+/*
+ * Each virtqueue indirect descriptor list must be physically contiguous.
+ * To allow us to malloc(9) each list individually, limit the number
+ * supported to what will fit in one page. With 4KB pages, this is a limit
+ * of 256 descriptors. If there is ever a need for more, we can switch to
+ * contigmalloc(9) for the larger allocations, similar to what
+ * bus_dmamem_alloc(9) does.
+ *
+ * Note the sizeof(struct vring_desc) is 16 bytes.
+ */
+#define VIRTIO_MAX_INDIRECT ((int)(PAGE_SIZE / 16))
+
+/*
+ * Maximum number of virtqueues per device.
+ */
+#define VIRTIO_MAX_VIRTQUEUE_PAIRS 8
+#define VIRTIO_MAX_VIRTQUEUES (VIRTIO_MAX_VIRTQUEUE_PAIRS * 2 + 1)
+
+/* VirtIO device IDs. */
+#define VIRTIO_ID_NETWORK 0x01
+#define VIRTIO_ID_BLOCK 0x02
+#define VIRTIO_ID_CONSOLE 0x03
+#define VIRTIO_ID_ENTROPY 0x04
+#define VIRTIO_ID_BALLOON 0x05
+#define VIRTIO_ID_IOMEMORY 0x06
+#define VIRTIO_ID_9P 0x09
+
+/* Status byte for guest to report progress. */
+#define VIRTIO_CONFIG_STATUS_RESET 0x00
+#define VIRTIO_CONFIG_STATUS_ACK 0x01
+#define VIRTIO_CONFIG_STATUS_DRIVER 0x02
+#define VIRTIO_CONFIG_STATUS_DRIVER_OK 0x04
+#define VIRTIO_CONFIG_STATUS_FEATURES_OK 0x08
+#define VIRTIO_CONFIG_STATUS_DEV_NEED_RESET 0x40
+#define VIRTIO_CONFIG_STATUS_FAILED 0x80
+
+/* The bit of the ISR which indicates a device has an interrupt. */
+#define VIRTIO_ISR_INTR 0x1
+/* The bit of the ISR which indicates a device configuration change. */
+#define VIRTIO_ISR_CONFIG 0x2
+/* Vector value used to disable MSI for queue. */
+#define VIRTIO_MSI_NO_VECTOR 0xFFFF
+
+/* The alignment to use between consumer and producer parts of vring. */
+#define VIRTIO_VRING_ALIGN 4096
+
+/*
+ * This structure is just a reference to read net device specific
+ * config space; it is just a shadow structure.
+ *
+ */
+struct virtio_net_config {
+ /* The config defining mac address (if VIRTIO_NET_F_MAC) */
+ uint8_t mac[RTE_ETHER_ADDR_LEN];
+ /* See VIRTIO_NET_F_STATUS and VIRTIO_NET_S_* above */
+ uint16_t status;
+ uint16_t max_virtqueue_pairs;
+ uint16_t mtu;
+ /*
+ * speed, in units of 1Mb. All values 0 to INT_MAX are legal.
+ * Any other value stands for unknown.
+ */
+ uint32_t speed;
+ /*
+ * 0x00 - half duplex
+ * 0x01 - full duplex
+ * Any other value stands for unknown.
+ */
+ uint8_t duplex;
+
+} __rte_packed;
+