Merge tag 'vfio-v3.15-rc1' of git://github.com/awilliam/linux-vfio

Pull VFIO updates from Alex Williamson:
 "VFIO updates for v3.15 include:

   - Allow the vfio-type1 IOMMU to support multiple domains within a
     container
   - Plumb path to query whether all domains are cache-coherent
   - Wire query into kvm-vfio device to avoid KVM x86 WBINVD emulation
   - Always select CONFIG_ANON_INODES, vfio depends on it (Arnd)

  The first patch also makes the vfio-type1 IOMMU driver completely
  independent of the bus_type of the devices it's handling, which
  enables it to be used for both vfio-pci and a future vfio-platform
  (and hopefully combinations involving both simultaneously)"

* tag 'vfio-v3.15-rc1' of git://github.com/awilliam/linux-vfio:
  vfio: always select ANON_INODES
  kvm/vfio: Support for DMA coherent IOMMUs
  vfio: Add external user check extension interface
  vfio/type1: Add extension to test DMA cache coherence of IOMMU
  vfio/iommu_type1: Multi-IOMMU domain support

3 files changed, 362 insertions, 301 deletions

diff --git a/drivers/vfio/Kconfig b/drivers/vfio/Kconfig
index 26b3d9d1409f..af7b204b9215 100644
--- a/drivers/vfio/Kconfig
+++ b/drivers/vfio/Kconfig
@@ -13,6 +13,7 @@ menuconfig VFIO
         depends on IOMMU_API
         select VFIO_IOMMU_TYPE1 if X86
         select VFIO_IOMMU_SPAPR_TCE if (PPC_POWERNV || PPC_PSERIES)
+        select ANON_INODES
         help
           VFIO provides a framework for secure userspace device drivers.
           See Documentation/vfio.txt for more details.
diff --git a/drivers/vfio/vfio.c b/drivers/vfio/vfio.c
index 21271d8df023..512f479d8a50 100644
--- a/drivers/vfio/vfio.c
+++ b/drivers/vfio/vfio.c
@@ -1413,6 +1413,12 @@ int vfio_external_user_iommu_id(struct vfio_group *group)
 }
 EXPORT_SYMBOL_GPL(vfio_external_user_iommu_id);
 
+long vfio_external_check_extension(struct vfio_group *group, unsigned long arg)
+{
+        return vfio_ioctl_check_extension(group->container, arg);
+}
+EXPORT_SYMBOL_GPL(vfio_external_check_extension);
+
 /**
  * Module/class support
  */
diff --git a/drivers/vfio/vfio_iommu_type1.c b/drivers/vfio/vfio_iommu_type1.c
index 54af4e933695..6673e7be507f 100644
--- a/drivers/vfio/vfio_iommu_type1.c
+++ b/drivers/vfio/vfio_iommu_type1.c
@@ -30,7 +30,6 @@
 #include <linux/iommu.h>
 #include <linux/module.h>
 #include <linux/mm.h>
-#include <linux/pci.h>          /* pci_bus_type */
 #include <linux/rbtree.h>
 #include <linux/sched.h>
 #include <linux/slab.h>
@@ -55,11 +54,17 @@ MODULE_PARM_DESC(disable_hugepages,
                  "Disable VFIO IOMMU support for IOMMU hugepages.");
 
 struct vfio_iommu {
-        struct iommu_domain     *domain;
+        struct list_head        domain_list;
         struct mutex            lock;
         struct rb_root          dma_list;
+        bool v2;
+};
+
+struct vfio_domain {
+        struct iommu_domain     *domain;
+        struct list_head        next;
         struct list_head        group_list;
-        bool                    cache;
+        int                     prot;           /* IOMMU_CACHE */
 };
 
 struct vfio_dma {
@@ -99,7 +104,7 @@ static struct vfio_dma *vfio_find_dma(struct vfio_iommu *iommu,
         return NULL;
 }
 
