intel-iommu: Use iommu_should_identity_map() at startup time too.

[safe/jmp/linux-2.6] / drivers / pci / intel-iommu.c

/*
 * 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/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/sysdev.h>
#include <asm/cacheflush.h>
#include <asm/iommu.h>
#include "pci.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 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_ADDR(gaw) ((((u64)1) << gaw) - 1)
#define DOMAIN_MAX_PFN(gaw)  ((((u64)1) << (gaw-VTD_PAGE_SHIFT)) - 1)

#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))


/* 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 int rwbf_quirk;

/*
 * 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, 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 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.
 */
struct dmar_domain *si_domain;

/* 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)

struct dmar_domain {
        int     id;                     /* domain id */
        unsigned long iommu_bmp;        /* 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 */
        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_DMAR_DEFAULT_ON
int dmar_disabled = 0;
#else
int dmar_disabled = 1;
#endif /*CONFIG_DMAR_DEFAULT_ON*/

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

#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;
                }

                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 *iommu_kmem_cache_alloc(struct kmem_cache *cachep)
{
        unsigned int flags;
        void *vaddr;

        /* trying to avoid low memory issues */
        flags = current->flags & PF_MEMALLOC;
        current->flags |= PF_MEMALLOC;
        vaddr = kmem_cache_alloc(cachep, GFP_ATOMIC);
        current->flags &= (~PF_MEMALLOC | flags);
        return vaddr;
}


static inline void *alloc_pgtable_page(void)
{
        unsigned int flags;
        void *vaddr;

        /* trying to avoid low memory issues */
        flags = current->flags & PF_MEMALLOC;
        current->flags |= PF_MEMALLOC;
        vaddr = (void *)get_zeroed_page(GFP_ATOMIC);
        current->flags &= (~PF_MEMALLOC | flags);
        return vaddr;
}

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

static inline void *alloc_domain_mem(void)
{
        return iommu_kmem_cache_alloc(iommu_domain_cache);
}

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

static inline void * alloc_devinfo_mem(void)
{
        return iommu_kmem_cache_alloc(iommu_devinfo_cache);
}

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

struct iova *alloc_iova_mem(void)
{
        return iommu_kmem_cache_alloc(iommu_iova_cache);
}

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


static inline int width_to_agaw(int width);

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;

        domain->iommu_coherency = 1;

        i = find_first_bit(&domain->iommu_bmp, g_num_of_iommus);
        for (; i < g_num_of_iommus; ) {
                if (!ecap_coherent(g_iommus[i]->ecap)) {
                        domain->iommu_coherency = 0;
                        break;
                }
                i = find_next_bit(&domain->iommu_bmp, g_num_of_iommus, i+1);
        }
}

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

        domain->iommu_snooping = 1;

        i = find_first_bit(&domain->iommu_bmp, g_num_of_iommus);
        for (; i < g_num_of_iommus; ) {
                if (!ecap_sc_support(g_iommus[i]->ecap)) {
                        domain->iommu_snooping = 0;
                        break;
                }
                i = find_next_bit(&domain->iommu_bmp, g_num_of_iommus, i+1);
        }
}

/* 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);
}

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->subordinate >= 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();
                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);
}

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

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 struct dma_pte *pfn_to_dma_pte(struct dmar_domain *domain,
                                      unsigned long pfn)
{
        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 (level == 1)
                        break;

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

                        tmp_page = alloc_pgtable_page();

                        if (!tmp_page)
                                return NULL;

                        domain_flush_cache(domain, tmp_page, VTD_PAGE_SIZE);
                        pteval = (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)
{
        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))
                        break;
                parent = phys_to_virt(dma_pte_addr(pte));
                total--;
        }
        return NULL;
}

/* clear last level pte, a tlb flush should be followed */
static void 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;
        struct dma_pte *first_pte, *pte;

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

        /* we don't need lock here; nobody else touches the iova range */
        while (start_pfn <= last_pfn) {
                first_pte = pte = dma_pfn_level_pte(domain, start_pfn, 1);
                if (!pte) {
                        start_pfn = align_to_level(start_pfn + 1, 2);
                        continue;
                }
                do { 
                        dma_clear_pte(pte);
                        start_pfn++;
                        pte++;
                } while (start_pfn <= last_pfn && !first_pte_in_page(pte));

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

/* 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;

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

        /* 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;

                while (tmp + level_size(level) - 1 <= last_pfn) {
                        first_pte = pte = dma_pfn_level_pte(domain, tmp, level);
                        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);
                        
                }
                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();
        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;

        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);

        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;

        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);

        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;

        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);

        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;

        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);

        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)
{
        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, domain ID 0 is reserved for non-present to present
         * mapping flush. Device IOTLB doesn't need to be flushed in this case.
         */
        if (!cap_caching_mode(iommu->cap) || did)
                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;

        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);

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

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

        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);

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

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

        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);

