define DOMAIN_MAX_ADDR(gaw)    (((uint64_t)__DOMAIN_MAX_PFN(gaw)) << VTD_PAGE_SHIFT)

#define IOVA_PFN(addr)          ((addr) >> PAGE_SHIFT)
#define DMA_32BIT_PFN           IOVA_PFN(DMA_BIT_MASK(32))
#define DMA_64BIT_PFN           IOVA_PFN(DMA_BIT_MASK(64))

/* page table handling */
#define LEVEL_STRIDE            (9)
#define LEVEL_MASK              (((u64)1 << LEVEL_STRIDE) - 1)

/*
 * This bitmap is used to advertise the page sizes our hardware support
 * to the IOMMU core, which will then use this information to split
 * physically contiguous memory regions it is mapping into page sizes
 * that we support.
 *
 * Traditionally the IOMMU core just handed us the mappings directly,
 * after making sure the size is an order of a 4KiB page and that the
 * mapping has natural alignment.
 *
 * To retain this behavior, we currently advertise that we support
 * all page sizes that are an order of 4KiB.
 *
 * If at some point we'd like to utilize the IOMMU core's new behavior,
 * we could change this to advertise the real page sizes we support.
 */
#define INTEL_IOMMU_PGSIZES     (~0xFFFUL)

static inline int agaw_to_level(int agaw)
{
        return agaw + 2;
}

static inline int agaw_to_width(int agaw)
{
        return 30 + agaw * LEVEL_STRIDE;
}

static inline int width_to_agaw(int width)
{
        return (width - 30) / LEVEL_STRIDE;
}

static inline unsigned int level_to_offset_bits(int level)
{
        return (level - 1) * LEVEL_STRIDE;
}

static inline int pfn_level_offset(unsigned long pfn, int level)
{
        return (pfn >> level_to_offset_bits(level)) & LEVEL_MASK;
}

static inline unsigned long level_mask(int level)
{
        return -1UL << level_to_offset_bits(level);
}

static inline unsigned long level_size(int level)
{
        return 1UL << level_to_offset_bits(level);
}

static inline unsigned long align_to_level(unsigned long pfn, int level)
{
        return (pfn + level_size(level) - 1) & level_mask(level);
}

static inline unsigned long lvl_to_nr_pages(unsigned int lvl)
{
        return  1 << ((lvl - 1) * LEVEL_STRIDE);
}

/* VT-d pages must always be _smaller_ than MM pages. Otherwise things
   are never going to work. */
static inline unsigned long dma_to_mm_pfn(unsigned long dma_pfn)
{
        return dma_pfn >> (PAGE_SHIFT - VTD_PAGE_SHIFT);
}

static inline unsigned long mm_to_dma_pfn(unsigned long mm_pfn)
{
        return mm_pfn << (PAGE_SHIFT - VTD_PAGE_SHIFT);
}
static inline unsigned long page_to_dma_pfn(struct page *pg)
{
        return mm_to_dma_pfn(page_to_pfn(pg));
}
static inline unsigned long virt_to_dma_pfn(void *p)
{
        return page_to_dma_pfn(virt_to_page(p));
}

/* global iommu list, set NULL for ignored DMAR units */
static struct intel_iommu **g_iommus;

static void __init check_tylersburg_isoch(void);
static int rwbf_quirk;

/*
 * set to 1 to panic kernel if can't successfully enable VT-d
 * (used when kernel is launched w/ TXT)
 */
static int force_on = 0;

/*
 * 0: Present
 * 1-11: Reserved
 * 12-63: Context Ptr (12 - (haw-1))
 * 64-127: Reserved
 */
struct root_entry {
        u64     val;
        u64     rsvd1;
};
#define ROOT_ENTRY_NR (VTD_PAGE_SIZE/sizeof(struct root_entry))
static inline bool root_present(struct root_entry *root)
{
        return (root->val & 1);
}
static inline void set_root_present(struct root_entry *root)
{
        root->val |= 1;
}
static inline void set_root_value(struct root_entry *root, unsigned long value)
{
        root->val |= value & VTD_PAGE_MASK;
}

static inline struct context_entry *
get_context_addr_from_root(struct root_entry *root)
{
        return (struct context_entry *)
                (root_present(root)?phys_to_virt(
                root->val & VTD_PAGE_MASK) :
                NULL);
}

/*
 * low 64 bits:
 * 0: present
 * 1: fault processing disable
 * 2-3: translation type
 * 12-63: address space root
 * high 64 bits:
 * 0-2: address width
 * 3-6: aval
 * 8-23: domain id
 */
struct context_entry {
        u64 lo;
        u64 hi;
};

static inline bool context_present(struct context_entry *context)
{
        return (context->lo & 1);
}
static inline void context_set_present(struct context_entry *context)
{
        context->lo |= 1;
}

static inline void context_set_fault_enable(struct context_entry *context)
{
        context->lo &= (((u64)-1) << 2) | 1;
}

static inline void context_set_translation_type(struct context_entry *context,
                                                unsigned long value)
{
        context->lo &= (((u64)-1) << 4) | 3;
        context->lo |= (value & 3) << 2;
}

static inline void context_set_address_root(struct context_entry *context,
                                            unsigned long value)
{
        context->lo |= value & VTD_PAGE_MASK;
}

static inline void context_set_address_width(struct context_entry *context,
                                             unsigned long value)
{
        context->hi |= value & 7;
}

static inline void context_set_domain_id(struct context_entry *context,
                                         unsigned long value)
{
        context->hi |= (value & ((1 << 16) - 1)) << 8;
}

static inline void context_clear_entry(struct context_entry *context)
{
        context->lo = 0;
        context->hi = 0;
}

/*
 * 0: readable
 * 1: writable
 * 2-6: reserved
 * 7: super page
 * 8-10: available
 * 11: snoop behavior
 * 12-63: Host physcial address
 */
struct dma_pte {
        u64 val;
};

static inline void dma_clear_pte(struct dma_pte *pte)
{
        pte->val = 0;
}

static inline void dma_set_pte_readable(struct dma_pte *pte)
{
        pte->val |= DMA_PTE_READ;
}

static inline void dma_set_pte_writable(struct dma_pte *pte)
{
        pte->val |= DMA_PTE_WRITE;
}

static inline void dma_set_pte_snp(struct dma_pte *pte)
{
        pte->val |= DMA_PTE_SNP;
}

static inline void dma_set_pte_prot(struct dma_pte *pte, unsigned long prot)
{
        pte->val = (pte->val & ~3) | (prot & 3);
}

static inline u64 dma_pte_addr(struct dma_pte *pte)
{
#ifdef CONFIG_64BIT
        return pte->val & VTD_PAGE_MASK;
#else
        /* Must have a full atomic 64-bit read */
        return  __cmpxchg64(&pte->val, 0ULL, 0ULL) & VTD_PAGE_MASK;
#endif
}

static inline void dma_set_pte_pfn(struct dma_pte *pte, unsigned long pfn)
{
        pte->val |= (uint64_t)pfn << VTD_PAGE_SHIFT;
}

static inline bool dma_pte_present(struct dma_pte *pte)
{
        return (pte->val & 3) != 0;
}

static inline bool dma_pte_superpage(struct dma_pte *pte)
{
        return (pte->val & (1 << 7));
}

static inline int first_pte_in_page(struct dma_pte *pte)
{
        return !((unsigned long)pte & ~VTD_PAGE_MASK);
}

/*
 * This domain is a statically identity mapping domain.
 *      1. This domain creats a static 1:1 mapping to all usable memory.
 *      2. It maps to each iommu if successful.
 *      3. Each iommu mapps to this domain if successful.
 */
static struct dmar_domain *si_domain;
static int hw_pass_through = 1;

/* devices under the same p2p bridge are owned in one domain */
#define DOMAIN_FLAG_P2P_MULTIPLE_DEVICES (1 << 0)

/* domain represents a virtual machine, more than one devices
 * across iommus may be owned in one domain, e.g. kvm guest.
 */
#define DOMAIN_FLAG_VIRTUAL_MACHINE     (1 << 1)

/* si_domain contains mulitple devices */
#define DOMAIN_FLAG_STATIC_IDENTITY     (1 << 2)

/* define the limit of IOMMUs supported in each domain */
#ifdef  CONFIG_X86
# define        IOMMU_UNITS_SUPPORTED   MAX_IO_APICS
#else
# define        IOMMU_UNITS_SUPPORTED   64
#endif

struct dmar_domain {
        int     id;                     /* domain id */
        int     nid;                    /* node id */
        DECLARE_BITMAP(iommu_bmp, IOMMU_UNITS_SUPPORTED);
                                        /* bitmap of iommus this domain uses*/

        struct list_head devices;       /* all devices' list */
        struct iova_domain iovad;       /* iova's that belong to this domain */

        struct dma_pte  *pgd;           /* virtual address */
        int             gaw;            /* max guest address width */

        /* adjusted guest address width, 0 is level 2 30-bit */
        int             agaw;

        int             flags;          /* flags to find out type of domain */

        int             iommu_coherency;/* indicate coherency of iommu access */
        int             iommu_snooping; /* indicate snooping control feature*/
        int             iommu_count;    /* reference count of iommu */
        int             iommu_superpage;/* Level of superpages supported:
                                           0 == 4KiB (no superpages), 1 == 2MiB,
                                           2 == 1GiB, 3 == 512GiB, 4 == 1TiB */
        spinlock_t      iommu_lock;     /* protect iommu set in domain */
        u64             max_addr;       /* maximum mapped address */
};

/* PCI domain-device relationship */
struct device_domain_info {
        struct list_head link;  /* link to domain siblings */
        struct list_head global; /* link to global list */
        int segment;            /* PCI domain */
        u8 bus;                 /* PCI bus number */
        u8 devfn;               /* PCI devfn number */
        struct pci_dev *dev; /* it's NULL for PCIe-to-PCI bridge */
        struct intel_iommu *iommu; /* IOMMU used by this device */
        struct dmar_domain *domain; /* pointer to domain */
};

static void flush_unmaps_timeout(unsigned long data);

DEFINE_TIMER(unmap_timer,  flush_unmaps_timeout, 0, 0);

#define HIGH_WATER_MARK 250
struct deferred_flush_tables {
        int next;
        struct iova *iova[HIGH_WATER_MARK];
        struct dmar_domain *domain[HIGH_WATER_MARK];
};

static struct deferred_flush_tables *deferred_flush;

/* bitmap for indexing intel_iommus */
static int g_num_of_iommus;

static DEFINE_SPINLOCK(async_umap_flush_lock);
static LIST_HEAD(unmaps_to_do);

static int timer_on;
static long list_size;

static void domain_remove_dev_info(struct dmar_domain *domain);

#ifdef CONFIG_INTEL_IOMMU_DEFAULT_ON
int dmar_disabled = 0;
#else
int dmar_disabled = 1;
#endif /*CONFIG_INTEL_IOMMU_DEFAULT_ON*/

int intel_iommu_enabled = 0;
EXPORT_SYMBOL_GPL(intel_iommu_enabled);

static int dmar_map_gfx = 1;
static int dmar_forcedac;
static int intel_iommu_strict;
static int intel_iommu_superpage = 1;

int intel_iommu_gfx_mapped;
EXPORT_SYMBOL_GPL(intel_iommu_gfx_mapped);