-static void vfio_insert_dma(struct vfio_iommu *iommu, struct vfio_dma *new)
+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;
@@ -118,7 +123,7 @@ static void vfio_insert_dma(struct vfio_iommu *iommu, struct vfio_dma *new)
         rb_insert_color(&new->node, &iommu->dma_list);
 }
 
-static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *old)
+static void vfio_unlink_dma(struct vfio_iommu *iommu, struct vfio_dma *old)
 {
         rb_erase(&old->node, &iommu->dma_list);
 }
@@ -322,32 +327,39 @@ static long vfio_unpin_pages(unsigned long pfn, long npage,
         return unlocked;
 }
 
-static int vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma,
-                            dma_addr_t iova, size_t *size)
+static void vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma)
 {
-        dma_addr_t start = iova, end = iova + *size;
+        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);
+
         while (iova < end) {
                 size_t unmapped;
                 phys_addr_t phys;
 
-                /*
-                 * We use the IOMMU to track the physical address.  This
-                 * saves us from having a lot more entries in our mapping
-                 * tree.  The downside is that we don't track the size
-                 * used to do the mapping.  We request unmap of a single
-                 * page, but expect IOMMUs that support large pages to
-                 * unmap a larger chunk.
-                 */
-                phys = iommu_iova_to_phys(iommu->domain, iova);
+                phys = iommu_iova_to_phys(domain->domain, iova);
                 if (WARN_ON(!phys)) {
                         iova += PAGE_SIZE;
                         continue;
                 }
 
-                unmapped = iommu_unmap(iommu->domain, iova, PAGE_SIZE);
-                if (!unmapped)
+                unmapped = iommu_unmap(domain->domain, iova, PAGE_SIZE);
+                if (WARN_ON(!unmapped))
                         break;
 
                 unlocked += vfio_unpin_pages(phys >> PAGE_SHIFT,
@@ -357,119 +369,26 @@ static int vfio_unmap_unpin(struct vfio_iommu *iommu, struct vfio_dma *dma,
         }
 
         vfio_lock_acct(-unlocked);
-
-        *size = iova - start;
-
-        return 0;
 }
 
-static int vfio_remove_dma_overlap(struct vfio_iommu *iommu, dma_addr_t start,
-                                   size_t *size, struct vfio_dma *dma)
+static void vfio_remove_dma(struct vfio_iommu *iommu, struct vfio_dma *dma)
 {
-        size_t offset, overlap, tmp;
-        struct vfio_dma *split;
-        int ret;
-
-        if (!*size)
-                return 0;
-
-        /*
-         * Existing dma region is completely covered, unmap all.  This is
-         * the likely case since userspace tends to map and unmap buffers
-         * in one shot rather than multiple mappings within a buffer.
-         */
-        if (likely(start <= dma->iova &&
-                   start + *size >= dma->iova + dma->size)) {
-                *size = dma->size;
-                ret = vfio_unmap_unpin(iommu, dma, dma->iova, size);
-                if (ret)
-                        return ret;
-
-                /*
-                 * Did we remove more than we have?  Should never happen
-                 * since a vfio_dma is contiguous in iova and vaddr.
-                 */
-                WARN_ON(*size != dma->size);
-
-                vfio_remove_dma(iommu, dma);
-                kfree(dma);
-                return 0;
-        }
-
-        /* Overlap low address of existing range */
-        if (start <= dma->iova) {
-                overlap = start + *size - dma->iova;
-                ret = vfio_unmap_unpin(iommu, dma, dma->iova, &overlap);
-                if (ret)
-                        return ret;
-
-                vfio_remove_dma(iommu, dma);
-
-                /*
-                 * Check, we may have removed to whole vfio_dma.  If not
-                 * fixup and re-insert.
-                 */
-                if (overlap < dma->size) {
-                        dma->iova += overlap;
-                        dma->vaddr += overlap;
-                        dma->size -= overlap;
-                        vfio_insert_dma(iommu, dma);
-                } else
-                        kfree(dma);
-
-                *size = overlap;
-                return 0;
-        }
-
-        /* Overlap high address of existing range */
-        if (start + *size >= dma->iova + dma->size) {
-                offset = start - dma->iova;
-                overlap = dma->size - offset;
-
-                ret = vfio_unmap_unpin(iommu, dma, start, &overlap);
-                if (ret)
-                        return ret;
-
-                dma->size -= overlap;
-                *size = overlap;
-                return 0;
-        }
-
-        /* Split existing */
-
-        /*
-         * Allocate our tracking structure early even though it may not
-         * be used.  An Allocation failure later loses track of pages and
-         * is more difficult to unwind.
-         */
-        split = kzalloc(sizeof(*split), GFP_KERNEL);
-        if (!split)
-                return -ENOMEM;
-
-        offset = start - dma->iova;
-
-        ret = vfio_unmap_unpin(iommu, dma, start, size);
-        if (ret || !*size) {
-                kfree(split);
-                return ret;
-        }
-
-        tmp = dma->size;
+        vfio_unmap_unpin(iommu, dma);
+        vfio_unlink_dma(iommu, dma);
+        kfree(dma);
+}
 