        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("Number of Domains supportd <%ld>\n", ndomains);
        nlongs = BITS_TO_LONGS(ndomains);

        /* 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");
                kfree(iommu->domain_ids);
                return -ENOMEM;
        }

        spin_lock_init(&iommu->lock);

        /*
         * 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;

        i = find_first_bit(iommu->domain_ids, cap_ndoms(iommu->cap));
        for (; i < 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);

                i = find_next_bit(iommu->domain_ids,
                        cap_ndoms(iommu->cap), i+1);
        }

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

        if (iommu->irq) {
                set_irq_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;

        memset(&domain->iommu_bmp, 0, sizeof(unsigned long));
        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);
        num = find_first_bit(iommu->domain_ids, ndomains);
        for (; num < ndomains; ) {
                if (iommu->domains[num] == domain) {
                        found = 1;
                        break;
                }
                num = find_next_bit(iommu->domain_ids,
                                    cap_ndoms(iommu->cap), num+1);
        }

        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_alloc_key;
static struct lock_class_key reserved_rbtree_key;

static void 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_alloc_lock,
                &reserved_alloc_key);
        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");

        /* 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");
                }
        }

}

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_count = 1;

        /* always allocate the top pgd */
        domain->pgd = (struct dma_pte *)alloc_pgtable_page();
        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;

        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);
                num = find_first_bit(iommu->domain_ids, ndomains);
                for (; num < ndomains; ) {
                        if (iommu->domains[num] == domain) {
                                id = num;
                                found = 1;
                                break;
                        }
                        num = find_next_bit(iommu->domain_ids,
                                            cap_ndoms(iommu->cap), num+1);
                }

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

                /* Skip top levels of page tables for
                 * iommu which has less agaw than default.
                 */
                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, 0, 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++;
                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 (tmp->is_pcie) /* 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 (tmp->is_pcie)
                return device_context_mapped(iommu, tmp->subordinate->number,
                                             0);
        else
                return device_context_mapped(iommu, tmp->bus->number,
                                             tmp->devfn);
}

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;

        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--) {
                uint64_t tmp;

                if (!sg_res) {
                        sg_res = (sg->offset + sg->length + VTD_PAGE_SIZE - 1) >> VTD_PAGE_SHIFT;
                        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;
                }
                if (!pte) {
                        first_pte = pte = pfn_to_dma_pte(domain, iov_pfn);
                        if (!pte)
                                return -ENOMEM;
                }
                /* 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);
                }
                pte++;
                if (!nr_pages || first_pte_in_page(pte)) {
                        domain_flush_cache(domain, first_pte,
                                           (void *)pte - (void *)first_pte);
                        pte = NULL;
                }
                iov_pfn++;
                pteval += VTD_PAGE_SIZE;
                sg_res--;
                if (!sg_res)
                        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 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);
                list_del(&info->link);
                list_del(&info->global);
                if (info->dev)
                        info->dev->dev.archdata.iommu = NULL;
                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 (dev_tmp->is_pcie) {
                        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));
                return NULL;
        }
        iommu = drhd->iommu;

        ret = iommu_attach_domain(domain, iommu);
        if (ret) {
                domain_exit(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) {
                        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;

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;

        printk(KERN_INFO
               "IOMMU: Setting identity map for device %s [0x%Lx - 0x%Lx]\n",
               pci_name(pdev), start, end);

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

        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 + 1);
}

#ifdef CONFIG_DMAR_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);

        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_DMAR_FLPY_WA */

/* Initialize each context entry as pass through.*/
static int __init init_context_pass_through(void)
{
        struct pci_dev *pdev = NULL;
        struct dmar_domain *domain;
        int ret;

        for_each_pci_dev(pdev) {
                domain = get_domain_for_dev(pdev, DEFAULT_DOMAIN_ADDRESS_WIDTH);
                ret = domain_context_mapping(domain, pdev,
                                             CONTEXT_TT_PASS_THROUGH);
                if (ret)
                        return ret;
        }
        return 0;
}

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

static int __init si_domain_work_fn(unsigned long start_pfn,
                                    unsigned long end_pfn, void *datax)
{
        int *ret = datax;

        *ret = iommu_domain_identity_map(si_domain,
                                         (uint64_t)start_pfn << PAGE_SHIFT,
                                         (uint64_t)end_pfn << PAGE_SHIFT);
        return *ret;

}

static int si_domain_init(void)
{
        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;

        for_each_online_node(nid) {
                work_with_active_regions(nid, si_domain_work_fn, &ret);
                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;


        list_for_each_entry(info, &si_domain->devices, link)
                if (info->dev == pdev)
                        return 1;
        return 0;
}

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

        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);

        return 0;
}

static int iommu_should_identity_map(struct pci_dev *pdev, int startup)
{
        if (iommu_identity_mapping == 2)
                return IS_GFX_DEVICE(pdev);

        if (!startup)
                return pdev->dma_mask > DMA_BIT_MASK(32);

        return 1;
}

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

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

        for_each_pci_dev(pdev) {
                if (iommu_should_identity_map(pdev, 1)) {
                        printk(KERN_INFO "IOMMU: identity mapping for device %s\n",
                               pci_name(pdev));

