text: /*-
   *   BSD LICENSE
   *
   *   Copyright(c) 2010-2014 Intel Corporation. All rights reserved.
   *   All rights reserved.
   *
   *   Redistribution and use in source and binary forms, with or without
   *   modification, are permitted provided that the following conditions
   *   are met:
   *
   *     * Redistributions of source code must retain the above copyright
   *       notice, this list of conditions and the following disclaimer.
   *     * Redistributions in binary form must reproduce the above copyright
   *       notice, this list of conditions and the following disclaimer in
   *       the documentation and/or other materials provided with the
   *       distribution.
   *     * Neither the name of Intel Corporation nor the names of its
   *       contributors may be used to endorse or promote products derived
   *       from this software without specific prior written permission.
   *
   *   THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
   *   "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
   *   LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
   *   A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
   *   OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
   *   SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
   *   LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
   *   DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
   *   THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
   *   (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
   *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
   */
  
  #ifndef _VIRTIO_NET_H_
  #define _VIRTIO_NET_H_
  
  /**
   * @file
   * Interface to vhost net
   */
  
  #include <stdint.h>
  #include <linux/virtio_ring.h>
  #include <linux/virtio_net.h>
  #include <sys/eventfd.h>
  #include <sys/socket.h>
  #include <linux/if.h>
  
  #include <rte_memory.h>
  #include <rte_mempool.h>
  #include <rte_mbuf.h>
  
  #define VHOST_MEMORY_MAX_NREGIONS 8
  
  /* Used to indicate that the device is running on a data core */
  #define VIRTIO_DEV_RUNNING 1
  
  /* Backend value set by guest. */
  #define VIRTIO_DEV_STOPPED -1
  
  
  /* Enum for virtqueue management. */
  enum {VIRTIO_RXQ, VIRTIO_TXQ, VIRTIO_QNUM};
  
  #define BUF_VECTOR_MAX 256
  
  /**
   * Structure contains buffer address, length and descriptor index
   * from vring to do scatter RX.
   */
  struct buf_vector {
  	uint64_t buf_addr;
  	uint32_t buf_len;
  	uint32_t desc_idx;
  };
  
  /**
   * Structure contains variables relevant to RX/TX virtqueues.
   */
  struct vhost_virtqueue {
  	struct vring_desc	*desc;			/**< Virtqueue descriptor ring. */
  	struct vring_avail	*avail;			/**< Virtqueue available ring. */
  	struct vring_used	*used;			/**< Virtqueue used ring. */
  	uint32_t		size;			/**< Size of descriptor ring. */
  	uint32_t		backend;		/**< Backend value to determine if device should started/stopped. */
  	uint16_t		vhost_hlen;		/**< Vhost header length (varies depending on RX merge buffers. */
  	volatile uint16_t	last_used_idx;		/**< Last index used on the available ring */
  	volatile uint16_t	last_used_idx_res;	/**< Used for multiple devices reserving buffers. */
  	eventfd_t		callfd;			/**< Used to notify the guest (trigger interrupt). */
  	eventfd_t		kickfd;			/**< Currently unused as polling mode is enabled. */
  	struct buf_vector	buf_vec[BUF_VECTOR_MAX];	/**< for scatter RX. */
  } __rte_cache_aligned;
  
  /**
   * Device structure contains all configuration information relating to the device.
   */
  struct virtio_net {
  	struct vhost_virtqueue	*virtqueue[VIRTIO_QNUM];	/**< Contains all virtqueue information. */
  	struct virtio_memory	*mem;		/**< QEMU memory and memory region information. */
  	uint64_t		features;	/**< Negotiated feature set. */
  	uint64_t		device_fh;	/**< device identifier. */
  	uint32_t		flags;		/**< Device flags. Only used to check if device is running on data core. */
  #define IF_NAME_SZ (PATH_MAX > IFNAMSIZ ? PATH_MAX : IFNAMSIZ)
  	char			ifname[IF_NAME_SZ];	/**< Name of the tap device or socket path. */
  	void			*priv;		/**< private context */
  } __rte_cache_aligned;
  
