// SPDX-License-Identifier: GPL-2.0-only
/*
 * VFIO: IOMMU DMA mapping support for Type1 IOMMU
 *
 * Copyright (C) 2012 Red Hat, Inc.  All rights reserved.
 *     Author: Alex Williamson <alex.williamson@redhat.com>
 *
 * Derived from original vfio:
 * Copyright 2010 Cisco Systems, Inc.  All rights reserved.
 * Author: Tom Lyon, pugs@cisco.com
 *
 * We arbitrarily define a Type1 IOMMU as one matching the below code.
 * It could be called the x86 IOMMU as it's designed for AMD-Vi & Intel
 * VT-d, but that makes it harder to re-use as theoretically anyone
 * implementing a similar IOMMU could make use of this.  We expect the
 * IOMMU to support the IOMMU API and have few to no restrictions around
 * the IOVA range that can be mapped.  The Type1 IOMMU is currently
 * optimized for relatively static mappings of a userspace process with
 * userspace pages pinned into memory.  We also assume devices and IOMMU
 * domains are PCI based as the IOMMU API is still centered around a
 * device/bus interface rather than a group interface.
 */

#include <linux/compat.h>
#include <linux/device.h>
#include <linux/fs.h>
#include <linux/highmem.h>
#include <linux/iommu.h>
#include <linux/module.h>
#include <linux/mm.h>
#include <linux/kthread.h>
#include <linux/rbtree.h>
#include <linux/sched/signal.h>
#include <linux/sched/mm.h>
#include <linux/slab.h>
#include <linux/uaccess.h>
#include <linux/vfio.h>
#include <linux/workqueue.h>
#include <linux/notifier.h>
#include <linux/mm_inline.h>
#include <linux/overflow.h>
#include "vfio.h"

#define DRIVER_VERSION  "0.2"
#define DRIVER_AUTHOR   "Alex Williamson <alex.williamson@redhat.com>"
#define DRIVER_DESC     "Type1 IOMMU driver for VFIO"

static bool allow_unsafe_interrupts;
module_param_named(allow_unsafe_interrupts,
                   allow_unsafe_interrupts, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(allow_unsafe_interrupts,
                 "Enable VFIO IOMMU support for on platforms without interrupt remapping support.");

static bool disable_hugepages;
module_param_named(disable_hugepages,
                   disable_hugepages, bool, S_IRUGO | S_IWUSR);
MODULE_PARM_DESC(disable_hugepages,
                 "Disable VFIO IOMMU support for IOMMU hugepages.");

static unsigned int dma_entry_limit __read_mostly = U16_MAX;
module_param_named(dma_entry_limit, dma_entry_limit, uint, 0644);
MODULE_PARM_DESC(dma_entry_limit,
                 "Maximum number of user DMA mappings per container (65535).");

struct vfio_iommu {
        struct list_head        domain_list;
        struct list_head        iova_list;
        struct mutex            lock;
        struct rb_root          dma_list;
        struct list_head        device_list;
        struct mutex            device_list_lock;
        unsigned int            dma_avail;
        unsigned int            vaddr_invalid_count;
        uint64_t                pgsize_bitmap;
        uint64_t                num_non_pinned_groups;
        bool                    v2;
        bool                    dirty_page_tracking;
        struct list_head        emulated_iommu_groups;
};

struct vfio_domain {
        struct iommu_domain     *domain;
        struct list_head        next;
        struct list_head        group_list;
        bool                    enforce_cache_coherency : 1;
};

struct vfio_dma {
        struct rb_node          node;
        dma_addr_t              iova;           /* Device address */
        unsigned long           vaddr;          /* Process virtual addr */
        size_t                  size;           /* Map size (bytes) */
        int                     prot;           /* IOMMU_READ/WRITE */
        bool                    iommu_mapped;
        bool                    lock_cap;       /* capable(CAP_IPC_LOCK) */
        bool                    vaddr_invalid;
        bool                    has_rsvd;       /* has 1 or more rsvd pfns */
        struct task_struct      *task;
        struct rb_root          pfn_list;       /* Ex-user pinned pfn list */
        unsigned long           *bitmap;
        struct mm_struct        *mm;
        size_t                  locked_vm;
};

struct vfio_batch {
        struct page             **pages;        /* for pin_user_pages_remote */
        struct page             *fallback_page; /* if pages alloc fails */
        unsigned int            capacity;       /* length of pages array */
        unsigned int            size;           /* of batch currently */
        unsigned int            offset;         /* of next entry in pages */
};

struct vfio_iommu_group {
        struct iommu_group      *iommu_group;
        struct list_head        next;
        bool                    pinned_page_dirty_scope;
};

struct vfio_iova {
        struct list_head        list;
        dma_addr_t              start;
        dma_addr_t              end;
};

/*
 * Guest RAM pinning working set or DMA target
 */
struct vfio_pfn {
        struct rb_node          node;
        dma_addr_t              iova;           /* Device address */
        unsigned long           pfn;            /* Host pfn */
        unsigned int            ref_count;
};

struct vfio_regions {
        struct list_head list;
        dma_addr_t iova;
        phys_addr_t phys;
        size_t len;
};

#define DIRTY_BITMAP_BYTES(n)   (ALIGN(n, BITS_PER_TYPE(u64)) / BITS_PER_BYTE)

/*
 * Input argument of number of bits to bitmap_set() is unsigned integer, which
 * further casts to signed integer for unaligned multi-bit operation,
 * __bitmap_set().
 * Then maximum bitmap size supported is 2^31 bits divided by 2^3 bits/byte,
 * that is 2^28 (256 MB) which maps to 2^31 * 2^12 = 2^43 (8TB) on 4K page
 * system.
 */
#define DIRTY_BITMAP_PAGES_MAX   ((u64)INT_MAX)
#define DIRTY_BITMAP_SIZE_MAX    DIRTY_BITMAP_BYTES(DIRTY_BITMAP_PAGES_MAX)

static int put_pfn(unsigned long pfn, int prot);

static struct vfio_iommu_group*
vfio_iommu_find_iommu_group(struct vfio_iommu *iommu,
                            struct iommu_group *iommu_group);

/*
 * This code handles mapping and unmapping of user data buffers
 * into DMA'ble space using the IOMMU
 */

static struct vfio_dma *vfio_find_dma(struct vfio_iommu *iommu,
                                      dma_addr_t start, size_t size)
{
        struct rb_node *node = iommu->dma_list.rb_node;

        WARN_ON(!size);

        while (node) {
                struct vfio_dma *dma = rb_entry(node, struct vfio_dma, node);

                if (start + size - 1 < dma->iova)
                        node = node->rb_left;
                else if (start > dma->iova + dma->size - 1)
                        node = node->rb_right;
                else
                        return dma;
        }

        return NULL;
}

static struct rb_node *vfio_find_dma_first_node(struct vfio_iommu *iommu,
                                                dma_addr_t start,
                                                dma_addr_t end)
{
        struct rb_node *res = NULL;
        struct rb_node *node = iommu->dma_list.rb_node;
        struct vfio_dma *dma_res = NULL;

        WARN_ON(end < start);

        while (node) {
                struct vfio_dma *dma = rb_entry(node, struct vfio_dma, node);

                if (start <= dma->iova + dma->size - 1) {
                        res = node;
                        dma_res = dma;
                        if (start >= dma->iova)
                                break;
                        node = node->rb_left;
                } else {
                        node = node->rb_right;
                }
        }
        if (res && dma_res->iova > end)
                res = NULL;
        return res;
}

static void vfio_link_dma(struct vfio_iommu *iommu, struct vfio_dma *new)
{
        struct rb_node **link = &iommu->dma_list.rb_node, *parent = NULL;
        struct vfio_dma *dma;

        WARN_ON(new->size != 0);

        while (*link) {
                parent = *link;
                dma = rb_entry(parent, struct vfio_dma, node);

                if (new->iova <= dma->iova)
                        link = &(*link)->rb_left;
                else
                        link = &(*link)->rb_right;
        }

        rb_link_node(&new->node, parent, link);
        rb_insert_color(&new->node, &iommu->dma_list);
}

static void vfio_unlink_dma(struct vfio_iommu *iommu, struct vfio_dma *old)
{
        rb_erase(&old->node, &iommu->dma_list);
}


static int vfio_dma_bitmap_alloc(struct vfio_dma *dma, size_t pgsize)
{
        uint64_t npages = dma->size / pgsize;

        if (npages > DIRTY_BITMAP_PAGES_MAX)
                return -EINVAL;

        /*
         * Allocate extra 64 bits that are used to calculate shift required for
         * bitmap_shift_left() to manipulate and club unaligned number of pages
         * in adjacent vfio_dma ranges.
         */
        dma->bitmap = kvzalloc(DIRTY_BITMAP_BYTES(npages) + sizeof(u64),
                               GFP_KERNEL);
        if (!dma->bitmap)
                return -ENOMEM;

        return 0;
}

static void vfio_dma_bitmap_free(struct vfio_dma *dma)
{
        kvfree(dma->bitmap);
        dma->bitmap = NULL;
}

static void vfio_dma_populate_bitmap(struct vfio_dma *dma, size_t pgsize)
{
        struct rb_node *p;
        unsigned long pgshift = __ffs(pgsize);

        for (p = rb_first(&dma->pfn_list); p; p = rb_next(p)) {
                struct vfio_pfn *vpfn = rb_entry(p, struct vfio_pfn, node);

                bitmap_set(dma->bitmap, (vpfn->iova - dma->iova) >> pgshift, 1);
        }
}

static void vfio_iommu_populate_bitmap_full(struct vfio_iommu *iommu)
{
        struct rb_node *n;
        unsigned long pgshift = __ffs(iommu->pgsize_bitmap);

        for (n = rb_first(&iommu->dma_list); n; n = rb_next(n)) {
                struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node);

                bitmap_set(dma->bitmap, 0, dma->size >> pgshift);
        }
}

static int vfio_dma_bitmap_alloc_all(struct vfio_iommu *iommu, size_t pgsize)
{
        struct rb_node *n;

        for (n = rb_first(&iommu->dma_list); n; n = rb_next(n)) {
                struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node);
                int ret;

                ret = vfio_dma_bitmap_alloc(dma, pgsize);
                if (ret) {
                        struct rb_node *p;

                        for (p = rb_prev(n); p; p = rb_prev(p)) {
                                struct vfio_dma *dma = rb_entry(p,
                                                        struct vfio_dma, node);

                                vfio_dma_bitmap_free(dma);
                        }
                        return ret;
                }
                vfio_dma_populate_bitmap(dma, pgsize);
        }
        return 0;
}

static void vfio_dma_bitmap_free_all(struct vfio_iommu *iommu)
{
        struct rb_node *n;

        for (n = rb_first(&iommu->dma_list); n; n = rb_next(n)) {
                struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node);

                vfio_dma_bitmap_free(dma);
        }
}

/*
 * Helper Functions for host iova-pfn list
 */

/*
 * Find the highest vfio_pfn that overlapping the range
 * [iova_start, iova_end) in rb tree.
 */
static struct vfio_pfn *vfio_find_vpfn_range(struct vfio_dma *dma,
                dma_addr_t iova_start, dma_addr_t iova_end)
{
        struct vfio_pfn *vpfn;
        struct rb_node *node = dma->pfn_list.rb_node;

        while (node) {
                vpfn = rb_entry(node, struct vfio_pfn, node);

                if (iova_end <= vpfn->iova)
                        node = node->rb_left;
                else if (iova_start > vpfn->iova)
                        node = node->rb_right;
                else
                        return vpfn;
        }
        return NULL;
}

static inline struct vfio_pfn *vfio_find_vpfn(struct vfio_dma *dma, dma_addr_t iova)
{
        return vfio_find_vpfn_range(dma, iova, iova + 1);
}

static void vfio_link_pfn(struct vfio_dma *dma,
                          struct vfio_pfn *new)
{
        struct rb_node **link, *parent = NULL;
        struct vfio_pfn *vpfn;

        link = &dma->pfn_list.rb_node;
        while (*link) {
                parent = *link;
                vpfn = rb_entry(parent, struct vfio_pfn, node);

                if (new->iova < vpfn->iova)
                        link = &(*link)->rb_left;
                else
                        link = &(*link)->rb_right;
        }

        rb_link_node(&new->node, parent, link);
        rb_insert_color(&new->node, &dma->pfn_list);
}

static void vfio_unlink_pfn(struct vfio_dma *dma, struct vfio_pfn *old)
{
        rb_erase(&old->node, &dma->pfn_list);
}

static int vfio_add_to_pfn_list(struct vfio_dma *dma, dma_addr_t iova,
                                unsigned long pfn)
{
        struct vfio_pfn *vpfn;

        vpfn = kzalloc_obj(*vpfn);
        if (!vpfn)
                return -ENOMEM;