                        ret = domain_context_mapping(si_domain, pdev,
                                                     CONTEXT_TT_MULTI_LEVEL);
                        if (ret)
                                return ret;
                        ret = domain_add_dev_info(si_domain, pdev);
                        if (ret)
                                return ret;
                }
        }

        return 0;
}

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;
        int pass_through = 1;

        /*
         * In case pass through can not be enabled, iommu tries to use identity
         * mapping.
         */
        if (iommu_pass_through)
                iommu_identity_mapping = 1;

        /*
         * for each drhd
         *    allocate root
         *    initialize and program root entry to not present
         * endfor
         */
        for_each_drhd_unit(drhd) {
                g_num_of_iommus++;
                /*
                 * lock not needed as this is only incremented in the single
                 * threaded kernel __init code path all other access are read
                 * only
                 */
        }

        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) {
                kfree(g_iommus);
                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
                 * amoung 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))
                        pass_through = 0;
        }
        if (iommu_pass_through)
                if (!pass_through) {
                        printk(KERN_INFO
                               "Pass Through is not supported by hardware.\n");
                        iommu_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 0x%Lx: using Register based "
                               "invalidation\n",
                               (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 0x%Lx: using Queued "
                               "invalidation\n",
                               (unsigned long long)drhd->reg_base_addr);
                }
        }

        /*
         * If pass through is set and enabled, context entries of all pci
         * devices are intialized by pass through translation type.
         */
        if (iommu_pass_through) {
                ret = init_context_pass_through();
                if (ret) {
                        printk(KERN_ERR "IOMMU: Pass through init failed.\n");
                        iommu_pass_through = 0;
                }
        }

        /*
         * 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_pass_through) {
#ifdef CONFIG_DMAR_BROKEN_GFX_WA
                if (!iommu_identity_mapping)
                        iommu_identity_mapping = 2;
#endif
                if (iommu_identity_mapping)
                        iommu_prepare_static_identity_mapping();
                /*
                 * 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)
                        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);
                iommu_disable_protect_mem_regions(iommu);

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

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

/* 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;
}

/* 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 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);
                        if (ret)
                                return 0;
                        ret = domain_context_mapping(si_domain, pdev, 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;

        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),
                                pdev->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),
                                 paddr >> VTD_PAGE_SHIFT, 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, 0, mm_to_dma_pfn(iova->pfn_lo), size);
        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;

                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];

                        mask = (iova->pfn_hi - iova->pfn_lo + 1) << PAGE_SHIFT;
                        mask = ilog2(mask >> VTD_PAGE_SHIFT);
                        iommu_flush_dev_iotlb(deferred_flush[i].domain[j],
                                        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);
                /* 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...
                 */
        }
}

static void intel_unmap_single(struct device *dev, dma_addr_t dev_addr, size_t size,
                               int dir)
{
        intel_unmap_page(dev, dev_addr, size, dir, NULL);
}

static void *intel_alloc_coherent(struct device *hwdev, size_t size,
                                  dma_addr_t *dma_handle, gfp_t flags)
{
        void *vaddr;
        int order;

        size = PAGE_ALIGN(size);
        order = get_order(size);
        flags &= ~(GFP_DMA | GFP_DMA32);

        vaddr = (void *)__get_free_pages(flags, order);
        if (!vaddr)
                return NULL;
        memset(vaddr, 0, size);

        *dma_handle = __intel_map_single(hwdev, virt_to_bus(vaddr), size,
                                         DMA_BIDIRECTIONAL,
                                         hwdev->coherent_dma_mask);
        if (*dma_handle)
                return vaddr;
        free_pages((unsigned long)vaddr, order);
        return NULL;
}

static void intel_free_coherent(struct device *hwdev, size_t size, void *vaddr,
                                dma_addr_t dma_handle)
{
        int order;

        size = PAGE_ALIGN(size);
        order = get_order(size);

        intel_unmap_single(hwdev, dma_handle, size, DMA_BIDIRECTIONAL);
        free_pages((unsigned long)vaddr, order);
}

static void intel_unmap_sg(struct device *hwdev, struct scatterlist *sglist,
                           int nelems, enum dma_data_direction dir,
                           struct dma_attrs *attrs)
{
        struct pci_dev *pdev = to_pci_dev(hwdev);
        struct dmar_domain *domain;
        unsigned long start_pfn, last_pfn;
        struct iova *iova;
        struct intel_iommu *iommu;

        if (iommu_no_mapping(hwdev))
                return;

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

        iommu = domain_get_iommu(domain);

        iova = find_iova(&domain->iovad, IOVA_PFN(sglist[0].dma_address));
        if (WARN_ONCE(!iova, "Driver unmaps unmatched sglist at PFN %llx\n",
                      (unsigned long long)sglist[0].dma_address))
                return;

