Initial import

1 files changed, 1054 insertions, 0 deletions

diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
new file mode 100644
index 000000000..57d8c37a0
--- /dev/null
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -0,0 +1,1054 @@
+/*
+ * VFIO: IOMMU DMA mapping support for Type1 IOMMU
+ *
+ * Copyright (C) 2012 Red Hat, Inc.  All rights reserved.
+ *     Author: Alex Williamson <alex.williamson@redhat.com>
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License version 2 as
+ * published by the Free Software Foundation.
+ *
+ * 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
+ * userpsace 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/iommu.h>
+#include <linux/module.h>
+#include <linux/mm.h>
+#include <linux/rbtree.h>
+#include <linux/sched.h>
+#include <linux/slab.h>
+#include <linux/uaccess.h>
+#include <linux/vfio.h>
+#include <linux/workqueue.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.");
+
+struct vfio_iommu {
+	struct list_head	domain_list;
+	struct mutex		lock;
+	struct rb_root		dma_list;
+	bool			v2;
+	bool			nesting;
+};
+
+struct vfio_domain {
+	struct iommu_domain	*domain;
+	struct list_head	next;
+	struct list_head	group_list;
+	int			prot;		/* IOMMU_CACHE */
+	bool			fgsp;		/* Fine-grained super pages */
+};
+
+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 */
+};
+
+struct vfio_group {
+	struct iommu_group	*iommu_group;
+	struct list_head	next;
+};
+
+/*
+ * 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 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);
+}
+
+struct vwork {
+	struct mm_struct	*mm;
+	long			npage;
+	struct work_struct	work;
+};
+
+/* delayed decrement/increment for locked_vm */
+static void vfio_lock_acct_bg(struct work_struct *work)
+{
+	struct vwork *vwork = container_of(work, struct vwork, work);
+	struct mm_struct *mm;
+
+	mm = vwork->mm;
+	down_write(&mm->mmap_sem);
+	mm->locked_vm += vwork->npage;
+	up_write(&mm->mmap_sem);
+	mmput(mm);
+	kfree(vwork);
+}
+
+static void vfio_lock_acct(long npage)
+{
+	struct vwork *vwork;
+	struct mm_struct *mm;
+
+	if (!current->mm || !npage)
+		return; /* process exited or nothing to do */
+
+	if (down_write_trylock(&current->mm->mmap_sem)) {
+		current->mm->locked_vm += npage;
+		up_write(&current->mm->mmap_sem);
+		return;
+	}
+
+	/*
+	 * Couldn't get mmap_sem lock, so must setup to update
+	 * mm->locked_vm later. If locked_vm were atomic, we
+	 * wouldn't need this silliness
+	 */
+	vwork = kmalloc(sizeof(struct vwork), GFP_KERNEL);
+	if (!vwork)
+		return;
+	mm = get_task_mm(current);
+	if (!mm) {
+		kfree(vwork);
+		return;
+	}
+	INIT_WORK(&vwork->work, vfio_lock_acct_bg);
+	vwork->mm = mm;
+	vwork->npage = npage;
+	schedule_work(&vwork->work);
+}
+
+/*
+ * 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.
+ */
+static bool is_invalid_reserved_pfn(unsigned long pfn)
+{
+	if (pfn_valid(pfn)) {
+		bool reserved;
+		struct page *tail = pfn_to_page(pfn);
+		struct page *head = compound_head(tail);
+		reserved = !!(PageReserved(head));
+		if (head != tail) {
+			/*
+			 * "head" is not a dangling pointer
+			 * (compound_head takes care of that)
+			 * but the hugepage may have been split
+			 * from under us (and we may not hold a
+			 * reference count on the head page so it can
+			 * be reused before we run PageReferenced), so
+			 * we've to check PageTail before returning
+			 * what we just read.
