Update Linux to v5.10.109

Sourced from [1]

[1] https://cdn.kernel.org/pub/linux/kernel/v5.x/linux-5.10.109.tar.xz

Change-Id: I19bca9fc6762d4e63bcf3e4cba88bbe560d9c76c
Signed-off-by: Olivier Deprez <olivier.deprez@arm.com>
diff --git a/drivers/vhost/vdpa.c b/drivers/vhost/vdpa.c
new file mode 100644
index 0000000..e4d6000
--- /dev/null
+++ b/drivers/vhost/vdpa.c
@@ -0,0 +1,1146 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (C) 2018-2020 Intel Corporation.
+ * Copyright (C) 2020 Red Hat, Inc.
+ *
+ * Author: Tiwei Bie <tiwei.bie@intel.com>
+ *         Jason Wang <jasowang@redhat.com>
+ *
+ * Thanks Michael S. Tsirkin for the valuable comments and
+ * suggestions.  And thanks to Cunming Liang and Zhihong Wang for all
+ * their supports.
+ */
+
+#include <linux/kernel.h>
+#include <linux/module.h>
+#include <linux/cdev.h>
+#include <linux/device.h>
+#include <linux/mm.h>
+#include <linux/iommu.h>
+#include <linux/uuid.h>
+#include <linux/vdpa.h>
+#include <linux/nospec.h>
+#include <linux/vhost.h>
+#include <linux/virtio_net.h>
+
+#include "vhost.h"
+
+enum {
+	VHOST_VDPA_BACKEND_FEATURES =
+	(1ULL << VHOST_BACKEND_F_IOTLB_MSG_V2) |
+	(1ULL << VHOST_BACKEND_F_IOTLB_BATCH),
+};
+
+#define VHOST_VDPA_DEV_MAX (1U << MINORBITS)
+
+struct vhost_vdpa {
+	struct vhost_dev vdev;
+	struct iommu_domain *domain;
+	struct vhost_virtqueue *vqs;
+	struct completion completion;
+	struct vdpa_device *vdpa;
+	struct device dev;
+	struct cdev cdev;
+	atomic_t opened;
+	int nvqs;
+	int virtio_id;
+	int minor;
+	struct eventfd_ctx *config_ctx;
+	int in_batch;
+	struct vdpa_iova_range range;
+};
+
+static DEFINE_IDA(vhost_vdpa_ida);
+
+static dev_t vhost_vdpa_major;
+
+static void handle_vq_kick(struct vhost_work *work)
+{
+	struct vhost_virtqueue *vq = container_of(work, struct vhost_virtqueue,
+						  poll.work);
+	struct vhost_vdpa *v = container_of(vq->dev, struct vhost_vdpa, vdev);
+	const struct vdpa_config_ops *ops = v->vdpa->config;
+
+	ops->kick_vq(v->vdpa, vq - v->vqs);
+}
+
+static irqreturn_t vhost_vdpa_virtqueue_cb(void *private)
+{
+	struct vhost_virtqueue *vq = private;
+	struct eventfd_ctx *call_ctx = vq->call_ctx.ctx;
+
+	if (call_ctx)
+		eventfd_signal(call_ctx, 1);
+
+	return IRQ_HANDLED;
+}
+
+static irqreturn_t vhost_vdpa_config_cb(void *private)
+{
+	struct vhost_vdpa *v = private;
+	struct eventfd_ctx *config_ctx = v->config_ctx;
+
+	if (config_ctx)
+		eventfd_signal(config_ctx, 1);
+
+	return IRQ_HANDLED;
+}
+
+static void vhost_vdpa_setup_vq_irq(struct vhost_vdpa *v, u16 qid)
+{
+	struct vhost_virtqueue *vq = &v->vqs[qid];
+	const struct vdpa_config_ops *ops = v->vdpa->config;
+	struct vdpa_device *vdpa = v->vdpa;
+	int ret, irq;
+
+	if (!ops->get_vq_irq)
+		return;
+
+	irq = ops->get_vq_irq(vdpa, qid);
+	irq_bypass_unregister_producer(&vq->call_ctx.producer);
+	if (!vq->call_ctx.ctx || irq < 0)
+		return;
+
+	vq->call_ctx.producer.token = vq->call_ctx.ctx;
+	vq->call_ctx.producer.irq = irq;
+	ret = irq_bypass_register_producer(&vq->call_ctx.producer);
+	if (unlikely(ret))
+		dev_info(&v->dev, "vq %u, irq bypass producer (token %p) registration fails, ret =  %d\n",
+			 qid, vq->call_ctx.producer.token, ret);
+}
+
+static void vhost_vdpa_unsetup_vq_irq(struct vhost_vdpa *v, u16 qid)
+{
+	struct vhost_virtqueue *vq = &v->vqs[qid];
+
+	irq_bypass_unregister_producer(&vq->call_ctx.producer);
+}
+
+static void vhost_vdpa_reset(struct vhost_vdpa *v)
+{
+	struct vdpa_device *vdpa = v->vdpa;
+
+	vdpa_reset(vdpa);
+	v->in_batch = 0;
+}
+
+static long vhost_vdpa_get_device_id(struct vhost_vdpa *v, u8 __user *argp)
+{
+	struct vdpa_device *vdpa = v->vdpa;
+	const struct vdpa_config_ops *ops = vdpa->config;
+	u32 device_id;
+
+	device_id = ops->get_device_id(vdpa);
+
+	if (copy_to_user(argp, &device_id, sizeof(device_id)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static long vhost_vdpa_get_status(struct vhost_vdpa *v, u8 __user *statusp)
+{
+	struct vdpa_device *vdpa = v->vdpa;
+	const struct vdpa_config_ops *ops = vdpa->config;
+	u8 status;
+
+	status = ops->get_status(vdpa);
+
+	if (copy_to_user(statusp, &status, sizeof(status)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static long vhost_vdpa_set_status(struct vhost_vdpa *v, u8 __user *statusp)
+{
+	struct vdpa_device *vdpa = v->vdpa;
+	const struct vdpa_config_ops *ops = vdpa->config;
+	u8 status, status_old;
+	int nvqs = v->nvqs;
+	u16 i;
+
+	if (copy_from_user(&status, statusp, sizeof(status)))
+		return -EFAULT;
+
+	status_old = ops->get_status(vdpa);
+
+	/*
+	 * Userspace shouldn't remove status bits unless reset the
+	 * status to 0.