        vpfn->iova = iova;
        vpfn->pfn = pfn;
        vpfn->ref_count = 1;
        vfio_link_pfn(dma, vpfn);
        return 0;
}

static void vfio_remove_from_pfn_list(struct vfio_dma *dma,
                                      struct vfio_pfn *vpfn)
{
        vfio_unlink_pfn(dma, vpfn);
        kfree(vpfn);
}

static struct vfio_pfn *vfio_iova_get_vfio_pfn(struct vfio_dma *dma,
                                               unsigned long iova)
{
        struct vfio_pfn *vpfn = vfio_find_vpfn(dma, iova);

        if (vpfn)
                vpfn->ref_count++;
        return vpfn;
}

static int vfio_iova_put_vfio_pfn(struct vfio_dma *dma, struct vfio_pfn *vpfn)
{
        int ret = 0;

        vpfn->ref_count--;
        if (!vpfn->ref_count) {
                ret = put_pfn(vpfn->pfn, dma->prot);
                vfio_remove_from_pfn_list(dma, vpfn);
        }
        return ret;
}

static int mm_lock_acct(struct task_struct *task, struct mm_struct *mm,
                        bool lock_cap, long npage)
{
        int ret = mmap_write_lock_killable(mm);

        if (ret)
                return ret;

        ret = __account_locked_vm(mm, abs(npage), npage > 0, task, lock_cap);
        mmap_write_unlock(mm);
        return ret;
}

static int vfio_lock_acct(struct vfio_dma *dma, long npage, bool async)
{
        struct mm_struct *mm;
        int ret;

        if (!npage)
                return 0;

        mm = dma->mm;
        if (async && !mmget_not_zero(mm))
                return -ESRCH; /* process exited */

        ret = mm_lock_acct(dma->task, mm, dma->lock_cap, npage);
        if (!ret)
                dma->locked_vm += npage;

        if (async)
                mmput(mm);

        return ret;
}

/*
 * Some mappings aren't backed by a struct page, for example an mmap'd
 * MMIO range for our own or another device.  These use a different
 * pfn conversion and shouldn't be tracked as locked pages.
 * For compound pages, any driver that sets the reserved bit in head
 * page needs to set the reserved bit in all subpages to be safe.
 */
static bool is_invalid_reserved_pfn(unsigned long pfn)
{
        if (pfn_valid(pfn))
                return PageReserved(pfn_to_page(pfn));

        return true;
}

static int put_pfn(unsigned long pfn, int prot)
{
        if (!is_invalid_reserved_pfn(pfn)) {
                struct page *page = pfn_to_page(pfn);

                unpin_user_pages_dirty_lock(&page, 1, prot & IOMMU_WRITE);
                return 1;
        }
        return 0;
}

#define VFIO_BATCH_MAX_CAPACITY (PAGE_SIZE / sizeof(struct page *))

static void __vfio_batch_init(struct vfio_batch *batch, bool single)
{
        batch->size = 0;
        batch->offset = 0;

        if (single || unlikely(disable_hugepages))
                goto fallback;

        batch->pages = (struct page **) __get_free_page(GFP_KERNEL);
        if (!batch->pages)
                goto fallback;

        batch->capacity = VFIO_BATCH_MAX_CAPACITY;
        return;

fallback:
        batch->pages = &batch->fallback_page;
        batch->capacity = 1;
}

static void vfio_batch_init(struct vfio_batch *batch)
{
        __vfio_batch_init(batch, false);
}

static void vfio_batch_init_single(struct vfio_batch *batch)
{
        __vfio_batch_init(batch, true);
}

static void vfio_batch_unpin(struct vfio_batch *batch, struct vfio_dma *dma)
{
        while (batch->size) {
                unsigned long pfn = page_to_pfn(batch->pages[batch->offset]);

                put_pfn(pfn, dma->prot);
                batch->offset++;
                batch->size--;
        }
}

static void vfio_batch_fini(struct vfio_batch *batch)
{
        if (batch->capacity == VFIO_BATCH_MAX_CAPACITY)
                free_page((unsigned long)batch->pages);
}

static int follow_fault_pfn(struct vm_area_struct *vma, struct mm_struct *mm,
                            unsigned long vaddr, unsigned long *pfn,
                            unsigned long *addr_mask, bool write_fault)
{
        struct follow_pfnmap_args args = { .vma = vma, .address = vaddr };
        int ret;

        ret = follow_pfnmap_start(&args);
        if (ret) {
                bool unlocked = false;

                ret = fixup_user_fault(mm, vaddr,
                                       FAULT_FLAG_REMOTE |
                                       (write_fault ?  FAULT_FLAG_WRITE : 0),
                                       &unlocked);
                if (unlocked)
                        return -EAGAIN;

                if (ret)
                        return ret;

                ret = follow_pfnmap_start(&args);
                if (ret)
                        return ret;
        }

        if (write_fault && !args.writable) {
                ret = -EFAULT;
        } else {
                *pfn = args.pfn;
                *addr_mask = args.addr_mask;
        }

        follow_pfnmap_end(&args);
        return ret;
}

/*
 * Returns the positive number of pfns successfully obtained or a negative
 * error code.  The initial pfn is stored in the pfn arg.  For page-backed
 * pfns, the provided batch is also updated to indicate the filled pages and
 * initial offset.  For VM_PFNMAP pfns, only the returned number of pfns and
 * returned initial pfn are provided; subsequent pfns are contiguous.
 */
static long vaddr_get_pfns(struct mm_struct *mm, unsigned long vaddr,
                           unsigned long npages, int prot, unsigned long *pfn,
                           struct vfio_batch *batch)
{
        unsigned long pin_pages = min_t(unsigned long, npages, batch->capacity);
        struct vm_area_struct *vma;
        unsigned int flags = 0;
        long ret;

        if (prot & IOMMU_WRITE)
                flags |= FOLL_WRITE;

        mmap_read_lock(mm);
        ret = pin_user_pages_remote(mm, vaddr, pin_pages, flags | FOLL_LONGTERM,
                                    batch->pages, NULL);
        if (ret > 0) {
                *pfn = page_to_pfn(batch->pages[0]);
                batch->size = ret;
                batch->offset = 0;
                goto done;
        } else if (!ret) {
                ret = -EFAULT;
        }

        vaddr = untagged_addr_remote(mm, vaddr);

retry:
        vma = vma_lookup(mm, vaddr);

        if (vma && vma->vm_flags & VM_PFNMAP) {
                unsigned long addr_mask;

                ret = follow_fault_pfn(vma, mm, vaddr, pfn, &addr_mask,
                                       prot & IOMMU_WRITE);
                if (ret == -EAGAIN)
                        goto retry;

                if (!ret) {
                        if (is_invalid_reserved_pfn(*pfn)) {
                                unsigned long epfn;

                                epfn = (*pfn | (~addr_mask >> PAGE_SHIFT)) + 1;
                                ret = min_t(long, npages, epfn - *pfn);
                        } else {
                                ret = -EFAULT;
                        }
                }
        }
done:
        mmap_read_unlock(mm);
        return ret;
}


static long vpfn_pages(struct vfio_dma *dma,
                dma_addr_t iova_start, long nr_pages)
{
        dma_addr_t iova_end = iova_start + (nr_pages << PAGE_SHIFT);
        struct vfio_pfn *top = vfio_find_vpfn_range(dma, iova_start, iova_end);
        long ret = 1;
        struct vfio_pfn *vpfn;
        struct rb_node *prev;
        struct rb_node *next;

        if (likely(!top))
                return 0;

        prev = next = &top->node;

        while ((prev = rb_prev(prev))) {
                vpfn = rb_entry(prev, struct vfio_pfn, node);
                if (vpfn->iova < iova_start)
                        break;
                ret++;
        }

        while ((next = rb_next(next))) {
                vpfn = rb_entry(next, struct vfio_pfn, node);
                if (vpfn->iova >= iova_end)
                        break;
                ret++;
        }

        return ret;
}

/*
 * Attempt to pin pages.  We really don't want to track all the pfns and
 * the iommu can only map chunks of consecutive pfns anyway, so get the
 * first page and all consecutive pages with the same locking.
 */
static long vfio_pin_pages_remote(struct vfio_dma *dma, unsigned long vaddr,
                                  unsigned long npage, unsigned long *pfn_base,
                                  unsigned long limit, struct vfio_batch *batch)
{
        unsigned long pfn;
        struct mm_struct *mm = current->mm;
        long ret, pinned = 0, lock_acct = 0;
        bool rsvd;
        dma_addr_t iova = vaddr - dma->vaddr + dma->iova;

        /* This code path is only user initiated */
        if (!mm)
                return -ENODEV;

        if (batch->size) {
                /* Leftover pages in batch from an earlier call. */
                *pfn_base = page_to_pfn(batch->pages[batch->offset]);
                pfn = *pfn_base;
                rsvd = is_invalid_reserved_pfn(*pfn_base);
        } else {
                *pfn_base = 0;
        }

        if (unlikely(disable_hugepages))
                npage = 1;

        while (npage) {
                if (!batch->size) {
                        /*
                         * Large mappings may take a while to repeatedly refill
                         * the batch, so conditionally relinquish the CPU when
                         * needed to avoid stalls.
                         */
                        cond_resched();

                        /* Empty batch, so refill it. */
                        ret = vaddr_get_pfns(mm, vaddr, npage, dma->prot,
                                             &pfn, batch);
                        if (ret < 0)
                                goto unpin_out;

                        if (!*pfn_base) {
                                *pfn_base = pfn;
                                rsvd = is_invalid_reserved_pfn(*pfn_base);
                        }

                        /* Handle pfnmap */
                        if (!batch->size) {
                                if (pfn != *pfn_base + pinned || !rsvd)
                                        goto out;

                                pinned += ret;
                                npage -= ret;
                                vaddr += (PAGE_SIZE * ret);
                                iova += (PAGE_SIZE * ret);
                                continue;
                        }
                }

                /*
                 * pfn is preset for the first iteration of this inner loop
                 * due to the fact that vaddr_get_pfns() needs to provide the
                 * initial pfn for pfnmaps.  Therefore to reduce redundancy,
                 * the next pfn is fetched at the end of the loop.
                 * A PageReserved() page could still qualify as page backed
                 * and rsvd here, and therefore continues to use the batch.
                 */
                while (true) {
                        long nr_pages, acct_pages = 0;

                        if (pfn != *pfn_base + pinned ||
                            rsvd != is_invalid_reserved_pfn(pfn))
                                goto out;

                        /*
                         * Using GUP with the FOLL_LONGTERM in
                         * vaddr_get_pfns() will not return invalid
                         * or reserved pages.
                         */
                        nr_pages = num_pages_contiguous(
                                        &batch->pages[batch->offset],
                                        batch->size);
                        if (!rsvd) {
                                acct_pages = nr_pages;
                                acct_pages -= vpfn_pages(dma, iova, nr_pages);
                        }

                        /*
                         * Reserved pages aren't counted against the user,
                         * externally pinned pages are already counted against
                         * the user.
                         */
                        if (acct_pages) {
                                if (!dma->lock_cap &&
                                    mm->locked_vm + lock_acct + acct_pages > limit) {
                                        pr_warn("%s: RLIMIT_MEMLOCK (%ld) exceeded\n",
                                                __func__, limit << PAGE_SHIFT);
                                        ret = -ENOMEM;
                                        goto unpin_out;
                                }
                                lock_acct += acct_pages;
                        }

                        pinned += nr_pages;
                        npage -= nr_pages;
                        vaddr += PAGE_SIZE * nr_pages;
                        iova += PAGE_SIZE * nr_pages;
                        batch->offset += nr_pages;
                        batch->size -= nr_pages;

                        if (!batch->size)
                                break;