+			 */
+			smp_rmb();
+			if (PageTail(tail))
+				return reserved;
+		}
+		return PageReserved(tail);
+	}
+
+	return true;
+}
+
+static int put_pfn(unsigned long pfn, int prot)
+{
+	if (!is_invalid_reserved_pfn(pfn)) {
+		struct page *page = pfn_to_page(pfn);
+		if (prot & IOMMU_WRITE)
+			SetPageDirty(page);
+		put_page(page);
+		return 1;
+	}
+	return 0;
+}
+
+static int vaddr_get_pfn(unsigned long vaddr, int prot, unsigned long *pfn)
+{
+	struct page *page[1];
+	struct vm_area_struct *vma;
+	int ret = -EFAULT;
+
+	if (get_user_pages_fast(vaddr, 1, !!(prot & IOMMU_WRITE), page) == 1) {
+		*pfn = page_to_pfn(page[0]);
+		return 0;
+	}
+
+	down_read(&current->mm->mmap_sem);
+
+	vma = find_vma_intersection(current->mm, vaddr, vaddr + 1);
+
+	if (vma && vma->vm_flags & VM_PFNMAP) {
+		*pfn = ((vaddr - vma->vm_start) >> PAGE_SHIFT) + vma->vm_pgoff;
+		if (is_invalid_reserved_pfn(*pfn))
+			ret = 0;
+	}
+
+	up_read(&current->mm->mmap_sem);
+
+	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(unsigned long vaddr, long npage,
+			   int prot, unsigned long *pfn_base)
+{
+	unsigned long limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
+	bool lock_cap = capable(CAP_IPC_LOCK);
+	long ret, i;
+	bool rsvd;
+
+	if (!current->mm)
+		return -ENODEV;
+
+	ret = vaddr_get_pfn(vaddr, prot, pfn_base);
+	if (ret)
+		return ret;
+
+	rsvd = is_invalid_reserved_pfn(*pfn_base);
+
+	if (!rsvd && !lock_cap && current->mm->locked_vm + 1 > limit) {
+		put_pfn(*pfn_base, prot);
+		pr_warn("%s: RLIMIT_MEMLOCK (%ld) exceeded\n", __func__,
+			limit << PAGE_SHIFT);
+		return -ENOMEM;
+	}
+
+	if (unlikely(disable_hugepages)) {
+		if (!rsvd)
+			vfio_lock_acct(1);
+		return 1;
+	}
+
+	/* Lock all the consecutive pages from pfn_base */
+	for (i = 1, vaddr += PAGE_SIZE; i < npage; i++, vaddr += PAGE_SIZE) {
+		unsigned long pfn = 0;
+
+		ret = vaddr_get_pfn(vaddr, prot, &pfn);
+		if (ret)
+			break;
+
+		if (pfn != *pfn_base + i ||
+		    rsvd != is_invalid_reserved_pfn(pfn)) {
+			put_pfn(pfn, prot);
+			break;
+		}
+
+		if (!rsvd && !lock_cap &&
+		    current->mm->locked_vm + i + 1 > limit) {
+			put_pfn(pfn, prot);
+			pr_warn("%s: RLIMIT_MEMLOCK (%ld) exceeded\n",
+				__func__, limit << PAGE_SHIFT);
+			break;
+		}
+	}
+
+	if (!rsvd)
+		vfio_lock_acct(i);
+
+	return i;
+}
+
+static long vfio_unpin_pages(unsigned long pfn, long npage,
+			     int prot, bool do_accounting)
+{
+	unsigned long unlocked = 0;
+	long i;
+
+	for (i = 0; i < npage; i++)
+		unlocked += put_pfn(pfn++, prot);
+
+	if (do_accounting)
+		vfio_lock_acct(-unlocked);
+
+	return unlocked;
+}
+
+static void vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma)
+{
+	dma_addr_t iova = dma->iova, end = dma->iova + dma->size;
+	struct vfio_domain *domain, *d;
+	long unlocked = 0;
+
+	if (!dma->size)
+		return;
+	/*
+	 * 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();
+	}
+
+	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;
+		}
+
+		unmapped = iommu_unmap(domain->domain, iova, len);
+		if (WARN_ON(!unmapped))
+			break;
+
+		unlocked += vfio_unpin_pages(phys >> PAGE_SHIFT,
+					     unmapped >> PAGE_SHIFT,
+					     dma->prot, false);
+		iova += unmapped;
+
+		cond_resched();
+	}
+
+	vfio_lock_acct(-unlocked);
+}
+
+static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma)
+{
+	vfio_unmap_unpin(iommu, dma);
+	vfio_unlink_dma(iommu, dma);
+	kfree(dma);
+}
+
+static unsigned long vfio_pgsize_bitmap(struct vfio_iommu *iommu)
+{
+	struct vfio_domain *domain;
+	unsigned long bitmap = PAGE_MASK;
+
+	mutex_lock(&iommu->lock);
+	list_for_each_entry(domain, &iommu->domain_list, next)
+		bitmap &= domain->domain->ops->pgsize_bitmap;
+	mutex_unlock(&iommu->lock);
+
+	return bitmap;
+}
+
+static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
+			     struct vfio_iommu_type1_dma_unmap *unmap)
+{
+	uint64_t mask;
+	struct vfio_dma *dma;
+	size_t unmapped = 0;