+	 */
+	if (status != 0 && (ops->get_status(vdpa) & ~status) != 0)
+		return -EINVAL;
+
+	ops->set_status(vdpa, status);
+
+	if ((status & VIRTIO_CONFIG_S_DRIVER_OK) && !(status_old & VIRTIO_CONFIG_S_DRIVER_OK))
+		for (i = 0; i < nvqs; i++)
+			vhost_vdpa_setup_vq_irq(v, i);
+
+	if ((status_old & VIRTIO_CONFIG_S_DRIVER_OK) && !(status & VIRTIO_CONFIG_S_DRIVER_OK))
+		for (i = 0; i < nvqs; i++)
+			vhost_vdpa_unsetup_vq_irq(v, i);
+
+	return 0;
+}
+
+static int vhost_vdpa_config_validate(struct vhost_vdpa *v,
+				      struct vhost_vdpa_config *c)
+{
+	long size = 0;
+
+	switch (v->virtio_id) {
+	case VIRTIO_ID_NET:
+		size = sizeof(struct virtio_net_config);
+		break;
+	}
+
+	if (c->len == 0 || c->off > size)
+		return -EINVAL;
+
+	if (c->len > size - c->off)
+		return -E2BIG;
+
+	return 0;
+}
+
+static long vhost_vdpa_get_config(struct vhost_vdpa *v,
+				  struct vhost_vdpa_config __user *c)
+{
+	struct vdpa_device *vdpa = v->vdpa;
+	struct vhost_vdpa_config config;
+	unsigned long size = offsetof(struct vhost_vdpa_config, buf);
+	u8 *buf;
+
+	if (copy_from_user(&config, c, size))
+		return -EFAULT;
+	if (vhost_vdpa_config_validate(v, &config))
+		return -EINVAL;
+	buf = kvzalloc(config.len, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	vdpa_get_config(vdpa, config.off, buf, config.len);
+
+	if (copy_to_user(c->buf, buf, config.len)) {
+		kvfree(buf);
+		return -EFAULT;
+	}
+
+	kvfree(buf);
+	return 0;
+}
+
+static long vhost_vdpa_set_config(struct vhost_vdpa *v,
+				  struct vhost_vdpa_config __user *c)
+{
+	struct vdpa_device *vdpa = v->vdpa;
+	const struct vdpa_config_ops *ops = vdpa->config;
+	struct vhost_vdpa_config config;
+	unsigned long size = offsetof(struct vhost_vdpa_config, buf);
+	u8 *buf;
+
+	if (copy_from_user(&config, c, size))
+		return -EFAULT;
+	if (vhost_vdpa_config_validate(v, &config))
+		return -EINVAL;
+	buf = kvzalloc(config.len, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	if (copy_from_user(buf, c->buf, config.len)) {
+		kvfree(buf);
+		return -EFAULT;
+	}
+
+	ops->set_config(vdpa, config.off, buf, config.len);
+
+	kvfree(buf);
+	return 0;
+}
+
+static long vhost_vdpa_get_features(struct vhost_vdpa *v, u64 __user *featurep)
+{
+	struct vdpa_device *vdpa = v->vdpa;
+	const struct vdpa_config_ops *ops = vdpa->config;
+	u64 features;
+
+	features = ops->get_features(vdpa);
+
+	if (copy_to_user(featurep, &features, sizeof(features)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static long vhost_vdpa_set_features(struct vhost_vdpa *v, u64 __user *featurep)
+{
+	struct vdpa_device *vdpa = v->vdpa;
+	const struct vdpa_config_ops *ops = vdpa->config;
+	u64 features;
+
+	/*
+	 * It's not allowed to change the features after they have
+	 * been negotiated.