#define DUMMY_DEVICE_DOMAIN_INFO ((struct device_domain_info *)(-1))
static DEFINE_SPINLOCK(device_domain_lock);
static LIST_HEAD(device_domain_list);

static struct iommu_ops intel_iommu_ops;

static int __init intel_iommu_setup(char *str)
{
        if (!str)
                return -EINVAL;
        while (*str) {
                if (!strncmp(str, "on", 2)) {
                        dmar_disabled = 0;
                        printk(KERN_INFO "Intel-IOMMU: enabled\n");
                } else if (!strncmp(str, "off", 3)) {
                        dmar_disabled = 1;
                        printk(KERN_INFO "Intel-IOMMU: disabled\n");
                } else if (!strncmp(str, "igfx_off", 8)) {
                        dmar_map_gfx = 0;
                        printk(KERN_INFO
                                "Intel-IOMMU: disable GFX device mapping\n");
                } else if (!strncmp(str, "forcedac", 8)) {
                        printk(KERN_INFO
                                "Intel-IOMMU: Forcing DAC for PCI devices\n");
                        dmar_forcedac = 1;
                } else if (!strncmp(str, "strict", 6)) {
                        printk(KERN_INFO
                                "Intel-IOMMU: disable batched IOTLB flush\n");
                        intel_iommu_strict = 1;
                } else if (!strncmp(str, "sp_off", 6)) {
                        printk(KERN_INFO
                                "Intel-IOMMU: disable supported super page\n");
                        intel_iommu_superpage = 0;
                }

                str += strcspn(str, ",");
                while (*str == ',')
                        str++;
        }
        return 0;
}
__setup("intel_iommu=", intel_iommu_setup);

static struct kmem_cache *iommu_domain_cache;
static struct kmem_cache *iommu_devinfo_cache;
static struct kmem_cache *iommu_iova_cache;

static inline void *alloc_pgtable_page(int node)
{
        struct page *page;
        void *vaddr = NULL;

        page = alloc_pages_node(node, GFP_ATOMIC | __GFP_ZERO, 0);
        if (page)
                vaddr = page_address(page);
        return vaddr;
}

static inline void free_pgtable_page(void *vaddr)
{
        free_page((unsigned long)vaddr);
}

static inline void *alloc_domain_mem(void)
{
        return kmem_cache_alloc(iommu_domain_cache, GFP_ATOMIC);
}

static void free_domain_mem(void *vaddr)
{
        kmem_cache_free(iommu_domain_cache, vaddr);
}

static inline void * alloc_devinfo_mem(void)
{
        return kmem_cache_alloc(iommu_devinfo_cache, GFP_ATOMIC);
}

static inline void free_devinfo_mem(void *vaddr)
{
        kmem_cache_free(iommu_devinfo_cache, vaddr);
}

struct iova *alloc_iova_mem(void)
{
        return kmem_cache_alloc(iommu_iova_cache, GFP_ATOMIC);
}

void free_iova_mem(struct iova *iova)
{
        kmem_cache_free(iommu_iova_cache, iova);
}


static int __iommu_calculate_agaw(struct intel_iommu *iommu, int max_gaw)
{
        unsigned long sagaw;
        int agaw = -1;

        sagaw = cap_sagaw(iommu->cap);
        for (agaw = width_to_agaw(max_gaw);
             agaw >= 0; agaw--) {
                if (test_bit(agaw, &sagaw))
                        break;
        }

        return agaw;
}

/*
 * Calculate max SAGAW for each iommu.
 */
int iommu_calculate_max_sagaw(struct intel_iommu *iommu)
{
        return __iommu_calculate_agaw(iommu, MAX_AGAW_WIDTH);
}

/*
 * calculate agaw for each iommu.
 * "SAGAW" may be different across iommus, use a default agaw, and
 * get a supported less agaw for iommus that don't support the default agaw.
 */
int iommu_calculate_agaw(struct intel_iommu *iommu)
{
        return __iommu_calculate_agaw(iommu, DEFAULT_DOMAIN_ADDRESS_WIDTH);
}

/* This functionin only returns single iommu in a domain */
static struct intel_iommu *domain_get_iommu(struct dmar_domain *domain)
{
        int iommu_id;

        /* si_domain and vm domain should not get here. */
        BUG_ON(domain->flags & DOMAIN_FLAG_VIRTUAL_MACHINE);
        BUG_ON(domain->flags & DOMAIN_FLAG_STATIC_IDENTITY);

        iommu_id = find_first_bit(domain->iommu_bmp, g_num_of_iommus);
        if (iommu_id < 0 || iommu_id >= g_num_of_iommus)
                return NULL;

        return g_iommus[iommu_id];
}

static void domain_update_iommu_coherency(struct dmar_domain *domain)
{
        int i;

        i = find_first_bit(domain->iommu_bmp, g_num_of_iommus);

        domain->iommu_coherency = i < g_num_of_iommus ? 1 : 0;

        for_each_set_bit(i, domain->iommu_bmp, g_num_of_iommus) {
                if (!ecap_coherent(g_iommus[i]->ecap)) {
                        domain->iommu_coherency = 0;
                        break;
                }
        }
}

static void domain_update_iommu_snooping(struct dmar_domain *domain)
{
        int i;

        domain->iommu_snooping = 1;

        for_each_set_bit(i, domain->iommu_bmp, g_num_of_iommus) {
                if (!ecap_sc_support(g_iommus[i]->ecap)) {
                        domain->iommu_snooping = 0;
                        break;
                }
        }
}

static void domain_update_iommu_superpage(struct dmar_domain *domain)
{
        struct dmar_drhd_unit *drhd;
        struct intel_iommu *iommu = NULL;
        int mask = 0xf;

        if (!intel_iommu_superpage) {
                domain->iommu_superpage = 0;
                return;
        }

        /* set iommu_superpage to the smallest common denominator */
        for_each_active_iommu(iommu, drhd) {
                mask &= cap_super_page_val(iommu->cap);
                if (!mask) {
                        break;
                }
        }
        domain->iommu_superpage = fls(mask);
}

/* Some capabilities may be different across iommus */
static void domain_update_iommu_cap(struct dmar_domain *domain)
{
        domain_update_iommu_coherency(domain);
        domain_update_iommu_snooping(domain);
        domain_update_iommu_superpage(domain);
}

static struct intel_iommu *device_to_iommu(int segment, u8 bus, u8 devfn)
{
        struct dmar_drhd_unit *drhd = NULL;
        int i;

        for_each_drhd_unit(drhd) {
                if (drhd->ignored)
                        continue;
                if (segment != drhd->segment)
                        continue;

                for (i = 0; i < drhd->devices_cnt; i++) {
                        if (drhd->devices[i] &&
                            drhd->devices[i]->bus->number == bus &&
                            drhd->devices[i]->devfn == devfn)
                                return drhd->iommu;
                        if (drhd->devices[i] &&
                            drhd->devices[i]->subordinate &&
                            drhd->devices[i]->subordinate->number <= bus &&
                            drhd->devices[i]->subordinate->busn_res.end >= bus)
                                return drhd->iommu;
                }

                if (drhd->include_all)
                        return drhd->iommu;
        }

        return NULL;
}

static void domain_flush_cache(struct dmar_domain *domain,
                               void *addr, int size)
{
        if (!domain->iommu_coherency)
                clflush_cache_range(addr, size);
}

/* Gets context entry for a given bus and devfn */
static struct context_entry * device_to_context_entry(struct intel_iommu *iommu,
                u8 bus, u8 devfn)
{
        struct root_entry *root;
        struct context_entry *context;
        unsigned long phy_addr;
        unsigned long flags;

        spin_lock_irqsave(&iommu->lock, flags);
        root = &iommu->root_entry[bus];
        context = get_context_addr_from_root(root);
        if (!context) {
                context = (struct context_entry *)
                                alloc_pgtable_page(iommu->node);
                if (!context) {
                        spin_unlock_irqrestore(&iommu->lock, flags);
                        return NULL;
                }
                __iommu_flush_cache(iommu, (void *)context, CONTEXT_SIZE);
                phy_addr = virt_to_phys((void *)context);
                set_root_value(root, phy_addr);
                set_root_present(root);
                __iommu_flush_cache(iommu, root, sizeof(*root));
        }
        spin_unlock_irqrestore(&iommu->lock, flags);
        return &context[devfn];
}

static int device_context_mapped(struct intel_iommu *iommu, u8 bus, u8 devfn)
{
        struct root_entry *root;
        struct context_entry *context;
        int ret;
        unsigned long flags;

        spin_lock_irqsave(&iommu->lock, flags);
        root = &iommu->root_entry[bus];
        context = get_context_addr_from_root(root);
        if (!context) {
                ret = 0;
                goto out;
        }
        ret = context_present(&context[devfn]);
out:
        spin_unlock_irqrestore(&iommu->lock, flags);
        return ret;
}

static void clear_context_table(struct intel_iommu *iommu, u8 bus, u8 devfn)
{
        struct root_entry *root;
        struct context_entry *context;
        unsigned long flags;

        spin_lock_irqsave(&iommu->lock, flags);
        root = &iommu->root_entry[bus];
        context = get_context_addr_from_root(root);
        if (context) {
                context_clear_entry(&context[devfn]);
                __iommu_flush_cache(iommu, &context[devfn], \
                        sizeof(*context));
        }
        spin_unlock_irqrestore(&iommu->lock, flags);
}

static void free_context_table(struct intel_iommu *iommu)
{
        struct root_entry *root;
        int i;
        unsigned long flags;
        struct context_entry *context;

        spin_lock_irqsave(&iommu->lock, flags);
        if (!iommu->root_entry) {
                goto out;
        }
        for (i = 0; i < ROOT_ENTRY_NR; i++) {
                root = &iommu->root_entry[i];
                context = get_context_addr_from_root(root);
                if (context)
                        free_pgtable_page(context);
        }
        free_pgtable_page(iommu->root_entry);
        iommu->root_entry = NULL;
out:
        spin_unlock_irqrestore(&iommu->lock, flags);
}

static struct dma_pte *pfn_to_dma_pte(struct dmar_domain *domain,
                                      unsigned long pfn, int target_level)
{
        int addr_width = agaw_to_width(domain->agaw) - VTD_PAGE_SHIFT;
        struct dma_pte *parent, *pte = NULL;
        int level = agaw_to_level(domain->agaw);
        int offset;

        BUG_ON(!domain->pgd);
        BUG_ON(addr_width < BITS_PER_LONG && pfn >> addr_width);
        parent = domain->pgd;

        while (level > 0) {
                void *tmp_page;

                offset = pfn_level_offset(pfn, level);
                pte = &parent[offset];
                if (!target_level && (dma_pte_superpage(pte) || !dma_pte_present(pte)))
                        break;
                if (level == target_level)
                        break;

                if (!dma_pte_present(pte)) {
                        uint64_t pteval;

                        tmp_page = alloc_pgtable_page(domain->nid);

                        if (!tmp_page)
                                return NULL;

                        domain_flush_cache(domain, tmp_page, VTD_PAGE_SIZE);
                        pteval = ((uint64_t)virt_to_dma_pfn(tmp_page) << VTD_PAGE_SHIFT) | DMA_PTE_READ | DMA_PTE_WRITE;
                        if (cmpxchg64(&pte->val, 0ULL, pteval)) {
                                /* Someone else set it while we were thinking; use theirs. */
                                free_pgtable_page(tmp_page);
                        } else {
                                dma_pte_addr(pte);
                                domain_flush_cache(domain, pte, sizeof(*pte));
                        }
                }
                parent = phys_to_virt(dma_pte_addr(pte));
                level--;
        }

        return pte;
}


/* return address's pte at specific level */
static struct dma_pte *dma_pfn_level_pte(struct dmar_domain *domain,
                                         unsigned long pfn,
                                         int level, int *large_page)
{
        struct dma_pte *parent, *pte = NULL;
        int total = agaw_to_level(domain->agaw);
        int offset;

        parent = domain->pgd;
        while (level <= total) {
                offset = pfn_level_offset(pfn, total);
                pte = &parent[offset];
                if (level == total)
                        return pte;

                if (!dma_pte_present(pte)) {
                        *large_page = total;
                        break;
                }

                if (pte->val & DMA_PTE_LARGE_PAGE) {
                        *large_page = total;
                        return pte;
                }

                parent = phys_to_virt(dma_pte_addr(pte));
                total--;
        }
        return NULL;
}

