vhost: add Tx offload capabilities
[dpdk.git] / lib / librte_vhost / vhost_rxtx.c
index 5f48566..5d9cc91 100644 (file)
  *   OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
  */
 
-#include <arpa/inet.h>
-#include <getopt.h>
-#include <linux/if_ether.h>
-#include <linux/if_vlan.h>
-#include <linux/virtio_net.h>
-#include <linux/virtio_ring.h>
-#include <signal.h>
 #include <stdint.h>
-#include <sys/eventfd.h>
-#include <sys/param.h>
-#include <unistd.h>
+#include <stdbool.h>
+#include <linux/virtio_net.h>
 
-#include <rte_atomic.h>
-#include <rte_cycles.h>
-#include <rte_ethdev.h>
-#include <rte_log.h>
-#include <rte_string_fns.h>
-#include <rte_malloc.h>
+#include <rte_mbuf.h>
+#include <rte_memcpy.h>
+#include <rte_ether.h>
+#include <rte_ip.h>
+#include <rte_virtio_net.h>
+#include <rte_tcp.h>
+#include <rte_udp.h>
+#include <rte_sctp.h>
 
-#include "main.h"
-#include "virtio-net.h"
-#include "vhost-net-cdev.h"
+#include "vhost-net.h"
 
-#define MAX_PKT_BURST 32               /* Max burst size for RX/TX */
+#define MAX_PKT_BURST 32
 
-/*
+static bool
+is_valid_virt_queue_idx(uint32_t idx, int is_tx, uint32_t qp_nb)
+{
+       return (is_tx ^ (idx & 1)) == 0 && idx < qp_nb * VIRTIO_QNUM;
+}
+
+/**
  * This function adds buffers to the virtio devices RX virtqueue. Buffers can
  * be received from the physical port or from another virtio device. A packet
- * count is returned to indicate the number of packets that were succesfully
- * added to the RX queue. This function works when mergeable is disabled.
+ * count is returned to indicate the number of packets that are succesfully
+ * added to the RX queue. This function works when the mbuf is scattered, but
+ * it doesn't support the mergeable feature.
  */
 static inline uint32_t __attribute__((always_inline))
-virtio_dev_rx(struct virtio_net *dev, struct rte_mbuf **pkts, uint32_t count)
+virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id,
+       struct rte_mbuf **pkts, uint32_t count)
 {
        struct vhost_virtqueue *vq;
        struct vring_desc *desc;
        struct rte_mbuf *buff;
        /* The virtio_hdr is initialised to 0. */
-       struct virtio_net_hdr_mrg_rxbuf virtio_hdr = {{0,0,0,0,0,0},0};
+       struct virtio_net_hdr_mrg_rxbuf virtio_hdr = {{0, 0, 0, 0, 0, 0}, 0};
        uint64_t buff_addr = 0;
        uint64_t buff_hdr_addr = 0;
-       uint32_t head[MAX_PKT_BURST], packet_len = 0;
+       uint32_t head[MAX_PKT_BURST];
        uint32_t head_idx, packet_success = 0;
        uint16_t avail_idx, res_cur_idx;
        uint16_t res_base_idx, res_end_idx;
@@ -80,10 +80,23 @@ virtio_dev_rx(struct virtio_net *dev, struct rte_mbuf **pkts, uint32_t count)
        uint8_t success = 0;
 
        LOG_DEBUG(VHOST_DATA, "(%"PRIu64") virtio_dev_rx()\n", dev->device_fh);
-       vq = dev->virtqueue[VIRTIO_RXQ];
+       if (unlikely(!is_valid_virt_queue_idx(queue_id, 0, dev->virt_qp_nb))) {
+               RTE_LOG(ERR, VHOST_DATA,
+                       "%s (%"PRIu64"): virtqueue idx:%d invalid.\n",
+                       __func__, dev->device_fh, queue_id);
+               return 0;
+       }
+
+       vq = dev->virtqueue[queue_id];
+       if (unlikely(vq->enabled == 0))
+               return 0;
+
        count = (count > MAX_PKT_BURST) ? MAX_PKT_BURST : count;
 