-        /* Resize the lower vfio_dma in place, before the below insert */
-        dma->size = offset;
+static unsigned long vfio_pgsize_bitmap(struct vfio_iommu *iommu)
+{
+        struct vfio_domain *domain;
+        unsigned long bitmap = PAGE_MASK;
 
-        /* Insert new for remainder, assuming it didn't all get unmapped */
-        if (likely(offset + *size < tmp)) {
-                split->size = tmp - offset - *size;
-                split->iova = dma->iova + offset + *size;
-                split->vaddr = dma->vaddr + offset + *size;
-                split->prot = dma->prot;
-                vfio_insert_dma(iommu, split);
-        } else
-                kfree(split);
+        mutex_lock(&iommu->lock);
+        list_for_each_entry(domain, &iommu->domain_list, next)
+                bitmap &= domain->domain->ops->pgsize_bitmap;
+        mutex_unlock(&iommu->lock);
 
-        return 0;
+        return bitmap;
 }
 
 static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
@@ -477,10 +396,10 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
 {
         uint64_t mask;
         struct vfio_dma *dma;
-        size_t unmapped = 0, size;
+        size_t unmapped = 0;
         int ret = 0;
 
-        mask = ((uint64_t)1 << __ffs(iommu->domain->ops->pgsize_bitmap)) - 1;
+        mask = ((uint64_t)1 << __ffs(vfio_pgsize_bitmap(iommu))) - 1;
 
         if (unmap->iova & mask)
                 return -EINVAL;
@@ -491,20 +410,61 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
 
         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))) {
-                size = unmap->size;
-                ret = vfio_remove_dma_overlap(iommu, unmap->iova, &size, dma);
-                if (ret || !size)
+                if (!iommu->v2 && unmap->iova > dma->iova)
                         break;
-                unmapped += size;
+                unmapped += dma->size;
+                vfio_remove_dma(iommu, dma);
         }
 
+unlock:
         mutex_unlock(&iommu->lock);
 
-        /*
-         * We may unmap more than requested, update the unmap struct so
-         * userspace can know.
-         */
+        /* Report how much was unmapped */
         unmap->size = unmapped;
 
         return ret;
@@ -516,22 +476,47 @@ static int vfio_dma_do_unmap(struct vfio_iommu *iommu,
  * 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_iommu *iommu, dma_addr_t iova,
+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(iommu->domain, iova,
+                ret = iommu_map(domain->domain, iova,
                                 (phys_addr_t)pfn << PAGE_SHIFT,
-                                PAGE_SIZE, prot);
+                                PAGE_SIZE, prot | domain->prot);
                 if (ret)
                         break;
         }
 
         for (; i < npage && i > 0; i--, iova -= PAGE_SIZE)
-                iommu_unmap(iommu->domain, 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;
+                }
+        }
+
+        return 0;
+
+unwind:
+        list_for_each_entry_continue_reverse(d, &iommu->domain_list, next)
+                iommu_unmap(d->domain, iova, npage << PAGE_SHIFT);
 
         return ret;
 }
@@ -545,12 +530,12 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu,
         long npage;
         int ret = 0, prot = 0;
         uint64_t mask;
-        struct vfio_dma *dma = NULL;
+        struct vfio_dma *dma;
         unsigned long pfn;
 
         end = map->iova + map->size;
 
