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	Version: linux-6.0.1 spark-3.0.0 hadoop-3.2.0-src hadoop-3.3.0-src spark-2.4.7 linux-4.15.13 hadoop-2.7.4-src Revert   Change

 // 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/dma-iommu.h>
 #include <linux/irqdomain.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;
     wait_queue_head_t   vaddr_wait;
     bool            v2;
     bool            nesting;
     bool            dirty_page_tracking;
     bool            container_open;
     struct list_head    emulated_iommu_groups;
 };
 
 struct vfio_domain {
     struct iommu_domain *domain;
     struct list_head    next;
     struct list_head    group_list;
     bool            fgsp : 1;   /* Fine-grained super pages */
     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;
     struct task_struct  *task;
     struct rb_root      pfn_list;   /* Ex-user pinned pfn list */
     unsigned long       *bitmap;
 };
 
 struct vfio_batch {
     struct page     **pages;    /* for pin_user_pages_remote */
     struct page     *fallback_page; /* if pages alloc fails */
     int         capacity;   /* length of pages array */
     int         size;       /* of batch currently */
     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)
 
 #define WAITED 1
 
 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;
 
     while (node) {
         struct vfio_dma *dma = rb_entry(node, struct vfio_dma, node);
 
         if (start + size <= dma->iova)
             node = node->rb_left;
         else if (start >= dma->iova + dma->size)
             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, u64 size)
 {
     struct rb_node *res = NULL;
     struct rb_node *node = iommu->dma_list.rb_node;
     struct vfio_dma *dma_res = NULL;
 
     while (node) {
         struct vfio_dma *dma = rb_entry(node, struct vfio_dma, node);
 
         if (start < dma->iova + dma->size) {
             res = node;
             dma_res = dma;
             if (start >= dma->iova)
                 break;
             node = node->rb_left;
         } else {
             node = node->rb_right;
         }
     }
     if (res && size && dma_res->iova >= start + size)
         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;
 
     while (*link) {
         parent = *link;
         dma = rb_entry(parent, struct vfio_dma, node);
 
         if (new->iova + new->size <= 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(n,
                             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
  */
 static struct vfio_pfn *vfio_find_vpfn(struct vfio_dma *dma, dma_addr_t iova)
 {
     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 < vpfn->iova)
             node = node->rb_left;
         else if (iova > vpfn->iova)
             node = node->rb_right;
         else
             return vpfn;
     }
     return NULL;
 }
 
 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(sizeof(*vpfn), GFP_KERNEL);
     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 vfio_lock_acct(struct vfio_dma *dma, long npage, bool async)
 {
     struct mm_struct *mm;
     int ret;
 
     if (!npage)
         return 0;
 
     mm = async ? get_task_mm(dma->task) : dma->task->mm;
     if (!mm)
         return -ESRCH; /* process exited */
 
     ret = mmap_write_lock_killable(mm);
     if (!ret) {
         ret = __account_locked_vm(mm, abs(npage), npage > 0, dma->task,
                       dma->lock_cap);
         mmap_write_unlock(mm);
     }
 
     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)
 {
     batch->size = 0;
     batch->offset = 0;
 
     if (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_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,
                 bool write_fault)
 {
     pte_t *ptep;
     spinlock_t *ptl;
     int ret;
 
     ret = follow_pte(vma->vm_mm, vaddr, &ptep, &ptl);
     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_pte(vma->vm_mm, vaddr, &ptep, &ptl);
         if (ret)
             return ret;
     }
 
     if (write_fault && !pte_write(*ptep))
         ret = -EFAULT;
     else
         *pfn = pte_pfn(*ptep);
 
     pte_unmap_unlock(ptep, ptl);
     return ret;
 }
 
 /*
  * Returns the positive number of pfns successfully obtained or a negative
  * error code.
  */
 static int vaddr_get_pfns(struct mm_struct *mm, unsigned long vaddr,
               long npages, int prot, unsigned long *pfn,
               struct page **pages)
 {
     struct vm_area_struct *vma;
     unsigned int flags = 0;
     int ret;
 
     if (prot & IOMMU_WRITE)
         flags |= FOLL_WRITE;
 
     mmap_read_lock(mm);
     ret = pin_user_pages_remote(mm, vaddr, npages, flags | FOLL_LONGTERM,
                     pages, NULL, NULL);
     if (ret > 0) {
         int i;
 
         /*
          * The zero page is always resident, we don't need to pin it
          * and it falls into our invalid/reserved test so we don't
          * unpin in put_pfn().  Unpin all zero pages in the batch here.
          */
         for (i = 0 ; i < ret; i++) {
             if (unlikely(is_zero_pfn(page_to_pfn(pages[i]))))
                 unpin_user_page(pages[i]);
         }
 
