diff --git a/MAINTAINERS b/MAINTAINERS
index 1689dcfec800..3d8550c76f4a 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -15946,6 +15946,13 @@ S:	Maintained
 F:	drivers/virtio/virtio_input.c
 F:	include/uapi/linux/virtio_input.h
 
+VIRTIO IOMMU DRIVER
+M:	Jean-Philippe Brucker <jean-philippe.brucker@arm.com>
+L:	virtualization@lists.linux-foundation.org
+S:	Maintained
+F:	drivers/iommu/virtio-iommu.c
+F:	include/uapi/linux/virtio_iommu.h
+
 VIRTUAL BOX GUEST DEVICE DRIVER
 M:	Hans de Goede <hdegoede@redhat.com>
 M:	Arnd Bergmann <arnd@arndb.de>
diff --git a/drivers/iommu/Kconfig b/drivers/iommu/Kconfig
index bf2bbfa2a399..db5f2b8c23f5 100644
--- a/drivers/iommu/Kconfig
+++ b/drivers/iommu/Kconfig
@@ -464,4 +464,15 @@ config QCOM_IOMMU
 	help
 	  Support for IOMMU on certain Qualcomm SoCs.
 
+config VIRTIO_IOMMU
+	bool "Virtio IOMMU driver"
+	depends on VIRTIO=y
+	select IOMMU_API
+	select INTERVAL_TREE
+	select ARM_DMA_USE_IOMMU if ARM
+	help
+	  Para-virtualised IOMMU driver with virtio.
+
+	  Say Y here if you intend to run this kernel as a guest.
+
 endif # IOMMU_SUPPORT
diff --git a/drivers/iommu/Makefile b/drivers/iommu/Makefile
index 5481e5fe1f95..bd7e55751d09 100644
--- a/drivers/iommu/Makefile
+++ b/drivers/iommu/Makefile
@@ -36,3 +36,4 @@ obj-$(CONFIG_EXYNOS_IOMMU) += exynos-iommu.o
 obj-$(CONFIG_FSL_PAMU) += fsl_pamu.o fsl_pamu_domain.o
 obj-$(CONFIG_S390_IOMMU) += s390-iommu.o
 obj-$(CONFIG_QCOM_IOMMU) += qcom_iommu.o
+obj-$(CONFIG_VIRTIO_IOMMU) += virtio-iommu.o
diff --git a/drivers/iommu/virtio-iommu.c b/drivers/iommu/virtio-iommu.c
new file mode 100644
index 000000000000..7540dab9c8dc
--- /dev/null
+++ b/drivers/iommu/virtio-iommu.c
@@ -0,0 +1,916 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Virtio driver for the paravirtualized IOMMU
+ *
+ * Copyright (C) 2018 Arm Limited
+ */
+
+#define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
+
+#include <linux/amba/bus.h>
+#include <linux/delay.h>
+#include <linux/dma-iommu.h>
+#include <linux/freezer.h>
+#include <linux/interval_tree.h>
+#include <linux/iommu.h>
+#include <linux/module.h>
+#include <linux/of_iommu.h>
+#include <linux/of_platform.h>
+#include <linux/pci.h>
+#include <linux/platform_device.h>
+#include <linux/virtio.h>
+#include <linux/virtio_config.h>
+#include <linux/virtio_ids.h>
+#include <linux/wait.h>
+
+#include <uapi/linux/virtio_iommu.h>
+
+#define MSI_IOVA_BASE			0x8000000
+#define MSI_IOVA_LENGTH			0x100000
+
+#define VIOMMU_REQUEST_VQ		0
+#define VIOMMU_NR_VQS			1
+
+struct viommu_dev {
+	struct iommu_device		iommu;
+	struct device			*dev;
+	struct virtio_device		*vdev;
+
+	struct ida			domain_ids;
+
+	struct virtqueue		*vqs[VIOMMU_NR_VQS];
+	spinlock_t			request_lock;
+	struct list_head		requests;
+
+	/* Device configuration */
+	struct iommu_domain_geometry	geometry;
+	u64				pgsize_bitmap;
+	u8				domain_bits;
+};
+
+struct viommu_mapping {
+	phys_addr_t			paddr;
+	struct interval_tree_node	iova;
+	u32				flags;
+};
+
+struct viommu_domain {
+	struct iommu_domain		domain;
+	struct viommu_dev		*viommu;
+	struct mutex			mutex; /* protects viommu pointer */
+	unsigned int			id;
+
+	spinlock_t			mappings_lock;
+	struct rb_root_cached		mappings;
+
+	unsigned long			nr_endpoints;