/* clear last level pte, a tlb flush should be followed */
static int dma_pte_clear_range(struct dmar_domain *domain,
                                unsigned long start_pfn,
                                unsigned long last_pfn)
{
        int addr_width = agaw_to_width(domain->agaw) - VTD_PAGE_SHIFT;
        unsigned int large_page = 1;
        struct dma_pte *first_pte, *pte;
        int order;

        BUG_ON(addr_width < BITS_PER_LONG && start_pfn >> addr_width);
        BUG_ON(addr_width < BITS_PER_LONG && last_pfn >> addr_width);
        BUG_ON(start_pfn > last_pfn);

        /* we don't need lock here; nobody else touches the iova range */
        do {
                large_page = 1;
                first_pte = pte = dma_pfn_level_pte(domain, start_pfn, 1, &large_page);
                if (!pte) {
                        start_pfn = align_to_level(start_pfn + 1, large_page + 1);
                        continue;
                }
                do {
                        dma_clear_pte(pte);
                        start_pfn += lvl_to_nr_pages(large_page);
                        pte++;
                } while (start_pfn <= last_pfn && !first_pte_in_page(pte));

                domain_flush_cache(domain, first_pte,
                                   (void *)pte - (void *)first_pte);

        } while (start_pfn && start_pfn <= last_pfn);

        order = (large_page - 1) * 9;
        return order;
}

/* free page table pages. last level pte should already be cleared */
static void dma_pte_free_pagetable(struct dmar_domain *domain,
                                   unsigned long start_pfn,
                                   unsigned long last_pfn)
{
        int addr_width = agaw_to_width(domain->agaw) - VTD_PAGE_SHIFT;
        struct dma_pte *first_pte, *pte;
        int total = agaw_to_level(domain->agaw);
        int level;
        unsigned long tmp;
        int large_page = 2;

        BUG_ON(addr_width < BITS_PER_LONG && start_pfn >> addr_width);
        BUG_ON(addr_width < BITS_PER_LONG && last_pfn >> addr_width);
        BUG_ON(start_pfn > last_pfn);

        /* We don't need lock here; nobody else touches the iova range */
        level = 2;
        while (level <= total) {
                tmp = align_to_level(start_pfn, level);

                /* If we can't even clear one PTE at this level, we're done */
                if (tmp + level_size(level) - 1 > last_pfn)
                        return;

                do {
                        large_page = level;
                        first_pte = pte = dma_pfn_level_pte(domain, tmp, level, &large_page);
                        if (large_page > level)
                                level = large_page + 1;
                        if (!pte) {
                                tmp = align_to_level(tmp + 1, level + 1);
                                continue;
                        }
                        do {
                                if (dma_pte_present(pte)) {
                                        free_pgtable_page(phys_to_virt(dma_pte_addr(pte)));
                                        dma_clear_pte(pte);
                                }
                                pte++;
                                tmp += level_size(level);
                        } while (!first_pte_in_page(pte) &&
                                 tmp + level_size(level) - 1 <= last_pfn);

                        domain_flush_cache(domain, first_pte,
                                           (void *)pte - (void *)first_pte);
                        
                } while (tmp && tmp + level_size(level) - 1 <= last_pfn);
                level++;
        }
        /* free pgd */
        if (start_pfn == 0 && last_pfn == DOMAIN_MAX_PFN(domain->gaw)) {
                free_pgtable_page(domain->pgd);
                domain->pgd = NULL;
        }
}

/* iommu handling */
static int iommu_alloc_root_entry(struct intel_iommu *iommu)
{
        struct root_entry *root;
        unsigned long flags;

        root = (struct root_entry *)alloc_pgtable_page(iommu->node);
        if (!root)
                return -ENOMEM;

        __iommu_flush_cache(iommu, root, ROOT_SIZE);

        spin_lock_irqsave(&iommu->lock, flags);
        iommu->root_entry = root;
        spin_unlock_irqrestore(&iommu->lock, flags);

        return 0;
}

static void iommu_set_root_entry(struct intel_iommu *iommu)
{
        void *addr;
        u32 sts;
        unsigned long flag;

        addr = iommu->root_entry;

        raw_spin_lock_irqsave(&iommu->register_lock, flag);
        dmar_writeq(iommu->reg + DMAR_RTADDR_REG, virt_to_phys(addr));

        writel(iommu->gcmd | DMA_GCMD_SRTP, iommu->reg + DMAR_GCMD_REG);

        /* Make sure hardware complete it */
        IOMMU_WAIT_OP(iommu, DMAR_GSTS_REG,
                      readl, (sts & DMA_GSTS_RTPS), sts);

        raw_spin_unlock_irqrestore(&iommu->register_lock, flag);
}

static void iommu_flush_write_buffer(struct intel_iommu *iommu)
{
        u32 val;
        unsigned long flag;

        if (!rwbf_quirk && !cap_rwbf(iommu->cap))
                return;

        raw_spin_lock_irqsave(&iommu->register_lock, flag);
        writel(iommu->gcmd | DMA_GCMD_WBF, iommu->reg + DMAR_GCMD_REG);

        /* Make sure hardware complete it */
        IOMMU_WAIT_OP(iommu, DMAR_GSTS_REG,
                      readl, (!(val & DMA_GSTS_WBFS)), val);

        raw_spin_unlock_irqrestore(&iommu->register_lock, flag);
}

/* return value determine if we need a write buffer flush */
static void __iommu_flush_context(struct intel_iommu *iommu,
                                  u16 did, u16 source_id, u8 function_mask,
                                  u64 type)
{
        u64 val = 0;
        unsigned long flag;

        switch (type) {
        case DMA_CCMD_GLOBAL_INVL:
                val = DMA_CCMD_GLOBAL_INVL;
                break;
        case DMA_CCMD_DOMAIN_INVL:
                val = DMA_CCMD_DOMAIN_INVL|DMA_CCMD_DID(did);
                break;
        case DMA_CCMD_DEVICE_INVL:
                val = DMA_CCMD_DEVICE_INVL|DMA_CCMD_DID(did)
                        | DMA_CCMD_SID(source_id) | DMA_CCMD_FM(function_mask);
                break;
        default:
                BUG();
        }
        val |= DMA_CCMD_ICC;

        raw_spin_lock_irqsave(&iommu->register_lock, flag);
        dmar_writeq(iommu->reg + DMAR_CCMD_REG, val);

        /* Make sure hardware complete it */
        IOMMU_WAIT_OP(iommu, DMAR_CCMD_REG,
                dmar_readq, (!(val & DMA_CCMD_ICC)), val);

        raw_spin_unlock_irqrestore(&iommu->register_lock, flag);
}

/* return value determine if we need a write buffer flush */
static void __iommu_flush_iotlb(struct intel_iommu *iommu, u16 did,
                                u64 addr, unsigned int size_order, u64 type)
{
        int tlb_offset = ecap_iotlb_offset(iommu->ecap);
        u64 val = 0, val_iva = 0;
        unsigned long flag;

        switch (type) {
        case DMA_TLB_GLOBAL_FLUSH:
                /* global flush doesn't need set IVA_REG */
                val = DMA_TLB_GLOBAL_FLUSH|DMA_TLB_IVT;
                break;
        case DMA_TLB_DSI_FLUSH:
                val = DMA_TLB_DSI_FLUSH|DMA_TLB_IVT|DMA_TLB_DID(did);
                break;
        case DMA_TLB_PSI_FLUSH:
                val = DMA_TLB_PSI_FLUSH|DMA_TLB_IVT|DMA_TLB_DID(did);
                /* Note: always flush non-leaf currently */
                val_iva = size_order | addr;
                break;
        default:
                BUG();
        }
        /* Note: set drain read/write */
#if 0
        /*
         * This is probably to be super secure.. Looks like we can
         * ignore it without any impact.
         */
        if (cap_read_drain(iommu->cap))
                val |= DMA_TLB_READ_DRAIN;
#endif
        if (cap_write_drain(iommu->cap))
                val |= DMA_TLB_WRITE_DRAIN;

        raw_spin_lock_irqsave(&iommu->register_lock, flag);
        /* Note: Only uses first TLB reg currently */
        if (val_iva)
                dmar_writeq(iommu->reg + tlb_offset, val_iva);
        dmar_writeq(iommu->reg + tlb_offset + 8, val);

        /* Make sure hardware complete it */
        IOMMU_WAIT_OP(iommu, tlb_offset + 8,
                dmar_readq, (!(val & DMA_TLB_IVT)), val);

        raw_spin_unlock_irqrestore(&iommu->register_lock, flag);

        /* check IOTLB invalidation granularity */
        if (DMA_TLB_IAIG(val) == 0)
                printk(KERN_ERR"IOMMU: flush IOTLB failed\n");
        if (DMA_TLB_IAIG(val) != DMA_TLB_IIRG(type))
                pr_debug("IOMMU: tlb flush request %Lx, actual %Lx\n",
                        (unsigned long long)DMA_TLB_IIRG(type),
                        (unsigned long long)DMA_TLB_IAIG(val));
}

static struct device_domain_info *iommu_support_dev_iotlb(
        struct dmar_domain *domain, int segment, u8 bus, u8 devfn)
{
        int found = 0;
        unsigned long flags;
        struct device_domain_info *info;
        struct intel_iommu *iommu = device_to_iommu(segment, bus, devfn);

        if (!ecap_dev_iotlb_support(iommu->ecap))
                return NULL;

        if (!iommu->qi)
                return NULL;

        spin_lock_irqsave(&device_domain_lock, flags);
        list_for_each_entry(info, &domain->devices, link)
                if (info->bus == bus && info->devfn == devfn) {
                        found = 1;
                        break;
                }
        spin_unlock_irqrestore(&device_domain_lock, flags);

        if (!found || !info->dev)
                return NULL;

        if (!pci_find_ext_capability(info->dev, PCI_EXT_CAP_ID_ATS))
                return NULL;

        if (!dmar_find_matched_atsr_unit(info->dev))
                return NULL;

        info->iommu = iommu;

        return info;
}

static void iommu_enable_dev_iotlb(struct device_domain_info *info)
{
        if (!info)
                return;

        pci_enable_ats(info->dev, VTD_PAGE_SHIFT);
}

static void iommu_disable_dev_iotlb(struct device_domain_info *info)
{
        if (!info->dev || !pci_ats_enabled(info->dev))
                return;

        pci_disable_ats(info->dev);
}

static void iommu_flush_dev_iotlb(struct dmar_domain *domain,
                                  u64 addr, unsigned mask)
{
        u16 sid, qdep;
        unsigned long flags;
        struct device_domain_info *info;

        spin_lock_irqsave(&device_domain_lock, flags);
        list_for_each_entry(info, &domain->devices, link) {
                if (!info->dev || !pci_ats_enabled(info->dev))
                        continue;

                sid = info->bus << 8 | info->devfn;
                qdep = pci_ats_queue_depth(info->dev);
                qi_flush_dev_iotlb(info->iommu, sid, qdep, addr, mask);
        }
        spin_unlock_irqrestore(&device_domain_lock, flags);
}

static void iommu_flush_iotlb_psi(struct intel_iommu *iommu, u16 did,
                                  unsigned long pfn, unsigned int pages, int map)
{
        unsigned int mask = ilog2(__roundup_pow_of_two(pages));
        uint64_t addr = (uint64_t)pfn << VTD_PAGE_SHIFT;

        BUG_ON(pages == 0);

        /*
         * Fallback to domain selective flush if no PSI support or the size is
         * too big.
         * PSI requires page size to be 2 ^ x, and the base address is naturally
         * aligned to the size
         */
        if (!cap_pgsel_inv(iommu->cap) || mask > cap_max_amask_val(iommu->cap))
                iommu->flush.flush_iotlb(iommu, did, 0, 0,
                                                DMA_TLB_DSI_FLUSH);
        else
                iommu->flush.flush_iotlb(iommu, did, addr, mask,
                                                DMA_TLB_PSI_FLUSH);