         *pfn = page_to_pfn(pages[0]);
         goto done;
     }
 
     vaddr = untagged_addr(vaddr);
 
 retry:
     vma = vma_lookup(mm, vaddr);
 
     if (vma && vma->vm_flags & VM_PFNMAP) {
         ret = follow_fault_pfn(vma, mm, vaddr, pfn, prot & IOMMU_WRITE);
         if (ret == -EAGAIN)
             goto retry;
 
         if (!ret) {
             if (is_invalid_reserved_pfn(*pfn))
                 ret = 1;
             else
                 ret = -EFAULT;
         }
     }
 done:
     mmap_read_unlock(mm);
     return ret;
 }
 
 static int vfio_wait(struct vfio_iommu *iommu)
 {
     DEFINE_WAIT(wait);
 
     prepare_to_wait(&iommu->vaddr_wait, &wait, TASK_KILLABLE);
     mutex_unlock(&iommu->lock);
     schedule();
     mutex_lock(&iommu->lock);
     finish_wait(&iommu->vaddr_wait, &wait);
     if (kthread_should_stop() || !iommu->container_open ||
         fatal_signal_pending(current)) {
         return -EFAULT;
     }
     return WAITED;
 }
 
 /*
  * Find dma struct and wait for its vaddr to be valid.  iommu lock is dropped
  * if the task waits, but is re-locked on return.  Return result in *dma_p.
  * Return 0 on success with no waiting, WAITED on success if waited, and -errno
  * on error.
  */
 static int vfio_find_dma_valid(struct vfio_iommu *iommu, dma_addr_t start,
                    size_t size, struct vfio_dma **dma_p)
 {
     int ret = 0;
 
     do {
         *dma_p = vfio_find_dma(iommu, start, size);
         if (!*dma_p)
             return -EINVAL;
         else if (!(*dma_p)->vaddr_invalid)
             return ret;
         else
             ret = vfio_wait(iommu);
     } while (ret == WAITED);
 
     return ret;
 }
 
 /*
  * Wait for all vaddr in the dma_list to become valid.  iommu lock is dropped
  * if the task waits, but is re-locked on return.  Return 0 on success with no
  * waiting, WAITED on success if waited, and -errno on error.
  */
 static int vfio_wait_all_valid(struct vfio_iommu *iommu)
 {
     int ret = 0;
 
     while (iommu->vaddr_invalid_count && ret >= 0)
         ret = vfio_wait(iommu);
 
     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,
                   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;
     }
 
     while (npage) {
         if (!batch->size) {
             /* Empty batch, so refill it. */
             long req_pages = min_t(long, npage, batch->capacity);
 
             ret = vaddr_get_pfns(mm, vaddr, req_pages, dma->prot,
                          &pfn, batch->pages);
             if (ret < 0)
                 goto unpin_out;
 
             batch->size = ret;
             batch->offset = 0;
 
             if (!*pfn_base) {
                 *pfn_base = pfn;
                 rsvd = is_invalid_reserved_pfn(*pfn_base);
             }
         }
 
         /*
          * pfn is preset for the first iteration of this inner loop and
          * updated at the end to handle a VM_PFNMAP pfn.  In that case,
          * batch->pages isn't valid (there's no struct page), so allow
          * batch->pages to be touched only when there's more than one
          * pfn to check, which guarantees the pfns are from a
          * !VM_PFNMAP vma.
          */
         while (true) {
             if (pfn != *pfn_base + pinned ||
                 rsvd != is_invalid_reserved_pfn(pfn))
                 goto out;
 
             /*
              * Reserved pages aren't counted against the user,
              * externally pinned pages are already counted against
              * the user.
              */
             if (!rsvd && !vfio_find_vpfn(dma, iova)) {
                 if (!dma->lock_cap &&
                     mm->locked_vm + lock_acct + 1 > limit) {
                     pr_warn("%s: RLIMIT_MEMLOCK (%ld) exceeded\n",
                         __func__, limit << PAGE_SHIFT);
                     ret = -ENOMEM;
                     goto unpin_out;
                 }
                 lock_acct++;
             }
 
             pinned++;
             npage--;
             vaddr += PAGE_SIZE;
             iova += PAGE_SIZE;
             batch->offset++;
             batch->size--;
 
             if (!batch->size)
                 break;
 
             pfn = page_to_pfn(batch->pages[batch->offset]);
         }
 
         if (unlikely(disable_hugepages))
             break;
     }
 
 out:
     ret = vfio_lock_acct(dma, lock_acct, false);
 
 unpin_out:
     if (batch->size == 1 && !batch->offset) {
         /* May be a VM_PFNMAP pfn, which the batch can't remember. */
         put_pfn(pfn, dma->prot);
         batch->size = 0;
     }
 