+};
+
+struct viommu_endpoint {
+	struct viommu_dev		*viommu;
+	struct viommu_domain		*vdomain;
+};
+
+struct viommu_request {
+	struct list_head		list;
+	void				*writeback;
+	unsigned int			write_offset;
+	unsigned int			len;
+	char				buf[];
+};
+
+#define to_viommu_domain(domain)	\
+	container_of(domain, struct viommu_domain, domain)
+
+static int viommu_get_req_errno(void *buf, size_t len)
+{
+	struct virtio_iommu_req_tail *tail = buf + len - sizeof(*tail);
+
+	switch (tail->status) {
+	case VIRTIO_IOMMU_S_OK:
+		return 0;
+	case VIRTIO_IOMMU_S_UNSUPP:
+		return -ENOSYS;
+	case VIRTIO_IOMMU_S_INVAL:
+		return -EINVAL;
+	case VIRTIO_IOMMU_S_RANGE:
+		return -ERANGE;
+	case VIRTIO_IOMMU_S_NOENT:
+		return -ENOENT;
+	case VIRTIO_IOMMU_S_FAULT:
+		return -EFAULT;
+	case VIRTIO_IOMMU_S_IOERR:
+	case VIRTIO_IOMMU_S_DEVERR:
+	default:
+		return -EIO;
+	}
+}
+
+static void viommu_set_req_status(void *buf, size_t len, int status)
+{
+	struct virtio_iommu_req_tail *tail = buf + len - sizeof(*tail);
+
+	tail->status = status;
+}
+
+static off_t viommu_get_write_desc_offset(struct viommu_dev *viommu,
+					  struct virtio_iommu_req_head *req,
+					  size_t len)
+{
+	size_t tail_size = sizeof(struct virtio_iommu_req_tail);
+
+	return len - tail_size;
+}
+
+/*
+ * __viommu_sync_req - Complete all in-flight requests
+ *
+ * Wait for all added requests to complete. When this function returns, all
+ * requests that were in-flight at the time of the call have completed.
+ */
+static int __viommu_sync_req(struct viommu_dev *viommu)
+{
+	int ret = 0;
+	unsigned int len;
+	size_t write_len;
+	struct viommu_request *req;
+	struct virtqueue *vq = viommu->vqs[VIOMMU_REQUEST_VQ];
+
+	assert_spin_locked(&viommu->request_lock);
+
+	virtqueue_kick(vq);
+
+	while (!list_empty(&viommu->requests)) {
+		len = 0;
+		req = virtqueue_get_buf(vq, &len);
+		if (!req)
+			continue;
+
+		if (!len)
+			viommu_set_req_status(req->buf, req->len,
+					      VIRTIO_IOMMU_S_IOERR);
+
+		write_len = req->len - req->write_offset;
+		if (req->writeback && len == write_len)
+			memcpy(req->writeback, req->buf + req->write_offset,
+			       write_len);
+
+		list_del(&req->list);
+		kfree(req);
+	}
+
+	return ret;
+}
+
+static int viommu_sync_req(struct viommu_dev *viommu)
+{
+	int ret;
+	unsigned long flags;
+
+	spin_lock_irqsave(&viommu->request_lock, flags);
+	ret = __viommu_sync_req(viommu);
+	if (ret)
+		dev_dbg(viommu->dev, "could not sync requests (%d)\n", ret);
+	spin_unlock_irqrestore(&viommu->request_lock, flags);
+
+	return ret;
+}
+
+/*
+ * __viommu_add_request - Add one request to the queue
+ * @buf: pointer to the request buffer
+ * @len: length of the request buffer
+ * @writeback: copy data back to the buffer when the request completes.
+ *
+ * Add a request to the queue. Only synchronize the queue if it's already full.
+ * Otherwise don't kick the queue nor wait for requests to complete.
+ *
+ * When @writeback is true, data written by the device, including the request
+ * status, is copied into @buf after the request completes. This is unsafe if
+ * the caller allocates @buf on stack and drops the lock between add_req() and
+ * sync_req().
+ *
+ * Return 0 if the request was successfully added to the queue.