        /*
         * In caching mode, changes of pages from non-present to present require
         * flush. However, device IOTLB doesn't need to be flushed in this case.
         */
        if (!cap_caching_mode(iommu->cap) || !map)
                iommu_flush_dev_iotlb(iommu->domains[did], addr, mask);
}

static void iommu_disable_protect_mem_regions(struct intel_iommu *iommu)
{
        u32 pmen;
        unsigned long flags;

        raw_spin_lock_irqsave(&iommu->register_lock, flags);
        pmen = readl(iommu->reg + DMAR_PMEN_REG);
        pmen &= ~DMA_PMEN_EPM;
        writel(pmen, iommu->reg + DMAR_PMEN_REG);

        /* wait for the protected region status bit to clear */
        IOMMU_WAIT_OP(iommu, DMAR_PMEN_REG,
                readl, !(pmen & DMA_PMEN_PRS), pmen);

        raw_spin_unlock_irqrestore(&iommu->register_lock, flags);
}

static int iommu_enable_translation(struct intel_iommu *iommu)
{
        u32 sts;
        unsigned long flags;

        raw_spin_lock_irqsave(&iommu->register_lock, flags);
        iommu->gcmd |= DMA_GCMD_TE;
        writel(iommu->gcmd, iommu->reg + DMAR_GCMD_REG);

        /* Make sure hardware complete it */
        IOMMU_WAIT_OP(iommu, DMAR_GSTS_REG,
                      readl, (sts & DMA_GSTS_TES), sts);

        raw_spin_unlock_irqrestore(&iommu->register_lock, flags);
        return 0;
}

static int iommu_disable_translation(struct intel_iommu *iommu)
{
        u32 sts;
        unsigned long flag;

        raw_spin_lock_irqsave(&iommu->register_lock, flag);
        iommu->gcmd &= ~DMA_GCMD_TE;
        writel(iommu->gcmd, iommu->reg + DMAR_GCMD_REG);

        /* Make sure hardware complete it */
        IOMMU_WAIT_OP(iommu, DMAR_GSTS_REG,
                      readl, (!(sts & DMA_GSTS_TES)), sts);

        raw_spin_unlock_irqrestore(&iommu->register_lock, flag);
        return 0;
}


static int iommu_init_domains(struct intel_iommu *iommu)
{
        unsigned long ndomains;
        unsigned long nlongs;

        ndomains = cap_ndoms(iommu->cap);
        pr_debug("IOMMU %d: Number of Domains supported <%ld>\n", iommu->seq_id,
                        ndomains);
        nlongs = BITS_TO_LONGS(ndomains);

        spin_lock_init(&iommu->lock);

        /* TBD: there might be 64K domains,
         * consider other allocation for future chip
         */
        iommu->domain_ids = kcalloc(nlongs, sizeof(unsigned long), GFP_KERNEL);
        if (!iommu->domain_ids) {
                printk(KERN_ERR "Allocating domain id array failed\n");
                return -ENOMEM;
        }
        iommu->domains = kcalloc(ndomains, sizeof(struct dmar_domain *),
                        GFP_KERNEL);
        if (!iommu->domains) {
                printk(KERN_ERR "Allocating domain array failed\n");
                return -ENOMEM;
        }

        /*
         * if Caching mode is set, then invalid translations are tagged
         * with domainid 0. Hence we need to pre-allocate it.
         */
        if (cap_caching_mode(iommu->cap))
                set_bit(0, iommu->domain_ids);
        return 0;
}


static void domain_exit(struct dmar_domain *domain);
static void vm_domain_exit(struct dmar_domain *domain);

void free_dmar_iommu(struct intel_iommu *iommu)
{
        struct dmar_domain *domain;
        int i;
        unsigned long flags;

        if ((iommu->domains) && (iommu->domain_ids)) {
                for_each_set_bit(i, iommu->domain_ids, cap_ndoms(iommu->cap)) {
                        domain = iommu->domains[i];
                        clear_bit(i, iommu->domain_ids);

                        spin_lock_irqsave(&domain->iommu_lock, flags);
                        if (--domain->iommu_count == 0) {
                                if (domain->flags & DOMAIN_FLAG_VIRTUAL_MACHINE)
                                        vm_domain_exit(domain);
                                else
                                        domain_exit(domain);
                        }
                        spin_unlock_irqrestore(&domain->iommu_lock, flags);
                }
        }

        if (iommu->gcmd & DMA_GCMD_TE)
                iommu_disable_translation(iommu);

        if (iommu->irq) {
                irq_set_handler_data(iommu->irq, NULL);
                /* This will mask the irq */
                free_irq(iommu->irq, iommu);
                destroy_irq(iommu->irq);
        }

        kfree(iommu->domains);
        kfree(iommu->domain_ids);

        g_iommus[iommu->seq_id] = NULL;

        /* if all iommus are freed, free g_iommus */
        for (i = 0; i < g_num_of_iommus; i++) {
                if (g_iommus[i])
                        break;
        }

        if (i == g_num_of_iommus)
                kfree(g_iommus);

        /* free context mapping */
        free_context_table(iommu);
}

static struct dmar_domain *alloc_domain(void)
{
        struct dmar_domain *domain;

        domain = alloc_domain_mem();
        if (!domain)
                return NULL;

        domain->nid = -1;
        memset(domain->iommu_bmp, 0, sizeof(domain->iommu_bmp));
        domain->flags = 0;

        return domain;
}

static int iommu_attach_domain(struct dmar_domain *domain,
                               struct intel_iommu *iommu)
{
        int num;
        unsigned long ndomains;
        unsigned long flags;

        ndomains = cap_ndoms(iommu->cap);

        spin_lock_irqsave(&iommu->lock, flags);

        num = find_first_zero_bit(iommu->domain_ids, ndomains);
        if (num >= ndomains) {
                spin_unlock_irqrestore(&iommu->lock, flags);
                printk(KERN_ERR "IOMMU: no free domain ids\n");
                return -ENOMEM;
        }

        domain->id = num;
        set_bit(num, iommu->domain_ids);
        set_bit(iommu->seq_id, domain->iommu_bmp);
        iommu->domains[num] = domain;
        spin_unlock_irqrestore(&iommu->lock, flags);

        return 0;
}

static void iommu_detach_domain(struct dmar_domain *domain,
                                struct intel_iommu *iommu)
{
        unsigned long flags;
        int num, ndomains;
        int found = 0;

        spin_lock_irqsave(&iommu->lock, flags);
        ndomains = cap_ndoms(iommu->cap);
        for_each_set_bit(num, iommu->domain_ids, ndomains) {
                if (iommu->domains[num] == domain) {
                        found = 1;
                        break;
                }
        }

        if (found) {
                clear_bit(num, iommu->domain_ids);
                clear_bit(iommu->seq_id, domain->iommu_bmp);
                iommu->domains[num] = NULL;
        }
        spin_unlock_irqrestore(&iommu->lock, flags);
}

static struct iova_domain reserved_iova_list;
static struct lock_class_key reserved_rbtree_key;

static int dmar_init_reserved_ranges(void)
{
        struct pci_dev *pdev = NULL;
        struct iova *iova;
        int i;

        init_iova_domain(&reserved_iova_list, DMA_32BIT_PFN);

        lockdep_set_class(&reserved_iova_list.iova_rbtree_lock,
                &reserved_rbtree_key);

        /* IOAPIC ranges shouldn't be accessed by DMA */
        iova = reserve_iova(&reserved_iova_list, IOVA_PFN(IOAPIC_RANGE_START),
                IOVA_PFN(IOAPIC_RANGE_END));
        if (!iova) {
                printk(KERN_ERR "Reserve IOAPIC range failed\n");
                return -ENODEV;
        }

        /* Reserve all PCI MMIO to avoid peer-to-peer access */
        for_each_pci_dev(pdev) {
                struct resource *r;

                for (i = 0; i < PCI_NUM_RESOURCES; i++) {
                        r = &pdev->resource[i];
                        if (!r->flags || !(r->flags & IORESOURCE_MEM))
                                continue;
                        iova = reserve_iova(&reserved_iova_list,
                                            IOVA_PFN(r->start),
                                            IOVA_PFN(r->end));
                        if (!iova) {
                                printk(KERN_ERR "Reserve iova failed\n");
                                return -ENODEV;
                        }
                }
        }
        return 0;
}

static void domain_reserve_special_ranges(struct dmar_domain *domain)
{
        copy_reserved_iova(&reserved_iova_list, &domain->iovad);
}

static inline int guestwidth_to_adjustwidth(int gaw)
{
        int agaw;
        int r = (gaw - 12) % 9;

        if (r == 0)
                agaw = gaw;
        else
                agaw = gaw + 9 - r;
        if (agaw > 64)
                agaw = 64;
        return agaw;
}

static int domain_init(struct dmar_domain *domain, int guest_width)
{
        struct intel_iommu *iommu;
        int adjust_width, agaw;
        unsigned long sagaw;

        init_iova_domain(&domain->iovad, DMA_32BIT_PFN);
        spin_lock_init(&domain->iommu_lock);

        domain_reserve_special_ranges(domain);

        /* calculate AGAW */
        iommu = domain_get_iommu(domain);
        if (guest_width > cap_mgaw(iommu->cap))
                guest_width = cap_mgaw(iommu->cap);
        domain->gaw = guest_width;
        adjust_width = guestwidth_to_adjustwidth(guest_width);
        agaw = width_to_agaw(adjust_width);
        sagaw = cap_sagaw(iommu->cap);
        if (!test_bit(agaw, &sagaw)) {
                /* hardware doesn't support it, choose a bigger one */
                pr_debug("IOMMU: hardware doesn't support agaw %d\n", agaw);
                agaw = find_next_bit(&sagaw, 5, agaw);
                if (agaw >= 5)
                        return -ENODEV;
        }
        domain->agaw = agaw;
        INIT_LIST_HEAD(&domain->devices);

        if (ecap_coherent(iommu->ecap))
                domain->iommu_coherency = 1;
        else
                domain->iommu_coherency = 0;

        if (ecap_sc_support(iommu->ecap))
                domain->iommu_snooping = 1;
        else
                domain->iommu_snooping = 0;

        domain->iommu_superpage = fls(cap_super_page_val(iommu->cap));
        domain->iommu_count = 1;
        domain->nid = iommu->node;

        /* always allocate the top pgd */
        domain->pgd = (struct dma_pte *)alloc_pgtable_page(domain->nid);
        if (!domain->pgd)
                return -ENOMEM;
        __iommu_flush_cache(iommu, domain->pgd, PAGE_SIZE);
        return 0;
}

static void domain_exit(struct dmar_domain *domain)
{
        struct dmar_drhd_unit *drhd;
        struct intel_iommu *iommu;

        /* Domain 0 is reserved, so dont process it */
        if (!domain)
                return;

        /* Flush any lazy unmaps that may reference this domain */
        if (!intel_iommu_strict)
                flush_unmaps_timeout(0);

        domain_remove_dev_info(domain);
        /* destroy iovas */
        put_iova_domain(&domain->iovad);

        /* clear ptes */
        dma_pte_clear_range(domain, 0, DOMAIN_MAX_PFN(domain->gaw));

        /* free page tables */
        dma_pte_free_pagetable(domain, 0, DOMAIN_MAX_PFN(domain->gaw));

        for_each_active_iommu(iommu, drhd)
                if (test_bit(iommu->seq_id, domain->iommu_bmp))
                        iommu_detach_domain(domain, iommu);

        free_domain_mem(domain);
}

static int domain_context_mapping_one(struct dmar_domain *domain, int segment,
                                 u8 bus, u8 devfn, int translation)
{
        struct context_entry *context;
        unsigned long flags;
        struct intel_iommu *iommu;
        struct dma_pte *pgd;
        unsigned long num;
        unsigned long ndomains;
        int id;
        int agaw;
        struct device_domain_info *info = NULL;

        pr_debug("Set context mapping for %02x:%02x.%d\n",
                bus, PCI_SLOT(devfn), PCI_FUNC(devfn));