+	 */
+	if (ops->get_status(vdpa) & VIRTIO_CONFIG_S_FEATURES_OK)
+		return -EBUSY;
+
+	if (copy_from_user(&features, featurep, sizeof(features)))
+		return -EFAULT;
+
+	if (vdpa_set_features(vdpa, features))
+		return -EINVAL;
+
+	return 0;
+}
+
+static long vhost_vdpa_get_vring_num(struct vhost_vdpa *v, u16 __user *argp)
+{
+	struct vdpa_device *vdpa = v->vdpa;
+	const struct vdpa_config_ops *ops = vdpa->config;
+	u16 num;
+
+	num = ops->get_vq_num_max(vdpa);
+
+	if (copy_to_user(argp, &num, sizeof(num)))
+		return -EFAULT;
+
+	return 0;
+}
+
+static void vhost_vdpa_config_put(struct vhost_vdpa *v)
+{
+	if (v->config_ctx) {
+		eventfd_ctx_put(v->config_ctx);
+		v->config_ctx = NULL;
+	}
+}
+
+static long vhost_vdpa_set_config_call(struct vhost_vdpa *v, u32 __user *argp)
+{
+	struct vdpa_callback cb;
+	int fd;
+	struct eventfd_ctx *ctx;
+
+	cb.callback = vhost_vdpa_config_cb;
+	cb.private = v;
+	if (copy_from_user(&fd, argp, sizeof(fd)))
+		return  -EFAULT;
+
+	ctx = fd == VHOST_FILE_UNBIND ? NULL : eventfd_ctx_fdget(fd);
+	swap(ctx, v->config_ctx);
+
+	if (!IS_ERR_OR_NULL(ctx))
+		eventfd_ctx_put(ctx);
+
+	if (IS_ERR(v->config_ctx)) {
+		long ret = PTR_ERR(v->config_ctx);
+
+		v->config_ctx = NULL;
+		return ret;
+	}
+
+	v->vdpa->config->set_config_cb(v->vdpa, &cb);
+
+	return 0;
+}
+
+static long vhost_vdpa_get_iova_range(struct vhost_vdpa *v, u32 __user *argp)
+{
+	struct vhost_vdpa_iova_range range = {
+		.first = v->range.first,
+		.last = v->range.last,
+	};
+
+	if (copy_to_user(argp, &range, sizeof(range)))
+		return -EFAULT;
+	return 0;
+}
+
+static long vhost_vdpa_vring_ioctl(struct vhost_vdpa *v, unsigned int cmd,
+				   void __user *argp)
+{
+	struct vdpa_device *vdpa = v->vdpa;
+	const struct vdpa_config_ops *ops = vdpa->config;
+	struct vdpa_vq_state vq_state;
+	struct vdpa_callback cb;
+	struct vhost_virtqueue *vq;
+	struct vhost_vring_state s;
+	u32 idx;
+	long r;
+
+	r = get_user(idx, (u32 __user *)argp);
+	if (r < 0)
+		return r;
+
+	if (idx >= v->nvqs)
+		return -ENOBUFS;
+
+	idx = array_index_nospec(idx, v->nvqs);
+	vq = &v->vqs[idx];
+
+	switch (cmd) {
+	case VHOST_VDPA_SET_VRING_ENABLE:
+		if (copy_from_user(&s, argp, sizeof(s)))
+			return -EFAULT;
+		ops->set_vq_ready(vdpa, idx, s.num);
+		return 0;
+	case VHOST_GET_VRING_BASE:
+		r = ops->get_vq_state(v->vdpa, idx, &vq_state);
+		if (r)
+			return r;
+
+		vq->last_avail_idx = vq_state.avail_index;
+		break;
+	}
+
+	r = vhost_vring_ioctl(&v->vdev, cmd, argp);
+	if (r)
+		return r;
+
+	switch (cmd) {
+	case VHOST_SET_VRING_ADDR:
+		if (ops->set_vq_address(vdpa, idx,
+					(u64)(uintptr_t)vq->desc,
+					(u64)(uintptr_t)vq->avail,
+					(u64)(uintptr_t)vq->used))
+			r = -EINVAL;
+		break;
+
+	case VHOST_SET_VRING_BASE:
+		vq_state.avail_index = vq->last_avail_idx;
+		if (ops->set_vq_state(vdpa, idx, &vq_state))
+			r = -EINVAL;
+		break;
+
+	case VHOST_SET_VRING_CALL:
+		if (vq->call_ctx.ctx) {
+			cb.callback = vhost_vdpa_virtqueue_cb;
+			cb.private = vq;
+		} else {
+			cb.callback = NULL;
+			cb.private = NULL;
+		}
+		ops->set_vq_cb(vdpa, idx, &cb);
+		vhost_vdpa_setup_vq_irq(v, idx);
+		break;
+
+	case VHOST_SET_VRING_NUM:
+		ops->set_vq_num(vdpa, idx, vq->num);
+		break;
+	}
+
+	return r;
+}
+
+static long vhost_vdpa_unlocked_ioctl(struct file *filep,