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

        /*  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);

        iommu_flush_iotlb_psi(iommu, domain->id, start_pfn,
                              (last_pfn - start_pfn + 1));

        /* free iova */
        __free_iova(&domain->iovad, iova);
}

static int intel_nontranslate_map_sg(struct device *hddev,
        struct scatterlist *sglist, int nelems, int dir)
{
        int i;
        struct scatterlist *sg;

        for_each_sg(sglist, sg, nelems, i) {
                BUG_ON(!sg_page(sg));
                sg->dma_address = page_to_phys(sg_page(sg)) + sg->offset;
                sg->dma_length = sg->length;
        }
        return nelems;
}

static int intel_map_sg(struct device *hwdev, struct scatterlist *sglist, int nelems,
                        enum dma_data_direction dir, struct dma_attrs *attrs)
{
        int i;
        struct pci_dev *pdev = to_pci_dev(hwdev);
        struct dmar_domain *domain;
        size_t size = 0;
        int prot = 0;
        size_t offset_pfn = 0;
        struct iova *iova = NULL;
        int ret;
        struct scatterlist *sg;
        unsigned long start_vpfn;
        struct intel_iommu *iommu;

        BUG_ON(dir == DMA_NONE);
        if (iommu_no_mapping(hwdev))
                return intel_nontranslate_map_sg(hwdev, sglist, nelems, dir);

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

        iommu = domain_get_iommu(domain);

        for_each_sg(sglist, sg, nelems, i)
                size += aligned_nrpages(sg->offset, sg->length);

        iova = intel_alloc_iova(hwdev, domain, dma_to_mm_pfn(size),
                                pdev->dma_mask);
        if (!iova) {
                sglist->dma_length = 0;
                return 0;
        }

        /*
         * 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;

        start_vpfn = mm_to_dma_pfn(iova->pfn_lo);

        ret = domain_sg_mapping(domain, start_vpfn, sglist, mm_to_dma_pfn(size), prot);
        if (unlikely(ret)) {
                /*  clear the page */
                dma_pte_clear_range(domain, start_vpfn,
                                    start_vpfn + size - 1);
                /* free page tables */
                dma_pte_free_pagetable(domain, start_vpfn,
                                       start_vpfn + size - 1);
                /* free iova */
                __free_iova(&domain->iovad, iova);
                return 0;
        }

        /* it's a non-present to present mapping. Only flush if caching mode */
        if (cap_caching_mode(iommu->cap))
                iommu_flush_iotlb_psi(iommu, 0, start_vpfn, offset_pfn);
        else
                iommu_flush_write_buffer(iommu);

        return nelems;
}

static int intel_mapping_error(struct device *dev, dma_addr_t dma_addr)
{
        return !dma_addr;
}

struct dma_map_ops intel_dma_ops = {
        .alloc_coherent = intel_alloc_coherent,
        .free_coherent = intel_free_coherent,
        .map_sg = intel_map_sg,
        .unmap_sg = intel_unmap_sg,
        .map_page = intel_map_page,
        .unmap_page = intel_unmap_page,
        .mapping_error = intel_mapping_error,
};

static inline int iommu_domain_cache_init(void)
{
        int ret = 0;

        iommu_domain_cache = kmem_cache_create("iommu_domain",
                                         sizeof(struct dmar_domain),
                                         0,
                                         SLAB_HWCACHE_ALIGN,

                                         NULL);
        if (!iommu_domain_cache) {
                printk(KERN_ERR "Couldn't create iommu_domain cache\n");
                ret = -ENOMEM;
        }

        return ret;
}

static inline int iommu_devinfo_cache_init(void)
{
        int ret = 0;

        iommu_devinfo_cache = kmem_cache_create("iommu_devinfo",
                                         sizeof(struct device_domain_info),
                                         0,
                                         SLAB_HWCACHE_ALIGN,
                                         NULL);
        if (!iommu_devinfo_cache) {
                printk(KERN_ERR "Couldn't create devinfo cache\n");
                ret = -ENOMEM;
        }

        return ret;
}

static inline int iommu_iova_cache_init(void)
{
        int ret = 0;

        iommu_iova_cache = kmem_cache_create("iommu_iova",
                                         sizeof(struct iova),
                                         0,
                                         SLAB_HWCACHE_ALIGN,
                                         NULL);
        if (!iommu_iova_cache) {
                printk(KERN_ERR "Couldn't create iova cache\n");
                ret = -ENOMEM;
        }

        return ret;
}

static int __init iommu_init_mempool(void)
{
        int ret;
        ret = iommu_iova_cache_init();
        if (ret)
                return ret;

        ret = iommu_domain_cache_init();
        if (ret)
                goto domain_error;

        ret = iommu_devinfo_cache_init();
        if (!ret)
                return ret;

        kmem_cache_destroy(iommu_domain_cache);
domain_error:
        kmem_cache_destroy(iommu_iova_cache);

        return -ENOMEM;
}

static void __init iommu_exit_mempool(void)
{
        kmem_cache_destroy(iommu_devinfo_cache);
        kmem_cache_destroy(iommu_domain_cache);
        kmem_cache_destroy(iommu_iova_cache);