        BUG_ON(!domain->pgd);
        BUG_ON(translation != CONTEXT_TT_PASS_THROUGH &&
               translation != CONTEXT_TT_MULTI_LEVEL);

        iommu = device_to_iommu(segment, bus, devfn);
        if (!iommu)
                return -ENODEV;

        context = device_to_context_entry(iommu, bus, devfn);
        if (!context)
                return -ENOMEM;
        spin_lock_irqsave(&iommu->lock, flags);
        if (context_present(context)) {
                spin_unlock_irqrestore(&iommu->lock, flags);
                return 0;
        }

        id = domain->id;
        pgd = domain->pgd;

        if (domain->flags & DOMAIN_FLAG_VIRTUAL_MACHINE ||
            domain->flags & DOMAIN_FLAG_STATIC_IDENTITY) {
                int found = 0;

                /* find an available domain id for this device in iommu */
                ndomains = cap_ndoms(iommu->cap);
                for_each_set_bit(num, iommu->domain_ids, ndomains) {
                        if (iommu->domains[num] == domain) {
                                id = num;
                                found = 1;
                                break;
                        }
                }

                if (found == 0) {
                        num = find_first_zero_bit(iommu->domain_ids, ndomains);
                        if (num >= ndomains) {
                                spin_unlock_irqrestore(&iommu->lock, flags);
                                printk(KERN_ERR "IOMMU: no free domain ids\n");
                                return -EFAULT;
                        }

                        set_bit(num, iommu->domain_ids);
                        iommu->domains[num] = domain;
                        id = num;
                }

                /* Skip top levels of page tables for
                 * iommu which has less agaw than default.
                 * Unnecessary for PT mode.
                 */
                if (translation != CONTEXT_TT_PASS_THROUGH) {
                        for (agaw = domain->agaw; agaw != iommu->agaw; agaw--) {
                                pgd = phys_to_virt(dma_pte_addr(pgd));
                                if (!dma_pte_present(pgd)) {
                                        spin_unlock_irqrestore(&iommu->lock, flags);
                                        return -ENOMEM;
                                }
                        }
                }
        }

        context_set_domain_id(context, id);

        if (translation != CONTEXT_TT_PASS_THROUGH) {
                info = iommu_support_dev_iotlb(domain, segment, bus, devfn);
                translation = info ? CONTEXT_TT_DEV_IOTLB :
                                     CONTEXT_TT_MULTI_LEVEL;
        }
        /*
         * In pass through mode, AW must be programmed to indicate the largest
         * AGAW value supported by hardware. And ASR is ignored by hardware.
         */
        if (unlikely(translation == CONTEXT_TT_PASS_THROUGH))
                context_set_address_width(context, iommu->msagaw);
        else {
                context_set_address_root(context, virt_to_phys(pgd));
                context_set_address_width(context, iommu->agaw);
        }

        context_set_translation_type(context, translation);
        context_set_fault_enable(context);
        context_set_present(context);
        domain_flush_cache(domain, context, sizeof(*context));

        /*
         * It's a non-present to present mapping. If hardware doesn't cache
         * non-present entry we only need to flush the write-buffer. If the
         * _does_ cache non-present entries, then it does so in the special
         * domain #0, which we have to flush:
         */
        if (cap_caching_mode(iommu->cap)) {
                iommu->flush.flush_context(iommu, 0,
                                           (((u16)bus) << 8) | devfn,
                                           DMA_CCMD_MASK_NOBIT,
                                           DMA_CCMD_DEVICE_INVL);
                iommu->flush.flush_iotlb(iommu, domain->id, 0, 0, DMA_TLB_DSI_FLUSH);
        } else {
                iommu_flush_write_buffer(iommu);
        }
        iommu_enable_dev_iotlb(info);
        spin_unlock_irqrestore(&iommu->lock, flags);

        spin_lock_irqsave(&domain->iommu_lock, flags);
        if (!test_and_set_bit(iommu->seq_id, domain->iommu_bmp)) {
                domain->iommu_count++;
                if (domain->iommu_count == 1)
                        domain->nid = iommu->node;
                domain_update_iommu_cap(domain);
        }
        spin_unlock_irqrestore(&domain->iommu_lock, flags);
        return 0;
}

static int
domain_context_mapping(struct dmar_domain *domain, struct pci_dev *pdev,
                        int translation)
{
        int ret;
        struct pci_dev *tmp, *parent;

        ret = domain_context_mapping_one(domain, pci_domain_nr(pdev->bus),
                                         pdev->bus->number, pdev->devfn,
                                         translation);
        if (ret)
                return ret;

        /* dependent device mapping */
        tmp = pci_find_upstream_pcie_bridge(pdev);
        if (!tmp)
                return 0;
        /* Secondary interface's bus number and devfn 0 */
        parent = pdev->bus->self;
        while (parent != tmp) {
                ret = domain_context_mapping_one(domain,
                                                 pci_domain_nr(parent->bus),
                                                 parent->bus->number,
                                                 parent->devfn, translation);
                if (ret)
                        return ret;
                parent = parent->bus->self;
        }
        if (pci_is_pcie(tmp)) /* this is a PCIe-to-PCI bridge */
                return domain_context_mapping_one(domain,
                                        pci_domain_nr(tmp->subordinate),
                                        tmp->subordinate->number, 0,
                                        translation);
        else /* this is a legacy PCI bridge */
                return domain_context_mapping_one(domain,
                                                  pci_domain_nr(tmp->bus),
                                                  tmp->bus->number,
                                                  tmp->devfn,
                                                  translation);
}

static int domain_context_mapped(struct pci_dev *pdev)
{
        int ret;
        struct pci_dev *tmp, *parent;
        struct intel_iommu *iommu;

        iommu = device_to_iommu(pci_domain_nr(pdev->bus), pdev->bus->number,
                                pdev->devfn);
        if (!iommu)
                return -ENODEV;

        ret = device_context_mapped(iommu, pdev->bus->number, pdev->devfn);
        if (!ret)
                return ret;
        /* dependent device mapping */
        tmp = pci_find_upstream_pcie_bridge(pdev);
        if (!tmp)
                return ret;
        /* Secondary interface's bus number and devfn 0 */
        parent = pdev->bus->self;
        while (parent != tmp) {
                ret = device_context_mapped(iommu, parent->bus->number,
                                            parent->devfn);
                if (!ret)
                        return ret;
                parent = parent->bus->self;
        }
        if (pci_is_pcie(tmp))
                return device_context_mapped(iommu, tmp->subordinate->number,
                                             0);
        else
                return device_context_mapped(iommu, tmp->bus->number,
                                             tmp->devfn);
}

/* Returns a number of VTD pages, but aligned to MM page size */
static inline unsigned long aligned_nrpages(unsigned long host_addr,
                                            size_t size)
{
        host_addr &= ~PAGE_MASK;
        return PAGE_ALIGN(host_addr + size) >> VTD_PAGE_SHIFT;
}

/* Return largest possible superpage level for a given mapping */
static inline int hardware_largepage_caps(struct dmar_domain *domain,
                                          unsigned long iov_pfn,
                                          unsigned long phy_pfn,
                                          unsigned long pages)
{
        int support, level = 1;
        unsigned long pfnmerge;

        support = domain->iommu_superpage;

        /* To use a large page, the virtual *and* physical addresses
           must be aligned to 2MiB/1GiB/etc. Lower bits set in either
           of them will mean we have to use smaller pages. So just
           merge them and check both at once. */
        pfnmerge = iov_pfn | phy_pfn;

        while (support && !(pfnmerge & ~VTD_STRIDE_MASK)) {
                pages >>= VTD_STRIDE_SHIFT;
                if (!pages)
                        break;
                pfnmerge >>= VTD_STRIDE_SHIFT;
                level++;
                support--;
        }
        return level;
}

static int __domain_mapping(struct dmar_domain *domain, unsigned long iov_pfn,
                            struct scatterlist *sg, unsigned long phys_pfn,
                            unsigned long nr_pages, int prot)
{
        struct dma_pte *first_pte = NULL, *pte = NULL;
        phys_addr_t uninitialized_var(pteval);
        int addr_width = agaw_to_width(domain->agaw) - VTD_PAGE_SHIFT;
        unsigned long sg_res;
        unsigned int largepage_lvl = 0;
        unsigned long lvl_pages = 0;

        BUG_ON(addr_width < BITS_PER_LONG && (iov_pfn + nr_pages - 1) >> addr_width);

        if ((prot & (DMA_PTE_READ|DMA_PTE_WRITE)) == 0)
                return -EINVAL;

        prot &= DMA_PTE_READ | DMA_PTE_WRITE | DMA_PTE_SNP;

        if (sg)
                sg_res = 0;
        else {
                sg_res = nr_pages + 1;
                pteval = ((phys_addr_t)phys_pfn << VTD_PAGE_SHIFT) | prot;
        }

        while (nr_pages > 0) {
                uint64_t tmp;

                if (!sg_res) {
                        sg_res = aligned_nrpages(sg->offset, sg->length);
                        sg->dma_address = ((dma_addr_t)iov_pfn << VTD_PAGE_SHIFT) + sg->offset;
                        sg->dma_length = sg->length;
                        pteval = page_to_phys(sg_page(sg)) | prot;
                        phys_pfn = pteval >> VTD_PAGE_SHIFT;
                }

                if (!pte) {
                        largepage_lvl = hardware_largepage_caps(domain, iov_pfn, phys_pfn, sg_res);

                        first_pte = pte = pfn_to_dma_pte(domain, iov_pfn, largepage_lvl);
                        if (!pte)
                                return -ENOMEM;
                        /* It is large page*/
                        if (largepage_lvl > 1) {
                                pteval |= DMA_PTE_LARGE_PAGE;
                                /* Ensure that old small page tables are removed to make room
                                   for superpage, if they exist. */
                                dma_pte_clear_range(domain, iov_pfn,
                                                    iov_pfn + lvl_to_nr_pages(largepage_lvl) - 1);
                                dma_pte_free_pagetable(domain, iov_pfn,
                                                       iov_pfn + lvl_to_nr_pages(largepage_lvl) - 1);
                        } else {
                                pteval &= ~(uint64_t)DMA_PTE_LARGE_PAGE;
                        }

                }
                /* We don't need lock here, nobody else
                 * touches the iova range
                 */
                tmp = cmpxchg64_local(&pte->val, 0ULL, pteval);
                if (tmp) {
                        static int dumps = 5;
                        printk(KERN_CRIT "ERROR: DMA PTE for vPFN 0x%lx already set (to %llx not %llx)\n",
                               iov_pfn, tmp, (unsigned long long)pteval);
                        if (dumps) {
                                dumps--;
                                debug_dma_dump_mappings(NULL);
                        }
                        WARN_ON(1);
                }

                lvl_pages = lvl_to_nr_pages(largepage_lvl);

                BUG_ON(nr_pages < lvl_pages);
                BUG_ON(sg_res < lvl_pages);

                nr_pages -= lvl_pages;
                iov_pfn += lvl_pages;
                phys_pfn += lvl_pages;
                pteval += lvl_pages * VTD_PAGE_SIZE;
                sg_res -= lvl_pages;

                /* If the next PTE would be the first in a new page, then we
                   need to flush the cache on the entries we've just written.
                   And then we'll need to recalculate 'pte', so clear it and
                   let it get set again in the if (!pte) block above.

                   If we're done (!nr_pages) we need to flush the cache too.