                        pfn = page_to_pfn(batch->pages[batch->offset]);
                }
        }

out:
        dma->has_rsvd |= rsvd;
        ret = vfio_lock_acct(dma, lock_acct, false);

unpin_out:
        if (ret < 0) {
                if (pinned && !rsvd) {
                        for (pfn = *pfn_base ; pinned ; pfn++, pinned--)
                                put_pfn(pfn, dma->prot);
                }
                vfio_batch_unpin(batch, dma);

                return ret;
        }

        return pinned;
}

static inline void put_valid_unreserved_pfns(unsigned long start_pfn,
                unsigned long npage, int prot)
{
        unpin_user_page_range_dirty_lock(pfn_to_page(start_pfn), npage,
                                         prot & IOMMU_WRITE);
}

static long vfio_unpin_pages_remote(struct vfio_dma *dma, dma_addr_t iova,
                                    unsigned long pfn, unsigned long npage,
                                    bool do_accounting)
{
        long unlocked = 0, locked = vpfn_pages(dma, iova, npage);

        if (dma->has_rsvd) {
                unsigned long i;

                for (i = 0; i < npage; i++)
                        if (put_pfn(pfn++, dma->prot))
                                unlocked++;
        } else {
                put_valid_unreserved_pfns(pfn, npage, dma->prot);
                unlocked = npage;
        }
        if (do_accounting)
                vfio_lock_acct(dma, locked - unlocked, true);

        return unlocked;
}

static int vfio_pin_page_external(struct vfio_dma *dma, unsigned long vaddr,
                                  unsigned long *pfn_base, bool do_accounting)
{
        struct vfio_batch batch;
        struct mm_struct *mm;
        int ret;

        mm = dma->mm;
        if (!mmget_not_zero(mm))
                return -ENODEV;

        vfio_batch_init_single(&batch);

        ret = vaddr_get_pfns(mm, vaddr, 1, dma->prot, pfn_base, &batch);
        if (ret != 1)
                goto out;

        ret = 0;

        if (do_accounting && !is_invalid_reserved_pfn(*pfn_base)) {
                ret = vfio_lock_acct(dma, 1, false);
                if (ret) {
                        put_pfn(*pfn_base, dma->prot);
                        if (ret == -ENOMEM)
                                pr_warn("%s: Task %s (%d) RLIMIT_MEMLOCK "
                                        "(%ld) exceeded\n", __func__,
                                        dma->task->comm, task_pid_nr(dma->task),
                                        task_rlimit(dma->task, RLIMIT_MEMLOCK));
                }
        }

out:
        vfio_batch_fini(&batch);
        mmput(mm);
        return ret;
}

static int vfio_unpin_page_external(struct vfio_dma *dma, dma_addr_t iova,
                                    bool do_accounting)
{
        int unlocked;
        struct vfio_pfn *vpfn = vfio_find_vpfn(dma, iova);

        if (!vpfn)
                return 0;

        unlocked = vfio_iova_put_vfio_pfn(dma, vpfn);

        if (do_accounting)
                vfio_lock_acct(dma, -unlocked, true);

        return unlocked;
}

static int vfio_iommu_type1_pin_pages(void *iommu_data,
                                      struct iommu_group *iommu_group,
                                      dma_addr_t user_iova,
                                      int npage, int prot,
                                      struct page **pages)
{
        struct vfio_iommu *iommu = iommu_data;
        struct vfio_iommu_group *group;
        int i, j, ret;
        unsigned long remote_vaddr;
        struct vfio_dma *dma;
        bool do_accounting;
        dma_addr_t iova_end;
        size_t iova_size;

        if (!iommu || !pages || npage <= 0)
                return -EINVAL;

        /* Supported for v2 version only */
        if (!iommu->v2)
                return -EACCES;

        if (check_mul_overflow(npage, PAGE_SIZE, &iova_size) ||
            check_add_overflow(user_iova, iova_size - 1, &iova_end))
                return -EOVERFLOW;

        mutex_lock(&iommu->lock);

        if (WARN_ONCE(iommu->vaddr_invalid_count,
                      "vfio_pin_pages not allowed with VFIO_UPDATE_VADDR\n")) {
                ret = -EBUSY;
                goto pin_done;
        }

        /* Fail if no dma_umap notifier is registered */
        if (list_empty(&iommu->device_list)) {
                ret = -EINVAL;
                goto pin_done;
        }

        /*
         * If iommu capable domain exist in the container then all pages are
         * already pinned and accounted. Accounting should be done if there is no
         * iommu capable domain in the container.
         */
        do_accounting = list_empty(&iommu->domain_list);

        for (i = 0; i < npage; i++) {
                unsigned long phys_pfn;
                dma_addr_t iova;
                struct vfio_pfn *vpfn;

                iova = user_iova + PAGE_SIZE * i;
                dma = vfio_find_dma(iommu, iova, PAGE_SIZE);
                if (!dma) {
                        ret = -EINVAL;
                        goto pin_unwind;
                }

                if ((dma->prot & prot) != prot) {
                        ret = -EPERM;
                        goto pin_unwind;
                }

                vpfn = vfio_iova_get_vfio_pfn(dma, iova);
                if (vpfn) {
                        pages[i] = pfn_to_page(vpfn->pfn);
                        continue;
                }

                remote_vaddr = dma->vaddr + (iova - dma->iova);
                ret = vfio_pin_page_external(dma, remote_vaddr, &phys_pfn,
                                             do_accounting);
                if (ret)
                        goto pin_unwind;

                if (!pfn_valid(phys_pfn)) {
                        ret = -EINVAL;
                        goto pin_unwind;
                }

                ret = vfio_add_to_pfn_list(dma, iova, phys_pfn);
                if (ret) {
                        if (put_pfn(phys_pfn, dma->prot) && do_accounting)
                                vfio_lock_acct(dma, -1, true);
                        goto pin_unwind;
                }

                pages[i] = pfn_to_page(phys_pfn);

                if (iommu->dirty_page_tracking) {
                        unsigned long pgshift = __ffs(iommu->pgsize_bitmap);

                        /*
                         * Bitmap populated with the smallest supported page
                         * size
                         */
                        bitmap_set(dma->bitmap,
                                   (iova - dma->iova) >> pgshift, 1);
                }
        }
        ret = i;

        group = vfio_iommu_find_iommu_group(iommu, iommu_group);
        if (!group->pinned_page_dirty_scope) {
                group->pinned_page_dirty_scope = true;
                iommu->num_non_pinned_groups--;
        }

        goto pin_done;

pin_unwind:
        pages[i] = NULL;
        for (j = 0; j < i; j++) {
                dma_addr_t iova;

                iova = user_iova + PAGE_SIZE * j;
                dma = vfio_find_dma(iommu, iova, PAGE_SIZE);
                vfio_unpin_page_external(dma, iova, do_accounting);
                pages[j] = NULL;
        }
pin_done:
        mutex_unlock(&iommu->lock);
        return ret;
}

static void vfio_iommu_type1_unpin_pages(void *iommu_data,
                                         dma_addr_t user_iova, int npage)
{
        struct vfio_iommu *iommu = iommu_data;
        bool do_accounting;
        dma_addr_t iova_end;
        size_t iova_size;
        int i;

        /* Supported for v2 version only */
        if (WARN_ON(!iommu->v2))
                return;

        if (WARN_ON(npage <= 0))
                return;

        if (WARN_ON(check_mul_overflow(npage, PAGE_SIZE, &iova_size) ||
                    check_add_overflow(user_iova, iova_size - 1, &iova_end)))
                return;

        mutex_lock(&iommu->lock);

        do_accounting = list_empty(&iommu->domain_list);
        for (i = 0; i < npage; i++) {
                dma_addr_t iova = user_iova + PAGE_SIZE * i;
                struct vfio_dma *dma;

                dma = vfio_find_dma(iommu, iova, PAGE_SIZE);
                if (!dma)
                        break;

                vfio_unpin_page_external(dma, iova, do_accounting);
        }

        mutex_unlock(&iommu->lock);

        WARN_ON(i != npage);
}

static long vfio_sync_unpin(struct vfio_dma *dma, struct vfio_domain *domain,
                            struct list_head *regions,
                            struct iommu_iotlb_gather *iotlb_gather)
{
        long unlocked = 0;
        struct vfio_regions *entry, *next;

        iommu_iotlb_sync(domain->domain, iotlb_gather);

        list_for_each_entry_safe(entry, next, regions, list) {
                unlocked += vfio_unpin_pages_remote(dma,
                                                    entry->iova,
                                                    entry->phys >> PAGE_SHIFT,
                                                    entry->len >> PAGE_SHIFT,
                                                    false);
                list_del(&entry->list);
                kfree(entry);
        }

        cond_resched();

        return unlocked;
}

/*
 * Generally, VFIO needs to unpin remote pages after each IOTLB flush.
 * Therefore, when using IOTLB flush sync interface, VFIO need to keep track
 * of these regions (currently using a list).
 *
 * This value specifies maximum number of regions for each IOTLB flush sync.
 */
#define VFIO_IOMMU_TLB_SYNC_MAX         512

static size_t unmap_unpin_fast(struct vfio_domain *domain,
                               struct vfio_dma *dma, dma_addr_t iova,
                               size_t len, phys_addr_t phys, long *unlocked,
                               struct list_head *unmapped_list,
                               int *unmapped_cnt,
                               struct iommu_iotlb_gather *iotlb_gather)
{
        size_t unmapped = 0;
        struct vfio_regions *entry = kzalloc_obj(*entry);

        if (entry) {
                unmapped = iommu_unmap_fast(domain->domain, iova, len,
                                            iotlb_gather);

                if (!unmapped) {
                        kfree(entry);
                } else {
                        entry->iova = iova;
                        entry->phys = phys;
                        entry->len  = unmapped;
                        list_add_tail(&entry->list, unmapped_list);

                        (*unmapped_cnt)++;
                }
        }

        /*
         * Sync if the number of fast-unmap regions hits the limit
         * or in case of errors.
         */
        if (*unmapped_cnt >= VFIO_IOMMU_TLB_SYNC_MAX || !unmapped) {
                *unlocked += vfio_sync_unpin(dma, domain, unmapped_list,
                                             iotlb_gather);
                *unmapped_cnt = 0;
        }

        return unmapped;
}

static size_t unmap_unpin_slow(struct vfio_domain *domain,
                               struct vfio_dma *dma, dma_addr_t iova,
                               size_t len, phys_addr_t phys,
                               long *unlocked)
{
        size_t unmapped = iommu_unmap(domain->domain, iova, len);

        if (unmapped) {
                *unlocked += vfio_unpin_pages_remote(dma, iova,
                                                     phys >> PAGE_SHIFT,
                                                     unmapped >> PAGE_SHIFT,
                                                     false);
                cond_resched();
        }
        return unmapped;
}

static long vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma,
                             bool do_accounting)
{
        struct vfio_domain *domain, *d;
        LIST_HEAD(unmapped_region_list);
        struct iommu_iotlb_gather iotlb_gather;
        int unmapped_region_cnt = 0;
        long unlocked = 0;
        size_t pos = 0;

        if (!dma->size)
                return 0;

        if (list_empty(&iommu->domain_list))
                return 0;

        /*
         * We use the IOMMU to track the physical addresses, otherwise we'd
         * need a much more complicated tracking system.  Unfortunately that
         * means we need to use one of the iommu domains to figure out the
         * pfns to unpin.  The rest need to be unmapped in advance so we have
         * no iommu translations remaining when the pages are unpinned.
         */
        domain = d = list_first_entry(&iommu->domain_list,
                                      struct vfio_domain, next);

        list_for_each_entry_continue(d, &iommu->domain_list, next) {
                iommu_unmap(d->domain, dma->iova, dma->size);
                cond_resched();
        }

        iommu_iotlb_gather_init(&iotlb_gather);
        while (pos < dma->size) {
                size_t unmapped, len;
                phys_addr_t phys, next;
                dma_addr_t iova = dma->iova + pos;

                phys = iommu_iova_to_phys(domain->domain, iova);
                if (WARN_ON(!phys)) {
                        pos += PAGE_SIZE;
                        continue;
                }

                /*
                 * To optimize for fewer iommu_unmap() calls, each of which
                 * may require hardware cache flushing, try to find the
                 * largest contiguous physical memory chunk to unmap.
                 */
                for (len = PAGE_SIZE; pos + len < dma->size; len += PAGE_SIZE) {
                        next = iommu_iova_to_phys(domain->domain, iova + len);
                        if (next != phys + len)
                                break;
                }

                /*
                 * First, try to use fast unmap/unpin. In case of failure,
                 * switch to slow unmap/unpin path.
                 */
                unmapped = unmap_unpin_fast(domain, dma, iova, len, phys,
                                            &unlocked, &unmapped_region_list,
                                            &unmapped_region_cnt,
                                            &iotlb_gather);
                if (!unmapped) {
                        unmapped = unmap_unpin_slow(domain, dma, iova, len,
                                                    phys, &unlocked);
                        if (WARN_ON(!unmapped))
                                break;
                }

                pos += unmapped;
        }

        dma->iommu_mapped = false;

        if (unmapped_region_cnt) {
                unlocked += vfio_sync_unpin(dma, domain, &unmapped_region_list,
                                            &iotlb_gather);
        }

        if (do_accounting) {
                vfio_lock_acct(dma, -unlocked, true);
                return 0;
        }
        return unlocked;
}

static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma)
{
        WARN_ON(!RB_EMPTY_ROOT(&dma->pfn_list));
        vfio_unmap_unpin(iommu, dma, true);
        vfio_unlink_dma(iommu, dma);
        put_task_struct(dma->task);
        mmdrop(dma->mm);
        vfio_dma_bitmap_free(dma);
        if (dma->vaddr_invalid)
                iommu->vaddr_invalid_count--;
        kfree(dma);
        iommu->dma_avail++;
}

static void vfio_update_pgsize_bitmap(struct vfio_iommu *iommu)
{
        struct vfio_domain *domain;

        iommu->pgsize_bitmap = ULONG_MAX;

        list_for_each_entry(domain, &iommu->domain_list, next)
                iommu->pgsize_bitmap &= domain->domain->pgsize_bitmap;