}

static void __init init_no_remapping_devices(void)
{
        struct dmar_drhd_unit *drhd;

        for_each_drhd_unit(drhd) {
                if (!drhd->include_all) {
                        int i;
                        for (i = 0; i < drhd->devices_cnt; i++)
                                if (drhd->devices[i] != NULL)
                                        break;
                        /* ignore DMAR unit if no pci devices exist */
                        if (i == drhd->devices_cnt)
                                drhd->ignored = 1;
                }
        }

        if (dmar_map_gfx)
                return;

        for_each_drhd_unit(drhd) {
                int i;
                if (drhd->ignored || drhd->include_all)
                        continue;

                for (i = 0; i < drhd->devices_cnt; i++)
                        if (drhd->devices[i] &&
                                !IS_GFX_DEVICE(drhd->devices[i]))
                                break;

                if (i < drhd->devices_cnt)
                        continue;

                /* bypass IOMMU if it is just for gfx devices */
                drhd->ignored = 1;
                for (i = 0; i < drhd->devices_cnt; i++) {
                        if (!drhd->devices[i])
                                continue;
                        drhd->devices[i]->dev.archdata.iommu = DUMMY_DEVICE_DOMAIN_INFO;
                }
        }
}

#ifdef CONFIG_SUSPEND
static int init_iommu_hw(void)
{
        struct dmar_drhd_unit *drhd;
        struct intel_iommu *iommu = NULL;

        for_each_active_iommu(iommu, drhd)
                if (iommu->qi)
                        dmar_reenable_qi(iommu);

        for_each_active_iommu(iommu, drhd) {
                iommu_flush_write_buffer(iommu);

                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);
                iommu_disable_protect_mem_regions(iommu);
                iommu_enable_translation(iommu);
        }

        return 0;
}

static void iommu_flush_all(void)
{
        struct dmar_drhd_unit *drhd;
        struct intel_iommu *iommu;

        for_each_active_iommu(iommu, drhd) {
                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 int iommu_suspend(struct sys_device *dev, pm_message_t state)
{
        struct dmar_drhd_unit *drhd;
        struct intel_iommu *iommu = NULL;
        unsigned long flag;

        for_each_active_iommu(iommu, drhd) {
                iommu->iommu_state = kzalloc(sizeof(u32) * MAX_SR_DMAR_REGS,
                                                 GFP_ATOMIC);
                if (!iommu->iommu_state)
                        goto nomem;
        }

        iommu_flush_all();

        for_each_active_iommu(iommu, drhd) {
                iommu_disable_translation(iommu);

                spin_lock_irqsave(&iommu->register_lock, flag);

                iommu->iommu_state[SR_DMAR_FECTL_REG] =
                        readl(iommu->reg + DMAR_FECTL_REG);
                iommu->iommu_state[SR_DMAR_FEDATA_REG] =
                        readl(iommu->reg + DMAR_FEDATA_REG);
                iommu->iommu_state[SR_DMAR_FEADDR_REG] =
                        readl(iommu->reg + DMAR_FEADDR_REG);
                iommu->iommu_state[SR_DMAR_FEUADDR_REG] =
                        readl(iommu->reg + DMAR_FEUADDR_REG);

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

nomem:
        for_each_active_iommu(iommu, drhd)
                kfree(iommu->iommu_state);

        return -ENOMEM;
}

static int iommu_resume(struct sys_device *dev)
{
        struct dmar_drhd_unit *drhd;
        struct intel_iommu *iommu = NULL;
        unsigned long flag;

        if (init_iommu_hw()) {
                WARN(1, "IOMMU setup failed, DMAR can not resume!\n");
                return -EIO;
        }

        for_each_active_iommu(iommu, drhd) {

                spin_lock_irqsave(&iommu->register_lock, flag);

                writel(iommu->iommu_state[SR_DMAR_FECTL_REG],
                        iommu->reg + DMAR_FECTL_REG);
                writel(iommu->iommu_state[SR_DMAR_FEDATA_REG],
                        iommu->reg + DMAR_FEDATA_REG);
                writel(iommu->iommu_state[SR_DMAR_FEADDR_REG],
                        iommu->reg + DMAR_FEADDR_REG);
                writel(iommu->iommu_state[SR_DMAR_FEUADDR_REG],
                        iommu->reg + DMAR_FEUADDR_REG);