-        mask = ((uint64_t)1 << __ffs(iommu->domain->ops->pgsize_bitmap)) - 1;
+        mask = ((uint64_t)1 << __ffs(vfio_pgsize_bitmap(iommu))) - 1;
 
         /* READ/WRITE from device perspective */
         if (map->flags & VFIO_DMA_MAP_FLAG_WRITE)
@@ -561,9 +546,6 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu,
         if (!prot)
                 return -EINVAL; /* No READ/WRITE? */
 
-        if (iommu->cache)
-                prot |= IOMMU_CACHE;
-
         if (vaddr & mask)
                 return -EINVAL;
         if (map->iova & mask)
@@ -588,180 +570,257 @@ static int vfio_dma_do_map(struct vfio_iommu *iommu,
                 return -EEXIST;
         }
 
-        for (iova = map->iova; iova < end; iova += size, vaddr += size) {
-                long i;
+        dma = kzalloc(sizeof(*dma), GFP_KERNEL);
+        if (!dma) {
+                mutex_unlock(&iommu->lock);
+                return -ENOMEM;
+        }
+
+        dma->iova = map->iova;
+        dma->vaddr = map->vaddr;
+        dma->prot = prot;
+
+        /* Insert zero-sized and grow as we map chunks of it */
+        vfio_link_dma(iommu, dma);
 
+        for (iova = map->iova; iova < end; iova += size, vaddr += size) {
                 /* Pin a contiguous chunk of memory */
                 npage = vfio_pin_pages(vaddr, (end - iova) >> PAGE_SHIFT,
                                        prot, &pfn);
                 if (npage <= 0) {
                         WARN_ON(!npage);
                         ret = (int)npage;
-                        goto out;
-                }
-
-                /* Verify pages are not already mapped */
-                for (i = 0; i < npage; i++) {
-                        if (iommu_iova_to_phys(iommu->domain,
-                                               iova + (i << PAGE_SHIFT))) {
-                                ret = -EBUSY;
-                                goto out_unpin;
-                        }
+                        break;
                 }
 
-                ret = iommu_map(iommu->domain, iova,
-                                (phys_addr_t)pfn << PAGE_SHIFT,
-                                npage << PAGE_SHIFT, prot);
+                /* Map it! */
+                ret = vfio_iommu_map(iommu, iova, pfn, npage, prot);
                 if (ret) {
-                        if (ret != -EBUSY ||
-                            map_try_harder(iommu, iova, pfn, npage, prot)) {
-                                goto out_unpin;
-                        }
+                        vfio_unpin_pages(pfn, npage, prot, true);
+                        break;
                 }
 
                 size = npage << PAGE_SHIFT;
+                dma->size += size;
+        }
 
-                /*
-                 * Check if we abut a region below - nothing below 0.
-                 * This is the most likely case when mapping chunks of
-                 * physically contiguous regions within a virtual address
-                 * range.  Update the abutting entry in place since iova
-                 * doesn't change.
-                 */
-                if (likely(iova)) {
-                        struct vfio_dma *tmp;
-                        tmp = vfio_find_dma(iommu, iova - 1, 1);
-                        if (tmp && tmp->prot == prot &&
-                            tmp->vaddr + tmp->size == vaddr) {
-                                tmp->size += size;
-                                iova = tmp->iova;
-                                size = tmp->size;
-                                vaddr = tmp->vaddr;
-                                dma = tmp;
-                        }
-                }
+        if (ret)
+                vfio_remove_dma(iommu, dma);
 