+				      unsigned int cmd, unsigned long arg)
+{
+	struct vhost_vdpa *v = filep->private_data;
+	struct vhost_dev *d = &v->vdev;
+	void __user *argp = (void __user *)arg;
+	u64 __user *featurep = argp;
+	u64 features;
+	long r = 0;
+
+	if (cmd == VHOST_SET_BACKEND_FEATURES) {
+		if (copy_from_user(&features, featurep, sizeof(features)))
+			return -EFAULT;
+		if (features & ~VHOST_VDPA_BACKEND_FEATURES)
+			return -EOPNOTSUPP;
+		vhost_set_backend_features(&v->vdev, features);
+		return 0;
+	}
+
+	mutex_lock(&d->mutex);
+
+	switch (cmd) {
+	case VHOST_VDPA_GET_DEVICE_ID:
+		r = vhost_vdpa_get_device_id(v, argp);
+		break;
+	case VHOST_VDPA_GET_STATUS:
+		r = vhost_vdpa_get_status(v, argp);
+		break;
+	case VHOST_VDPA_SET_STATUS:
+		r = vhost_vdpa_set_status(v, argp);
+		break;
+	case VHOST_VDPA_GET_CONFIG:
+		r = vhost_vdpa_get_config(v, argp);
+		break;
+	case VHOST_VDPA_SET_CONFIG:
+		r = vhost_vdpa_set_config(v, argp);
+		break;
+	case VHOST_GET_FEATURES:
+		r = vhost_vdpa_get_features(v, argp);
+		break;
+	case VHOST_SET_FEATURES:
+		r = vhost_vdpa_set_features(v, argp);
+		break;
+	case VHOST_VDPA_GET_VRING_NUM:
+		r = vhost_vdpa_get_vring_num(v, argp);
+		break;
+	case VHOST_SET_LOG_BASE:
+	case VHOST_SET_LOG_FD:
+		r = -ENOIOCTLCMD;
+		break;
+	case VHOST_VDPA_SET_CONFIG_CALL:
+		r = vhost_vdpa_set_config_call(v, argp);
+		break;
+	case VHOST_GET_BACKEND_FEATURES:
+		features = VHOST_VDPA_BACKEND_FEATURES;
+		if (copy_to_user(featurep, &features, sizeof(features)))
+			r = -EFAULT;
+		break;
+	case VHOST_VDPA_GET_IOVA_RANGE:
+		r = vhost_vdpa_get_iova_range(v, argp);
+		break;
+	default:
+		r = vhost_dev_ioctl(&v->vdev, cmd, argp);
+		if (r == -ENOIOCTLCMD)
+			r = vhost_vdpa_vring_ioctl(v, cmd, argp);
+		break;
+	}
+
+	mutex_unlock(&d->mutex);
+	return r;
+}
+
+static void vhost_vdpa_iotlb_unmap(struct vhost_vdpa *v, u64 start, u64 last)
+{
+	struct vhost_dev *dev = &v->vdev;
+	struct vhost_iotlb *iotlb = dev->iotlb;
+	struct vhost_iotlb_map *map;
+	struct page *page;
+	unsigned long pfn, pinned;
+
+	while ((map = vhost_iotlb_itree_first(iotlb, start, last)) != NULL) {
+		pinned = map->size >> PAGE_SHIFT;
+		for (pfn = map->addr >> PAGE_SHIFT;
+		     pinned > 0; pfn++, pinned--) {
+			page = pfn_to_page(pfn);
+			if (map->perm & VHOST_ACCESS_WO)
+				set_page_dirty_lock(page);
+			unpin_user_page(page);
+		}
+		atomic64_sub(map->size >> PAGE_SHIFT, &dev->mm->pinned_vm);
+		vhost_iotlb_map_free(iotlb, map);
+	}
+}
+
+static void vhost_vdpa_iotlb_free(struct vhost_vdpa *v)
+{
+	struct vhost_dev *dev = &v->vdev;
+
+	vhost_vdpa_iotlb_unmap(v, 0ULL, 0ULL - 1);
+	kfree(dev->iotlb);
+	dev->iotlb = NULL;
+}
+
+static int perm_to_iommu_flags(u32 perm)
+{
+	int flags = 0;
+
+	switch (perm) {
+	case VHOST_ACCESS_WO:
+		flags |= IOMMU_WRITE;
+		break;
+	case VHOST_ACCESS_RO:
+		flags |= IOMMU_READ;
+		break;
+	case VHOST_ACCESS_RW:
+		flags |= (IOMMU_WRITE | IOMMU_READ);
+		break;
+	default:
+		WARN(1, "invalidate vhost IOTLB permission\n");
+		break;
+	}
+
+	return flags | IOMMU_CACHE;
+}
+
+static int vhost_vdpa_map(struct vhost_vdpa *v,
+			  u64 iova, u64 size, u64 pa, u32 perm)
+{
+	struct vhost_dev *dev = &v->vdev;
+	struct vdpa_device *vdpa = v->vdpa;
+	const struct vdpa_config_ops *ops = vdpa->config;
+	int r = 0;
+
+	r = vhost_iotlb_add_range(dev->iotlb, iova, iova + size - 1,
