+/* 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
+
+#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;
+ struct vring_avail *avail;
+ struct vring_used *used;
+ uint32_t size;
+
+ /* Last index used on the available ring */
+ volatile uint16_t last_used_idx;
+#define VIRTIO_INVALID_EVENTFD (-1)
+#define VIRTIO_UNINITIALIZED_EVENTFD (-2)
+
+ /* Backend value to determine if device should started/stopped */
+ int backend;
+ /* Used to notify the guest (trigger interrupt) */
+ int callfd;
+ /* Currently unused as polling mode is enabled */
+ int kickfd;
+ int enabled;
+
+ /* Physical address of used ring, for logging */
+ uint64_t log_guest_addr;
+} __rte_cache_aligned;
+
+/* Old kernels have no such macro defined */
+#ifndef VIRTIO_NET_F_GUEST_ANNOUNCE
+ #define VIRTIO_NET_F_GUEST_ANNOUNCE 21
+#endif
+
+
+/*
+ * Make an extra wrapper for VIRTIO_NET_F_MQ and
+ * VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX as they are
+ * introduced since kernel v3.8. This makes our
+ * code buildable for older kernel.
+ */
+#ifdef VIRTIO_NET_F_MQ
+ #define VHOST_MAX_QUEUE_PAIRS VIRTIO_NET_CTRL_MQ_VQ_PAIRS_MAX
+ #define VHOST_SUPPORTS_MQ (1ULL << VIRTIO_NET_F_MQ)
+#else
+ #define VHOST_MAX_QUEUE_PAIRS 1
+ #define VHOST_SUPPORTS_MQ 0
+#endif
+
+/*
+ * Define virtio 1.0 for older kernels
+ */
+#ifndef VIRTIO_F_VERSION_1
+ #define VIRTIO_F_VERSION_1 32
+#endif
+
+/**
+ * Device structure contains all configuration information relating
+ * to the device.
+ */
+struct virtio_net {
+ /* Frontend (QEMU) memory and memory region information */
+ struct virtio_memory *mem;
+ uint64_t features;
+ uint64_t protocol_features;
+ int vid;
+ uint32_t flags;
+ uint16_t vhost_hlen;
+ /* to tell if we need broadcast rarp packet */
+ rte_atomic16_t broadcast_rarp;
+ uint32_t virt_qp_nb;
+ struct vhost_virtqueue *virtqueue[VHOST_MAX_QUEUE_PAIRS * 2];
+#define IF_NAME_SZ (PATH_MAX > IFNAMSIZ ? PATH_MAX : IFNAMSIZ)
+ char ifname[IF_NAME_SZ];
+ uint64_t log_size;
+ uint64_t log_base;
+ uint64_t log_addr;
+ struct ether_addr mac;
+
+} __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;
+ uint64_t guest_phys_address_end;
+ uint64_t memory_size;
+ uint64_t userspace_address;
+ uint64_t address_offset;
+};
+
+
+/**
+ * Memory structure includes region and mapping information.
+ */
+struct virtio_memory {
+ /* Base QEMU userspace address of the memory file. */
+ uint64_t base_address;
+ uint64_t mapped_address;
+ uint64_t mapped_size;
+ uint32_t nregions;
+ struct virtio_memory_regions regions[0];
+};
+
+