-                /*
-                 * Check if we abut a region above - nothing above ~0 + 1.
-                 * If we abut above and below, remove and free.  If only
-                 * abut above, remove, modify, reinsert.
-                 */
-                if (likely(iova + size)) {
-                        struct vfio_dma *tmp;
-                        tmp = vfio_find_dma(iommu, iova + size, 1);
-                        if (tmp && tmp->prot == prot &&
-                            tmp->vaddr == vaddr + size) {
-                                vfio_remove_dma(iommu, tmp);
-                                if (dma) {
-                                        dma->size += tmp->size;
-                                        kfree(tmp);
-                                } else {
-                                        size += tmp->size;
-                                        tmp->size = size;
-                                        tmp->iova = iova;
-                                        tmp->vaddr = vaddr;
-                                        vfio_insert_dma(iommu, tmp);
-                                        dma = tmp;
-                                }
-                        }
-                }
+        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 (!dma) {
-                        dma = kzalloc(sizeof(*dma), GFP_KERNEL);
-                        if (!dma) {
-                                iommu_unmap(iommu->domain, iova, size);
-                                ret = -ENOMEM;
-                                goto out_unpin;
+                        if (WARN_ON(!phys)) {
+                                iova += PAGE_SIZE;
+                                continue;
                         }
 
-                        dma->size = size;
-                        dma->iova = iova;
-                        dma->vaddr = vaddr;
-                        dma->prot = prot;
-                        vfio_insert_dma(iommu, dma);
-                }
-        }
+                        size = PAGE_SIZE;
 
-        WARN_ON(ret);
-        mutex_unlock(&iommu->lock);
-        return ret;
+                        while (iova + size < dma->iova + dma->size &&
+                               phys + size == iommu_iova_to_phys(d->domain,
+                                                                 iova + size))
+                                size += PAGE_SIZE;
 
-out_unpin:
-        vfio_unpin_pages(pfn, npage, prot, true);
+                        ret = iommu_map(domain->domain, iova, phys,
+                                        size, dma->prot | domain->prot);
+                        if (ret)
+                                return ret;
 
-out:
-        iova = map->iova;
-        size = map->size;
-        while ((dma = vfio_find_dma(iommu, iova, size))) {
-                int r = vfio_remove_dma_overlap(iommu, iova,
-                                                &size, dma);
-                if (WARN_ON(r || !size))
-                        break;
+                        iova += size;
+                }
         }
 
-        mutex_unlock(&iommu->lock);
-        return ret;
+        return 0;
 }
 
 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, *tmp;
+        struct vfio_group *group, *g;
+        struct vfio_domain *domain, *d;
+        struct bus_type *bus = NULL;
         int ret;
 
-        group = kzalloc(sizeof(*group), GFP_KERNEL);
-        if (!group)
-                return -ENOMEM;
-
         mutex_lock(&iommu->lock);
 
-        list_for_each_entry(tmp, &iommu->group_list, next) {
-                if (tmp->iommu_group == iommu_group) {
+        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);
-                        kfree(group);
                         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;
+        }
+
+        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_domain_has_cap(domain->domain, 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_domain_has_cap(domain->domain, IOMMU_CAP_CACHE_COHERENCY))
+                domain->prot |= IOMMU_CACHE;
+
         /*
-         * TODO: Domain have capabilities that might change as we add
-         * groups (see iommu->cache, currently never set).  Check for
-         * them and potentially disallow groups to be attached when it
-         * would change capabilities (ugh).
+         * 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.
          */
-        ret = iommu_attach_group(iommu->domain, iommu_group);
-        if (ret) {
-                mutex_unlock(&iommu->lock);
-                kfree(group);
-                return ret;
+        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;
+                }
         }
 