-       /* As many data cores may want access to available buffers, they need to be reserved. */
+       /*
+        * As many data cores may want access to available buffers,
+        * they need to be reserved.
+        */
        do {
                res_base_idx = vq->last_used_idx_res;
                avail_idx = *((volatile uint16_t *)&vq->avail->idx);
@@ -98,23 +111,30 @@ virtio_dev_rx(struct virtio_net *dev, struct rte_mbuf **pkts, uint32_t count)
 
                res_end_idx = res_base_idx + count;
                /* vq->last_used_idx_res is atomically updated. */
-               success = rte_atomic16_cmpset(&vq->last_used_idx_res, res_base_idx,
-                                                                       res_end_idx);
+               /* TODO: Allow to disable cmpset if no concurrency in application. */
+               success = rte_atomic16_cmpset(&vq->last_used_idx_res,
+                               res_base_idx, res_end_idx);
        } while (unlikely(success == 0));
        res_cur_idx = res_base_idx;
-       LOG_DEBUG(VHOST_DATA, "(%"PRIu64") Current Index %d| End Index %d\n", dev->device_fh, res_cur_idx, res_end_idx);
+       LOG_DEBUG(VHOST_DATA, "(%"PRIu64") Current Index %d| End Index %d\n",
+                       dev->device_fh, res_cur_idx, res_end_idx);
 
        /* Prefetch available ring to retrieve indexes. */
        rte_prefetch0(&vq->avail->ring[res_cur_idx & (vq->size - 1)]);
 
        /* Retrieve all of the head indexes first to avoid caching issues. */
        for (head_idx = 0; head_idx < count; head_idx++)
-               head[head_idx] = vq->avail->ring[(res_cur_idx + head_idx) & (vq->size - 1)];
+               head[head_idx] = vq->avail->ring[(res_cur_idx + head_idx) &
+                                       (vq->size - 1)];
 
        /*Prefetch descriptor index. */
        rte_prefetch0(&vq->desc[head[packet_success]]);
 
        while (res_cur_idx != res_end_idx) {
+               uint32_t offset = 0, vb_offset = 0;
+               uint32_t pkt_len, len_to_cpy, data_len, total_copied = 0;
+               uint8_t hdr = 0, uncompleted_pkt = 0;
+
                /* Get descriptor from available ring */
                desc = &vq->desc[head[packet_success]];
 
@@ -123,41 +143,85 @@ virtio_dev_rx(struct virtio_net *dev, struct rte_mbuf **pkts, uint32_t count)
                /* Convert from gpa to vva (guest physical addr -> vhost virtual addr) */
                buff_addr = gpa_to_vva(dev, desc->addr);
                /* Prefetch buffer address. */
-               rte_prefetch0((void*)(uintptr_t)buff_addr);
+               rte_prefetch0((void *)(uintptr_t)buff_addr);
 
                /* Copy virtio_hdr to packet and increment buffer address */
                buff_hdr_addr = buff_addr;
-               packet_len = rte_pktmbuf_data_len(buff) + vq->vhost_hlen;
 