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

        for_each_active_iommu(iommu, drhd)
                kfree(iommu->iommu_state);

        return 0;
}

static struct sysdev_class iommu_sysclass = {
        .name           = "iommu",
        .resume         = iommu_resume,
        .suspend        = iommu_suspend,
};

static struct sys_device device_iommu = {
        .cls    = &iommu_sysclass,
};

static int __init init_iommu_sysfs(void)
{
        int error;

        error = sysdev_class_register(&iommu_sysclass);
        if (error)
                return error;

        error = sysdev_register(&device_iommu);
        if (error)
                sysdev_class_unregister(&iommu_sysclass);

        return error;
}

#else
static int __init init_iommu_sysfs(void)
{
        return 0;
}
#endif  /* CONFIG_PM */

int __init intel_iommu_init(void)
{
        int ret = 0;

        if (dmar_table_init())
                return  -ENODEV;

        if (dmar_dev_scope_init())
                return  -ENODEV;

        /*
         * Check the need for DMA-remapping initialization now.
         * Above initialization will also be used by Interrupt-remapping.
         */
        if (no_iommu || (swiotlb && !iommu_pass_through) || dmar_disabled)
                return -ENODEV;

        iommu_init_mempool();
        dmar_init_reserved_ranges();

        init_no_remapping_devices();

        ret = init_dmars();
        if (ret) {
                printk(KERN_ERR "IOMMU: dmar init failed\n");
                put_iova_domain(&reserved_iova_list);
                iommu_exit_mempool();
                return ret;
        }
        printk(KERN_INFO
        "PCI-DMA: Intel(R) Virtualization Technology for Directed I/O\n");

        init_timer(&unmap_timer);
        force_iommu = 1;

        if (!iommu_pass_through) {
                printk(KERN_INFO
                       "Multi-level page-table translation for DMAR.\n");
                dma_ops = &intel_dma_ops;
        } else
                printk(KERN_INFO
                       "DMAR: Pass through translation for DMAR.\n");

        init_iommu_sysfs();

        register_iommu(&intel_iommu_ops);

        return 0;
}

static void iommu_detach_dependent_devices(struct intel_iommu *iommu,
                                           struct pci_dev *pdev)
{
        struct pci_dev *tmp, *parent;

        if (!iommu || !pdev)
                return;

        /* dependent device detach */
        tmp = pci_find_upstream_pcie_bridge(pdev);
        /* Secondary interface's bus number and devfn 0 */
        if (tmp) {
                parent = pdev->bus->self;
                while (parent != tmp) {
                        iommu_detach_dev(iommu, parent->bus->number,
                                         parent->devfn);
                        parent = parent->bus->self;
                }
                if (tmp->is_pcie) /* this is a PCIE-to-PCI bridge */
                        iommu_detach_dev(iommu,
                                tmp->subordinate->number, 0);
                else /* this is a legacy PCI bridge */
                        iommu_detach_dev(iommu, tmp->bus->number,
                                         tmp->devfn);
        }
}

static void domain_remove_one_dev_info(struct dmar_domain *domain,
                                          struct pci_dev *pdev)
{
        struct device_domain_info *info;
        struct intel_iommu *iommu;
        unsigned long flags;
        int found = 0;
        struct list_head *entry, *tmp;

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

        spin_lock_irqsave(&device_domain_lock, flags);
        list_for_each_safe(entry, tmp, &domain->devices) {
                info = list_entry(entry, struct device_domain_info, link);
                /* No need to compare PCI domain; it has to be the same */
                if (info->bus == pdev->bus->number &&
                    info->devfn == pdev->devfn) {
                        list_del(&info->link);
                        list_del(&info->global);
                        if (info->dev)
                                info->dev->dev.archdata.iommu = NULL;
                        spin_unlock_irqrestore(&device_domain_lock, flags);

                        iommu_disable_dev_iotlb(info);
                        iommu_detach_dev(iommu, info->bus, info->devfn);
                        iommu_detach_dependent_devices(iommu, pdev);
                        free_devinfo_mem(info);

                        spin_lock_irqsave(&device_domain_lock, flags);

                        if (found)
                                break;
                        else
                                continue;
                }

                /* if there is no other devices under the same iommu
                 * owned by this domain, clear this iommu in iommu_bmp
                 * update iommu count and coherency
                 */
                if (iommu == device_to_iommu(info->segment, info->bus,
                                            info->devfn))
                        found = 1;
        }

        if (found == 0) {
                unsigned long tmp_flags;
                spin_lock_irqsave(&domain->iommu_lock, tmp_flags);
                clear_bit(iommu->seq_id, &domain->iommu_bmp);
                domain->iommu_count--;
                domain_update_iommu_cap(domain);
                spin_unlock_irqrestore(&domain->iommu_lock, tmp_flags);
        }

        spin_unlock_irqrestore(&device_domain_lock, flags);
}

static void vm_domain_remove_all_dev_info(struct dmar_domain *domain)
{
        struct device_domain_info *info;
        struct intel_iommu *iommu;
        unsigned long flags1, flags2;

        spin_lock_irqsave(&device_domain_lock, flags1);
        while (!list_empty(&domain->devices)) {
                info = list_entry(domain->devices.next,
                        struct device_domain_info, link);
                list_del(&info->link);
                list_del(&info->global);
                if (info->dev)
                        info->dev->dev.archdata.iommu = NULL;

                spin_unlock_irqrestore(&device_domain_lock, flags1);