+				  pa, perm);
+	if (r)
+		return r;
+
+	if (ops->dma_map) {
+		r = ops->dma_map(vdpa, iova, size, pa, perm);
+	} else if (ops->set_map) {
+		if (!v->in_batch)
+			r = ops->set_map(vdpa, dev->iotlb);
+	} else {
+		r = iommu_map(v->domain, iova, pa, size,
+			      perm_to_iommu_flags(perm));
+	}
+
+	if (r)
+		vhost_iotlb_del_range(dev->iotlb, iova, iova + size - 1);
+	else
+		atomic64_add(size >> PAGE_SHIFT, &dev->mm->pinned_vm);
+
+	return r;
+}
+
+static void vhost_vdpa_unmap(struct vhost_vdpa *v, u64 iova, u64 size)
+{
+	struct vhost_dev *dev = &v->vdev;
+	struct vdpa_device *vdpa = v->vdpa;
+	const struct vdpa_config_ops *ops = vdpa->config;
+
+	vhost_vdpa_iotlb_unmap(v, iova, iova + size - 1);
+
+	if (ops->dma_map) {
+		ops->dma_unmap(vdpa, iova, size);
+	} else if (ops->set_map) {
+		if (!v->in_batch)
+			ops->set_map(vdpa, dev->iotlb);
+	} else {
+		iommu_unmap(v->domain, iova, size);
+	}
+}
+
+static int vhost_vdpa_process_iotlb_update(struct vhost_vdpa *v,
+					   struct vhost_iotlb_msg *msg)
+{
+	struct vhost_dev *dev = &v->vdev;
+	struct vhost_iotlb *iotlb = dev->iotlb;
+	struct page **page_list;
+	unsigned long list_size = PAGE_SIZE / sizeof(struct page *);
+	unsigned int gup_flags = FOLL_LONGTERM;
+	unsigned long npages, cur_base, map_pfn, last_pfn = 0;
+	unsigned long lock_limit, sz2pin, nchunks, i;
+	u64 iova = msg->iova;
+	long pinned;
+	int ret = 0;
+
+	if (msg->iova < v->range.first || !msg->size ||
+	    msg->iova > U64_MAX - msg->size + 1 ||
+	    msg->iova + msg->size - 1 > v->range.last)
+		return -EINVAL;
+
+	if (vhost_iotlb_itree_first(iotlb, msg->iova,
+				    msg->iova + msg->size - 1))
+		return -EEXIST;
+
+	/* Limit the use of memory for bookkeeping */
+	page_list = (struct page **) __get_free_page(GFP_KERNEL);
+	if (!page_list)
+		return -ENOMEM;
+
+	if (msg->perm & VHOST_ACCESS_WO)
+		gup_flags |= FOLL_WRITE;
+
+	npages = PAGE_ALIGN(msg->size + (iova & ~PAGE_MASK)) >> PAGE_SHIFT;
+	if (!npages) {
+		ret = -EINVAL;
+		goto free;
+	}
+
+	mmap_read_lock(dev->mm);
+
+	lock_limit = rlimit(RLIMIT_MEMLOCK) >> PAGE_SHIFT;
+	if (npages + atomic64_read(&dev->mm->pinned_vm) > lock_limit) {
+		ret = -ENOMEM;
+		goto unlock;
+	}
+
+	cur_base = msg->uaddr & PAGE_MASK;
+	iova &= PAGE_MASK;
+	nchunks = 0;
+
+	while (npages) {
+		sz2pin = min_t(unsigned long, npages, list_size);
+		pinned = pin_user_pages(cur_base, sz2pin,
+					gup_flags, page_list, NULL);
+		if (sz2pin != pinned) {
+			if (pinned < 0) {
+				ret = pinned;
+			} else {
+				unpin_user_pages(page_list, pinned);
+				ret = -ENOMEM;
+			}
+			goto out;
+		}
+		nchunks++;
+
+		if (!last_pfn)
+			map_pfn = page_to_pfn(page_list[0]);
+
+		for (i = 0; i < pinned; i++) {
+			unsigned long this_pfn = page_to_pfn(page_list[i]);
+			u64 csize;
+
+			if (last_pfn && (this_pfn != last_pfn + 1)) {
+				/* Pin a contiguous chunk of memory */
+				csize = (last_pfn - map_pfn + 1) << PAGE_SHIFT;
+				ret = vhost_vdpa_map(v, iova, csize,
+						     map_pfn << PAGE_SHIFT,
+						     msg->perm);
+				if (ret) {
+					/*
+					 * Unpin the pages that are left unmapped
+					 * from this point on in the current
+					 * page_list. The remaining outstanding
+					 * ones which may stride across several
+					 * chunks will be covered in the common
+					 * error path subsequently.