+ */
+static int __viommu_add_req(struct viommu_dev *viommu, void *buf, size_t len,
+			    bool writeback)
+{
+	int ret;
+	off_t write_offset;
+	struct viommu_request *req;
+	struct scatterlist top_sg, bottom_sg;
+	struct scatterlist *sg[2] = { &top_sg, &bottom_sg };
+	struct virtqueue *vq = viommu->vqs[VIOMMU_REQUEST_VQ];
+
+	assert_spin_locked(&viommu->request_lock);
+
+	write_offset = viommu_get_write_desc_offset(viommu, buf, len);
+	if (write_offset <= 0)
+		return -EINVAL;
+
+	req = kzalloc(sizeof(*req) + len, GFP_ATOMIC);
+	if (!req)
+		return -ENOMEM;
+
+	req->len = len;
+	if (writeback) {
+		req->writeback = buf + write_offset;
+		req->write_offset = write_offset;
+	}
+	memcpy(&req->buf, buf, write_offset);
+
+	sg_init_one(&top_sg, req->buf, write_offset);
+	sg_init_one(&bottom_sg, req->buf + write_offset, len - write_offset);
+
+	ret = virtqueue_add_sgs(vq, sg, 1, 1, req, GFP_ATOMIC);
+	if (ret == -ENOSPC) {
+		/* If the queue is full, sync and retry */
+		if (!__viommu_sync_req(viommu))
+			ret = virtqueue_add_sgs(vq, sg, 1, 1, req, GFP_ATOMIC);
+	}
+	if (ret)
+		goto err_free;
+
+	list_add_tail(&req->list, &viommu->requests);
+	return 0;
+
+err_free:
+	kfree(req);
+	return ret;
+}
+
+static int viommu_add_req(struct viommu_dev *viommu, void *buf, size_t len)
+{
+	int ret;
+	unsigned long flags;
+
+	spin_lock_irqsave(&viommu->request_lock, flags);
+	ret = __viommu_add_req(viommu, buf, len, false);
+	if (ret)
+		dev_dbg(viommu->dev, "could not add request: %d\n", ret);
+	spin_unlock_irqrestore(&viommu->request_lock, flags);
+
+	return ret;
+}
+
+/*
+ * Send a request and wait for it to complete. Return the request status (as an
+ * errno)
+ */
+static int viommu_send_req_sync(struct viommu_dev *viommu, void *buf,
+				size_t len)
+{
+	int ret;
+	unsigned long flags;
+
+	spin_lock_irqsave(&viommu->request_lock, flags);
+
+	ret = __viommu_add_req(viommu, buf, len, true);
+	if (ret) {
+		dev_dbg(viommu->dev, "could not add request (%d)\n", ret);
+		goto out_unlock;
+	}
+
+	ret = __viommu_sync_req(viommu);
+	if (ret) {
+		dev_dbg(viommu->dev, "could not sync requests (%d)\n", ret);
+		/* Fall-through (get the actual request status) */
+	}
+
+	ret = viommu_get_req_errno(buf, len);
+out_unlock:
+	spin_unlock_irqrestore(&viommu->request_lock, flags);
+	return ret;
+}
+
+/*
+ * viommu_add_mapping - add a mapping to the internal tree
+ *
+ * On success, return the new mapping. Otherwise return NULL.
+ */
+static int viommu_add_mapping(struct viommu_domain *vdomain, unsigned long iova,
+			      phys_addr_t paddr, size_t size, u32 flags)
+{
+	unsigned long irqflags;
+	struct viommu_mapping *mapping;
+
+	mapping = kzalloc(sizeof(*mapping), GFP_ATOMIC);
+	if (!mapping)
+		return -ENOMEM;
+
+	mapping->paddr		= paddr;
+	mapping->iova.start	= iova;
+	mapping->iova.last	= iova + size - 1;
+	mapping->flags		= flags;
+
+	spin_lock_irqsave(&vdomain->mappings_lock, irqflags);
+	interval_tree_insert(&mapping->iova, &vdomain->mappings);
+	spin_unlock_irqrestore(&vdomain->mappings_lock, irqflags);
+
+	return 0;
+}
+
+/*
+ * viommu_del_mappings - remove mappings from the internal tree
+ *
+ * @vdomain: the domain
+ * @iova: start of the range
+ * @size: size of the range. A size of 0 corresponds to the entire address
+ *	space.
+ *
+ * On success, returns the number of unmapped bytes (>= size)
+ */
+static size_t viommu_del_mappings(struct viommu_domain *vdomain,
+				  unsigned long iova, size_t size)
+{
+	size_t unmapped = 0;
+	unsigned long flags;
+	unsigned long last = iova + size - 1;
+	struct viommu_mapping *mapping = NULL;
+	struct interval_tree_node *node, *next;
+
+	spin_lock_irqsave(&vdomain->mappings_lock, flags);
+	next = interval_tree_iter_first(&vdomain->mappings, iova, last);
+	while (next) {
+		node = next;
+		mapping = container_of(node, struct viommu_mapping, iova);
+		next = interval_tree_iter_next(node, iova, last);
+
+		/* Trying to split a mapping? */
+		if (mapping->iova.start < iova)
+			break;
+
+		/*
+		 * Virtio-iommu doesn't allow UNMAP to split a mapping created
+		 * with a single MAP request, so remove the full mapping.
+		 */
+		unmapped += mapping->iova.last - mapping->iova.start + 1;
+
+		interval_tree_remove(node, &vdomain->mappings);
+		kfree(mapping);
+	}
+	spin_unlock_irqrestore(&vdomain->mappings_lock, flags);
+
+	return unmapped;
+}
+
+/*
+ * viommu_replay_mappings - re-send MAP requests
+ *
+ * When reattaching a domain that was previously detached from all endpoints,
+ * mappings were deleted from the device. Re-create the mappings available in
+ * the internal tree.