                   Also if we've been setting superpages, we may need to
                   recalculate 'pte' and switch back to smaller pages for the
                   end of the mapping, if the trailing size is not enough to
                   use another superpage (i.e. sg_res < lvl_pages). */
                pte++;
                if (!nr_pages || first_pte_in_page(pte) ||
                    (largepage_lvl > 1 && sg_res < lvl_pages)) {
                        domain_flush_cache(domain, first_pte,
                                           (void *)pte - (void *)first_pte);
                        pte = NULL;
                }

                if (!sg_res && nr_pages)
                        sg = sg_next(sg);
        }
        return 0;
}

static inline int domain_sg_mapping(struct dmar_domain *domain, unsigned long iov_pfn,
                                    struct scatterlist *sg, unsigned long nr_pages,
                                    int prot)
{
        return __domain_mapping(domain, iov_pfn, sg, 0, nr_pages, prot);
}

static inline int domain_pfn_mapping(struct dmar_domain *domain, unsigned long iov_pfn,
                                     unsigned long phys_pfn, unsigned long nr_pages,
                                     int prot)
{
        return __domain_mapping(domain, iov_pfn, NULL, phys_pfn, nr_pages, prot);
}

static void iommu_detach_dev(struct intel_iommu *iommu, u8 bus, u8 devfn)
{
        if (!iommu)
                return;

        clear_context_table(iommu, bus, devfn);
        iommu->flush.flush_context(iommu, 0, 0, 0,
                                           DMA_CCMD_GLOBAL_INVL);
        iommu->flush.flush_iotlb(iommu, 0, 0, 0, DMA_TLB_GLOBAL_FLUSH);
}

static inline void unlink_domain_info(struct device_domain_info *info)
{
        assert_spin_locked(&device_domain_lock);
        list_del(&info->link);
        list_del(&info->global);
        if (info->dev)
                info->dev->dev.archdata.iommu = NULL;
}

static void domain_remove_dev_info(struct dmar_domain *domain)
{
        struct device_domain_info *info;
        unsigned long flags;
        struct intel_iommu *iommu;

        spin_lock_irqsave(&device_domain_lock, flags);
        while (!list_empty(&domain->devices)) {
                info = list_entry(domain->devices.next,
                        struct device_domain_info, link);
                unlink_domain_info(info);
                spin_unlock_irqrestore(&device_domain_lock, flags);

                iommu_disable_dev_iotlb(info);
                iommu = device_to_iommu(info->segment, info->bus, info->devfn);
                iommu_detach_dev(iommu, info->bus, info->devfn);
                free_devinfo_mem(info);

                spin_lock_irqsave(&device_domain_lock, flags);
        }
        spin_unlock_irqrestore(&device_domain_lock, flags);
}

/*
 * find_domain
 * Note: we use struct pci_dev->dev.archdata.iommu stores the info
 */
static struct dmar_domain *
find_domain(struct pci_dev *pdev)
{
        struct device_domain_info *info;

        /* No lock here, assumes no domain exit in normal case */
        info = pdev->dev.archdata.iommu;
        if (info)
                return info->domain;
        return NULL;
}

/* domain is initialized */
static struct dmar_domain *get_domain_for_dev(struct pci_dev *pdev, int gaw)
{
        struct dmar_domain *domain, *found = NULL;
        struct intel_iommu *iommu;
        struct dmar_drhd_unit *drhd;
        struct device_domain_info *info, *tmp;
        struct pci_dev *dev_tmp;
        unsigned long flags;
        int bus = 0, devfn = 0;
        int segment;
        int ret;

        domain = find_domain(pdev);
        if (domain)
                return domain;

        segment = pci_domain_nr(pdev->bus);

        dev_tmp = pci_find_upstream_pcie_bridge(pdev);
        if (dev_tmp) {
                if (pci_is_pcie(dev_tmp)) {
                        bus = dev_tmp->subordinate->number;
                        devfn = 0;
                } else {
                        bus = dev_tmp->bus->number;
                        devfn = dev_tmp->devfn;
                }
                spin_lock_irqsave(&device_domain_lock, flags);
                list_for_each_entry(info, &device_domain_list, global) {
                        if (info->segment == segment &&
                            info->bus == bus && info->devfn == devfn) {
                                found = info->domain;
                                break;

                        }
                }
                spin_unlock_irqrestore(&device_domain_lock, flags);
                /* pcie-pci bridge already has a domain, uses it */
                if (found) {
                        domain = found;
                        goto found_domain;
                }
        }

        domain = alloc_domain();
        if (!domain)
                goto error;

        /* Allocate new domain for the device */
        drhd = dmar_find_matched_drhd_unit(pdev);
        if (!drhd) {
                printk(KERN_ERR "IOMMU: can't find DMAR for device %s\n",
                        pci_name(pdev));
                free_domain_mem(domain);
                return NULL;
        }
        iommu = drhd->iommu;

        ret = iommu_attach_domain(domain, iommu);
        if (ret) {
                free_domain_mem(domain);
                goto error;
        }

        if (domain_init(domain, gaw)) {
                domain_exit(domain);
                goto error;
        }

        /* register pcie-to-pci device */
        if (dev_tmp) {
                info = alloc_devinfo_mem();
                if (!info) {
                        domain_exit(domain);
                        goto error;
                }
                info->segment = segment;
                info->bus = bus;
                info->devfn = devfn;
                info->dev = NULL;
                info->domain = domain;
                /* This domain is shared by devices under p2p bridge */
                domain->flags |= DOMAIN_FLAG_P2P_MULTIPLE_DEVICES;

                /* pcie-to-pci bridge already has a domain, uses it */
                found = NULL;
                spin_lock_irqsave(&device_domain_lock, flags);
                list_for_each_entry(tmp, &device_domain_list, global) {
                        if (tmp->segment == segment &&
                            tmp->bus == bus && tmp->devfn == devfn) {
                                found = tmp->domain;
                                break;
                        }
                }
                if (found) {
                        spin_unlock_irqrestore(&device_domain_lock, flags);
                        free_devinfo_mem(info);
                        domain_exit(domain);
                        domain = found;
                } else {
                        list_add(&info->link, &domain->devices);
                        list_add(&info->global, &device_domain_list);
                        spin_unlock_irqrestore(&device_domain_lock, flags);
                }
        }

found_domain:
        info = alloc_devinfo_mem();
        if (!info)
                goto error;
        info->segment = segment;
        info->bus = pdev->bus->number;
        info->devfn = pdev->devfn;
        info->dev = pdev;
        info->domain = domain;
        spin_lock_irqsave(&device_domain_lock, flags);
        /* somebody is fast */
        found = find_domain(pdev);
        if (found != NULL) {
                spin_unlock_irqrestore(&device_domain_lock, flags);
                if (found != domain) {
                        domain_exit(domain);
                        domain = found;
                }
                free_devinfo_mem(info);
                return domain;
        }
        list_add(&info->link, &domain->devices);
        list_add(&info->global, &device_domain_list);
        pdev->dev.archdata.iommu = info;
        spin_unlock_irqrestore(&device_domain_lock, flags);
        return domain;
error:
        /* recheck it here, maybe others set it */
        return find_domain(pdev);
}

static int iommu_identity_mapping;
#define IDENTMAP_ALL            1
#define IDENTMAP_GFX            2
#define IDENTMAP_AZALIA         4

static int iommu_domain_identity_map(struct dmar_domain *domain,
                                     unsigned long long start,
                                     unsigned long long end)
{
        unsigned long first_vpfn = start >> VTD_PAGE_SHIFT;
        unsigned long last_vpfn = end >> VTD_PAGE_SHIFT;

        if (!reserve_iova(&domain->iovad, dma_to_mm_pfn(first_vpfn),
                          dma_to_mm_pfn(last_vpfn))) {
                printk(KERN_ERR "IOMMU: reserve iova failed\n");
                return -ENOMEM;
        }

        pr_debug("Mapping reserved region %llx-%llx for domain %d\n",
                 start, end, domain->id);
        /*
         * RMRR range might have overlap with physical memory range,
         * clear it first
         */
        dma_pte_clear_range(domain, first_vpfn, last_vpfn);

        return domain_pfn_mapping(domain, first_vpfn, first_vpfn,
                                  last_vpfn - first_vpfn + 1,
                                  DMA_PTE_READ|DMA_PTE_WRITE);
}

static int iommu_prepare_identity_map(struct pci_dev *pdev,
                                      unsigned long long start,
                                      unsigned long long end)
{
        struct dmar_domain *domain;
        int ret;

        domain = get_domain_for_dev(pdev, DEFAULT_DOMAIN_ADDRESS_WIDTH);
        if (!domain)
                return -ENOMEM;

        /* For _hardware_ passthrough, don't bother. But for software
           passthrough, we do it anyway -- it may indicate a memory
           range which is reserved in E820, so which didn't get set
           up to start with in si_domain */
        if (domain == si_domain && hw_pass_through) {
                printk("Ignoring identity map for HW passthrough device %s [0x%Lx - 0x%Lx]\n",
                       pci_name(pdev), start, end);
                return 0;
        }

        printk(KERN_INFO
               "IOMMU: Setting identity map for device %s [0x%Lx - 0x%Lx]\n",
               pci_name(pdev), start, end);
        
        if (end < start) {
                WARN(1, "Your BIOS is broken; RMRR ends before it starts!\n"
                        "BIOS vendor: %s; Ver: %s; Product Version: %s\n",
                        dmi_get_system_info(DMI_BIOS_VENDOR),
                        dmi_get_system_info(DMI_BIOS_VERSION),
                     dmi_get_system_info(DMI_PRODUCT_VERSION));
                ret = -EIO;
                goto error;
        }

        if (end >> agaw_to_width(domain->agaw)) {
                WARN(1, "Your BIOS is broken; RMRR exceeds permitted address width (%d bits)\n"
                     "BIOS vendor: %s; Ver: %s; Product Version: %s\n",
                     agaw_to_width(domain->agaw),
                     dmi_get_system_info(DMI_BIOS_VENDOR),
                     dmi_get_system_info(DMI_BIOS_VERSION),
                     dmi_get_system_info(DMI_PRODUCT_VERSION));
                ret = -EIO;
                goto error;
        }

        ret = iommu_domain_identity_map(domain, start, end);
        if (ret)
                goto error;

        /* context entry init */
        ret = domain_context_mapping(domain, pdev, CONTEXT_TT_MULTI_LEVEL);
        if (ret)
                goto error;

        return 0;

 error:
        domain_exit(domain);
        return ret;
}

static inline int iommu_prepare_rmrr_dev(struct dmar_rmrr_unit *rmrr,
        struct pci_dev *pdev)
{
        if (pdev->dev.archdata.iommu == DUMMY_DEVICE_DOMAIN_INFO)
                return 0;
        return iommu_prepare_identity_map(pdev, rmrr->base_address,
                rmrr->end_address);
}

#ifdef CONFIG_INTEL_IOMMU_FLOPPY_WA
static inline void iommu_prepare_isa(void)
{
        struct pci_dev *pdev;
        int ret;

        pdev = pci_get_class(PCI_CLASS_BRIDGE_ISA << 8, NULL);
        if (!pdev)
                return;

        printk(KERN_INFO "IOMMU: Prepare 0-16MiB unity mapping for LPC\n");
        ret = iommu_prepare_identity_map(pdev, 0, 16*1024*1024 - 1);

        if (ret)
                printk(KERN_ERR "IOMMU: Failed to create 0-16MiB identity map; "
                       "floppy might not work\n");