+					 */
+					unpin_user_pages(&page_list[i],
+							 pinned - i);
+					goto out;
+				}
+
+				map_pfn = this_pfn;
+				iova += csize;
+				nchunks = 0;
+			}
+
+			last_pfn = this_pfn;
+		}
+
+		cur_base += pinned << PAGE_SHIFT;
+		npages -= pinned;
+	}
+
+	/* Pin the rest chunk */
+	ret = vhost_vdpa_map(v, iova, (last_pfn - map_pfn + 1) << PAGE_SHIFT,
+			     map_pfn << PAGE_SHIFT, msg->perm);
+out:
+	if (ret) {
+		if (nchunks) {
+			unsigned long pfn;
+
+			/*
+			 * Unpin the outstanding pages which are yet to be
+			 * mapped but haven't due to vdpa_map() or
+			 * pin_user_pages() failure.
+			 *
+			 * Mapped pages are accounted in vdpa_map(), hence
+			 * the corresponding unpinning will be handled by
+			 * vdpa_unmap().
+			 */
+			WARN_ON(!last_pfn);
+			for (pfn = map_pfn; pfn <= last_pfn; pfn++)
+				unpin_user_page(pfn_to_page(pfn));
+		}
+		vhost_vdpa_unmap(v, msg->iova, msg->size);
+	}
+unlock:
+	mmap_read_unlock(dev->mm);
+free:
+	free_page((unsigned long)page_list);
+	return ret;
+}
+
+static int vhost_vdpa_process_iotlb_msg(struct vhost_dev *dev,
+					struct vhost_iotlb_msg *msg)
+{
+	struct vhost_vdpa *v = container_of(dev, struct vhost_vdpa, vdev);
+	struct vdpa_device *vdpa = v->vdpa;
+	const struct vdpa_config_ops *ops = vdpa->config;
+	int r = 0;
+
+	mutex_lock(&dev->mutex);
+
+	r = vhost_dev_check_owner(dev);
+	if (r)
+		goto unlock;
+
+	switch (msg->type) {
+	case VHOST_IOTLB_UPDATE:
+		r = vhost_vdpa_process_iotlb_update(v, msg);
+		break;
+	case VHOST_IOTLB_INVALIDATE:
+		vhost_vdpa_unmap(v, msg->iova, msg->size);
+		break;
+	case VHOST_IOTLB_BATCH_BEGIN:
+		v->in_batch = true;
+		break;
+	case VHOST_IOTLB_BATCH_END:
+		if (v->in_batch && ops->set_map)
+			ops->set_map(vdpa, dev->iotlb);
+		v->in_batch = false;
+		break;
+	default:
+		r = -EINVAL;
+		break;
+	}
+unlock:
+	mutex_unlock(&dev->mutex);
+
+	return r;
+}
+
+static ssize_t vhost_vdpa_chr_write_iter(struct kiocb *iocb,
+					 struct iov_iter *from)
+{
+	struct file *file = iocb->ki_filp;
+	struct vhost_vdpa *v = file->private_data;
+	struct vhost_dev *dev = &v->vdev;
+
+	return vhost_chr_write_iter(dev, from);
+}
+
+static int vhost_vdpa_alloc_domain(struct vhost_vdpa *v)
+{
+	struct vdpa_device *vdpa = v->vdpa;
+	const struct vdpa_config_ops *ops = vdpa->config;
+	struct device *dma_dev = vdpa_get_dma_dev(vdpa);
+	struct bus_type *bus;
+	int ret;
+
+	/* Device want to do DMA by itself */
+	if (ops->set_map || ops->dma_map)
+		return 0;
+
+	bus = dma_dev->bus;
+	if (!bus)
+		return -EFAULT;
+
+	if (!iommu_capable(bus, IOMMU_CAP_CACHE_COHERENCY))
+		return -ENOTSUPP;
+
+	v->domain = iommu_domain_alloc(bus);
+	if (!v->domain)
+		return -EIO;
+
+	ret = iommu_attach_device(v->domain, dma_dev);
+	if (ret)
+		goto err_attach;
+
+	return 0;
+
+err_attach:
+	iommu_domain_free(v->domain);
+	return ret;
+}
+
+static void vhost_vdpa_free_domain(struct vhost_vdpa *v)
+{
+	struct vdpa_device *vdpa = v->vdpa;
+	struct device *dma_dev = vdpa_get_dma_dev(vdpa);
+
+	if (v->domain) {
+		iommu_detach_device(v->domain, dma_dev);
+		iommu_domain_free(v->domain);
+	}
+
+	v->domain = NULL;
+}
+
+static void vhost_vdpa_set_iova_range(struct vhost_vdpa *v)
+{
+	struct vdpa_iova_range *range = &v->range;
+	struct iommu_domain_geometry geo;
+	struct vdpa_device *vdpa = v->vdpa;
+	const struct vdpa_config_ops *ops = vdpa->config;
+
+	if (ops->get_iova_range) {
+		*range = ops->get_iova_range(vdpa);
+	} else if (v->domain &&