+	int ret = 0;
+
+	mask = ((uint64_t)1 << __ffs(vfio_pgsize_bitmap(iommu))) - 1;
+
+	if (unmap->iova & mask)
+		return -EINVAL;
+	if (!unmap->size || unmap->size & mask)
+		return -EINVAL;
+
+	WARN_ON(mask & PAGE_MASK);
+
+	mutex_lock(&iommu->lock);
+
+	/*
+	 * 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) {
+		dma = vfio_find_dma(iommu, unmap->iova, 0);
+		if (dma && dma->iova != unmap->iova) {
+			ret = -EINVAL;
+			goto unlock;
+		}
+		dma = vfio_find_dma(iommu, unmap->iova + unmap->size - 1, 0);
+		if (dma && dma->iova + dma->size != unmap->iova + unmap->size) {
+			ret = -EINVAL;
+			goto unlock;
+		}
+	}
+
+	while ((dma = vfio_find_dma(iommu, unmap->iova, unmap->size))) {
+		if (!iommu->v2 && unmap->iova > dma->iova)
+			break;
+		unmapped += dma->size;
+		vfio_remove_dma(iommu, dma);
+	}
+
+unlock:
+	mutex_unlock(&iommu->lock);
+
+	/* Report how much was unmapped */
+	unmap->size = unmapped;
+
+	return ret;
+}
+
+/*
+ * Turns out AMD IOMMU has a page table bug where it won't map large pages
+ * to a region that previously mapped smaller pages.  This should be fixed
+ * soon, so this is just a temporary workaround to break mappings down into
+ * PAGE_SIZE.  Better to map smaller pages than nothing.
+ */
+static int map_try_harder(struct vfio_domain *domain, dma_addr_t iova,
+			  unsigned long pfn, long npage, int prot)
+{
+	long i;
+	int ret;
+
+	for (i = 0; i < npage; i++, pfn++, iova += PAGE_SIZE) {
+		ret = iommu_map(domain->domain, iova,
+				(phys_addr_t)pfn << PAGE_SHIFT,
+				PAGE_SIZE, prot | domain->prot);
+		if (ret)
+			break;
+	}
+
+	for (; i < npage && i > 0; i--, iova -= PAGE_SIZE)
+		iommu_unmap(domain->domain, iova, PAGE_SIZE);
+
+	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 | d->prot);
+		if (ret) {
+			if (ret != -EBUSY ||
+			    map_try_harder(d, iova, pfn, npage, prot))
+				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);
+
+	return ret;
+}
+
+static int vfio_dma_do_map(struct vfio_iommu *iommu,
+			   struct vfio_iommu_type1_dma_map *map)
+{
+	dma_addr_t iova = map->iova;
+	unsigned long vaddr = map->vaddr;
+	size_t size = map->size;
+	long npage;
+	int ret = 0, prot = 0;
+	uint64_t mask;
+	struct vfio_dma *dma;
+	unsigned long pfn;
+
+	/* Verify that none of our __u64 fields overflow */
+	if (map->size != size || map->vaddr != vaddr || map->iova != iova)
+		return -EINVAL;
+
+	mask = ((uint64_t)1 << __ffs(vfio_pgsize_bitmap(iommu))) - 1;
+
+	WARN_ON(mask & PAGE_MASK);
+
+	/* 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 || !size || (size | iova | vaddr) & mask)
+		return -EINVAL;
+
+	/* Don't allow IOVA or virtual address wrap */
+	if (iova + size - 1 < iova || vaddr + size - 1 < vaddr)
+		return -EINVAL;
+
+	mutex_lock(&iommu->lock);
+
+	if (vfio_find_dma(iommu, iova, size)) {
+		mutex_unlock(&iommu->lock);
+		return -EEXIST;
+	}
+
+	dma = kzalloc(sizeof(*dma), GFP_KERNEL);
+	if (!dma) {
+		mutex_unlock(&iommu->lock);
+		return -ENOMEM;
+	}
+
+	dma->iova = iova;
+	dma->vaddr = vaddr;
+	dma->prot = prot;
+
+	/* Insert zero-sized and grow as we map chunks of it */
+	vfio_link_dma(iommu, dma);
+
+	while (size) {
+		/* Pin a contiguous chunk of memory */
+		npage = vfio_pin_pages(vaddr + dma->size,
+				       size >> PAGE_SHIFT, prot, &pfn);
+		if (npage <= 0) {
+			WARN_ON(!npage);
+			ret = (int)npage;
+			break;
+		}
+
+		/* Map it! */
+		ret = vfio_iommu_map(iommu, iova + dma->size, pfn, npage, prot);
+		if (ret) {
+			vfio_unpin_pages(pfn, npage, prot, true);
+			break;
+		}
+
+		size -= npage << PAGE_SHIFT;
+		dma->size += npage << PAGE_SHIFT;
+	}
+
+	if (ret)
+		vfio_remove_dma(iommu, dma);
+
+	mutex_unlock(&iommu->lock);
+	return ret;
+}
+
+static int vfio_bus_type(struct device *dev, void *data)
+{
+	struct bus_type **bus = data;
+
+	if (*bus && *bus != dev->bus)
+		return -EINVAL;
+
+	*bus = dev->bus;
+
+	return 0;
+}
+
+static int vfio_iommu_replay(struct vfio_iommu *iommu,