  /**
   * Information relating to memory regions including offsets to addresses in QEMUs memory file.
   */
  struct virtio_memory_regions {
  	uint64_t	guest_phys_address;	/**< Base guest physical address of region. */
  	uint64_t	guest_phys_address_end;	/**< End guest physical address of region. */
  	uint64_t	memory_size;		/**< Size of region. */
  	uint64_t	userspace_address;	/**< Base userspace address of region. */
  	uint64_t	address_offset;		/**< Offset of region for address translation. */
  };
  
  
  /**
   * Memory structure includes region and mapping information.
   */
  struct virtio_memory {
  	uint64_t	base_address;	/**< Base QEMU userspace address of the memory file. */
  	uint64_t	mapped_address;	/**< Mapped address of memory file base in our applications memory space. */
  	uint64_t	mapped_size;	/**< Total size of memory file. */
  	uint32_t	nregions;	/**< Number of memory regions. */
  	struct virtio_memory_regions      regions[0]; /**< Memory region information. */
  };
  
  /**
   * Device operations to add/remove device.
   *
   * Make sure to set VIRTIO_DEV_RUNNING to the device flags in new_device and
   * remove it in destroy_device.
   *
   */
  struct virtio_net_device_ops {
  	int (*new_device)(struct virtio_net *);	/**< Add device. */
  	void (*destroy_device)(volatile struct virtio_net *);	/**< Remove device. */
  };
  
  static inline uint16_t __attribute__((always_inline))
  rte_vring_available_entries(struct virtio_net *dev, uint16_t queue_id)
  {
  	struct vhost_virtqueue *vq = dev->virtqueue[queue_id];
  	return *(volatile uint16_t *)&vq->avail->idx - vq->last_used_idx_res;
  }
  
  /**
   * Function to convert guest physical addresses to vhost virtual addresses.
   * This is used to convert guest virtio buffer addresses.
   */
  static inline uint64_t __attribute__((always_inline))
  gpa_to_vva(struct virtio_net *dev, uint64_t guest_pa)
  {
  	struct virtio_memory_regions *region;
  	uint32_t regionidx;
  	uint64_t vhost_va = 0;
  
  	for (regionidx = 0; regionidx < dev->mem->nregions; regionidx++) {
  		region = &dev->mem->regions[regionidx];
  		if ((guest_pa >= region->guest_phys_address) &&
  			(guest_pa <= region->guest_phys_address_end)) {
  			vhost_va = region->address_offset + guest_pa;
  			break;
  		}
  	}
  	return vhost_va;
  }
  
  /**
   *  Disable features in feature_mask. Returns 0 on success.
   */
  int rte_vhost_feature_disable(uint64_t feature_mask);
  
  /**
   *  Enable features in feature_mask. Returns 0 on success.
   */
  int rte_vhost_feature_enable(uint64_t feature_mask);
  
  /* Returns currently supported vhost features */
  uint64_t rte_vhost_feature_get(void);
  
  int rte_vhost_enable_guest_notification(struct virtio_net *dev, uint16_t queue_id, int enable);
  
  /* Register vhost driver. dev_name could be different for multiple instance support. */
  int rte_vhost_driver_register(const char *dev_name);
  
  /* Register callbacks. */
  int rte_vhost_driver_callback_register(struct virtio_net_device_ops const * const);
  /* Start vhost driver session blocking loop. */
  int rte_vhost_driver_session_start(void);
  
  /**
   * This function adds buffers to the virtio devices RX virtqueue. Buffers can
   * be received from the physical port or from another virtual device. A packet
   * count is returned to indicate the number of packets that were succesfully
   * added to the RX queue.
   * @param queue_id
   *  virtio queue index in mq case
   * @return
   *  num of packets enqueued
   */
  uint16_t rte_vhost_enqueue_burst(struct virtio_net *dev, uint16_t queue_id,
  	struct rte_mbuf **pkts, uint16_t count);
  
  /**
   * This function gets guest buffers from the virtio device TX virtqueue,
   * construct host mbufs, copies guest buffer content to host mbufs and
   * store them in pkts to be processed.
   * @param mbuf_pool
   *  mbuf_pool where host mbuf is allocated.
   * @param queue_id
   *  virtio queue index in mq case.
   * @return
   *  num of packets dequeued
   */
  uint16_t rte_vhost_dequeue_burst(struct virtio_net *dev, uint16_t queue_id,
  	struct rte_mempool *mbuf_pool, struct rte_mbuf **pkts, uint16_t count);
  
  #endif /* _VIRTIO_NET_H_ */
  