+ */
+static int viommu_replay_mappings(struct viommu_domain *vdomain)
+{
+	int ret = 0;
+	unsigned long flags;
+	struct viommu_mapping *mapping;
+	struct interval_tree_node *node;
+	struct virtio_iommu_req_map map;
+
+	spin_lock_irqsave(&vdomain->mappings_lock, flags);
+	node = interval_tree_iter_first(&vdomain->mappings, 0, -1UL);
+	while (node) {
+		mapping = container_of(node, struct viommu_mapping, iova);
+		map = (struct virtio_iommu_req_map) {
+			.head.type	= VIRTIO_IOMMU_T_MAP,
+			.domain		= cpu_to_le32(vdomain->id),
+			.virt_start	= cpu_to_le64(mapping->iova.start),
+			.virt_end	= cpu_to_le64(mapping->iova.last),
+			.phys_start	= cpu_to_le64(mapping->paddr),
+			.flags		= cpu_to_le32(mapping->flags),
+		};
+
+		ret = viommu_send_req_sync(vdomain->viommu, &map, sizeof(map));
+		if (ret)
+			break;
+
+		node = interval_tree_iter_next(node, 0, -1UL);
+	}
+	spin_unlock_irqrestore(&vdomain->mappings_lock, flags);
+
+	return ret;
+}
+
+/* IOMMU API */
+
+static struct iommu_domain *viommu_domain_alloc(unsigned type)
+{
+	struct viommu_domain *vdomain;
+
+	if (type != IOMMU_DOMAIN_UNMANAGED && type != IOMMU_DOMAIN_DMA)
+		return NULL;
+
+	vdomain = kzalloc(sizeof(*vdomain), GFP_KERNEL);
+	if (!vdomain)
+		return NULL;
+
+	mutex_init(&vdomain->mutex);
+	spin_lock_init(&vdomain->mappings_lock);
+	vdomain->mappings = RB_ROOT_CACHED;
+
+	if (type == IOMMU_DOMAIN_DMA &&
+	    iommu_get_dma_cookie(&vdomain->domain)) {
+		kfree(vdomain);
+		return NULL;
+	}
+
+	return &vdomain->domain;
+}
+
+static int viommu_domain_finalise(struct viommu_dev *viommu,
+				  struct iommu_domain *domain)
+{
+	int ret;
+	struct viommu_domain *vdomain = to_viommu_domain(domain);
+	unsigned int max_domain = viommu->domain_bits > 31 ? ~0 :
+				  (1U << viommu->domain_bits) - 1;
+
+	vdomain->viommu		= viommu;
+
+	domain->pgsize_bitmap	= viommu->pgsize_bitmap;
+	domain->geometry	= viommu->geometry;
+
+	ret = ida_alloc_max(&viommu->domain_ids, max_domain, GFP_KERNEL);
+	if (ret >= 0)
+		vdomain->id = (unsigned int)ret;
+
+	return ret > 0 ? 0 : ret;
+}
+
+static void viommu_domain_free(struct iommu_domain *domain)
+{
+	struct viommu_domain *vdomain = to_viommu_domain(domain);
+
+	iommu_put_dma_cookie(domain);
+
+	/* Free all remaining mappings (size 2^64) */
+	viommu_del_mappings(vdomain, 0, 0);
+
+	if (vdomain->viommu)
+		ida_free(&vdomain->viommu->domain_ids, vdomain->id);
+
+	kfree(vdomain);
+}
+
+static int viommu_attach_dev(struct iommu_domain *domain, struct device *dev)
+{
+	int i;
+	int ret = 0;
+	struct virtio_iommu_req_attach req;
+	struct iommu_fwspec *fwspec = dev->iommu_fwspec;
+	struct viommu_endpoint *vdev = fwspec->iommu_priv;
+	struct viommu_domain *vdomain = to_viommu_domain(domain);
+
+	mutex_lock(&vdomain->mutex);
+	if (!vdomain->viommu) {
+		/*
+		 * Properly initialize the domain now that we know which viommu
+		 * owns it.
+		 */
+		ret = viommu_domain_finalise(vdev->viommu, domain);
+	} else if (vdomain->viommu != vdev->viommu) {
+		dev_err(dev, "cannot attach to foreign vIOMMU\n");
+		ret = -EXDEV;
+	}
+	mutex_unlock(&vdomain->mutex);
+
+	if (ret)
+		return ret;
+
+	/*
+	 * In the virtio-iommu device, when attaching the endpoint to a new
+	 * domain, it is detached from the old one and, if as as a result the
+	 * old domain isn't attached to any endpoint, all mappings are removed
+	 * from the old domain and it is freed.
+	 *
+	 * In the driver the old domain still exists, and its mappings will be
+	 * recreated if it gets reattached to an endpoint. Otherwise it will be
+	 * freed explicitly.
+	 *
+	 * vdev->vdomain is protected by group->mutex
+	 */
+	if (vdev->vdomain)
+		vdev->vdomain->nr_endpoints--;
+
+	req = (struct virtio_iommu_req_attach) {
+		.head.type	= VIRTIO_IOMMU_T_ATTACH,
+		.domain		= cpu_to_le32(vdomain->id),
+	};
+
+	for (i = 0; i < fwspec->num_ids; i++) {
+		req.endpoint = cpu_to_le32(fwspec->ids[i]);
+
+		ret = viommu_send_req_sync(vdomain->viommu, &req, sizeof(req));
+		if (ret)
+			return ret;
+	}
+
+	if (!vdomain->nr_endpoints) {
+		/*
+		 * This endpoint is the first to be attached to the domain.