        /*
         * In case the IOMMU supports page sizes smaller than PAGE_SIZE
         * we pretend PAGE_SIZE is supported and hide sub-PAGE_SIZE sizes.
         * That way the user will be able to map/unmap buffers whose size/
         * start address is aligned with PAGE_SIZE. Pinning code uses that
         * granularity while iommu driver can use the sub-PAGE_SIZE size
         * to map the buffer.
         */
        if (iommu->pgsize_bitmap & ~PAGE_MASK) {
                iommu->pgsize_bitmap &= PAGE_MASK;
                iommu->pgsize_bitmap |= PAGE_SIZE;
        }
}

static int update_user_bitmap(u64 __user *bitmap, struct vfio_iommu *iommu,
                              struct vfio_dma *dma, dma_addr_t base_iova,
                              size_t pgsize)
{
        unsigned long pgshift = __ffs(pgsize);
        unsigned long nbits = dma->size >> pgshift;
        unsigned long bit_offset = (dma->iova - base_iova) >> pgshift;
        unsigned long copy_offset = bit_offset / BITS_PER_LONG;
        unsigned long shift = bit_offset % BITS_PER_LONG;
        unsigned long leftover;

        /*
         * mark all pages dirty if any IOMMU capable device is not able
         * to report dirty pages and all pages are pinned and mapped.
         */
        if (iommu->num_non_pinned_groups && dma->iommu_mapped)
                bitmap_set(dma->bitmap, 0, nbits);

        if (shift) {
                bitmap_shift_left(dma->bitmap, dma->bitmap, shift,
                                  nbits + shift);

                if (copy_from_user(&leftover,
                                   (void __user *)(bitmap + copy_offset),
                                   sizeof(leftover)))
                        return -EFAULT;

                bitmap_or(dma->bitmap, dma->bitmap, &leftover, shift);
        }

        if (copy_to_user((void __user *)(bitmap + copy_offset), dma->bitmap,
                         DIRTY_BITMAP_BYTES(nbits + shift)))
                return -EFAULT;

        return 0;
}

static int vfio_iova_dirty_bitmap(u64 __user *bitmap, struct vfio_iommu *iommu,
                                  dma_addr_t iova, dma_addr_t iova_end, size_t pgsize)
{
        struct vfio_dma *dma;
        struct rb_node *n;
        unsigned long pgshift = __ffs(pgsize);
        int ret;

        /*
         * GET_BITMAP request must fully cover vfio_dma mappings.  Multiple
         * vfio_dma mappings may be clubbed by specifying large ranges, but
         * there must not be any previous mappings bisected by the range.
         * An error will be returned if these conditions are not met.
         */
        dma = vfio_find_dma(iommu, iova, 1);
        if (dma && dma->iova != iova)
                return -EINVAL;

        dma = vfio_find_dma(iommu, iova_end, 1);
        if (dma && dma->iova + dma->size - 1 != iova_end)
                return -EINVAL;

        for (n = rb_first(&iommu->dma_list); n; n = rb_next(n)) {
                struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node);

                if (dma->iova < iova)
                        continue;

                if (dma->iova > iova_end)
                        break;

                ret = update_user_bitmap(bitmap, iommu, dma, iova, pgsize);
                if (ret)
                        return ret;

                /*
                 * Re-populate bitmap to include all pinned pages which are
                 * considered as dirty but exclude pages which are unpinned and
                 * pages which are marked dirty by vfio_dma_rw()
                 */
                bitmap_clear(dma->bitmap, 0, dma->size >> pgshift);
                vfio_dma_populate_bitmap(dma, pgsize);
        }
        return 0;
}

static int verify_bitmap_size(uint64_t npages, uint64_t bitmap_size)
{
        if (!npages || !bitmap_size || (bitmap_size > DIRTY_BITMAP_SIZE_MAX) ||
            (bitmap_size < DIRTY_BITMAP_BYTES(npages)))
                return -EINVAL;

        return 0;
}

/*
 * Notify VFIO drivers using vfio_register_emulated_iommu_dev() to invalidate
 * and unmap iovas within the range we're about to unmap. Drivers MUST unpin
 * pages in response to an invalidation.
 */
static void vfio_notify_dma_unmap(struct vfio_iommu *iommu,
                                  struct vfio_dma *dma)
{
        struct vfio_device *device;

        if (list_empty(&iommu->device_list))
                return;

        /*
         * The device is expected to call vfio_unpin_pages() for any IOVA it has
         * pinned within the range. Since vfio_unpin_pages() will eventually
         * call back down to this code and try to obtain the iommu->lock we must
         * drop it.
         */
        mutex_lock(&iommu->device_list_lock);
        mutex_unlock(&iommu->lock);

        list_for_each_entry(device, &iommu->device_list, iommu_entry)
                device->ops->dma_unmap(device, dma->iova, dma->size);

        mutex_unlock(&iommu->device_list_lock);
        mutex_lock(&iommu->lock);
}

static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
                             struct vfio_iommu_type1_dma_unmap *unmap,
                             struct vfio_bitmap *bitmap)
{
        struct vfio_dma *dma, *dma_last = NULL;
        size_t unmapped = 0, pgsize;
        int ret = -EINVAL, retries = 0;
        unsigned long pgshift;
        dma_addr_t iova = unmap->iova;
        dma_addr_t iova_end;
        size_t size = unmap->size;
        bool unmap_all = unmap->flags & VFIO_DMA_UNMAP_FLAG_ALL;
        bool invalidate_vaddr = unmap->flags & VFIO_DMA_UNMAP_FLAG_VADDR;
        struct rb_node *n, *first_n;

        mutex_lock(&iommu->lock);

        /* Cannot update vaddr if mdev is present. */
        if (invalidate_vaddr && !list_empty(&iommu->emulated_iommu_groups)) {
                ret = -EBUSY;
                goto unlock;
        }

        if (iova != unmap->iova || size != unmap->size) {
                ret = -EOVERFLOW;
                goto unlock;
        }

        pgshift = __ffs(iommu->pgsize_bitmap);
        pgsize = (size_t)1 << pgshift;

        if (iova & (pgsize - 1))
                goto unlock;

        if (unmap_all) {
                if (iova || size)
                        goto unlock;
                iova_end = ~(dma_addr_t)0;
        } else {
                if (!size || size & (pgsize - 1))
                        goto unlock;

                if (check_add_overflow(iova, size - 1, &iova_end)) {
                        ret = -EOVERFLOW;
                        goto unlock;
                }
        }

        /* When dirty tracking is enabled, allow only min supported pgsize */
        if ((unmap->flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) &&
            (!iommu->dirty_page_tracking || (bitmap->pgsize != pgsize))) {
                goto unlock;
        }

        WARN_ON((pgsize - 1) & PAGE_MASK);
again:
        /*
         * vfio-iommu-type1 (v1) - User mappings were coalesced together to
         * avoid tracking individual mappings.  This means that the granularity
         * of the original mapping was lost and the user was allowed to attempt
         * to unmap any range.  Depending on the contiguousness of physical
         * memory and page sizes supported by the IOMMU, arbitrary unmaps may
         * or may not have worked.  We only guaranteed unmap granularity
         * matching the original mapping; even though it was untracked here,
         * the original mappings are reflected in IOMMU mappings.  This
         * resulted in a couple unusual behaviors.  First, if a range is not
         * able to be unmapped, ex. a set of 4k pages that was mapped as a
         * 2M hugepage into the IOMMU, the unmap ioctl returns success but with
         * a zero sized unmap.  Also, if an unmap request overlaps the first
         * address of a hugepage, the IOMMU will unmap the entire hugepage.
         * This also returns success and the returned unmap size reflects the
         * actual size unmapped.
         *
         * We attempt to maintain compatibility with this "v1" interface, but
         * we take control out of the hands of the IOMMU.  Therefore, an unmap
         * request offset from the beginning of the original mapping will
         * return success with zero sized unmap.  And an unmap request covering
         * the first iova of mapping will unmap the entire range.
         *
         * The v2 version of this interface intends to be more deterministic.
         * Unmap requests must fully cover previous mappings.  Multiple
         * mappings may still be unmaped by specifying large ranges, but there
         * must not be any previous mappings bisected by the range.  An error
         * will be returned if these conditions are not met.  The v2 interface
         * will only return success and a size of zero if there were no
         * mappings within the range.
         */
        if (iommu->v2 && !unmap_all) {
                dma = vfio_find_dma(iommu, iova, 1);
                if (dma && dma->iova != iova)
                        goto unlock;

                dma = vfio_find_dma(iommu, iova_end, 1);
                if (dma && dma->iova + dma->size - 1 != iova_end)
                        goto unlock;
        }

        ret = 0;
        n = first_n = vfio_find_dma_first_node(iommu, iova, iova_end);

        while (n) {
                dma = rb_entry(n, struct vfio_dma, node);
                if (dma->iova > iova_end)
                        break;

                if (!iommu->v2 && iova > dma->iova)
                        break;

                if (invalidate_vaddr) {
                        if (dma->vaddr_invalid) {
                                struct rb_node *last_n = n;

                                for (n = first_n; n != last_n; n = rb_next(n)) {
                                        dma = rb_entry(n,
                                                       struct vfio_dma, node);
                                        dma->vaddr_invalid = false;
                                        iommu->vaddr_invalid_count--;
                                }
                                ret = -EINVAL;
                                unmapped = 0;
                                break;
                        }
                        dma->vaddr_invalid = true;
                        iommu->vaddr_invalid_count++;
                        unmapped += dma->size;
                        n = rb_next(n);
                        continue;
                }

                if (!RB_EMPTY_ROOT(&dma->pfn_list)) {
                        if (dma_last == dma) {
                                BUG_ON(++retries > 10);
                        } else {
                                dma_last = dma;
                                retries = 0;
                        }

                        vfio_notify_dma_unmap(iommu, dma);
                        goto again;
                }

                if (unmap->flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) {
                        ret = update_user_bitmap(bitmap->data, iommu, dma,
                                                 iova, pgsize);
                        if (ret)
                                break;
                }

                unmapped += dma->size;
                n = rb_next(n);
                vfio_remove_dma(iommu, dma);
        }

unlock:
        mutex_unlock(&iommu->lock);

        /* Report how much was unmapped */
        unmap->size = unmapped;

        return ret;
}

static int vfio_iommu_map(struct vfio_iommu *iommu, dma_addr_t iova,
                          unsigned long pfn, long npage, int prot)
{
        struct vfio_domain *d;
        int ret;

        list_for_each_entry(d, &iommu->domain_list, next) {
                ret = iommu_map(d->domain, iova, (phys_addr_t)pfn << PAGE_SHIFT,
                                npage << PAGE_SHIFT, prot | IOMMU_CACHE,
                                GFP_KERNEL_ACCOUNT);
                if (ret)
                        goto unwind;

                cond_resched();
        }

        return 0;

unwind:
        list_for_each_entry_continue_reverse(d, &iommu->domain_list, next) {
                iommu_unmap(d->domain, iova, npage << PAGE_SHIFT);
                cond_resched();
        }

        return ret;
}

static int vfio_pin_map_dma(struct vfio_iommu *iommu, struct vfio_dma *dma,
                            size_t map_size)
{
        dma_addr_t iova = dma->iova;
        unsigned long vaddr = dma->vaddr;
        struct vfio_batch batch;
        size_t size = map_size;
        long npage;
        unsigned long pfn, limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
        int ret = 0;

        vfio_batch_init(&batch);

        while (size) {
                /* Pin a contiguous chunk of memory */
                npage = vfio_pin_pages_remote(dma, vaddr + dma->size,
                                              size >> PAGE_SHIFT, &pfn, limit,
                                              &batch);
                if (npage <= 0) {
                        WARN_ON(!npage);
                        ret = (int)npage;
                        break;
                }

                /* Map it! */
                ret = vfio_iommu_map(iommu, iova + dma->size, pfn, npage,
                                     dma->prot);
                if (ret) {
                        vfio_unpin_pages_remote(dma, iova + dma->size, pfn,
                                                npage, true);
                        vfio_batch_unpin(&batch, dma);
                        break;
                }

                size -= npage << PAGE_SHIFT;
                dma->size += npage << PAGE_SHIFT;
        }

        vfio_batch_fini(&batch);
        dma->iommu_mapped = true;

        if (ret)
                vfio_remove_dma(iommu, dma);

        return ret;
}

/*
 * Check dma map request is within a valid iova range
 */
static bool vfio_iommu_iova_dma_valid(struct vfio_iommu *iommu,
                                      dma_addr_t start, dma_addr_t end)
{
        struct list_head *iova = &iommu->iova_list;
        struct vfio_iova *node;

        list_for_each_entry(node, iova, list) {
                if (start >= node->start && end <= node->end)
                        return true;
        }