}
#else
static inline void iommu_prepare_isa(void)
{
        return;
}
#endif /* !CONFIG_INTEL_IOMMU_FLPY_WA */

static int md_domain_init(struct dmar_domain *domain, int guest_width);

static int __init si_domain_init(int hw)
{
        struct dmar_drhd_unit *drhd;
        struct intel_iommu *iommu;
        int nid, ret = 0;

        si_domain = alloc_domain();
        if (!si_domain)
                return -EFAULT;

        pr_debug("Identity mapping domain is domain %d\n", si_domain->id);

        for_each_active_iommu(iommu, drhd) {
                ret = iommu_attach_domain(si_domain, iommu);
                if (ret) {
                        domain_exit(si_domain);
                        return -EFAULT;
                }
        }

        if (md_domain_init(si_domain, DEFAULT_DOMAIN_ADDRESS_WIDTH)) {
                domain_exit(si_domain);
                return -EFAULT;
        }

        si_domain->flags = DOMAIN_FLAG_STATIC_IDENTITY;

        if (hw)
                return 0;

        for_each_online_node(nid) {
                unsigned long start_pfn, end_pfn;
                int i;

                for_each_mem_pfn_range(i, nid, &start_pfn, &end_pfn, NULL) {
                        ret = iommu_domain_identity_map(si_domain,
                                        PFN_PHYS(start_pfn), PFN_PHYS(end_pfn));
                        if (ret)
                                return ret;
                }
        }

        return 0;
}

static void domain_remove_one_dev_info(struct dmar_domain *domain,
                                          struct pci_dev *pdev);
static int identity_mapping(struct pci_dev *pdev)
{
        struct device_domain_info *info;

        if (likely(!iommu_identity_mapping))
                return 0;

        info = pdev->dev.archdata.iommu;
        if (info && info != DUMMY_DEVICE_DOMAIN_INFO)
                return (info->domain == si_domain);

        return 0;
}

static int domain_add_dev_info(struct dmar_domain *domain,
                               struct pci_dev *pdev,
                               int translation)
{
        struct device_domain_info *info;
        unsigned long flags;
        int ret;

        info = alloc_devinfo_mem();
        if (!info)
                return -ENOMEM;

        info->segment = pci_domain_nr(pdev->bus);
        info->bus = pdev->bus->number;
        info->devfn = pdev->devfn;
        info->dev = pdev;
        info->domain = domain;

        spin_lock_irqsave(&device_domain_lock, flags);
        list_add(&info->link, &domain->devices);
        list_add(&info->global, &device_domain_list);
        pdev->dev.archdata.iommu = info;
        spin_unlock_irqrestore(&device_domain_lock, flags);

        ret = domain_context_mapping(domain, pdev, translation);
        if (ret) {
                spin_lock_irqsave(&device_domain_lock, flags);
                unlink_domain_info(info);
                spin_unlock_irqrestore(&device_domain_lock, flags);
                free_devinfo_mem(info);
                return ret;
        }

        return 0;
}

static bool device_has_rmrr(struct pci_dev *dev)
{
        struct dmar_rmrr_unit *rmrr;
        int i;

        for_each_rmrr_units(rmrr) {
                for (i = 0; i < rmrr->devices_cnt; i++) {
                        /*
                         * Return TRUE if this RMRR contains the device that
                         * is passed in.
                         */
                        if (rmrr->devices[i] == dev)
                                return true;
                }
        }
        return false;
}

static int iommu_should_identity_map(struct pci_dev *pdev, int startup)
{

        /*
         * We want to prevent any device associated with an RMRR from
         * getting placed into the SI Domain. This is done because
         * problems exist when devices are moved in and out of domains
         * and their respective RMRR info is lost. We exempt USB devices
         * from this process due to their usage of RMRRs that are known
         * to not be needed after BIOS hand-off to OS.
         */
        if (device_has_rmrr(pdev) &&
            (pdev->class >> 8) != PCI_CLASS_SERIAL_USB)
                return 0;

        if ((iommu_identity_mapping & IDENTMAP_AZALIA) && IS_AZALIA(pdev))
                return 1;

        if ((iommu_identity_mapping & IDENTMAP_GFX) && IS_GFX_DEVICE(pdev))
                return 1;

        if (!(iommu_identity_mapping & IDENTMAP_ALL))
                return 0;

        /*
         * We want to start off with all devices in the 1:1 domain, and
         * take them out later if we find they can't access all of memory.
         *
         * However, we can't do this for PCI devices behind bridges,
         * because all PCI devices behind the same bridge will end up
         * with the same source-id on their transactions.
         *
         * Practically speaking, we can't change things around for these
         * devices at run-time, because we can't be sure there'll be no
         * DMA transactions in flight for any of their siblings.
         * 
         * So PCI devices (unless they're on the root bus) as well as
         * their parent PCI-PCI or PCIe-PCI bridges must be left _out_ of
         * the 1:1 domain, just in _case_ one of their siblings turns out
         * not to be able to map all of memory.
         */
        if (!pci_is_pcie(pdev)) {
                if (!pci_is_root_bus(pdev->bus))
                        return 0;
                if (pdev->class >> 8 == PCI_CLASS_BRIDGE_PCI)
                        return 0;
        } else if (pci_pcie_type(pdev) == PCI_EXP_TYPE_PCI_BRIDGE)
                return 0;

        /* 
         * At boot time, we don't yet know if devices will be 64-bit capable.
         * Assume that they will -- if they turn out not to be, then we can 
         * take them out of the 1:1 domain later.
         */
        if (!startup) {
                /*
                 * If the device's dma_mask is less than the system's memory
                 * size then this is not a candidate for identity mapping.
                 */
                u64 dma_mask = pdev->dma_mask;

                if (pdev->dev.coherent_dma_mask &&
                    pdev->dev.coherent_dma_mask < dma_mask)
                        dma_mask = pdev->dev.coherent_dma_mask;

                return dma_mask >= dma_get_required_mask(&pdev->dev);
        }

        return 1;
}

static int __init iommu_prepare_static_identity_mapping(int hw)
{
        struct pci_dev *pdev = NULL;
        int ret;

        ret = si_domain_init(hw);
        if (ret)
                return -EFAULT;

        for_each_pci_dev(pdev) {
                if (iommu_should_identity_map(pdev, 1)) {
                        ret = domain_add_dev_info(si_domain, pdev,
                                             hw ? CONTEXT_TT_PASS_THROUGH :
                                                  CONTEXT_TT_MULTI_LEVEL);
                        if (ret) {
                                /* device not associated with an iommu */
                                if (ret == -ENODEV)
                                        continue;
                                return ret;
                        }
                        pr_info("IOMMU: %s identity mapping for device %s\n",
                                hw ? "hardware" : "software", pci_name(pdev));
                }
        }

        return 0;
}

static int __init init_dmars(void)
{
        struct dmar_drhd_unit *drhd;
        struct dmar_rmrr_unit *rmrr;
        struct pci_dev *pdev;
        struct intel_iommu *iommu;
        int i, ret;

        /*
         * for each drhd
         *    allocate root
         *    initialize and program root entry to not present
         * endfor
         */
        for_each_drhd_unit(drhd) {
                /*
                 * lock not needed as this is only incremented in the single
                 * threaded kernel __init code path all other access are read
                 * only
                 */
                if (g_num_of_iommus < IOMMU_UNITS_SUPPORTED) {
                        g_num_of_iommus++;
                        continue;
                }
                printk_once(KERN_ERR "intel-iommu: exceeded %d IOMMUs\n",
                          IOMMU_UNITS_SUPPORTED);
        }

        g_iommus = kcalloc(g_num_of_iommus, sizeof(struct intel_iommu *),
                        GFP_KERNEL);
        if (!g_iommus) {
                printk(KERN_ERR "Allocating global iommu array failed\n");
                ret = -ENOMEM;
                goto error;
        }

        deferred_flush = kzalloc(g_num_of_iommus *
                sizeof(struct deferred_flush_tables), GFP_KERNEL);
        if (!deferred_flush) {
                ret = -ENOMEM;
                goto error;
        }

        for_each_drhd_unit(drhd) {
                if (drhd->ignored)
                        continue;

                iommu = drhd->iommu;
                g_iommus[iommu->seq_id] = iommu;

                ret = iommu_init_domains(iommu);
                if (ret)
                        goto error;

                /*
                 * TBD:
                 * we could share the same root & context tables
                 * among all IOMMU's. Need to Split it later.
                 */
                ret = iommu_alloc_root_entry(iommu);
                if (ret) {
                        printk(KERN_ERR "IOMMU: allocate root entry failed\n");
                        goto error;
                }
                if (!ecap_pass_through(iommu->ecap))
                        hw_pass_through = 0;
        }

        /*
         * Start from the sane iommu hardware state.
         */
        for_each_drhd_unit(drhd) {
                if (drhd->ignored)
                        continue;

                iommu = drhd->iommu;

                /*
                 * If the queued invalidation is already initialized by us
                 * (for example, while enabling interrupt-remapping) then
                 * we got the things already rolling from a sane state.
                 */
                if (iommu->qi)
                        continue;

                /*
                 * Clear any previous faults.
                 */
                dmar_fault(-1, iommu);
                /*
                 * Disable queued invalidation if supported and already enabled
                 * before OS handover.
                 */
                dmar_disable_qi(iommu);
        }

        for_each_drhd_unit(drhd) {
                if (drhd->ignored)
                        continue;

                iommu = drhd->iommu;

                if (dmar_enable_qi(iommu)) {
                        /*
                         * Queued Invalidate not enabled, use Register Based
                         * Invalidate
                         */
                        iommu->flush.flush_context = __iommu_flush_context;
                        iommu->flush.flush_iotlb = __iommu_flush_iotlb;
                        printk(KERN_INFO "IOMMU %d 0x%Lx: using Register based "
                               "invalidation\n",
                                iommu->seq_id,
                               (unsigned long long)drhd->reg_base_addr);
                } else {
                        iommu->flush.flush_context = qi_flush_context;
                        iommu->flush.flush_iotlb = qi_flush_iotlb;
                        printk(KERN_INFO "IOMMU %d 0x%Lx: using Queued "
                               "invalidation\n",
                                iommu->seq_id,
                               (unsigned long long)drhd->reg_base_addr);
                }
        }

        if (iommu_pass_through)
                iommu_identity_mapping |= IDENTMAP_ALL;

#ifdef CONFIG_INTEL_IOMMU_BROKEN_GFX_WA
        iommu_identity_mapping |= IDENTMAP_GFX;
#endif

        check_tylersburg_isoch();

        /*
         * If pass through is not set or not enabled, setup context entries for
         * identity mappings for rmrr, gfx, and isa and may fall back to static
         * identity mapping if iommu_identity_mapping is set.
         */
        if (iommu_identity_mapping) {
                ret = iommu_prepare_static_identity_mapping(hw_pass_through);
                if (ret) {
                        printk(KERN_CRIT "Failed to setup IOMMU pass-through\n");
                        goto error;
                }
        }
        /*
         * For each rmrr
         *   for each dev attached to rmrr
         *   do
         *     locate drhd for dev, alloc domain for dev
         *     allocate free domain
         *     allocate page table entries for rmrr
         *     if context not allocated for bus
         *           allocate and init context
         *           set present in root table for this bus
         *     init context with domain, translation etc
         *    endfor
         * endfor
         */
        printk(KERN_INFO "IOMMU: Setting RMRR:\n");
        for_each_rmrr_units(rmrr) {
                for (i = 0; i < rmrr->devices_cnt; i++) {
                        pdev = rmrr->devices[i];
                        /*
                         * some BIOS lists non-exist devices in DMAR
                         * table.
                         */
                        if (!pdev)
                                continue;
                        ret = iommu_prepare_rmrr_dev(rmrr, pdev);
                        if (ret)
                                printk(KERN_ERR
                                       "IOMMU: mapping reserved region failed\n");
                }
        }

        iommu_prepare_isa();