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

                /* clear this iommu in iommu_bmp, update iommu count
                 * and capabilities
                 */
                spin_lock_irqsave(&domain->iommu_lock, flags2);
                if (test_and_clear_bit(iommu->seq_id,
                                       &domain->iommu_bmp)) {
                        domain->iommu_count--;
                        domain_update_iommu_cap(domain);
                }
                spin_unlock_irqrestore(&domain->iommu_lock, flags2);

                free_devinfo_mem(info);
                spin_lock_irqsave(&device_domain_lock, flags1);
        }
        spin_unlock_irqrestore(&device_domain_lock, flags1);
}

/* domain id for virtual machine, it won't be set in context */
static unsigned long vm_domid;

static int vm_domain_min_agaw(struct dmar_domain *domain)
{
        int i;
        int min_agaw = domain->agaw;

        i = find_first_bit(&domain->iommu_bmp, g_num_of_iommus);
        for (; i < g_num_of_iommus; ) {
                if (min_agaw > g_iommus[i]->agaw)
                        min_agaw = g_iommus[i]->agaw;

                i = find_next_bit(&domain->iommu_bmp, g_num_of_iommus, i+1);
        }

        return min_agaw;
}

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

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

        domain->id = vm_domid++;
        memset(&domain->iommu_bmp, 0, sizeof(unsigned long));
        domain->flags = DOMAIN_FLAG_VIRTUAL_MACHINE;

        return domain;
}

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

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

        domain_reserve_special_ranges(domain);

        /* calculate AGAW */
        domain->gaw = guest_width;
        adjust_width = guestwidth_to_adjustwidth(guest_width);
        domain->agaw = width_to_agaw(adjust_width);

        INIT_LIST_HEAD(&domain->devices);

        domain->iommu_count = 0;
        domain->iommu_coherency = 0;
        domain->max_addr = 0;

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

static void iommu_free_vm_domain(struct dmar_domain *domain)
{
        unsigned long flags;
        struct dmar_drhd_unit *drhd;
        struct intel_iommu *iommu;
        unsigned long i;
        unsigned long ndomains;

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

                ndomains = cap_ndoms(iommu->cap);
                i = find_first_bit(iommu->domain_ids, ndomains);
                for (; i < ndomains; ) {
                        if (iommu->domains[i] == domain) {
                                spin_lock_irqsave(&iommu->lock, flags);
                                clear_bit(i, iommu->domain_ids);
                                iommu->domains[i] = NULL;
                                spin_unlock_irqrestore(&iommu->lock, flags);
                                break;
                        }
                        i = find_next_bit(iommu->domain_ids, ndomains, i+1);
                }
        }
}

static void vm_domain_exit(struct dmar_domain *domain)
{
        /* Domain 0 is reserved, so dont process it */
        if (!domain)
                return;

        vm_domain_remove_all_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));

        iommu_free_vm_domain(domain);
        free_domain_mem(domain);
}

static int intel_iommu_domain_init(struct iommu_domain *domain)
{
        struct dmar_domain *dmar_domain;

        dmar_domain = iommu_alloc_vm_domain();
        if (!dmar_domain) {
                printk(KERN_ERR
                        "intel_iommu_domain_init: dmar_domain == NULL\n");
                return -ENOMEM;
        }
        if (md_domain_init(dmar_domain, DEFAULT_DOMAIN_ADDRESS_WIDTH)) {
                printk(KERN_ERR
                        "intel_iommu_domain_init() failed\n");
                vm_domain_exit(dmar_domain);
                return -ENOMEM;
        }
        domain->priv = dmar_domain;

        return 0;
}

static void intel_iommu_domain_destroy(struct iommu_domain *domain)
{
        struct dmar_domain *dmar_domain = domain->priv;

        domain->priv = NULL;
        vm_domain_exit(dmar_domain);
}

static int intel_iommu_attach_device(struct iommu_domain *domain,
                                     struct device *dev)
{
        struct dmar_domain *dmar_domain = domain->priv;
        struct pci_dev *pdev = to_pci_dev(dev);
        struct intel_iommu *iommu;
        int addr_width;
        u64 end;
        int ret;

        /* normally pdev is not mapped */
        if (unlikely(domain_context_mapped(pdev))) {
                struct dmar_domain *old_domain;

                old_domain = find_domain(pdev);
                if (old_domain) {
                        if (dmar_domain->flags & DOMAIN_FLAG_VIRTUAL_MACHINE ||
                            dmar_domain->flags & DOMAIN_FLAG_STATIC_IDENTITY)
                                domain_remove_one_dev_info(old_domain, pdev);
                        else
                                domain_remove_dev_info(old_domain);
                }
        }