        /*
         * Check for list_empty() as well since a container with
         * a single mdev device will have an empty list.
         */
        return list_empty(iova);
}

static int vfio_change_dma_owner(struct vfio_dma *dma)
{
        struct task_struct *task = current->group_leader;
        struct mm_struct *mm = current->mm;
        long npage = dma->locked_vm;
        bool lock_cap;
        int ret;

        if (mm == dma->mm)
                return 0;

        lock_cap = capable(CAP_IPC_LOCK);
        ret = mm_lock_acct(task, mm, lock_cap, npage);
        if (ret)
                return ret;

        if (mmget_not_zero(dma->mm)) {
                mm_lock_acct(dma->task, dma->mm, dma->lock_cap, -npage);
                mmput(dma->mm);
        }

        if (dma->task != task) {
                put_task_struct(dma->task);
                dma->task = get_task_struct(task);
        }
        mmdrop(dma->mm);
        dma->mm = mm;
        mmgrab(dma->mm);
        dma->lock_cap = lock_cap;
        return 0;
}

static int vfio_dma_do_map(struct vfio_iommu *iommu,
                           struct vfio_iommu_type1_dma_map *map)
{
        bool set_vaddr = map->flags & VFIO_DMA_MAP_FLAG_VADDR;
        dma_addr_t iova = map->iova;
        dma_addr_t iova_end;
        unsigned long vaddr = map->vaddr;
        unsigned long vaddr_end;
        size_t size = map->size;
        int ret = 0, prot = 0;
        size_t pgsize;
        struct vfio_dma *dma;

        /* Verify that none of our __u64 fields overflow */
        if (map->size != size || map->vaddr != vaddr || map->iova != iova)
                return -EOVERFLOW;

        if (!size)
                return -EINVAL;

        if (check_add_overflow(iova, size - 1, &iova_end) ||
            check_add_overflow(vaddr, size - 1, &vaddr_end))
                return -EOVERFLOW;

        /* READ/WRITE from device perspective */
        if (map->flags & VFIO_DMA_MAP_FLAG_WRITE)
                prot |= IOMMU_WRITE;
        if (map->flags & VFIO_DMA_MAP_FLAG_READ)
                prot |= IOMMU_READ;

        if ((prot && set_vaddr) || (!prot && !set_vaddr))
                return -EINVAL;

        mutex_lock(&iommu->lock);

        pgsize = (size_t)1 << __ffs(iommu->pgsize_bitmap);

        WARN_ON((pgsize - 1) & PAGE_MASK);

        if ((size | iova | vaddr) & (pgsize - 1)) {
                ret = -EINVAL;
                goto out_unlock;
        }

        dma = vfio_find_dma(iommu, iova, size);
        if (set_vaddr) {
                if (!dma) {
                        ret = -ENOENT;
                } else if (!dma->vaddr_invalid || dma->iova != iova ||
                           dma->size != size) {
                        ret = -EINVAL;
                } else {
                        ret = vfio_change_dma_owner(dma);
                        if (ret)
                                goto out_unlock;
                        dma->vaddr = vaddr;
                        dma->vaddr_invalid = false;
                        iommu->vaddr_invalid_count--;
                }
                goto out_unlock;
        } else if (dma) {
                ret = -EEXIST;
                goto out_unlock;
        }

        if (!iommu->dma_avail) {
                ret = -ENOSPC;
                goto out_unlock;
        }

        if (!vfio_iommu_iova_dma_valid(iommu, iova, iova_end)) {
                ret = -EINVAL;
                goto out_unlock;
        }

        dma = kzalloc_obj(*dma);
        if (!dma) {
                ret = -ENOMEM;
                goto out_unlock;
        }

        iommu->dma_avail--;
        dma->iova = iova;
        dma->vaddr = vaddr;
        dma->prot = prot;

        /*
         * We need to be able to both add to a task's locked memory and test
         * against the locked memory limit and we need to be able to do both
         * outside of this call path as pinning can be asynchronous via the
         * external interfaces for mdev devices.  RLIMIT_MEMLOCK requires a
         * task_struct. Save the group_leader so that all DMA tracking uses
         * the same task, to make debugging easier.  VM locked pages requires
         * an mm_struct, so grab the mm in case the task dies.
         */
        get_task_struct(current->group_leader);
        dma->task = current->group_leader;
        dma->lock_cap = capable(CAP_IPC_LOCK);
        dma->mm = current->mm;
        mmgrab(dma->mm);

        dma->pfn_list = RB_ROOT;

        /* Insert zero-sized and grow as we map chunks of it */
        vfio_link_dma(iommu, dma);

        /* Don't pin and map if container doesn't contain IOMMU capable domain*/
        if (list_empty(&iommu->domain_list))
                dma->size = size;
        else
                ret = vfio_pin_map_dma(iommu, dma, size);

        if (!ret && iommu->dirty_page_tracking) {
                ret = vfio_dma_bitmap_alloc(dma, pgsize);
                if (ret)
                        vfio_remove_dma(iommu, dma);
        }

out_unlock:
        mutex_unlock(&iommu->lock);
        return ret;
}

static int vfio_iommu_replay(struct vfio_iommu *iommu,
                             struct vfio_domain *domain)
{
        struct vfio_batch batch;
        struct vfio_domain *d = NULL;
        struct rb_node *n;
        unsigned long limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
        int ret;

        /* Arbitrarily pick the first domain in the list for lookups */
        if (!list_empty(&iommu->domain_list))
                d = list_first_entry(&iommu->domain_list,
                                     struct vfio_domain, next);

        vfio_batch_init(&batch);

        n = rb_first(&iommu->dma_list);

        for (; n; n = rb_next(n)) {
                struct vfio_dma *dma;
                size_t pos = 0;

                dma = rb_entry(n, struct vfio_dma, node);

                while (pos < dma->size) {
                        dma_addr_t iova = dma->iova + pos;
                        phys_addr_t phys;
                        size_t size;

                        if (dma->iommu_mapped) {
                                phys_addr_t p;
                                dma_addr_t i;

                                if (WARN_ON(!d)) { /* mapped w/o a domain?! */
                                        ret = -EINVAL;
                                        goto unwind;
                                }

                                phys = iommu_iova_to_phys(d->domain, iova);

                                if (WARN_ON(!phys)) {
                                        pos += PAGE_SIZE;
                                        continue;
                                }

                                size = PAGE_SIZE;
                                p = phys + size;
                                i = iova + size;
                                while (pos + size < dma->size &&
                                       p == iommu_iova_to_phys(d->domain, i)) {
                                        size += PAGE_SIZE;
                                        p += PAGE_SIZE;
                                        i += PAGE_SIZE;
                                }
                        } else {
                                unsigned long pfn;
                                unsigned long vaddr = dma->vaddr + pos;
                                size_t n = dma->size - pos;
                                long npage;

                                npage = vfio_pin_pages_remote(dma, vaddr,
                                                              n >> PAGE_SHIFT,
                                                              &pfn, limit,
                                                              &batch);
                                if (npage <= 0) {
                                        WARN_ON(!npage);
                                        ret = (int)npage;
                                        goto unwind;
                                }

                                phys = pfn << PAGE_SHIFT;
                                size = npage << PAGE_SHIFT;
                        }

                        ret = iommu_map(domain->domain, iova, phys, size,
                                        dma->prot | IOMMU_CACHE,
                                        GFP_KERNEL_ACCOUNT);
                        if (ret) {
                                if (!dma->iommu_mapped) {
                                        vfio_unpin_pages_remote(dma, iova,
                                                        phys >> PAGE_SHIFT,
                                                        size >> PAGE_SHIFT,
                                                        true);
                                        vfio_batch_unpin(&batch, dma);
                                }
                                goto unwind;
                        }

                        pos += size;
                }
        }

        /* All dmas are now mapped, defer to second tree walk for unwind */
        for (n = rb_first(&iommu->dma_list); n; n = rb_next(n)) {
                struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node);

                dma->iommu_mapped = true;
        }

        vfio_batch_fini(&batch);
        return 0;

unwind:
        for (; n; n = rb_prev(n)) {
                struct vfio_dma *dma = rb_entry(n, struct vfio_dma, node);
                size_t pos = 0;

                if (dma->iommu_mapped) {
                        iommu_unmap(domain->domain, dma->iova, dma->size);
                        continue;
                }

                while (pos < dma->size) {
                        dma_addr_t iova = dma->iova + pos;
                        phys_addr_t phys, p;
                        size_t size;
                        dma_addr_t i;

                        phys = iommu_iova_to_phys(domain->domain, iova);
                        if (!phys) {
                                pos += PAGE_SIZE;
                                continue;
                        }

                        size = PAGE_SIZE;
                        p = phys + size;
                        i = iova + size;
                        while (pos + size < dma->size &&
                               p == iommu_iova_to_phys(domain->domain, i)) {
                                size += PAGE_SIZE;
                                p += PAGE_SIZE;
                                i += PAGE_SIZE;
                        }

                        iommu_unmap(domain->domain, iova, size);
                        vfio_unpin_pages_remote(dma, iova, phys >> PAGE_SHIFT,
                                                size >> PAGE_SHIFT, true);
                }
        }

        vfio_batch_fini(&batch);
        return ret;
}

static struct vfio_iommu_group *find_iommu_group(struct vfio_domain *domain,
                                                 struct iommu_group *iommu_group)
{
        struct vfio_iommu_group *g;

        list_for_each_entry(g, &domain->group_list, next) {
                if (g->iommu_group == iommu_group)
                        return g;
        }

        return NULL;
}

static struct vfio_iommu_group*
vfio_iommu_find_iommu_group(struct vfio_iommu *iommu,
                            struct iommu_group *iommu_group)
{
        struct vfio_iommu_group *group;
        struct vfio_domain *domain;

        list_for_each_entry(domain, &iommu->domain_list, next) {
                group = find_iommu_group(domain, iommu_group);
                if (group)
                        return group;
        }

        list_for_each_entry(group, &iommu->emulated_iommu_groups, next)
                if (group->iommu_group == iommu_group)
                        return group;
        return NULL;
}

static bool vfio_iommu_has_sw_msi(struct list_head *group_resv_regions,
                                  phys_addr_t *base)
{
        struct iommu_resv_region *region;
        bool ret = false;

        list_for_each_entry(region, group_resv_regions, list) {
                /*
                 * The presence of any 'real' MSI regions should take
                 * precedence over the software-managed one if the
                 * IOMMU driver happens to advertise both types.
                 */
                if (region->type == IOMMU_RESV_MSI) {
                        ret = false;
                        break;
                }

                if (region->type == IOMMU_RESV_SW_MSI) {
                        *base = region->start;
                        ret = true;
                }
        }

        return ret;
}

/*
 * This is a helper function to insert an address range to iova list.
 * The list is initially created with a single entry corresponding to
 * the IOMMU domain geometry to which the device group is attached.
 * The list aperture gets modified when a new domain is added to the
 * container if the new aperture doesn't conflict with the current one
 * or with any existing dma mappings. The list is also modified to
 * exclude any reserved regions associated with the device group.
 */
static int vfio_iommu_iova_insert(struct list_head *head,
                                  dma_addr_t start, dma_addr_t end)
{
        struct vfio_iova *region;

        region = kmalloc_obj(*region);
        if (!region)
                return -ENOMEM;

        INIT_LIST_HEAD(&region->list);
        region->start = start;
        region->end = end;

        list_add_tail(&region->list, head);
        return 0;
}

/*
 * Check the new iommu aperture conflicts with existing aper or with any
 * existing dma mappings.
 */
static bool vfio_iommu_aper_conflict(struct vfio_iommu *iommu,
                                     dma_addr_t start, dma_addr_t end)
{
        struct vfio_iova *first, *last;
        struct list_head *iova = &iommu->iova_list;

        if (list_empty(iova))
                return false;

        /* Disjoint sets, return conflict */
        first = list_first_entry(iova, struct vfio_iova, list);
        last = list_last_entry(iova, struct vfio_iova, list);
        if (start > last->end || end < first->start)
                return true;

        /* Check for any existing dma mappings below the new start */
        if (start > first->start) {
                if (vfio_find_dma(iommu, first->start, start - first->start))
                        return true;
        }

        /* Check for any existing dma mappings beyond the new end */
        if (end < last->end) {
                if (vfio_find_dma(iommu, end + 1, last->end - end))
                        return true;
        }

        return false;
}

/*
 * Resize iommu iova aperture window. This is called only if the new
 * aperture has no conflict with existing aperture and dma mappings.
 */
static int vfio_iommu_aper_resize(struct list_head *iova,
                                  dma_addr_t start, dma_addr_t end)
{
        struct vfio_iova *node, *next;

        if (list_empty(iova))
                return vfio_iommu_iova_insert(iova, start, end);