     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 long vfio_unpin_pages_remote(struct vfio_dma *dma, dma_addr_t iova,
                     unsigned long pfn, long npage,
                     bool do_accounting)
 {
     long unlocked = 0, locked = 0;
     long i;
 
     for (i = 0; i < npage; i++, iova += PAGE_SIZE) {
         if (put_pfn(pfn++, dma->prot)) {
             unlocked++;
             if (vfio_find_vpfn(dma, iova))
                 locked++;
         }
     }
 
     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 page *pages[1];
     struct mm_struct *mm;
     int ret;
 
     mm = get_task_mm(dma->task);
     if (!mm)
         return -ENODEV;
 
     ret = vaddr_get_pfns(mm, vaddr, 1, dma->prot, pfn_base, pages);
     if (ret != 1)
         goto out;
 
     ret = 0;
 
     if (do_accounting && !is_invalid_reserved_pfn(*pfn_base)) {
         ret = vfio_lock_acct(dma, 1, true);
         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:
     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;
 
     if (!iommu || !pages)
         return -EINVAL;
 
     /* Supported for v2 version only */
     if (!iommu->v2)
         return -EACCES;
 
     mutex_lock(&iommu->lock);
 
     /*
      * Wait for all necessary vaddr's to be valid so they can be used in
      * the main loop without dropping the lock, to avoid racing vs unmap.
      */
 again:
     if (iommu->vaddr_invalid_count) {
         for (i = 0; i < npage; i++) {
             iova = user_iova + PAGE_SIZE * i;
             ret = vfio_find_dma_valid(iommu, iova, PAGE_SIZE, &dma);
             if (ret < 0)
                 goto pin_done;
             if (ret == WAITED)
                 goto again;
         }
     }
 
     /* 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;
         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;
 
         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;
     int i;
 
     /* Supported for v2 version only */
     if (WARN_ON(!iommu->v2))
         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(sizeof(*entry), GFP_KERNEL);
 
     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);
 
             *iova += unmapped;
             (*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);
         *iova += unmapped;
         cond_resched();
     }
     return unmapped;
 }
 
 static long vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma,
                  bool do_accounting)
 {
     dma_addr_t iova = dma->iova, end = dma->iova + dma->size;
     struct vfio_domain *domain, *d;
     LIST_HEAD(unmapped_region_list);
     struct iommu_iotlb_gather iotlb_gather;
     int unmapped_region_cnt = 0;
     long unlocked = 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 (iova < end) {
         size_t unmapped, len;
         phys_addr_t phys, next;
 
         phys = iommu_iova_to_phys(domain->domain, iova);
         if (WARN_ON(!phys)) {
             iova += 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;
              !domain->fgsp && iova + len < end; 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;
         }
     }
 
     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);
     vfio_dma_bitmap_free(dma);
     if (dma->vaddr_invalid) {
         iommu->vaddr_invalid_count--;
         wake_up_all(&iommu->vaddr_wait);
     }
     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, size_t size, 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 + size - 1, 0);
     if (dma && dma->iova + dma->size != iova + size)
         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 + size - 1)
             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;
     u64 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);
 
     pgshift = __ffs(iommu->pgsize_bitmap);
     pgsize = (size_t)1 << pgshift;
 
     if (iova & (pgsize - 1))
         goto unlock;
 
     if (unmap_all) {
         if (iova || size)
             goto unlock;
         size = U64_MAX;
     } else if (!size || size & (pgsize - 1) ||
            iova + size - 1 < iova || size > SIZE_MAX) {
         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 + size - 1, 0);
         if (dma && dma->iova + dma->size != iova + size)
             goto unlock;
     }
 
     ret = 0;
     n = first_n = vfio_find_dma_first_node(iommu, iova, size);
 
     while (n) {
         dma = rb_entry(n, struct vfio_dma, node);
         if (dma->iova >= iova + size)
             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);
         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_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;
     unsigned long vaddr = map->vaddr;
     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 -EINVAL;
 
     /* 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 || (size | iova | vaddr) & (pgsize - 1)) {
         ret = -EINVAL;
         goto out_unlock;
     }
 