+		   !iommu_domain_get_attr(v->domain,
+		   DOMAIN_ATTR_GEOMETRY, &geo) &&
+		   geo.force_aperture) {
+		range->first = geo.aperture_start;
+		range->last = geo.aperture_end;
+	} else {
+		range->first = 0;
+		range->last = ULLONG_MAX;
+	}
+}
+
+static int vhost_vdpa_open(struct inode *inode, struct file *filep)
+{
+	struct vhost_vdpa *v;
+	struct vhost_dev *dev;
+	struct vhost_virtqueue **vqs;
+	int nvqs, i, r, opened;
+
+	v = container_of(inode->i_cdev, struct vhost_vdpa, cdev);
+
+	opened = atomic_cmpxchg(&v->opened, 0, 1);
+	if (opened)
+		return -EBUSY;
+
+	nvqs = v->nvqs;
+	vhost_vdpa_reset(v);
+
+	vqs = kmalloc_array(nvqs, sizeof(*vqs), GFP_KERNEL);
+	if (!vqs) {
+		r = -ENOMEM;
+		goto err;
+	}
+
+	dev = &v->vdev;
+	for (i = 0; i < nvqs; i++) {
+		vqs[i] = &v->vqs[i];
+		vqs[i]->handle_kick = handle_vq_kick;
+	}
+	vhost_dev_init(dev, vqs, nvqs, 0, 0, 0, false,
+		       vhost_vdpa_process_iotlb_msg);
+
+	dev->iotlb = vhost_iotlb_alloc(0, 0);
+	if (!dev->iotlb) {
+		r = -ENOMEM;
+		goto err_init_iotlb;
+	}
+
+	r = vhost_vdpa_alloc_domain(v);
+	if (r)
+		goto err_init_iotlb;
+
+	vhost_vdpa_set_iova_range(v);
+
+	filep->private_data = v;
+
+	return 0;
+
+err_init_iotlb:
+	vhost_dev_cleanup(&v->vdev);
+	kfree(vqs);
+err:
+	atomic_dec(&v->opened);
+	return r;
+}
+
+static void vhost_vdpa_clean_irq(struct vhost_vdpa *v)
+{
+	int i;
+
+	for (i = 0; i < v->nvqs; i++)
+		vhost_vdpa_unsetup_vq_irq(v, i);
+}
+
+static int vhost_vdpa_release(struct inode *inode, struct file *filep)
+{
+	struct vhost_vdpa *v = filep->private_data;
+	struct vhost_dev *d = &v->vdev;
+
+	mutex_lock(&d->mutex);
+	filep->private_data = NULL;
+	vhost_vdpa_reset(v);
+	vhost_dev_stop(&v->vdev);
+	vhost_vdpa_iotlb_free(v);
+	vhost_vdpa_free_domain(v);
+	vhost_vdpa_config_put(v);
+	vhost_vdpa_clean_irq(v);
+	vhost_dev_cleanup(&v->vdev);
+	kfree(v->vdev.vqs);
+	mutex_unlock(&d->mutex);
+
+	atomic_dec(&v->opened);
+	complete(&v->completion);
+
+	return 0;
+}
+
+#ifdef CONFIG_MMU
+static vm_fault_t vhost_vdpa_fault(struct vm_fault *vmf)
+{
+	struct vhost_vdpa *v = vmf->vma->vm_file->private_data;
+	struct vdpa_device *vdpa = v->vdpa;
+	const struct vdpa_config_ops *ops = vdpa->config;
+	struct vdpa_notification_area notify;
+	struct vm_area_struct *vma = vmf->vma;
+	u16 index = vma->vm_pgoff;
+
+	notify = ops->get_vq_notification(vdpa, index);
+
+	vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);
+	if (remap_pfn_range(vma, vmf->address & PAGE_MASK,
+			    notify.addr >> PAGE_SHIFT, PAGE_SIZE,
+			    vma->vm_page_prot))
+		return VM_FAULT_SIGBUS;
+
+	return VM_FAULT_NOPAGE;
+}
+
+static const struct vm_operations_struct vhost_vdpa_vm_ops = {
+	.fault = vhost_vdpa_fault,
+};
+
+static int vhost_vdpa_mmap(struct file *file, struct vm_area_struct *vma)
+{
+	struct vhost_vdpa *v = vma->vm_file->private_data;
+	struct vdpa_device *vdpa = v->vdpa;
+	const struct vdpa_config_ops *ops = vdpa->config;
+	struct vdpa_notification_area notify;
+	unsigned long index = vma->vm_pgoff;
+
+	if (vma->vm_end - vma->vm_start != PAGE_SIZE)
+		return -EINVAL;
+	if ((vma->vm_flags & VM_SHARED) == 0)
+		return -EINVAL;
+	if (vma->vm_flags & VM_READ)
+		return -EINVAL;
+	if (index > 65535)
+		return -EINVAL;
+	if (!ops->get_vq_notification)
+		return -ENOTSUPP;
+
+	/* To be safe and easily modelled by userspace, We only
+	 * support the doorbell which sits on the page boundary and
+	 * does not share the page with other registers.