        /* Adjust iova list start */
        list_for_each_entry_safe(node, next, iova, list) {
                if (start < node->start)
                        break;
                if (start >= node->start && start < node->end) {
                        node->start = start;
                        break;
                }
                /* Delete nodes before new start */
                list_del(&node->list);
                kfree(node);
        }

        /* Adjust iova list end */
        list_for_each_entry_safe(node, next, iova, list) {
                if (end > node->end)
                        continue;
                if (end > node->start && end <= node->end) {
                        node->end = end;
                        continue;
                }
                /* Delete nodes after new end */
                list_del(&node->list);
                kfree(node);
        }

        return 0;
}

/*
 * Check reserved region conflicts with existing dma mappings
 */
static bool vfio_iommu_resv_conflict(struct vfio_iommu *iommu,
                                     struct list_head *resv_regions)
{
        struct iommu_resv_region *region;

        /* Check for conflict with existing dma mappings */
        list_for_each_entry(region, resv_regions, list) {
                if (region->type == IOMMU_RESV_DIRECT_RELAXABLE)
                        continue;

                if (vfio_find_dma(iommu, region->start, region->length))
                        return true;
        }

        return false;
}

/*
 * Check iova region overlap with  reserved regions and
 * exclude them from the iommu iova range
 */
static int vfio_iommu_resv_exclude(struct list_head *iova,
                                   struct list_head *resv_regions)
{
        struct iommu_resv_region *resv;
        struct vfio_iova *n, *next;

        list_for_each_entry(resv, resv_regions, list) {
                phys_addr_t start, end;

                if (resv->type == IOMMU_RESV_DIRECT_RELAXABLE)
                        continue;

                start = resv->start;
                end = resv->start + resv->length - 1;

                list_for_each_entry_safe(n, next, iova, list) {
                        int ret = 0;

                        /* No overlap */
                        if (start > n->end || end < n->start)
                                continue;
                        /*
                         * Insert a new node if current node overlaps with the
                         * reserve region to exclude that from valid iova range.
                         * Note that, new node is inserted before the current
                         * node and finally the current node is deleted keeping
                         * the list updated and sorted.
                         */
                        if (start > n->start)
                                ret = vfio_iommu_iova_insert(&n->list, n->start,
                                                             start - 1);
                        if (!ret && end < n->end)
                                ret = vfio_iommu_iova_insert(&n->list, end + 1,
                                                             n->end);
                        if (ret)
                                return ret;

                        list_del(&n->list);
                        kfree(n);
                }
        }

        if (list_empty(iova))
                return -EINVAL;

        return 0;
}

static void vfio_iommu_resv_free(struct list_head *resv_regions)
{
        struct iommu_resv_region *n, *next;

        list_for_each_entry_safe(n, next, resv_regions, list) {
                list_del(&n->list);
                kfree(n);
        }
}

static void vfio_iommu_iova_free(struct list_head *iova)
{
        struct vfio_iova *n, *next;

        list_for_each_entry_safe(n, next, iova, list) {
                list_del(&n->list);
                kfree(n);
        }
}

static int vfio_iommu_iova_get_copy(struct vfio_iommu *iommu,
                                    struct list_head *iova_copy)
{
        struct list_head *iova = &iommu->iova_list;
        struct vfio_iova *n;
        int ret;

        list_for_each_entry(n, iova, list) {
                ret = vfio_iommu_iova_insert(iova_copy, n->start, n->end);
                if (ret)
                        goto out_free;
        }

        return 0;

out_free:
        vfio_iommu_iova_free(iova_copy);
        return ret;
}

static void vfio_iommu_iova_insert_copy(struct vfio_iommu *iommu,
                                        struct list_head *iova_copy)
{
        struct list_head *iova = &iommu->iova_list;

        vfio_iommu_iova_free(iova);

        list_splice_tail(iova_copy, iova);
}

static int vfio_iommu_domain_alloc(struct device *dev, void *data)
{
        struct iommu_domain **domain = data;

        *domain = iommu_paging_domain_alloc(dev);
        return 1; /* Don't iterate */
}

static int vfio_iommu_type1_attach_group(void *iommu_data,
                struct iommu_group *iommu_group, enum vfio_group_type type)
{
        struct vfio_iommu *iommu = iommu_data;
        struct vfio_iommu_group *group;
        struct vfio_domain *domain, *d;
        bool resv_msi;
        phys_addr_t resv_msi_base = 0;
        struct iommu_domain_geometry *geo;
        LIST_HEAD(iova_copy);
        LIST_HEAD(group_resv_regions);
        int ret = -EBUSY;

        mutex_lock(&iommu->lock);

        /* Attach could require pinning, so disallow while vaddr is invalid. */
        if (iommu->vaddr_invalid_count)
                goto out_unlock;

        /* Check for duplicates */
        ret = -EINVAL;
        if (vfio_iommu_find_iommu_group(iommu, iommu_group))
                goto out_unlock;

        ret = -ENOMEM;
        group = kzalloc_obj(*group);
        if (!group)
                goto out_unlock;
        group->iommu_group = iommu_group;

        if (type == VFIO_EMULATED_IOMMU) {
                list_add(&group->next, &iommu->emulated_iommu_groups);
                /*
                 * An emulated IOMMU group cannot dirty memory directly, it can
                 * only use interfaces that provide dirty tracking.
                 * The iommu scope can only be promoted with the addition of a
                 * dirty tracking group.
                 */
                group->pinned_page_dirty_scope = true;
                ret = 0;
                goto out_unlock;
        }

        ret = -ENOMEM;
        domain = kzalloc_obj(*domain);
        if (!domain)
                goto out_free_group;

        /*
         * Going via the iommu_group iterator avoids races, and trivially gives
         * us a representative device for the IOMMU API call. We don't actually
         * want to iterate beyond the first device (if any).
         */
        iommu_group_for_each_dev(iommu_group, &domain->domain,
                                 vfio_iommu_domain_alloc);
        if (IS_ERR(domain->domain)) {
                ret = PTR_ERR(domain->domain);
                goto out_free_domain;
        }

        ret = iommu_attach_group(domain->domain, group->iommu_group);
        if (ret)
                goto out_domain;

        /* Get aperture info */
        geo = &domain->domain->geometry;
        if (vfio_iommu_aper_conflict(iommu, geo->aperture_start,
                                     geo->aperture_end)) {
                ret = -EINVAL;
                goto out_detach;
        }

        ret = iommu_get_group_resv_regions(iommu_group, &group_resv_regions);
        if (ret)
                goto out_detach;

        if (vfio_iommu_resv_conflict(iommu, &group_resv_regions)) {
                ret = -EINVAL;
                goto out_detach;
        }

        /*
         * We don't want to work on the original iova list as the list
         * gets modified and in case of failure we have to retain the
         * original list. Get a copy here.
         */
        ret = vfio_iommu_iova_get_copy(iommu, &iova_copy);
        if (ret)
                goto out_detach;

        ret = vfio_iommu_aper_resize(&iova_copy, geo->aperture_start,
                                     geo->aperture_end);
        if (ret)
                goto out_detach;

        ret = vfio_iommu_resv_exclude(&iova_copy, &group_resv_regions);
        if (ret)
                goto out_detach;

        resv_msi = vfio_iommu_has_sw_msi(&group_resv_regions, &resv_msi_base);

        INIT_LIST_HEAD(&domain->group_list);
        list_add(&group->next, &domain->group_list);

        if (!allow_unsafe_interrupts &&
            !iommu_group_has_isolated_msi(iommu_group)) {
                pr_warn("%s: No interrupt remapping support.  Use the module param \"allow_unsafe_interrupts\" to enable VFIO IOMMU support on this platform\n",
                       __func__);
                ret = -EPERM;
                goto out_detach;
        }

        /*
         * If the IOMMU can block non-coherent operations (ie PCIe TLPs with
         * no-snoop set) then VFIO always turns this feature on because on Intel
         * platforms it optimizes KVM to disable wbinvd emulation.
         */
        if (domain->domain->ops->enforce_cache_coherency)
                domain->enforce_cache_coherency =
                        domain->domain->ops->enforce_cache_coherency(
                                domain->domain);

        /*
         * Try to match an existing compatible domain.  We don't want to
         * preclude an IOMMU driver supporting multiple bus_types and being
         * able to include different bus_types in the same IOMMU domain, so
         * we test whether the domains use the same iommu_ops rather than
         * testing if they're on the same bus_type.
         */
        list_for_each_entry(d, &iommu->domain_list, next) {
                if (d->domain->ops == domain->domain->ops &&
                    d->enforce_cache_coherency ==
                            domain->enforce_cache_coherency) {
                        iommu_detach_group(domain->domain, group->iommu_group);
                        if (!iommu_attach_group(d->domain,
                                                group->iommu_group)) {
                                list_add(&group->next, &d->group_list);
                                iommu_domain_free(domain->domain);
                                kfree(domain);
                                goto done;
                        }

                        ret = iommu_attach_group(domain->domain,
                                                 group->iommu_group);
                        if (ret)
                                goto out_domain;
                }
        }

        /* replay mappings on new domains */
        ret = vfio_iommu_replay(iommu, domain);
        if (ret)
                goto out_detach;

        if (resv_msi) {
                ret = iommu_get_msi_cookie(domain->domain, resv_msi_base);
                if (ret && ret != -ENODEV)
                        goto out_detach;
        }

        list_add(&domain->next, &iommu->domain_list);
        vfio_update_pgsize_bitmap(iommu);
done:
        /* Delete the old one and insert new iova list */
        vfio_iommu_iova_insert_copy(iommu, &iova_copy);

        /*
         * An iommu backed group can dirty memory directly and therefore
         * demotes the iommu scope until it declares itself dirty tracking
         * capable via the page pinning interface.
         */
        iommu->num_non_pinned_groups++;
        mutex_unlock(&iommu->lock);
        vfio_iommu_resv_free(&group_resv_regions);

        return 0;

out_detach:
        iommu_detach_group(domain->domain, group->iommu_group);
out_domain:
        iommu_domain_free(domain->domain);
        vfio_iommu_iova_free(&iova_copy);
        vfio_iommu_resv_free(&group_resv_regions);
out_free_domain:
        kfree(domain);
out_free_group:
        kfree(group);
out_unlock:
        mutex_unlock(&iommu->lock);
        return ret;
}

static void vfio_iommu_unmap_unpin_all(struct vfio_iommu *iommu)
{
        struct rb_node *node;

        while ((node = rb_first(&iommu->dma_list)))
                vfio_remove_dma(iommu, rb_entry(node, struct vfio_dma, node));
}

static void vfio_iommu_unmap_unpin_reaccount(struct vfio_iommu *iommu)
{
        struct rb_node *n, *p;

        n = rb_first(&iommu->dma_list);
        for (; n; n = rb_next(n)) {
                struct vfio_dma *dma;
                long locked = 0, unlocked = 0;

                dma = rb_entry(n, struct vfio_dma, node);
                unlocked += vfio_unmap_unpin(iommu, dma, false);
                p = rb_first(&dma->pfn_list);
                for (; p; p = rb_next(p)) {
                        struct vfio_pfn *vpfn = rb_entry(p, struct vfio_pfn,
                                                         node);

                        if (!is_invalid_reserved_pfn(vpfn->pfn))
                                locked++;
                }
                vfio_lock_acct(dma, locked - unlocked, true);
        }
}

/*
 * Called when a domain is removed in detach. It is possible that
 * the removed domain decided the iova aperture window. Modify the
 * iova aperture with the smallest window among existing domains.
 */
static void vfio_iommu_aper_expand(struct vfio_iommu *iommu,
                                   struct list_head *iova_copy)
{
        struct vfio_domain *domain;
        struct vfio_iova *node;
        dma_addr_t start = 0;
        dma_addr_t end = (dma_addr_t)~0;

        if (list_empty(iova_copy))
                return;

        list_for_each_entry(domain, &iommu->domain_list, next) {
                struct iommu_domain_geometry *geo = &domain->domain->geometry;

                if (geo->aperture_start > start)
                        start = geo->aperture_start;
                if (geo->aperture_end < end)
                        end = geo->aperture_end;
        }

        /* Modify aperture limits. The new aper is either same or bigger */
        node = list_first_entry(iova_copy, struct vfio_iova, list);
        node->start = start;
        node = list_last_entry(iova_copy, struct vfio_iova, list);
        node->end = end;
}