        /*
         * for each drhd
         *   enable fault log
         *   global invalidate context cache
         *   global invalidate iotlb
         *   enable translation
         */
        for_each_drhd_unit(drhd) {
                if (drhd->ignored) {
                        /*
                         * we always have to disable PMRs or DMA may fail on
                         * this device
                         */
                        if (force_on)
                                iommu_disable_protect_mem_regions(drhd->iommu);
                        continue;
                }
                iommu = drhd->iommu;

                iommu_flush_write_buffer(iommu);

                ret = dmar_set_interrupt(iommu);
                if (ret)
                        goto error;

                iommu_set_root_entry(iommu);

                iommu->flush.flush_context(iommu, 0, 0, 0, DMA_CCMD_GLOBAL_INVL);
                iommu->flush.flush_iotlb(iommu, 0, 0, 0, DMA_TLB_GLOBAL_FLUSH);

                ret = iommu_enable_translation(iommu);
                if (ret)
                        goto error;

                iommu_disable_protect_mem_regions(iommu);
        }

        return 0;
error:
        for_each_drhd_unit(drhd) {
                if (drhd->ignored)
                        continue;
                iommu = drhd->iommu;
                free_iommu(iommu);
        }
        kfree(g_iommus);
        return ret;
}

/* This takes a number of _MM_ pages, not VTD pages */
static struct iova *intel_alloc_iova(struct device *dev,
                                     struct dmar_domain *domain,
                                     unsigned long nrpages, uint64_t dma_mask)
{
        struct pci_dev *pdev = to_pci_dev(dev);
        struct iova *iova = NULL;

        /* Restrict dma_mask to the width that the iommu can handle */
        dma_mask = min_t(uint64_t, DOMAIN_MAX_ADDR(domain->gaw), dma_mask);

        if (!dmar_forcedac && dma_mask > DMA_BIT_MASK(32)) {
                /*
                 * First try to allocate an io virtual address in
                 * DMA_BIT_MASK(32) and if that fails then try allocating
                 * from higher range
                 */
                iova = alloc_iova(&domain->iovad, nrpages,
                                  IOVA_PFN(DMA_BIT_MASK(32)), 1);
                if (iova)
                        return iova;
        }
        iova = alloc_iova(&domain->iovad, nrpages, IOVA_PFN(dma_mask), 1);
        if (unlikely(!iova)) {
                printk(KERN_ERR "Allocating %ld-page iova for %s failed",
                       nrpages, pci_name(pdev));
                return NULL;
        }

        return iova;
}

static struct dmar_domain *__get_valid_domain_for_dev(struct pci_dev *pdev)
{
        struct dmar_domain *domain;
        int ret;

        domain = get_domain_for_dev(pdev,
                        DEFAULT_DOMAIN_ADDRESS_WIDTH);
        if (!domain) {
                printk(KERN_ERR
                        "Allocating domain for %s failed", pci_name(pdev));
                return NULL;
        }

        /* make sure context mapping is ok */
        if (unlikely(!domain_context_mapped(pdev))) {
                ret = domain_context_mapping(domain, pdev,
                                             CONTEXT_TT_MULTI_LEVEL);
                if (ret) {
                        printk(KERN_ERR
                                "Domain context map for %s failed",
                                pci_name(pdev));
                        return NULL;
                }
        }

        return domain;
}

static inline struct dmar_domain *get_valid_domain_for_dev(struct pci_dev *dev)
{
        struct device_domain_info *info;

        /* No lock here, assumes no domain exit in normal case */
        info = dev->dev.archdata.iommu;
        if (likely(info))
                return info->domain;

        return __get_valid_domain_for_dev(dev);
}

static int iommu_dummy(struct pci_dev *pdev)
{
        return pdev->dev.archdata.iommu == DUMMY_DEVICE_DOMAIN_INFO;
}

/* Check if the pdev needs to go through non-identity map and unmap process.*/
static int iommu_no_mapping(struct device *dev)
{
        struct pci_dev *pdev;
        int found;

        if (unlikely(dev->bus != &pci_bus_type))
                return 1;

        pdev = to_pci_dev(dev);
        if (iommu_dummy(pdev))
                return 1;

        if (!iommu_identity_mapping)
                return 0;

        found = identity_mapping(pdev);
        if (found) {
                if (iommu_should_identity_map(pdev, 0))
                        return 1;
                else {
                        /*
                         * 32 bit DMA is removed from si_domain and fall back
                         * to non-identity mapping.
                         */
                        domain_remove_one_dev_info(si_domain, pdev);
                        printk(KERN_INFO "32bit %s uses non-identity mapping\n",
                               pci_name(pdev));
                        return 0;
                }
        } else {
                /*
                 * In case of a detached 64 bit DMA device from vm, the device
                 * is put into si_domain for identity mapping.
                 */
                if (iommu_should_identity_map(pdev, 0)) {
                        int ret;
                        ret = domain_add_dev_info(si_domain, pdev,
                                                  hw_pass_through ?
                                                  CONTEXT_TT_PASS_THROUGH :
                                                  CONTEXT_TT_MULTI_LEVEL);
                        if (!ret) {
                                printk(KERN_INFO "64bit %s uses identity mapping\n",
                                       pci_name(pdev));
                                return 1;
                        }
                }
        }

        return 0;
}

static dma_addr_t __intel_map_single(struct device *hwdev, phys_addr_t paddr,
                                     size_t size, int dir, u64 dma_mask)
{
        struct pci_dev *pdev = to_pci_dev(hwdev);
        struct dmar_domain *domain;
        phys_addr_t start_paddr;
        struct iova *iova;
        int prot = 0;
        int ret;
        struct intel_iommu *iommu;
        unsigned long paddr_pfn = paddr >> PAGE_SHIFT;

        BUG_ON(dir == DMA_NONE);

        if (iommu_no_mapping(hwdev))
                return paddr;

        domain = get_valid_domain_for_dev(pdev);
        if (!domain)
                return 0;

        iommu = domain_get_iommu(domain);
        size = aligned_nrpages(paddr, size);

        iova = intel_alloc_iova(hwdev, domain, dma_to_mm_pfn(size), dma_mask);
        if (!iova)
                goto error;

        /*
         * Check if DMAR supports zero-length reads on write only
         * mappings..
         */
        if (dir == DMA_TO_DEVICE || dir == DMA_BIDIRECTIONAL || \
                        !cap_zlr(iommu->cap))
                prot |= DMA_PTE_READ;
        if (dir == DMA_FROM_DEVICE || dir == DMA_BIDIRECTIONAL)
                prot |= DMA_PTE_WRITE;
        /*
         * paddr - (paddr + size) might be partial page, we should map the whole
         * page.  Note: if two part of one page are separately mapped, we
         * might have two guest_addr mapping to the same host paddr, but this
         * is not a big problem
         */
        ret = domain_pfn_mapping(domain, mm_to_dma_pfn(iova->pfn_lo),
                                 mm_to_dma_pfn(paddr_pfn), size, prot);
        if (ret)
                goto error;

        /* it's a non-present to present mapping. Only flush if caching mode */
        if (cap_caching_mode(iommu->cap))
                iommu_flush_iotlb_psi(iommu, domain->id, mm_to_dma_pfn(iova->pfn_lo), size, 1);
        else
                iommu_flush_write_buffer(iommu);

        start_paddr = (phys_addr_t)iova->pfn_lo << PAGE_SHIFT;
        start_paddr += paddr & ~PAGE_MASK;
        return start_paddr;

error:
        if (iova)
                __free_iova(&domain->iovad, iova);
        printk(KERN_ERR"Device %s request: %zx@%llx dir %d --- failed\n",
                pci_name(pdev), size, (unsigned long long)paddr, dir);
        return 0;
}

static dma_addr_t intel_map_page(struct device *dev, struct page *page,
                                 unsigned long offset, size_t size,
                                 enum dma_data_direction dir,
                                 struct dma_attrs *attrs)
{
        return __intel_map_single(dev, page_to_phys(page) + offset, size,
                                  dir, to_pci_dev(dev)->dma_mask);
}

static void flush_unmaps(void)
{
        int i, j;

        timer_on = 0;

        /* just flush them all */
        for (i = 0; i < g_num_of_iommus; i++) {
                struct intel_iommu *iommu = g_iommus[i];
                if (!iommu)
                        continue;

                if (!deferred_flush[i].next)
                        continue;

                /* In caching mode, global flushes turn emulation expensive */
                if (!cap_caching_mode(iommu->cap))
                        iommu->flush.flush_iotlb(iommu, 0, 0, 0,
                                         DMA_TLB_GLOBAL_FLUSH);
                for (j = 0; j < deferred_flush[i].next; j++) {
                        unsigned long mask;
                        struct iova *iova = deferred_flush[i].iova[j];
                        struct dmar_domain *domain = deferred_flush[i].domain[j];

                        /* On real hardware multiple invalidations are expensive */
                        if (cap_caching_mode(iommu->cap))
                                iommu_flush_iotlb_psi(iommu, domain->id,
                                iova->pfn_lo, iova->pfn_hi - iova->pfn_lo + 1, 0);
                        else {
                                mask = ilog2(mm_to_dma_pfn(iova->pfn_hi - iova->pfn_lo + 1));
                                iommu_flush_dev_iotlb(deferred_flush[i].domain[j],
                                                (uint64_t)iova->pfn_lo << PAGE_SHIFT, mask);
                        }
                        __free_iova(&deferred_flush[i].domain[j]->iovad, iova);
                }
                deferred_flush[i].next = 0;
        }

        list_size = 0;
}

static void flush_unmaps_timeout(unsigned long data)
{
        unsigned long flags;

        spin_lock_irqsave(&async_umap_flush_lock, flags);
        flush_unmaps();
        spin_unlock_irqrestore(&async_umap_flush_lock, flags);
}

static void add_unmap(struct dmar_domain *dom, struct iova *iova)
{
        unsigned long flags;
        int next, iommu_id;
        struct intel_iommu *iommu;

        spin_lock_irqsave(&async_umap_flush_lock, flags);
        if (list_size == HIGH_WATER_MARK)
                flush_unmaps();

        iommu = domain_get_iommu(dom);
        iommu_id = iommu->seq_id;

        next = deferred_flush[iommu_id].next;
        deferred_flush[iommu_id].domain[next] = dom;
        deferred_flush[iommu_id].iova[next] = iova;
        deferred_flush[iommu_id].next++;

        if (!timer_on) {
                mod_timer(&unmap_timer, jiffies + msecs_to_jiffies(10));
                timer_on = 1;
        }
        list_size++;
        spin_unlock_irqrestore(&async_umap_flush_lock, flags);
}

static void intel_unmap_page(struct device *dev, dma_addr_t dev_addr,
                             size_t size, enum dma_data_direction dir,
                             struct dma_attrs *attrs)
{
        struct pci_dev *pdev = to_pci_dev(dev);
        struct dmar_domain *domain;
        unsigned long start_pfn, last_pfn;
        struct iova *iova;
        struct intel_iommu *iommu;

        if (iommu_no_mapping(dev))
                return;

        domain = find_domain(pdev);
        BUG_ON(!domain);

        iommu = domain_get_iommu(domain);

        iova = find_iova(&domain->iovad, IOVA_PFN(dev_addr));
        if (WARN_ONCE(!iova, "Driver unmaps unmatched page at PFN %llx\n",
                      (unsigned long long)dev_addr))
                return;

        start_pfn = mm_to_dma_pfn(iova->pfn_lo);
        last_pfn = mm_to_dma_pfn(iova->pfn_hi + 1) - 1;

        pr_debug("Device %s unmapping: pfn %lx-%lx\n",
                 pci_name(pdev), start_pfn, last_pfn);

        /*  clear the whole page */
        dma_pte_clear_range(domain, start_pfn, last_pfn);

        /* free page tables */
        dma_pte_free_pagetable(domain, start_pfn, last_pfn);

        if (intel_iommu_strict) {
                iommu_flush_iotlb_psi(iommu, domain->id, start_pfn,
                                      last_pfn - start_pfn + 1, 0);
                /* free iova */
                __free_iova(&domain->iovad, iova);
        } else {
                add_unmap(domain, iova);
                /*
                 * queue up the release of the unmap to save the 1/6th of the
                 * cpu used up by the iotlb flush operation...
                 */
        }
}