+			     struct vfio_domain *domain)
+{
+	struct vfio_domain *d;
+	struct rb_node *n;
+	int ret;
+
+	/* Arbitrarily pick the first domain in the list for lookups */
+	d = list_first_entry(&iommu->domain_list, struct vfio_domain, next);
+	n = rb_first(&iommu->dma_list);
+
+	/* If there's not a domain, there better not be any mappings */
+	if (WARN_ON(n && !d))
+		return -EINVAL;
+
+	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 = iommu_iova_to_phys(d->domain, iova);
+			size_t size;
+
+			if (WARN_ON(!phys)) {
+				iova += PAGE_SIZE;
+				continue;
+			}
+
+			size = PAGE_SIZE;
+
+			while (iova + size < dma->iova + dma->size &&
+			       phys + size == iommu_iova_to_phys(d->domain,
+								 iova + size))
+				size += PAGE_SIZE;
+
+			ret = iommu_map(domain->domain, iova, phys,
+					size, dma->prot | domain->prot);
+			if (ret)
+				return ret;
+
+			iova += size;
+		}
+	}
+
+	return 0;
+}
+
+/*
+ * 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 | domain->prot);
+	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 int vfio_iommu_type1_attach_group(void *iommu_data,
+					 struct iommu_group *iommu_group)
+{
+	struct vfio_iommu *iommu = iommu_data;
+	struct vfio_group *group, *g;
+	struct vfio_domain *domain, *d;
+	struct bus_type *bus = NULL;
+	int ret;
+
+	mutex_lock(&iommu->lock);
+
+	list_for_each_entry(d, &iommu->domain_list, next) {
+		list_for_each_entry(g, &d->group_list, next) {
+			if (g->iommu_group != iommu_group)
+				continue;
+
+			mutex_unlock(&iommu->lock);
+			return -EINVAL;
+		}
+	}
+
+	group = kzalloc(sizeof(*group), GFP_KERNEL);
+	domain = kzalloc(sizeof(*domain), GFP_KERNEL);
+	if (!group || !domain) {
+		ret = -ENOMEM;
+		goto out_free;
+	}
+
+	group->iommu_group = iommu_group;
+
+	/* Determine bus_type in order to allocate a domain */
+	ret = iommu_group_for_each_dev(iommu_group, &bus, vfio_bus_type);
+	if (ret)
+		goto out_free;
+
+	domain->domain = iommu_domain_alloc(bus);
+	if (!domain->domain) {
+		ret = -EIO;
+		goto out_free;
+	}
+
+	if (iommu->nesting) {
+		int attr = 1;
+
+		ret = iommu_domain_set_attr(domain->domain, DOMAIN_ATTR_NESTING,
+					    &attr);
+		if (ret)
+			goto out_domain;
+	}
+
+	ret = iommu_attach_group(domain->domain, iommu_group);
+	if (ret)
+		goto out_domain;
+
+	INIT_LIST_HEAD(&domain->group_list);
+	list_add(&group->next, &domain->group_list);
+
+	if (!allow_unsafe_interrupts &&
+	    !iommu_capable(bus, IOMMU_CAP_INTR_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 (iommu_capable(bus, IOMMU_CAP_CACHE_COHERENCY))
+		domain->prot |= IOMMU_CACHE;
+
+	/*
+	 * 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->prot == domain->prot) {
+			iommu_detach_group(domain->domain, iommu_group);
+			if (!iommu_attach_group(d->domain, iommu_group)) {
+				list_add(&group->next, &d->group_list);
+				iommu_domain_free(domain->domain);
+				kfree(domain);
+				mutex_unlock(&iommu->lock);
+				return 0;
+			}
+
+			ret = iommu_attach_group(domain->domain, 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;
+
+	list_add(&domain->next, &iommu->domain_list);
+
+	mutex_unlock(&iommu->lock);
+
+	return 0;
+
+out_detach:
+	iommu_detach_group(domain->domain, iommu_group);
+out_domain:
+	iommu_domain_free(domain->domain);
+out_free:
+	kfree(domain);
+	kfree(group);
+	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_type1_detach_group(void *iommu_data,
+					  struct iommu_group *iommu_group)
+{
+	struct vfio_iommu *iommu = iommu_data;
+	struct vfio_domain *domain;
+	struct vfio_group *group;
+
+	mutex_lock(&iommu->lock);
+
+	list_for_each_entry(domain, &iommu->domain_list, next) {
+		list_for_each_entry(group, &domain->group_list, next) {
+			if (group->iommu_group != iommu_group)
+				continue;
+
+			iommu_detach_group(domain->domain, iommu_group);
+			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, then all the mappings go away too.