/*
 * Called when a group is detached. The reserved regions for that
 * group can be part of valid iova now. But since reserved regions
 * may be duplicated among groups, populate the iova valid regions
 * list again.
 */
static int vfio_iommu_resv_refresh(struct vfio_iommu *iommu,
                                   struct list_head *iova_copy)
{
        struct vfio_domain *d;
        struct vfio_iommu_group *g;
        struct vfio_iova *node;
        dma_addr_t start, end;
        LIST_HEAD(resv_regions);
        int ret;

        if (list_empty(iova_copy))
                return -EINVAL;

        list_for_each_entry(d, &iommu->domain_list, next) {
                list_for_each_entry(g, &d->group_list, next) {
                        ret = iommu_get_group_resv_regions(g->iommu_group,
                                                           &resv_regions);
                        if (ret)
                                goto done;
                }
        }

        node = list_first_entry(iova_copy, struct vfio_iova, list);
        start = node->start;
        node = list_last_entry(iova_copy, struct vfio_iova, list);
        end = node->end;

        /* purge the iova list and create new one */
        vfio_iommu_iova_free(iova_copy);

        ret = vfio_iommu_aper_resize(iova_copy, start, end);
        if (ret)
                goto done;

        /* Exclude current reserved regions from iova ranges */
        ret = vfio_iommu_resv_exclude(iova_copy, &resv_regions);
done:
        vfio_iommu_resv_free(&resv_regions);
        return ret;
}

static void vfio_iommu_type1_detach_group(void *iommu_data,
                                          struct iommu_group *iommu_group)
{
        struct vfio_iommu *iommu = iommu_data;
        struct vfio_domain *domain;
        struct vfio_iommu_group *group;
        bool update_dirty_scope = false;
        LIST_HEAD(iova_copy);

        mutex_lock(&iommu->lock);
        list_for_each_entry(group, &iommu->emulated_iommu_groups, next) {
                if (group->iommu_group != iommu_group)
                        continue;
                update_dirty_scope = !group->pinned_page_dirty_scope;
                list_del(&group->next);
                kfree(group);

                if (list_empty(&iommu->emulated_iommu_groups) &&
                    list_empty(&iommu->domain_list)) {
                        WARN_ON(!list_empty(&iommu->device_list));
                        vfio_iommu_unmap_unpin_all(iommu);
                }
                goto detach_group_done;
        }

        /*
         * Get a copy of iova list. This will be used to update
         * and to replace the current one later. Please note that
         * we will leave the original list as it is if update fails.
         */
        vfio_iommu_iova_get_copy(iommu, &iova_copy);

        list_for_each_entry(domain, &iommu->domain_list, next) {
                group = find_iommu_group(domain, iommu_group);
                if (!group)
                        continue;

                iommu_detach_group(domain->domain, group->iommu_group);
                update_dirty_scope = !group->pinned_page_dirty_scope;
                list_del(&group->next);
                kfree(group);
                /*
                 * Group ownership provides privilege, if the group list is
                 * empty, the domain goes away. If it's the last domain with
                 * iommu and external domain doesn't exist, then all the
                 * mappings go away too. If it's the last domain with iommu and
                 * external domain exist, update accounting
                 */
                if (list_empty(&domain->group_list)) {
                        if (list_is_singular(&iommu->domain_list)) {
                                if (list_empty(&iommu->emulated_iommu_groups)) {
                                        WARN_ON(!list_empty(
                                                &iommu->device_list));
                                        vfio_iommu_unmap_unpin_all(iommu);
                                } else {
                                        vfio_iommu_unmap_unpin_reaccount(iommu);
                                }
                        }
                        iommu_domain_free(domain->domain);
                        list_del(&domain->next);
                        kfree(domain);
                        vfio_iommu_aper_expand(iommu, &iova_copy);
                        vfio_update_pgsize_bitmap(iommu);
                }
                break;
        }

        if (!vfio_iommu_resv_refresh(iommu, &iova_copy))
                vfio_iommu_iova_insert_copy(iommu, &iova_copy);
        else
                vfio_iommu_iova_free(&iova_copy);

detach_group_done:
        /*
         * Removal of a group without dirty tracking may allow the iommu scope
         * to be promoted.
         */
        if (update_dirty_scope) {
                iommu->num_non_pinned_groups--;
                if (iommu->dirty_page_tracking)
                        vfio_iommu_populate_bitmap_full(iommu);
        }
        mutex_unlock(&iommu->lock);
}

static void *vfio_iommu_type1_open(unsigned long arg)
{
        struct vfio_iommu *iommu;

        iommu = kzalloc_obj(*iommu);
        if (!iommu)
                return ERR_PTR(-ENOMEM);

        switch (arg) {
        case VFIO_TYPE1_IOMMU:
                break;
        case __VFIO_RESERVED_TYPE1_NESTING_IOMMU:
        case VFIO_TYPE1v2_IOMMU:
                iommu->v2 = true;
                break;
        default:
                kfree(iommu);
                return ERR_PTR(-EINVAL);
        }

        INIT_LIST_HEAD(&iommu->domain_list);
        INIT_LIST_HEAD(&iommu->iova_list);
        iommu->dma_list = RB_ROOT;
        iommu->dma_avail = dma_entry_limit;
        mutex_init(&iommu->lock);
        mutex_init(&iommu->device_list_lock);
        INIT_LIST_HEAD(&iommu->device_list);
        iommu->pgsize_bitmap = PAGE_MASK;
        INIT_LIST_HEAD(&iommu->emulated_iommu_groups);

        return iommu;
}

static void vfio_release_domain(struct vfio_domain *domain)
{
        struct vfio_iommu_group *group, *group_tmp;

        list_for_each_entry_safe(group, group_tmp,
                                 &domain->group_list, next) {
                iommu_detach_group(domain->domain, group->iommu_group);
                list_del(&group->next);
                kfree(group);
        }

        iommu_domain_free(domain->domain);
}

static void vfio_iommu_type1_release(void *iommu_data)
{
        struct vfio_iommu *iommu = iommu_data;
        struct vfio_domain *domain, *domain_tmp;
        struct vfio_iommu_group *group, *next_group;

        list_for_each_entry_safe(group, next_group,
                        &iommu->emulated_iommu_groups, next) {
                list_del(&group->next);
                kfree(group);
        }

        vfio_iommu_unmap_unpin_all(iommu);

        list_for_each_entry_safe(domain, domain_tmp,
                                 &iommu->domain_list, next) {
                vfio_release_domain(domain);
                list_del(&domain->next);
                kfree(domain);
        }

        vfio_iommu_iova_free(&iommu->iova_list);

        kfree(iommu);
}

static int vfio_domains_have_enforce_cache_coherency(struct vfio_iommu *iommu)
{
        struct vfio_domain *domain;
        int ret = 1;

        mutex_lock(&iommu->lock);
        list_for_each_entry(domain, &iommu->domain_list, next) {
                if (!(domain->enforce_cache_coherency)) {
                        ret = 0;
                        break;
                }
        }
        mutex_unlock(&iommu->lock);

        return ret;
}

static bool vfio_iommu_has_emulated(struct vfio_iommu *iommu)
{
        bool ret;

        mutex_lock(&iommu->lock);
        ret = !list_empty(&iommu->emulated_iommu_groups);
        mutex_unlock(&iommu->lock);
        return ret;
}

static int vfio_iommu_type1_check_extension(struct vfio_iommu *iommu,
                                            unsigned long arg)
{
        switch (arg) {
        case VFIO_TYPE1_IOMMU:
        case VFIO_TYPE1v2_IOMMU:
        case VFIO_UNMAP_ALL:
                return 1;
        case VFIO_UPDATE_VADDR:
                /*
                 * Disable this feature if mdevs are present.  They cannot
                 * safely pin/unpin/rw while vaddrs are being updated.
                 */
                return iommu && !vfio_iommu_has_emulated(iommu);
        case VFIO_DMA_CC_IOMMU:
                if (!iommu)
                        return 0;
                return vfio_domains_have_enforce_cache_coherency(iommu);
        default:
                return 0;
        }
}

static int vfio_iommu_iova_add_cap(struct vfio_info_cap *caps,
                 struct vfio_iommu_type1_info_cap_iova_range *cap_iovas,
                 size_t size)
{
        struct vfio_info_cap_header *header;
        struct vfio_iommu_type1_info_cap_iova_range *iova_cap;

        header = vfio_info_cap_add(caps, size,
                                   VFIO_IOMMU_TYPE1_INFO_CAP_IOVA_RANGE, 1);
        if (IS_ERR(header))
                return PTR_ERR(header);

        iova_cap = container_of(header,
                                struct vfio_iommu_type1_info_cap_iova_range,
                                header);
        iova_cap->nr_iovas = cap_iovas->nr_iovas;
        memcpy(iova_cap->iova_ranges, cap_iovas->iova_ranges,
               cap_iovas->nr_iovas * sizeof(*cap_iovas->iova_ranges));
        return 0;
}

static int vfio_iommu_iova_build_caps(struct vfio_iommu *iommu,
                                      struct vfio_info_cap *caps)
{
        struct vfio_iommu_type1_info_cap_iova_range *cap_iovas;
        struct vfio_iova *iova;
        size_t size;
        int iovas = 0, i = 0, ret;

        list_for_each_entry(iova, &iommu->iova_list, list)
                iovas++;

        if (!iovas) {
                /*
                 * Return 0 as a container with a single mdev device
                 * will have an empty list
                 */
                return 0;
        }

        size = struct_size(cap_iovas, iova_ranges, iovas);

        cap_iovas = kzalloc(size, GFP_KERNEL);
        if (!cap_iovas)
                return -ENOMEM;

        cap_iovas->nr_iovas = iovas;

        list_for_each_entry(iova, &iommu->iova_list, list) {
                cap_iovas->iova_ranges[i].start = iova->start;
                cap_iovas->iova_ranges[i].end = iova->end;
                i++;
        }

        ret = vfio_iommu_iova_add_cap(caps, cap_iovas, size);

        kfree(cap_iovas);
        return ret;
}

static int vfio_iommu_migration_build_caps(struct vfio_iommu *iommu,
                                           struct vfio_info_cap *caps)
{
        struct vfio_iommu_type1_info_cap_migration cap_mig = {};

        cap_mig.header.id = VFIO_IOMMU_TYPE1_INFO_CAP_MIGRATION;
        cap_mig.header.version = 1;

        cap_mig.flags = 0;
        /* support minimum pgsize */
        cap_mig.pgsize_bitmap = (size_t)1 << __ffs(iommu->pgsize_bitmap);
        cap_mig.max_dirty_bitmap_size = DIRTY_BITMAP_SIZE_MAX;

        return vfio_info_add_capability(caps, &cap_mig.header, sizeof(cap_mig));
}

static int vfio_iommu_dma_avail_build_caps(struct vfio_iommu *iommu,
                                           struct vfio_info_cap *caps)
{
        struct vfio_iommu_type1_info_dma_avail cap_dma_avail;

        cap_dma_avail.header.id = VFIO_IOMMU_TYPE1_INFO_DMA_AVAIL;
        cap_dma_avail.header.version = 1;

        cap_dma_avail.avail = iommu->dma_avail;

        return vfio_info_add_capability(caps, &cap_dma_avail.header,
                                        sizeof(cap_dma_avail));
}

static int vfio_iommu_type1_get_info(struct vfio_iommu *iommu,
                                     unsigned long arg)
{
        struct vfio_iommu_type1_info info = {};
        unsigned long minsz;
        struct vfio_info_cap caps = { .buf = NULL, .size = 0 };
        int ret;

        minsz = offsetofend(struct vfio_iommu_type1_info, iova_pgsizes);

        if (copy_from_user(&info, (void __user *)arg, minsz))
                return -EFAULT;

        if (info.argsz < minsz)
                return -EINVAL;

        minsz = min_t(size_t, info.argsz, sizeof(info));

        mutex_lock(&iommu->lock);
        info.flags = VFIO_IOMMU_INFO_PGSIZES;

        info.iova_pgsizes = iommu->pgsize_bitmap;

        ret = vfio_iommu_migration_build_caps(iommu, &caps);

        if (!ret)
                ret = vfio_iommu_dma_avail_build_caps(iommu, &caps);

        if (!ret)
                ret = vfio_iommu_iova_build_caps(iommu, &caps);

        mutex_unlock(&iommu->lock);

        if (ret)
                return ret;

        if (caps.size) {
                info.flags |= VFIO_IOMMU_INFO_CAPS;

                if (info.argsz < sizeof(info) + caps.size) {
                        info.argsz = sizeof(info) + caps.size;
                } else {
                        vfio_info_cap_shift(&caps, sizeof(info));
                        if (copy_to_user((void __user *)arg +
                                        sizeof(info), caps.buf,
                                        caps.size)) {
                                kfree(caps.buf);
                                return -EFAULT;
                        }
                        info.cap_offset = sizeof(info);
                }

                kfree(caps.buf);
        }

        return copy_to_user((void __user *)arg, &info, minsz) ?
                        -EFAULT : 0;
}

static int vfio_iommu_type1_map_dma(struct vfio_iommu *iommu,
                                    unsigned long arg)
{
        struct vfio_iommu_type1_dma_map map;
        unsigned long minsz;
        uint32_t mask = VFIO_DMA_MAP_FLAG_READ | VFIO_DMA_MAP_FLAG_WRITE |
                        VFIO_DMA_MAP_FLAG_VADDR;