+		 * Replay existing mappings (e.g. SW MSI).
+		 */
+		ret = viommu_replay_mappings(vdomain);
+		if (ret)
+			return ret;
+	}
+
+	vdomain->nr_endpoints++;
+	vdev->vdomain = vdomain;
+
+	return 0;
+}
+
+static int viommu_map(struct iommu_domain *domain, unsigned long iova,
+		      phys_addr_t paddr, size_t size, int prot)
+{
+	int ret;
+	int flags;
+	struct virtio_iommu_req_map map;
+	struct viommu_domain *vdomain = to_viommu_domain(domain);
+
+	flags = (prot & IOMMU_READ ? VIRTIO_IOMMU_MAP_F_READ : 0) |
+		(prot & IOMMU_WRITE ? VIRTIO_IOMMU_MAP_F_WRITE : 0) |
+		(prot & IOMMU_MMIO ? VIRTIO_IOMMU_MAP_F_MMIO : 0);
+
+	ret = viommu_add_mapping(vdomain, iova, paddr, size, flags);
+	if (ret)
+		return ret;
+
+	map = (struct virtio_iommu_req_map) {
+		.head.type	= VIRTIO_IOMMU_T_MAP,
+		.domain		= cpu_to_le32(vdomain->id),
+		.virt_start	= cpu_to_le64(iova),
+		.phys_start	= cpu_to_le64(paddr),
+		.virt_end	= cpu_to_le64(iova + size - 1),
+		.flags		= cpu_to_le32(flags),
+	};
+
+	if (!vdomain->nr_endpoints)
+		return 0;
+
+	ret = viommu_send_req_sync(vdomain->viommu, &map, sizeof(map));
+	if (ret)
+		viommu_del_mappings(vdomain, iova, size);
+
+	return ret;
+}
+
+static size_t viommu_unmap(struct iommu_domain *domain, unsigned long iova,
+			   size_t size)
+{
+	int ret = 0;
+	size_t unmapped;
+	struct virtio_iommu_req_unmap unmap;
+	struct viommu_domain *vdomain = to_viommu_domain(domain);
+
+	unmapped = viommu_del_mappings(vdomain, iova, size);
+	if (unmapped < size)
+		return 0;
+
+	/* Device already removed all mappings after detach. */
+	if (!vdomain->nr_endpoints)
+		return unmapped;
+
+	unmap = (struct virtio_iommu_req_unmap) {
+		.head.type	= VIRTIO_IOMMU_T_UNMAP,
+		.domain		= cpu_to_le32(vdomain->id),
+		.virt_start	= cpu_to_le64(iova),
+		.virt_end	= cpu_to_le64(iova + unmapped - 1),
+	};
+
+	ret = viommu_add_req(vdomain->viommu, &unmap, sizeof(unmap));
+	return ret ? 0 : unmapped;
+}
+
+static phys_addr_t viommu_iova_to_phys(struct iommu_domain *domain,
+				       dma_addr_t iova)
+{
+	u64 paddr = 0;
+	unsigned long flags;
+	struct viommu_mapping *mapping;
+	struct interval_tree_node *node;
+	struct viommu_domain *vdomain = to_viommu_domain(domain);
+
+	spin_lock_irqsave(&vdomain->mappings_lock, flags);
+	node = interval_tree_iter_first(&vdomain->mappings, iova, iova);
+	if (node) {
+		mapping = container_of(node, struct viommu_mapping, iova);
+		paddr = mapping->paddr + (iova - mapping->iova.start);
+	}
+	spin_unlock_irqrestore(&vdomain->mappings_lock, flags);
+
+	return paddr;
+}
+
+static void viommu_iotlb_sync(struct iommu_domain *domain)
+{
+	struct viommu_domain *vdomain = to_viommu_domain(domain);
+
+	viommu_sync_req(vdomain->viommu);
+}
+
+static void viommu_get_resv_regions(struct device *dev, struct list_head *head)
+{
+	struct iommu_resv_region *region;
+	int prot = IOMMU_WRITE | IOMMU_NOEXEC | IOMMU_MMIO;
+
+	region = iommu_alloc_resv_region(MSI_IOVA_BASE, MSI_IOVA_LENGTH, prot,
+					 IOMMU_RESV_SW_MSI);
+	if (!region)
+		return;
+
+	list_add_tail(&region->list, head);
+	iommu_dma_get_resv_regions(dev, head);
+}
+
+static void viommu_put_resv_regions(struct device *dev, struct list_head *head)
+{
+	struct iommu_resv_region *entry, *next;
+
+	list_for_each_entry_safe(entry, next, head, list)
+		kfree(entry);
+}
+
+static struct iommu_ops viommu_ops;
+static struct virtio_driver virtio_iommu_drv;
+
+static int viommu_match_node(struct device *dev, void *data)
+{
+	return dev->parent->fwnode == data;
+}
+
+static struct viommu_dev *viommu_get_by_fwnode(struct fwnode_handle *fwnode)
+{
+	struct device *dev = driver_find_device(&virtio_iommu_drv.driver, NULL,
+						fwnode, viommu_match_node);