+			 */
+			if (list_empty(&domain->group_list)) {
+				if (list_is_singular(&iommu->domain_list))
+					vfio_iommu_unmap_unpin_all(iommu);
+				iommu_domain_free(domain->domain);
+				list_del(&domain->next);
+				kfree(domain);
+			}
+			goto done;
+		}
+	}
+
+done:
+	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;
+	case VFIO_TYPE1v2_IOMMU:
+		iommu->v2 = true;
+		break;
+	default:
+		kfree(iommu);
+		return ERR_PTR(-EINVAL);
+	}
+
+	INIT_LIST_HEAD(&iommu->domain_list);
+	iommu->dma_list = RB_ROOT;
+	mutex_init(&iommu->lock);
+
+	return iommu;
+}
+
+static void vfio_iommu_type1_release(void *iommu_data)
+{
+	struct vfio_iommu *iommu = iommu_data;
+	struct vfio_domain *domain, *domain_tmp;
+	struct vfio_group *group, *group_tmp;
+
+	vfio_iommu_unmap_unpin_all(iommu);
+
+	list_for_each_entry_safe(domain, domain_tmp,
+				 &iommu->domain_list, next) {
+		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);
+		list_del(&domain->next);
+		kfree(domain);
+	}
+
+	kfree(iommu);
+}
+
+static int vfio_domains_have_iommu_cache(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->prot & IOMMU_CACHE)) {
+			ret = 0;
+			break;
+		}
+	}
+	mutex_unlock(&iommu->lock);
+
+	return ret;
+}
+
+static long vfio_iommu_type1_ioctl(void *iommu_data,
+				   unsigned int cmd, unsigned long arg)
+{
+	struct vfio_iommu *iommu = iommu_data;
+	unsigned long minsz;
+
+	if (cmd == VFIO_CHECK_EXTENSION) {
+		switch (arg) {
+		case VFIO_TYPE1_IOMMU:
+		case VFIO_TYPE1v2_IOMMU:
+		case VFIO_TYPE1_NESTING_IOMMU:
+			return 1;
+		case VFIO_DMA_CC_IOMMU:
+			if (!iommu)
+				return 0;
+			return vfio_domains_have_iommu_cache(iommu);
+		default:
+			return 0;
+		}
+	} else if (cmd == VFIO_IOMMU_GET_INFO) {
+		struct vfio_iommu_type1_info info;
+
+		minsz = offsetofend(struct vfio_iommu_type1_info, iova_pgsizes);
+
+		if (copy_from_user(&info, (void __user *)arg, minsz))
+			return -EFAULT;
+
+		if (info.argsz < minsz)
+			return -EINVAL;
+
+		info.flags = 0;
+
+		info.iova_pgsizes = vfio_pgsize_bitmap(iommu);
+
+		return copy_to_user((void __user *)arg, &info, minsz);
+
+	} else if (cmd == VFIO_IOMMU_MAP_DMA) {
+		struct vfio_iommu_type1_dma_map map;
+		uint32_t mask = VFIO_DMA_MAP_FLAG_READ |
+				VFIO_DMA_MAP_FLAG_WRITE;
+
+		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);
+
+	} else if (cmd == VFIO_IOMMU_UNMAP_DMA) {
+		struct vfio_iommu_type1_dma_unmap unmap;
+		long 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)
+			return -EINVAL;
+
+		ret = vfio_dma_do_unmap(iommu, &unmap);
+		if (ret)
+			return ret;
+
+		return copy_to_user((void __user *)arg, &unmap, minsz);
+	}
+
+	return -ENOTTY;
+}
+
+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,
+};
+
+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);