                /*
                 * If the descriptors are chained the header and data are
                 * placed in separate buffers.
                 */
-               if (desc->flags & VRING_DESC_F_NEXT) {
-                       desc->len = vq->vhost_hlen;
+               if ((desc->flags & VRING_DESC_F_NEXT) &&
+                       (desc->len == vq->vhost_hlen)) {
                        desc = &vq->desc[desc->next];
                        /* Buffer address translation. */
                        buff_addr = gpa_to_vva(dev, desc->addr);
-                       desc->len = rte_pktmbuf_data_len(buff);
                } else {
-                       buff_addr += vq->vhost_hlen;
-                       desc->len = packet_len;
+                       vb_offset += vq->vhost_hlen;
+                       hdr = 1;
+               }
+
+               pkt_len = rte_pktmbuf_pkt_len(buff);
+               data_len = rte_pktmbuf_data_len(buff);
+               len_to_cpy = RTE_MIN(data_len,
+                       hdr ? desc->len - vq->vhost_hlen : desc->len);
+               while (total_copied < pkt_len) {
+                       /* Copy mbuf data to buffer */
+                       rte_memcpy((void *)(uintptr_t)(buff_addr + vb_offset),
+                               rte_pktmbuf_mtod_offset(buff, const void *, offset),
+                               len_to_cpy);
+                       PRINT_PACKET(dev, (uintptr_t)(buff_addr + vb_offset),
+                               len_to_cpy, 0);
+
+                       offset += len_to_cpy;
+                       vb_offset += len_to_cpy;
+                       total_copied += len_to_cpy;
+
+                       /* The whole packet completes */
+                       if (total_copied == pkt_len)
+                               break;
+
+                       /* The current segment completes */
+                       if (offset == data_len) {
+                               buff = buff->next;
+                               offset = 0;
+                               data_len = rte_pktmbuf_data_len(buff);
+                       }
+
+                       /* The current vring descriptor done */
+                       if (vb_offset == desc->len) {
+                               if (desc->flags & VRING_DESC_F_NEXT) {
+                                       desc = &vq->desc[desc->next];
+                                       buff_addr = gpa_to_vva(dev, desc->addr);
+                                       vb_offset = 0;
+                               } else {
+                                       /* Room in vring buffer is not enough */
+                                       uncompleted_pkt = 1;
+                                       break;
+                               }
+                       }
+                       len_to_cpy = RTE_MIN(data_len - offset, desc->len - vb_offset);
                }
 
                /* Update used ring with desc information */
-               vq->used->ring[res_cur_idx & (vq->size - 1)].id = head[packet_success];
-               vq->used->ring[res_cur_idx & (vq->size - 1)].len = packet_len;
+               vq->used->ring[res_cur_idx & (vq->size - 1)].id =
+                                                       head[packet_success];
 
-               /* Copy mbuf data to buffer */
-               rte_memcpy((void *)(uintptr_t)buff_addr,
-                       rte_pktmbuf_mtod(buff, const void *),
-                       rte_pktmbuf_data_len(buff));
-               PRINT_PACKET(dev, (uintptr_t)buff_addr,
-                       rte_pktmbuf_data_len(buff), 0);
+               /* Drop the packet if it is uncompleted */
+               if (unlikely(uncompleted_pkt == 1))
+                       vq->used->ring[res_cur_idx & (vq->size - 1)].len =
+                                                       vq->vhost_hlen;
+               else
+                       vq->used->ring[res_cur_idx & (vq->size - 1)].len =
+                                                       pkt_len + vq->vhost_hlen;
 
                res_cur_idx++;
                packet_success++;
 
+               if (unlikely(uncompleted_pkt == 1))
+                       continue;
+
                rte_memcpy((void *)(uintptr_t)buff_hdr_addr,
                        (const void *)&virtio_hdr, vq->vhost_hlen);
 
@@ -178,16 +242,19 @@ virtio_dev_rx(struct virtio_net *dev, struct rte_mbuf **pkts, uint32_t count)
        *(volatile uint16_t *)&vq->used->idx += count;
        vq->last_used_idx = res_end_idx;
 
+       /* flush used->idx update before we read avail->flags. */
+       rte_mb();
+
        /* Kick the guest if necessary. */
        if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT))
-               eventfd_write((int)vq->kickfd, 1);
+               eventfd_write(vq->callfd, (eventfd_t)1);
        return count;
 }
 
 static inline uint32_t __attribute__((always_inline))
-copy_from_mbuf_to_vring(struct virtio_net *dev,
-       uint16_t res_base_idx, uint16_t res_end_idx,
-       struct rte_mbuf *pkt)
+copy_from_mbuf_to_vring(struct virtio_net *dev, uint32_t queue_id,
+                       uint16_t res_base_idx, uint16_t res_end_idx,
+                       struct rte_mbuf *pkt)
 {
        uint32_t vec_idx = 0;
        uint32_t entry_success = 0;
@@ -215,9 +282,9 @@ copy_from_mbuf_to_vring(struct virtio_net *dev,
         * Convert from gpa to vva
         * (guest physical addr -> vhost virtual addr)
         */
-       vq = dev->virtqueue[VIRTIO_RXQ];
-       vb_addr =
-               gpa_to_vva(dev, vq->buf_vec[vec_idx].buf_addr);
+       vq = dev->virtqueue[queue_id];
+
+       vb_addr = gpa_to_vva(dev, vq->buf_vec[vec_idx].buf_addr);
        vb_hdr_addr = vb_addr;
 