     /* Don't allow IOVA or virtual address wrap */
     if (iova + size - 1 < iova || vaddr + size - 1 < vaddr) {
         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 {
             dma->vaddr = vaddr;
             dma->vaddr_invalid = false;
             iommu->vaddr_invalid_count--;
             wake_up_all(&iommu->vaddr_wait);
         }
         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 + size - 1)) {
         ret = -EINVAL;
         goto out_unlock;
     }
 
     dma = kzalloc(sizeof(*dma), GFP_KERNEL);
     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 and VM locked pages requires an mm_struct, however
      * holding an indefinite mm reference is not recommended, therefore we
      * only hold a reference to a task.  We could hold a reference to
      * current, however QEMU uses this call path through vCPU threads,
      * which can be killed resulting in a NULL mm and failure in the unmap
      * path when called via a different thread.  Avoid this problem by
      * using the group_leader as threads within the same group require
      * both CLONE_THREAD and CLONE_VM and will therefore use the same
      * mm_struct.
      *
      * Previously we also used the task for testing CAP_IPC_LOCK at the
      * time of pinning and accounting, however has_capability() makes use
      * of real_cred, a copy-on-write field, so we can't guarantee that it
      * matches group_leader, or in fact that it might not change by the
      * time it's evaluated.  If a process were to call MAP_DMA with
      * CAP_IPC_LOCK but later drop it, it doesn't make sense that they
      * possibly see different results for an iommu_mapped vfio_dma vs
      * externally mapped.  Therefore track CAP_IPC_LOCK in vfio_dma at the
      * time of calling MAP_DMA.
      */
     get_task_struct(current->group_leader);
     dma->task = current->group_leader;
     dma->lock_cap = capable(CAP_IPC_LOCK);
 
     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;
 
     ret = vfio_wait_all_valid(iommu);
     if (ret < 0)
         return 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;
         dma_addr_t iova;
 
         dma = rb_entry(n, struct vfio_dma, node);
         iova = dma->iova;
 
         while (iova < dma->iova + dma->size) {
             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)) {
                     iova += PAGE_SIZE;
                     continue;
                 }
 
                 size = PAGE_SIZE;
                 p = phys + size;
                 i = iova + size;
                 while (i < dma->iova + 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 +
                              (iova - dma->iova);
                 size_t n = dma->iova + dma->size - iova;
                 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);
             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;
             }
 
             iova += 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);
         dma_addr_t iova;
 
         if (dma->iommu_mapped) {
             iommu_unmap(domain->domain, dma->iova, dma->size);
             continue;
         }
 
         iova = dma->iova;
         while (iova < dma->iova + dma->size) {
             phys_addr_t phys, p;
             size_t size;
             dma_addr_t i;
 
             phys = iommu_iova_to_phys(domain->domain, iova);
             if (!phys) {
                 iova += PAGE_SIZE;
                 continue;
             }
 
             size = PAGE_SIZE;
             p = phys + size;
             i = iova + size;
             while (i < dma->iova + 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;
 }
 
 /*
  * We change our unmap behavior slightly depending on whether the IOMMU
  * supports fine-grained superpages.  IOMMUs like AMD-Vi will use a superpage
  * for practically any contiguous power-of-two mapping we give it.  This means
  * we don't need to look for contiguous chunks ourselves to make unmapping
  * more efficient.  On IOMMUs with coarse-grained super pages, like Intel VT-d
  * with discrete 2M/1G/512G/1T superpages, identifying contiguous chunks
  * significantly boosts non-hugetlbfs mappings and doesn't seem to hurt when
  * hugetlbfs is in use.
  */
 static void vfio_test_domain_fgsp(struct vfio_domain *domain)
 {
     struct page *pages;
     int ret, order = get_order(PAGE_SIZE * 2);
 
     pages = alloc_pages(GFP_KERNEL | __GFP_ZERO, order);
     if (!pages)
         return;
 
     ret = iommu_map(domain->domain, 0, page_to_phys(pages), PAGE_SIZE * 2,
             IOMMU_READ | IOMMU_WRITE | IOMMU_CACHE);
     if (!ret) {
         size_t unmapped = iommu_unmap(domain->domain, 0, PAGE_SIZE);
 
         if (unmapped == PAGE_SIZE)
             iommu_unmap(domain->domain, PAGE_SIZE, PAGE_SIZE);
         else
             domain->fgsp = true;
     }
 
     __free_pages(pages, order);
 }
 
 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(sizeof(*region), GFP_KERNEL);
     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);
 }
 
 /* Redundantly walks non-present capabilities to simplify caller */
 static int vfio_iommu_device_capable(struct device *dev, void *data)
 {
     return device_iommu_capable(dev, (enum iommu_cap)data);
 }
 
 static int vfio_iommu_domain_alloc(struct device *dev, void *data)
 {
     struct iommu_domain **domain = data;
 