+	 */
+	notify = ops->get_vq_notification(vdpa, index);
+	if (notify.addr & (PAGE_SIZE - 1))
+		return -EINVAL;
+	if (vma->vm_end - vma->vm_start != notify.size)
+		return -ENOTSUPP;
+
+	vma->vm_flags |= VM_IO | VM_PFNMAP | VM_DONTEXPAND | VM_DONTDUMP;
+	vma->vm_ops = &vhost_vdpa_vm_ops;
+	return 0;
+}
+#endif /* CONFIG_MMU */
+
+static const struct file_operations vhost_vdpa_fops = {
+	.owner		= THIS_MODULE,
+	.open		= vhost_vdpa_open,
+	.release	= vhost_vdpa_release,
+	.write_iter	= vhost_vdpa_chr_write_iter,
+	.unlocked_ioctl	= vhost_vdpa_unlocked_ioctl,
+#ifdef CONFIG_MMU
+	.mmap		= vhost_vdpa_mmap,
+#endif /* CONFIG_MMU */
+	.compat_ioctl	= compat_ptr_ioctl,
+};
+
+static void vhost_vdpa_release_dev(struct device *device)
+{
+	struct vhost_vdpa *v =
+	       container_of(device, struct vhost_vdpa, dev);
+
+	ida_simple_remove(&vhost_vdpa_ida, v->minor);
+	kfree(v->vqs);
+	kfree(v);
+}
+
+static int vhost_vdpa_probe(struct vdpa_device *vdpa)
+{
+	const struct vdpa_config_ops *ops = vdpa->config;
+	struct vhost_vdpa *v;
+	int minor;
+	int r;
+
+	/* Currently, we only accept the network devices. */
+	if (ops->get_device_id(vdpa) != VIRTIO_ID_NET)
+		return -ENOTSUPP;
+
+	v = kzalloc(sizeof(*v), GFP_KERNEL | __GFP_RETRY_MAYFAIL);
+	if (!v)
+		return -ENOMEM;
+
+	minor = ida_simple_get(&vhost_vdpa_ida, 0,
+			       VHOST_VDPA_DEV_MAX, GFP_KERNEL);
+	if (minor < 0) {
+		kfree(v);
+		return minor;
+	}
+
+	atomic_set(&v->opened, 0);
+	v->minor = minor;
+	v->vdpa = vdpa;
+	v->nvqs = vdpa->nvqs;
+	v->virtio_id = ops->get_device_id(vdpa);
+
+	device_initialize(&v->dev);
+	v->dev.release = vhost_vdpa_release_dev;
+	v->dev.parent = &vdpa->dev;
+	v->dev.devt = MKDEV(MAJOR(vhost_vdpa_major), minor);
+	v->vqs = kmalloc_array(v->nvqs, sizeof(struct vhost_virtqueue),
+			       GFP_KERNEL);
+	if (!v->vqs) {
+		r = -ENOMEM;
+		goto err;
+	}
+
+	r = dev_set_name(&v->dev, "vhost-vdpa-%u", minor);
+	if (r)
+		goto err;
+
+	cdev_init(&v->cdev, &vhost_vdpa_fops);
+	v->cdev.owner = THIS_MODULE;
+
+	r = cdev_device_add(&v->cdev, &v->dev);
+	if (r)
+		goto err;
+
+	init_completion(&v->completion);
+	vdpa_set_drvdata(vdpa, v);
+
+	return 0;
+
+err:
+	put_device(&v->dev);
+	return r;
+}
+
+static void vhost_vdpa_remove(struct vdpa_device *vdpa)
+{
+	struct vhost_vdpa *v = vdpa_get_drvdata(vdpa);
+	int opened;
+
+	cdev_device_del(&v->cdev, &v->dev);
+
+	do {
+		opened = atomic_cmpxchg(&v->opened, 0, 1);
+		if (!opened)
+			break;
+		wait_for_completion(&v->completion);
+	} while (1);
+
+	put_device(&v->dev);
+}
+
+static struct vdpa_driver vhost_vdpa_driver = {
+	.driver = {
+		.name	= "vhost_vdpa",
+	},
+	.probe	= vhost_vdpa_probe,
+	.remove	= vhost_vdpa_remove,
+};
+
+static int __init vhost_vdpa_init(void)
+{
+	int r;
+
+	r = alloc_chrdev_region(&vhost_vdpa_major, 0, VHOST_VDPA_DEV_MAX,
+				"vhost-vdpa");
+	if (r)
+		goto err_alloc_chrdev;
+
+	r = vdpa_register_driver(&vhost_vdpa_driver);
+	if (r)
+		goto err_vdpa_register_driver;
+
+	return 0;
+
+err_vdpa_register_driver:
+	unregister_chrdev_region(vhost_vdpa_major, VHOST_VDPA_DEV_MAX);
+err_alloc_chrdev:
+	return r;
+}
+module_init(vhost_vdpa_init);
+
+static void __exit vhost_vdpa_exit(void)
+{
+	vdpa_unregister_driver(&vhost_vdpa_driver);
+	unregister_chrdev_region(vhost_vdpa_major, VHOST_VDPA_DEV_MAX);
+}
+module_exit(vhost_vdpa_exit);
+
+MODULE_VERSION("0.0.1");
+MODULE_LICENSE("GPL v2");
+MODULE_AUTHOR("Intel Corporation");
+MODULE_DESCRIPTION("vDPA-based vhost backend for virtio");