+	put_device(dev);
+
+	return dev ? dev_to_virtio(dev)->priv : NULL;
+}
+
+static int viommu_add_device(struct device *dev)
+{
+	int ret;
+	struct iommu_group *group;
+	struct viommu_endpoint *vdev;
+	struct viommu_dev *viommu = NULL;
+	struct iommu_fwspec *fwspec = dev->iommu_fwspec;
+
+	if (!fwspec || fwspec->ops != &viommu_ops)
+		return -ENODEV;
+
+	viommu = viommu_get_by_fwnode(fwspec->iommu_fwnode);
+	if (!viommu)
+		return -ENODEV;
+
+	vdev = kzalloc(sizeof(*vdev), GFP_KERNEL);
+	if (!vdev)
+		return -ENOMEM;
+
+	vdev->viommu = viommu;
+	fwspec->iommu_priv = vdev;
+
+	ret = iommu_device_link(&viommu->iommu, dev);
+	if (ret)
+		goto err_free_dev;
+
+	/*
+	 * Last step creates a default domain and attaches to it. Everything
+	 * must be ready.
+	 */
+	group = iommu_group_get_for_dev(dev);
+	if (IS_ERR(group)) {
+		ret = PTR_ERR(group);
+		goto err_unlink_dev;
+	}
+
+	iommu_group_put(group);
+
+	return PTR_ERR_OR_ZERO(group);
+
+err_unlink_dev:
+	iommu_device_unlink(&viommu->iommu, dev);
+err_free_dev:
+	kfree(vdev);
+
+	return ret;
+}
+
+static void viommu_remove_device(struct device *dev)
+{
+	struct viommu_endpoint *vdev;
+	struct iommu_fwspec *fwspec = dev->iommu_fwspec;
+
+	if (!fwspec || fwspec->ops != &viommu_ops)
+		return;
+
+	vdev = fwspec->iommu_priv;
+
+	iommu_group_remove_device(dev);
+	iommu_device_unlink(&vdev->viommu->iommu, dev);
+	kfree(vdev);
+}
+
+static struct iommu_group *viommu_device_group(struct device *dev)
+{
+	if (dev_is_pci(dev))
+		return pci_device_group(dev);
+	else
+		return generic_device_group(dev);
+}
+
+static int viommu_of_xlate(struct device *dev, struct of_phandle_args *args)
+{
+	return iommu_fwspec_add_ids(dev, args->args, 1);
+}
+
+static struct iommu_ops viommu_ops = {
+	.domain_alloc		= viommu_domain_alloc,
+	.domain_free		= viommu_domain_free,
+	.attach_dev		= viommu_attach_dev,
+	.map			= viommu_map,
+	.unmap			= viommu_unmap,
+	.iova_to_phys		= viommu_iova_to_phys,
+	.iotlb_sync		= viommu_iotlb_sync,
+	.add_device		= viommu_add_device,
+	.remove_device		= viommu_remove_device,
+	.device_group		= viommu_device_group,
+	.get_resv_regions	= viommu_get_resv_regions,
+	.put_resv_regions	= viommu_put_resv_regions,
+	.of_xlate		= viommu_of_xlate,
+};
+
+static int viommu_init_vqs(struct viommu_dev *viommu)
+{
+	struct virtio_device *vdev = dev_to_virtio(viommu->dev);
+	const char *name = "request";
+	void *ret;
+
+	ret = virtio_find_single_vq(vdev, NULL, name);
+	if (IS_ERR(ret)) {
+		dev_err(viommu->dev, "cannot find VQ\n");
+		return PTR_ERR(ret);
+	}
+
+	viommu->vqs[VIOMMU_REQUEST_VQ] = ret;
+
+	return 0;
+}
+
+static int viommu_probe(struct virtio_device *vdev)
+{
+	struct device *parent_dev = vdev->dev.parent;
+	struct viommu_dev *viommu = NULL;
+	struct device *dev = &vdev->dev;
+	u64 input_start = 0;
+	u64 input_end = -1UL;
+	int ret;
+
+	if (!virtio_has_feature(vdev, VIRTIO_F_VERSION_1) ||
+	    !virtio_has_feature(vdev, VIRTIO_IOMMU_F_MAP_UNMAP))
+		return -ENODEV;
+
+	viommu = devm_kzalloc(dev, sizeof(*viommu), GFP_KERNEL);
+	if (!viommu)
+		return -ENOMEM;
+
+	spin_lock_init(&viommu->request_lock);
+	ida_init(&viommu->domain_ids);
+	viommu->dev = dev;
+	viommu->vdev = vdev;
+	INIT_LIST_HEAD(&viommu->requests);
+
+	ret = viommu_init_vqs(viommu);
+	if (ret)
+		return ret;
+
+	virtio_cread(vdev, struct virtio_iommu_config, page_size_mask,
+		     &viommu->pgsize_bitmap);
+
+	if (!viommu->pgsize_bitmap) {
+		ret = -EINVAL;
+		goto err_free_vqs;
+	}
+
+	viommu->domain_bits = 32;
+
+	/* Optional features */
+	virtio_cread_feature(vdev, VIRTIO_IOMMU_F_INPUT_RANGE,
+			     struct virtio_iommu_config, input_range.start,
+			     &input_start);
+