        minsz = offsetofend(struct vfio_iommu_type1_dma_map, size);

        if (copy_from_user(&map, (void __user *)arg, minsz))
                return -EFAULT;

        if (map.argsz < minsz || map.flags & ~mask)
                return -EINVAL;

        return vfio_dma_do_map(iommu, &map);
}

static int vfio_iommu_type1_unmap_dma(struct vfio_iommu *iommu,
                                      unsigned long arg)
{
        struct vfio_iommu_type1_dma_unmap unmap;
        struct vfio_bitmap bitmap = { 0 };
        uint32_t mask = VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP |
                        VFIO_DMA_UNMAP_FLAG_VADDR |
                        VFIO_DMA_UNMAP_FLAG_ALL;
        unsigned long minsz;
        int ret;

        minsz = offsetofend(struct vfio_iommu_type1_dma_unmap, size);

        if (copy_from_user(&unmap, (void __user *)arg, minsz))
                return -EFAULT;

        if (unmap.argsz < minsz || unmap.flags & ~mask)
                return -EINVAL;

        if ((unmap.flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) &&
            (unmap.flags & (VFIO_DMA_UNMAP_FLAG_ALL |
                            VFIO_DMA_UNMAP_FLAG_VADDR)))
                return -EINVAL;

        if (unmap.flags & VFIO_DMA_UNMAP_FLAG_GET_DIRTY_BITMAP) {
                unsigned long pgshift;

                if (unmap.argsz < (minsz + sizeof(bitmap)))
                        return -EINVAL;

                if (copy_from_user(&bitmap,
                                   (void __user *)(arg + minsz),
                                   sizeof(bitmap)))
                        return -EFAULT;

                if (!access_ok((void __user *)bitmap.data, bitmap.size))
                        return -EINVAL;

                pgshift = __ffs(bitmap.pgsize);
                ret = verify_bitmap_size(unmap.size >> pgshift,
                                         bitmap.size);
                if (ret)
                        return ret;
        }

        ret = vfio_dma_do_unmap(iommu, &unmap, &bitmap);
        if (ret)
                return ret;

        return copy_to_user((void __user *)arg, &unmap, minsz) ?
                        -EFAULT : 0;
}

static int vfio_iommu_type1_dirty_pages(struct vfio_iommu *iommu,
                                        unsigned long arg)
{
        struct vfio_iommu_type1_dirty_bitmap dirty;
        uint32_t mask = VFIO_IOMMU_DIRTY_PAGES_FLAG_START |
                        VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP |
                        VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP;
        unsigned long minsz;
        int ret = 0;

        if (!iommu->v2)
                return -EACCES;

        minsz = offsetofend(struct vfio_iommu_type1_dirty_bitmap, flags);

        if (copy_from_user(&dirty, (void __user *)arg, minsz))
                return -EFAULT;

        if (dirty.argsz < minsz || dirty.flags & ~mask)
                return -EINVAL;

        /* only one flag should be set at a time */
        if (__ffs(dirty.flags) != __fls(dirty.flags))
                return -EINVAL;

        if (dirty.flags & VFIO_IOMMU_DIRTY_PAGES_FLAG_START) {
                size_t pgsize;

                mutex_lock(&iommu->lock);
                pgsize = 1 << __ffs(iommu->pgsize_bitmap);
                if (!iommu->dirty_page_tracking) {
                        ret = vfio_dma_bitmap_alloc_all(iommu, pgsize);
                        if (!ret)
                                iommu->dirty_page_tracking = true;
                }
                mutex_unlock(&iommu->lock);
                return ret;
        } else if (dirty.flags & VFIO_IOMMU_DIRTY_PAGES_FLAG_STOP) {
                mutex_lock(&iommu->lock);
                if (iommu->dirty_page_tracking) {
                        iommu->dirty_page_tracking = false;
                        vfio_dma_bitmap_free_all(iommu);
                }
                mutex_unlock(&iommu->lock);
                return 0;
        } else if (dirty.flags & VFIO_IOMMU_DIRTY_PAGES_FLAG_GET_BITMAP) {
                struct vfio_iommu_type1_dirty_bitmap_get range;
                unsigned long pgshift;
                size_t data_size = dirty.argsz - minsz;
                size_t size, iommu_pgsize;
                dma_addr_t iova, iova_end;

                if (!data_size || data_size < sizeof(range))
                        return -EINVAL;

                if (copy_from_user(&range, (void __user *)(arg + minsz),
                                   sizeof(range)))
                        return -EFAULT;

                iova = range.iova;
                size = range.size;

                if (iova != range.iova || size != range.size)
                        return -EOVERFLOW;

                if (!size)
                        return -EINVAL;

                if (check_add_overflow(iova, size - 1, &iova_end))
                        return -EOVERFLOW;

                if (!access_ok((void __user *)range.bitmap.data,
                               range.bitmap.size))
                        return -EINVAL;

                pgshift = __ffs(range.bitmap.pgsize);
                ret = verify_bitmap_size(size >> pgshift,
                                         range.bitmap.size);
                if (ret)
                        return ret;

                mutex_lock(&iommu->lock);

                iommu_pgsize = (size_t)1 << __ffs(iommu->pgsize_bitmap);

                /* allow only smallest supported pgsize */
                if (range.bitmap.pgsize != iommu_pgsize) {
                        ret = -EINVAL;
                        goto out_unlock;
                }
                if (iova & (iommu_pgsize - 1)) {
                        ret = -EINVAL;
                        goto out_unlock;
                }
                if (size & (iommu_pgsize - 1)) {
                        ret = -EINVAL;
                        goto out_unlock;
                }

                if (iommu->dirty_page_tracking)
                        ret = vfio_iova_dirty_bitmap(range.bitmap.data,
                                                     iommu, iova, iova_end,
                                                     range.bitmap.pgsize);
                else
                        ret = -EINVAL;
out_unlock:
                mutex_unlock(&iommu->lock);

                return ret;
        }

        return -EINVAL;
}

static long vfio_iommu_type1_ioctl(void *iommu_data,
                                   unsigned int cmd, unsigned long arg)
{
        struct vfio_iommu *iommu = iommu_data;

        switch (cmd) {
        case VFIO_CHECK_EXTENSION:
                return vfio_iommu_type1_check_extension(iommu, arg);
        case VFIO_IOMMU_GET_INFO:
                return vfio_iommu_type1_get_info(iommu, arg);
        case VFIO_IOMMU_MAP_DMA:
                return vfio_iommu_type1_map_dma(iommu, arg);
        case VFIO_IOMMU_UNMAP_DMA:
                return vfio_iommu_type1_unmap_dma(iommu, arg);
        case VFIO_IOMMU_DIRTY_PAGES:
                return vfio_iommu_type1_dirty_pages(iommu, arg);
        default:
                return -ENOTTY;
        }
}

static void vfio_iommu_type1_register_device(void *iommu_data,
                                             struct vfio_device *vdev)
{
        struct vfio_iommu *iommu = iommu_data;

        if (!vdev->ops->dma_unmap)
                return;

        /*
         * list_empty(&iommu->device_list) is tested under the iommu->lock while
         * iteration for dma_unmap must be done under the device_list_lock.
         * Holding both locks here allows avoiding the device_list_lock in
         * several fast paths. See vfio_notify_dma_unmap()
         */
        mutex_lock(&iommu->lock);
        mutex_lock(&iommu->device_list_lock);
        list_add(&vdev->iommu_entry, &iommu->device_list);
        mutex_unlock(&iommu->device_list_lock);
        mutex_unlock(&iommu->lock);
}

static void vfio_iommu_type1_unregister_device(void *iommu_data,
                                               struct vfio_device *vdev)
{
        struct vfio_iommu *iommu = iommu_data;

        if (!vdev->ops->dma_unmap)
                return;

        mutex_lock(&iommu->lock);
        mutex_lock(&iommu->device_list_lock);
        list_del(&vdev->iommu_entry);
        mutex_unlock(&iommu->device_list_lock);
        mutex_unlock(&iommu->lock);
}

static int vfio_iommu_type1_dma_rw_chunk(struct vfio_iommu *iommu,
                                         dma_addr_t user_iova, void *data,
                                         size_t count, bool write,
                                         size_t *copied)
{
        struct mm_struct *mm;
        unsigned long vaddr;
        struct vfio_dma *dma;
        bool kthread = current->mm == NULL;
        size_t offset;

        *copied = 0;

        dma = vfio_find_dma(iommu, user_iova, 1);
        if (!dma)
                return -EINVAL;

        if ((write && !(dma->prot & IOMMU_WRITE)) ||
                        !(dma->prot & IOMMU_READ))
                return -EPERM;

        mm = dma->mm;
        if (!mmget_not_zero(mm))
                return -EPERM;

        if (kthread)
                kthread_use_mm(mm);
        else if (current->mm != mm)
                goto out;

        offset = user_iova - dma->iova;

        if (count > dma->size - offset)
                count = dma->size - offset;

        vaddr = dma->vaddr + offset;

        if (write) {
                *copied = copy_to_user((void __user *)vaddr, data,
                                         count) ? 0 : count;
                if (*copied && iommu->dirty_page_tracking) {
                        unsigned long pgshift = __ffs(iommu->pgsize_bitmap);
                        /*
                         * Bitmap populated with the smallest supported page
                         * size
                         */
                        bitmap_set(dma->bitmap, offset >> pgshift,
                                   ((offset + *copied - 1) >> pgshift) -
                                   (offset >> pgshift) + 1);
                }
        } else
                *copied = copy_from_user(data, (void __user *)vaddr,
                                           count) ? 0 : count;
        if (kthread)
                kthread_unuse_mm(mm);
out:
        mmput(mm);
        return *copied ? 0 : -EFAULT;
}

static int vfio_iommu_type1_dma_rw(void *iommu_data, dma_addr_t user_iova,
                                   void *data, size_t count, bool write)
{
        struct vfio_iommu *iommu = iommu_data;
        int ret = 0;
        size_t done;

        mutex_lock(&iommu->lock);

        if (WARN_ONCE(iommu->vaddr_invalid_count,
                      "vfio_dma_rw not allowed with VFIO_UPDATE_VADDR\n")) {
                ret = -EBUSY;
                goto out;
        }

        while (count > 0) {
                ret = vfio_iommu_type1_dma_rw_chunk(iommu, user_iova, data,
                                                    count, write, &done);
                if (ret)
                        break;

                count -= done;
                data += done;
                user_iova += done;
        }

out:
        mutex_unlock(&iommu->lock);
        return ret;
}

static struct iommu_domain *
vfio_iommu_type1_group_iommu_domain(void *iommu_data,
                                    struct iommu_group *iommu_group)
{
        struct iommu_domain *domain = ERR_PTR(-ENODEV);
        struct vfio_iommu *iommu = iommu_data;
        struct vfio_domain *d;

        if (!iommu || !iommu_group)
                return ERR_PTR(-EINVAL);

        mutex_lock(&iommu->lock);
        list_for_each_entry(d, &iommu->domain_list, next) {
                if (find_iommu_group(d, iommu_group)) {
                        domain = d->domain;
                        break;
                }
        }
        mutex_unlock(&iommu->lock);

        return domain;
}

static const struct vfio_iommu_driver_ops vfio_iommu_driver_ops_type1 = {
        .name                   = "vfio-iommu-type1",
        .owner                  = THIS_MODULE,
        .open                   = vfio_iommu_type1_open,
        .release                = vfio_iommu_type1_release,
        .ioctl                  = vfio_iommu_type1_ioctl,
        .attach_group           = vfio_iommu_type1_attach_group,
        .detach_group           = vfio_iommu_type1_detach_group,
        .pin_pages              = vfio_iommu_type1_pin_pages,
        .unpin_pages            = vfio_iommu_type1_unpin_pages,
        .register_device        = vfio_iommu_type1_register_device,
        .unregister_device      = vfio_iommu_type1_unregister_device,
        .dma_rw                 = vfio_iommu_type1_dma_rw,
        .group_iommu_domain     = vfio_iommu_type1_group_iommu_domain,
};

static int __init vfio_iommu_type1_init(void)
{
        return vfio_register_iommu_driver(&vfio_iommu_driver_ops_type1);
}

static void __exit vfio_iommu_type1_cleanup(void)
{
        vfio_unregister_iommu_driver(&vfio_iommu_driver_ops_type1);
}

module_init(vfio_iommu_type1_init);
module_exit(vfio_iommu_type1_cleanup);

MODULE_VERSION(DRIVER_VERSION);
MODULE_LICENSE("GPL v2");
MODULE_AUTHOR(DRIVER_AUTHOR);
MODULE_DESCRIPTION(DRIVER_DESC);