     *domain = iommu_domain_alloc(dev->bus);
     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, msi_remap;
     phys_addr_t resv_msi_base = 0;
     struct iommu_domain_geometry *geo;
     LIST_HEAD(iova_copy);
     LIST_HEAD(group_resv_regions);
     int ret = -EINVAL;
 
     mutex_lock(&iommu->lock);
 
     /* Check for duplicates */
     if (vfio_iommu_find_iommu_group(iommu, iommu_group))
         goto out_unlock;
 
     ret = -ENOMEM;
     group = kzalloc(sizeof(*group), GFP_KERNEL);
     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(sizeof(*domain), GFP_KERNEL);
     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).
      */
     ret = -EIO;
     iommu_group_for_each_dev(iommu_group, &domain->domain,
                  vfio_iommu_domain_alloc);
     if (!domain->domain)
         goto out_free_domain;
 
     if (iommu->nesting) {
         ret = iommu_enable_nesting(domain->domain);
         if (ret)
             goto out_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);
 
     msi_remap = irq_domain_check_msi_remap() ||
             iommu_group_for_each_dev(iommu_group, (void *)IOMMU_CAP_INTR_REMAP,
                          vfio_iommu_device_capable);
 
     if (!allow_unsafe_interrupts && !msi_remap) {
         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;
         }
     }
 
     vfio_test_domain_fgsp(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(sizeof(*iommu), GFP_KERNEL);
     if (!iommu)
         return ERR_PTR(-ENOMEM);
 
     switch (arg) {
     case VFIO_TYPE1_IOMMU:
         break;
     case VFIO_TYPE1_NESTING_IOMMU:
         iommu->nesting = true;
         fallthrough;
     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;
     iommu->container_open = true;
     mutex_init(&iommu->lock);
     mutex_init(&iommu->device_list_lock);
     INIT_LIST_HEAD(&iommu->device_list);
     init_waitqueue_head(&iommu->vaddr_wait);
     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 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_TYPE1_NESTING_IOMMU:
     case VFIO_UNMAP_ALL:
     case VFIO_UPDATE_VADDR:
         return 1;
     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 };
     unsigned long capsz;
     int ret;
 
     minsz = offsetofend(struct vfio_iommu_type1_info, iova_pgsizes);
 
     /* For backward compatibility, cannot require this */
     capsz = offsetofend(struct vfio_iommu_type1_info, cap_offset);
 
     if (copy_from_user(&info, (void __user *)arg, minsz))
         return -EFAULT;
 
     if (info.argsz < minsz)
         return -EINVAL;
 
     if (info.argsz >= capsz) {
         minsz = capsz;
         info.cap_offset = 0; /* output, no-recopy necessary */
     }
 
     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 iommu_pgsize;
 
         if (!data_size || data_size < sizeof(range))
             return -EINVAL;
 
         if (copy_from_user(&range, (void __user *)(arg + minsz),
                    sizeof(range)))
             return -EFAULT;
 
         if (range.iova + range.size < range.iova)
             return -EINVAL;
         if (!access_ok((void __user *)range.bitmap.data,
                    range.bitmap.size))
             return -EINVAL;
 
         pgshift = __ffs(range.bitmap.pgsize);
         ret = verify_bitmap_size(range.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 (range.iova & (iommu_pgsize - 1)) {
             ret = -EINVAL;
             goto out_unlock;
         }
         if (!range.size || range.size & (iommu_pgsize - 1)) {
             ret = -EINVAL;
             goto out_unlock;
         }
 
         if (iommu->dirty_page_tracking)
             ret = vfio_iova_dirty_bitmap(range.bitmap.data,
                              iommu, range.iova,
                              range.size,
                              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;
     int ret;
 
     *copied = 0;
 
     ret = vfio_find_dma_valid(iommu, user_iova, 1, &dma);
     if (ret < 0)
         return ret;
 
     if ((write && !(dma->prot & IOMMU_WRITE)) ||
             !(dma->prot & IOMMU_READ))
         return -EPERM;
 
     mm = get_task_mm(dma->task);
 
     if (!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);
     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;
     }
 
     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 void vfio_iommu_type1_notify(void *iommu_data,
                     enum vfio_iommu_notify_type event)
 {
     struct vfio_iommu *iommu = iommu_data;
 
     if (event != VFIO_IOMMU_CONTAINER_CLOSE)
         return;
     mutex_lock(&iommu->lock);
     iommu->container_open = false;
     mutex_unlock(&iommu->lock);
     wake_up_all(&iommu->vaddr_wait);
 }
 
 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,
     .notify         = vfio_iommu_type1_notify,
 };
 
 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);