-        group->iommu_group = iommu_group;
-        list_add(&group->next, &iommu->group_list);
+        /* 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(group, &iommu->group_list, next) {
-                if (group->iommu_group == iommu_group) {
-                        iommu_detach_group(iommu->domain, iommu_group);
+        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);
-                        break;
+                        /*
+                         * 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);
 }
 
@@ -769,40 +828,17 @@ static void *vfio_iommu_type1_open(unsigned long arg)
 {
         struct vfio_iommu *iommu;
 
-        if (arg != VFIO_TYPE1_IOMMU)
+        if (arg != VFIO_TYPE1_IOMMU && arg != VFIO_TYPE1v2_IOMMU)
                 return ERR_PTR(-EINVAL);
 
         iommu = kzalloc(sizeof(*iommu), GFP_KERNEL);
         if (!iommu)
                 return ERR_PTR(-ENOMEM);
 
-        INIT_LIST_HEAD(&iommu->group_list);
+        INIT_LIST_HEAD(&iommu->domain_list);
         iommu->dma_list = RB_ROOT;
         mutex_init(&iommu->lock);
-
-        /*
-         * Wish we didn't have to know about bus_type here.
-         */
-        iommu->domain = iommu_domain_alloc(&pci_bus_type);
-        if (!iommu->domain) {
-                kfree(iommu);
-                return ERR_PTR(-EIO);
-        }
-
-        /*
-         * Wish we could specify required capabilities rather than create
-         * a domain, see what comes out and hope it doesn't change along
-         * the way.  Fortunately we know interrupt remapping is global for
-         * our iommus.
-         */
-        if (!allow_unsafe_interrupts &&
-            !iommu_domain_has_cap(iommu->domain, 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__);
-                iommu_domain_free(iommu->domain);
-                kfree(iommu);
-                return ERR_PTR(-EPERM);
-        }
+        iommu->v2 = (arg == VFIO_TYPE1v2_IOMMU);
 
         return iommu;
 }
@@ -810,26 +846,42 @@ static void *vfio_iommu_type1_open(unsigned long arg)
 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;
-        struct rb_node *node;
 
-        list_for_each_entry_safe(group, group_tmp, &iommu->group_list, next) {
-                iommu_detach_group(iommu->domain, group->iommu_group);
-                list_del(&group->next);
-                kfree(group);
+        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);
         }
 
-        while ((node = rb_first(&iommu->dma_list))) {
-                struct vfio_dma *dma = rb_entry(node, struct vfio_dma, node);
-                size_t size = dma->size;
-                vfio_remove_dma_overlap(iommu, dma->iova, &size, dma);
-                if (WARN_ON(!size))
+        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);
 
-        iommu_domain_free(iommu->domain);
-        iommu->domain = NULL;
-        kfree(iommu);
+        return ret;
 }
 
 static long vfio_iommu_type1_ioctl(void *iommu_data,
@@ -841,7 +893,12 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
         if (cmd == VFIO_CHECK_EXTENSION) {
                 switch (arg) {
                 case VFIO_TYPE1_IOMMU:
+                case VFIO_TYPE1v2_IOMMU:
                         return 1;
+                case VFIO_DMA_CC_IOMMU:
+                        if (!iommu)
+                                return 0;
+                        return vfio_domains_have_iommu_cache(iommu);
                 default:
                         return 0;
                 }
@@ -858,7 +915,7 @@ static long vfio_iommu_type1_ioctl(void *iommu_data,
 
                 info.flags = 0;
 
-                info.iova_pgsizes = iommu->domain->ops->pgsize_bitmap;
+                info.iova_pgsizes = vfio_pgsize_bitmap(iommu);
 
                 return copy_to_user((void __user *)arg, &info, minsz);
 
@@ -911,9 +968,6 @@ static const struct vfio_iommu_driver_ops vfio_iommu_driver_ops_type1 = {
 
 static int __init vfio_iommu_type1_init(void)
 {
-        if (!iommu_present(&pci_bus_type))
-                return -ENODEV;
-
         return vfio_register_iommu_driver(&vfio_iommu_driver_ops_type1);
 }