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

        /* check if this iommu agaw is sufficient for max mapped address */
        addr_width = agaw_to_width(iommu->agaw);
        end = DOMAIN_MAX_ADDR(addr_width);
        end = end & VTD_PAGE_MASK;
        if (end < dmar_domain->max_addr) {
                printk(KERN_ERR "%s: iommu agaw (%d) is not "
                       "sufficient for the mapped address (%llx)\n",
                       __func__, iommu->agaw, dmar_domain->max_addr);
                return -EFAULT;
        }

        ret = domain_add_dev_info(dmar_domain, pdev);
        if (ret)
                return ret;

        ret = domain_context_mapping(dmar_domain, pdev, CONTEXT_TT_MULTI_LEVEL);
        return ret;
}

static void intel_iommu_detach_device(struct iommu_domain *domain,
                                      struct device *dev)
{
        struct dmar_domain *dmar_domain = domain->priv;
        struct pci_dev *pdev = to_pci_dev(dev);

        domain_remove_one_dev_info(dmar_domain, pdev);
}

static int intel_iommu_map_range(struct iommu_domain *domain,
                                 unsigned long iova, phys_addr_t hpa,
                                 size_t size, int iommu_prot)
{
        struct dmar_domain *dmar_domain = domain->priv;
        u64 max_addr;
        int addr_width;
        int prot = 0;
        int ret;

        if (iommu_prot & IOMMU_READ)
                prot |= DMA_PTE_READ;
        if (iommu_prot & IOMMU_WRITE)
                prot |= DMA_PTE_WRITE;
        if ((iommu_prot & IOMMU_CACHE) && dmar_domain->iommu_snooping)
                prot |= DMA_PTE_SNP;

        max_addr = iova + size;
        if (dmar_domain->max_addr < max_addr) {
                int min_agaw;
                u64 end;

                /* check if minimum agaw is sufficient for mapped address */
                min_agaw = vm_domain_min_agaw(dmar_domain);
                addr_width = agaw_to_width(min_agaw);
                end = DOMAIN_MAX_ADDR(addr_width);
                end = end & VTD_PAGE_MASK;
                if (end < max_addr) {
                        printk(KERN_ERR "%s: iommu agaw (%d) is not "
                               "sufficient for the mapped address (%llx)\n",
                               __func__, min_agaw, max_addr);
                        return -EFAULT;
                }
                dmar_domain->max_addr = max_addr;
        }
        /* Round up size to next multiple of PAGE_SIZE, if it and
           the low bits of hpa would take us onto the next page */
        size = aligned_nrpages(hpa, size);
        ret = domain_pfn_mapping(dmar_domain, iova >> VTD_PAGE_SHIFT,
                                 hpa >> VTD_PAGE_SHIFT, size, prot);
        return ret;
}

static void intel_iommu_unmap_range(struct iommu_domain *domain,
                                    unsigned long iova, size_t size)
{
        struct dmar_domain *dmar_domain = domain->priv;

        dma_pte_clear_range(dmar_domain, iova >> VTD_PAGE_SHIFT,
                            (iova + size - 1) >> VTD_PAGE_SHIFT);

        if (dmar_domain->max_addr == iova + size)
                dmar_domain->max_addr = iova;
}

static phys_addr_t intel_iommu_iova_to_phys(struct iommu_domain *domain,
                                            unsigned long iova)
{
        struct dmar_domain *dmar_domain = domain->priv;
        struct dma_pte *pte;
        u64 phys = 0;

        pte = pfn_to_dma_pte(dmar_domain, iova >> VTD_PAGE_SHIFT);
        if (pte)
                phys = dma_pte_addr(pte);

        return phys;
}

static int intel_iommu_domain_has_cap(struct iommu_domain *domain,
                                      unsigned long cap)
{
        struct dmar_domain *dmar_domain = domain->priv;

        if (cap == IOMMU_CAP_CACHE_COHERENCY)
                return dmar_domain->iommu_snooping;

        return 0;
}

static struct iommu_ops intel_iommu_ops = {
        .domain_init    = intel_iommu_domain_init,
        .domain_destroy = intel_iommu_domain_destroy,
        .attach_dev     = intel_iommu_attach_device,
        .detach_dev     = intel_iommu_detach_device,
        .map            = intel_iommu_map_range,
        .unmap          = intel_iommu_unmap_range,
        .iova_to_phys   = intel_iommu_iova_to_phys,
        .domain_has_cap = intel_iommu_domain_has_cap,
};

static void __devinit quirk_iommu_rwbf(struct pci_dev *dev)
{
        /*
         * Mobile 4 Series Chipset neglects to set RWBF capability,
         * but needs it:
         */
        printk(KERN_INFO "DMAR: Forcing write-buffer flush capability\n");
        rwbf_quirk = 1;
}

DECLARE_PCI_FIXUP_HEADER(PCI_VENDOR_ID_INTEL, 0x2a40, quirk_iommu_rwbf);