// 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
  ",
  			 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)
  		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);
  }
  
  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->vdpa;
  	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))
  		return PTR_ERR(v->config_ctx);
  
  	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
  ");
  		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->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;
  
  	r = vhost_dev_check_owner(dev);
  	if (r)
  		return r;
  
  	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;
  	}
  
  	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)
  {
  	struct vhost_virtqueue *vq;
  	int i;
  
  	for (i = 0; i < v->nvqs; i++) {
  		vq = &v->vqs[i];
  		if (vq->call_ctx.producer.irq)
  			irq_bypass_unregister_producer(&vq->call_ctx.producer);
  	}
  }

  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_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");