        /* Prefetch buffer address. */
@@ -235,15 +302,13 @@ copy_from_mbuf_to_vring(struct virtio_net *dev,
 
        seg_avail = rte_pktmbuf_data_len(pkt);
        vb_offset = vq->vhost_hlen;
-       vb_avail =
-               vq->buf_vec[vec_idx].buf_len - vq->vhost_hlen;
+       vb_avail = vq->buf_vec[vec_idx].buf_len - vq->vhost_hlen;
 
        entry_len = vq->vhost_hlen;
 
        if (vb_avail == 0) {
                uint32_t desc_idx =
                        vq->buf_vec[vec_idx].desc_idx;
-               vq->desc[desc_idx].len = vq->vhost_hlen;
 
                if ((vq->desc[desc_idx].flags
                        & VRING_DESC_F_NEXT) == 0) {
@@ -259,8 +324,7 @@ copy_from_mbuf_to_vring(struct virtio_net *dev,
                }
 
                vec_idx++;
-               vb_addr =
-                       gpa_to_vva(dev, vq->buf_vec[vec_idx].buf_addr);
+               vb_addr = gpa_to_vva(dev, vq->buf_vec[vec_idx].buf_addr);
 
                /* Prefetch buffer address. */
                rte_prefetch0((void *)(uintptr_t)vb_addr);
@@ -273,7 +337,7 @@ copy_from_mbuf_to_vring(struct virtio_net *dev,
        while (cpy_len > 0) {
                /* Copy mbuf data to vring buffer */
                rte_memcpy((void *)(uintptr_t)(vb_addr + vb_offset),
-                       (const void *)(rte_pktmbuf_mtod(pkt, char*) + seg_offset),
+                       rte_pktmbuf_mtod_offset(pkt, const void *, seg_offset),
                        cpy_len);
 
                PRINT_PACKET(dev,
@@ -328,7 +392,6 @@ copy_from_mbuf_to_vring(struct virtio_net *dev,
                                         */
                                        uint32_t desc_idx =
                                                vq->buf_vec[vec_idx].desc_idx;
-                                       vq->desc[desc_idx].len = vb_offset;
 
                                        if ((vq->desc[desc_idx].flags &
                                                VRING_DESC_F_NEXT) == 0) {
@@ -363,26 +426,13 @@ copy_from_mbuf_to_vring(struct virtio_net *dev,
                                /*
                                 * This whole packet completes.
                                 */
-                               uint32_t desc_idx =
-                                       vq->buf_vec[vec_idx].desc_idx;
-                               vq->desc[desc_idx].len = vb_offset;
-
-                               while (vq->desc[desc_idx].flags &
-                                       VRING_DESC_F_NEXT) {
-                                       desc_idx = vq->desc[desc_idx].next;
-                                        vq->desc[desc_idx].len = 0;
-                               }
-
                                /* Update used ring with desc information */
                                vq->used->ring[cur_idx & (vq->size - 1)].id
                                        = vq->buf_vec[vec_idx].desc_idx;
                                vq->used->ring[cur_idx & (vq->size - 1)].len
                                        = entry_len;
-                               entry_len = 0;
-                               cur_idx++;
                                entry_success++;
-                               seg_avail = 0;
-                               cpy_len = RTE_MIN(vb_avail, seg_avail);
+                               break;
                        }
                }
        }
@@ -390,73 +440,87 @@ copy_from_mbuf_to_vring(struct virtio_net *dev,
        return entry_success;
 }
 