+	virtio_cread_feature(vdev, VIRTIO_IOMMU_F_INPUT_RANGE,
+			     struct virtio_iommu_config, input_range.end,
+			     &input_end);
+
+	virtio_cread_feature(vdev, VIRTIO_IOMMU_F_DOMAIN_BITS,
+			     struct virtio_iommu_config, domain_bits,
+			     &viommu->domain_bits);
+
+	viommu->geometry = (struct iommu_domain_geometry) {
+		.aperture_start	= input_start,
+		.aperture_end	= input_end,
+		.force_aperture	= true,
+	};
+
+	viommu_ops.pgsize_bitmap = viommu->pgsize_bitmap;
+
+	virtio_device_ready(vdev);
+
+	ret = iommu_device_sysfs_add(&viommu->iommu, dev, NULL, "%s",
+				     virtio_bus_name(vdev));
+	if (ret)
+		goto err_free_vqs;
+
+	iommu_device_set_ops(&viommu->iommu, &viommu_ops);
+	iommu_device_set_fwnode(&viommu->iommu, parent_dev->fwnode);
+
+	iommu_device_register(&viommu->iommu);
+
+#ifdef CONFIG_PCI
+	if (pci_bus_type.iommu_ops != &viommu_ops) {
+		pci_request_acs();
+		ret = bus_set_iommu(&pci_bus_type, &viommu_ops);
+		if (ret)
+			goto err_unregister;
+	}
+#endif
+#ifdef CONFIG_ARM_AMBA
+	if (amba_bustype.iommu_ops != &viommu_ops) {
+		ret = bus_set_iommu(&amba_bustype, &viommu_ops);
+		if (ret)
+			goto err_unregister;
+	}
+#endif
+	if (platform_bus_type.iommu_ops != &viommu_ops) {
+		ret = bus_set_iommu(&platform_bus_type, &viommu_ops);
+		if (ret)
+			goto err_unregister;
+	}
+
+	vdev->priv = viommu;
+
+	dev_info(dev, "input address: %u bits\n",
+		 order_base_2(viommu->geometry.aperture_end));
+	dev_info(dev, "page mask: %#llx\n", viommu->pgsize_bitmap);
+
+	return 0;
+
+err_unregister:
+	iommu_device_sysfs_remove(&viommu->iommu);
+	iommu_device_unregister(&viommu->iommu);
+err_free_vqs:
+	vdev->config->del_vqs(vdev);
+
+	return ret;
+}
+
+static void viommu_remove(struct virtio_device *vdev)
+{
+	struct viommu_dev *viommu = vdev->priv;
+
+	iommu_device_sysfs_remove(&viommu->iommu);
+	iommu_device_unregister(&viommu->iommu);
+
+	/* Stop all virtqueues */
+	vdev->config->reset(vdev);
+	vdev->config->del_vqs(vdev);
+
+	dev_info(&vdev->dev, "device removed\n");
+}
+
+static void viommu_config_changed(struct virtio_device *vdev)
+{
+	dev_warn(&vdev->dev, "config changed\n");
+}
+
+static unsigned int features[] = {
+	VIRTIO_IOMMU_F_MAP_UNMAP,
+	VIRTIO_IOMMU_F_DOMAIN_BITS,
+	VIRTIO_IOMMU_F_INPUT_RANGE,
+};
+
+static struct virtio_device_id id_table[] = {
+	{ VIRTIO_ID_IOMMU, VIRTIO_DEV_ANY_ID },
+	{ 0 },
+};
+
+static struct virtio_driver virtio_iommu_drv = {
+	.driver.name		= KBUILD_MODNAME,
+	.driver.owner		= THIS_MODULE,
+	.id_table		= id_table,
+	.feature_table		= features,
+	.feature_table_size	= ARRAY_SIZE(features),
+	.probe			= viommu_probe,
+	.remove			= viommu_remove,
+	.config_changed		= viommu_config_changed,
+};
+
+module_virtio_driver(virtio_iommu_drv);
+
+MODULE_DESCRIPTION("Virtio IOMMU driver");
+MODULE_AUTHOR("Jean-Philippe Brucker <jean-philippe.brucker@arm.com>");
+MODULE_LICENSE("GPL v2");
diff --git a/include/uapi/linux/virtio_ids.h b/include/uapi/linux/virtio_ids.h
index 6d5c3b2d4f4d..cfe47c5d9a56 100644
--- a/include/uapi/linux/virtio_ids.h
+++ b/include/uapi/linux/virtio_ids.h
@@ -43,5 +43,6 @@
 #define VIRTIO_ID_INPUT        18 /* virtio input */
 #define VIRTIO_ID_VSOCK        19 /* virtio vsock transport */
 #define VIRTIO_ID_CRYPTO       20 /* virtio crypto */
+#define VIRTIO_ID_IOMMU        23 /* virtio IOMMU */
 
 #endif /* _LINUX_VIRTIO_IDS_H */
diff --git a/include/uapi/linux/virtio_iommu.h b/include/uapi/linux/virtio_iommu.h
new file mode 100644
index 000000000000..e7c05e3afa44
--- /dev/null
+++ b/include/uapi/linux/virtio_iommu.h
@@ -0,0 +1,104 @@
+/* SPDX-License-Identifier: BSD-3-Clause */
+/*
+ * Virtio-iommu definition v0.9
+ *
+ * Copyright (C) 2018 Arm Ltd.
+ */
+#ifndef _UAPI_LINUX_VIRTIO_IOMMU_H
+#define _UAPI_LINUX_VIRTIO_IOMMU_H
+
+#include <linux/types.h>
+
+/* Feature bits */
+#define VIRTIO_IOMMU_F_INPUT_RANGE		0
+#define VIRTIO_IOMMU_F_DOMAIN_BITS		1
+#define VIRTIO_IOMMU_F_MAP_UNMAP		2
+#define VIRTIO_IOMMU_F_BYPASS			3
+
+struct virtio_iommu_range {
+	__u64					start;
+	__u64					end;
+};
+
+struct virtio_iommu_config {
+	/* Supported page sizes */
+	__u64					page_size_mask;
+	/* Supported IOVA range */
+	struct virtio_iommu_range		input_range;
+	/* Max domain ID size */
+	__u8					domain_bits;
+	__u8					padding[3];
+};
+
+/* Request types */
+#define VIRTIO_IOMMU_T_ATTACH			0x01
+#define VIRTIO_IOMMU_T_DETACH			0x02
+#define VIRTIO_IOMMU_T_MAP			0x03
+#define VIRTIO_IOMMU_T_UNMAP			0x04
+
+/* Status types */
+#define VIRTIO_IOMMU_S_OK			0x00
+#define VIRTIO_IOMMU_S_IOERR			0x01
+#define VIRTIO_IOMMU_S_UNSUPP			0x02
+#define VIRTIO_IOMMU_S_DEVERR			0x03
+#define VIRTIO_IOMMU_S_INVAL			0x04
+#define VIRTIO_IOMMU_S_RANGE			0x05
+#define VIRTIO_IOMMU_S_NOENT			0x06
+#define VIRTIO_IOMMU_S_FAULT			0x07
+
+struct virtio_iommu_req_head {
+	__u8					type;
+	__u8					reserved[3];
+};
+
+struct virtio_iommu_req_tail {
+	__u8					status;
+	__u8					reserved[3];
+};
+
+struct virtio_iommu_req_attach {
+	struct virtio_iommu_req_head		head;
+	__le32					domain;
+	__le32					endpoint;
+	__u8					reserved[8];
+	struct virtio_iommu_req_tail		tail;
+};
+
+struct virtio_iommu_req_detach {
+	struct virtio_iommu_req_head		head;
+	__le32					domain;
+	__le32					endpoint;
+	__u8					reserved[8];
+	struct virtio_iommu_req_tail		tail;
+};
+
+#define VIRTIO_IOMMU_MAP_F_READ			(1 << 0)
+#define VIRTIO_IOMMU_MAP_F_WRITE		(1 << 1)
+#define VIRTIO_IOMMU_MAP_F_EXEC			(1 << 2)
+#define VIRTIO_IOMMU_MAP_F_MMIO			(1 << 3)
+
+#define VIRTIO_IOMMU_MAP_F_MASK			(VIRTIO_IOMMU_MAP_F_READ |	\
+						 VIRTIO_IOMMU_MAP_F_WRITE |	\
+						 VIRTIO_IOMMU_MAP_F_EXEC |	\
+						 VIRTIO_IOMMU_MAP_F_MMIO)
+
+struct virtio_iommu_req_map {
+	struct virtio_iommu_req_head		head;
+	__le32					domain;
+	__le64					virt_start;
+	__le64					virt_end;
+	__le64					phys_start;
+	__le32					flags;
+	struct virtio_iommu_req_tail		tail;
+};
+
+struct virtio_iommu_req_unmap {
+	struct virtio_iommu_req_head		head;
+	__le32					domain;
+	__le64					virt_start;
+	__le64					virt_end;
+	__u8					reserved[4];
+	struct virtio_iommu_req_tail		tail;
+};
+
+#endif