+static inline void __attribute__((always_inline))
+update_secure_len(struct vhost_virtqueue *vq, uint32_t id,
+       uint32_t *secure_len, uint32_t *vec_idx)
+{
+       uint16_t wrapped_idx = id & (vq->size - 1);
+       uint32_t idx = vq->avail->ring[wrapped_idx];
+       uint8_t next_desc;
+       uint32_t len = *secure_len;
+       uint32_t vec_id = *vec_idx;
+
+       do {
+               next_desc = 0;
+               len += vq->desc[idx].len;
+               vq->buf_vec[vec_id].buf_addr = vq->desc[idx].addr;
+               vq->buf_vec[vec_id].buf_len = vq->desc[idx].len;
+               vq->buf_vec[vec_id].desc_idx = idx;
+               vec_id++;
+
+               if (vq->desc[idx].flags & VRING_DESC_F_NEXT) {
+                       idx = vq->desc[idx].next;
+                       next_desc = 1;
+               }
+       } while (next_desc);
+
+       *secure_len = len;
+       *vec_idx = vec_id;
+}
+
 /*
- * This function adds buffers to the virtio devices RX virtqueue. Buffers can
- * be received from the physical port or from another virtio device. A packet
- * count is returned to indicate the number of packets that were succesfully
- * added to the RX queue. This function works for mergeable RX.
+ * This function works for mergeable RX.
  */
 static inline uint32_t __attribute__((always_inline))
-virtio_dev_merge_rx(struct virtio_net *dev, struct rte_mbuf **pkts,
-       uint32_t count)
+virtio_dev_merge_rx(struct virtio_net *dev, uint16_t queue_id,
+       struct rte_mbuf **pkts, uint32_t count)
 {
        struct vhost_virtqueue *vq;
        uint32_t pkt_idx = 0, entry_success = 0;
-       uint16_t avail_idx, res_cur_idx;
-       uint16_t res_base_idx, res_end_idx;
+       uint16_t avail_idx;
+       uint16_t res_base_idx, res_cur_idx;
        uint8_t success = 0;
 
        LOG_DEBUG(VHOST_DATA, "(%"PRIu64") virtio_dev_merge_rx()\n",
                dev->device_fh);
-       vq = dev->virtqueue[VIRTIO_RXQ];
+       if (unlikely(!is_valid_virt_queue_idx(queue_id, 0, dev->virt_qp_nb))) {
+               RTE_LOG(ERR, VHOST_DATA,
+                       "%s (%"PRIu64"): virtqueue idx:%d invalid.\n",
+                       __func__, dev->device_fh, queue_id);
+               return 0;
+       }
+
+       vq = dev->virtqueue[queue_id];
+       if (unlikely(vq->enabled == 0))
+               return 0;
+
        count = RTE_MIN((uint32_t)MAX_PKT_BURST, count);
 
        if (count == 0)
                return 0;
 
        for (pkt_idx = 0; pkt_idx < count; pkt_idx++) {
-               uint32_t secure_len = 0;
-               uint16_t need_cnt;
-               uint32_t vec_idx = 0;
                uint32_t pkt_len = pkts[pkt_idx]->pkt_len + vq->vhost_hlen;
-               uint16_t i, id;
 
                do {
                        /*
                         * As many data cores may want access to available
                         * buffers, they need to be reserved.
                         */
+                       uint32_t secure_len = 0;
+                       uint32_t vec_idx = 0;
+
                        res_base_idx = vq->last_used_idx_res;
                        res_cur_idx = res_base_idx;
 
                        do {
                                avail_idx = *((volatile uint16_t *)&vq->avail->idx);
-                               if (unlikely(res_cur_idx == avail_idx)) {
-                                       LOG_DEBUG(VHOST_DATA,
-                                               "(%"PRIu64") Failed "
-                                               "to get enough desc from "
-                                               "vring\n",
-                                               dev->device_fh);
-                                       return pkt_idx;
-                               } else {
-                                       uint16_t wrapped_idx =
-                                               (res_cur_idx) & (vq->size - 1);
-                                       uint32_t idx =
-                                               vq->avail->ring[wrapped_idx];
-                                       uint8_t next_desc;
-
-                                       do {
-                                               next_desc = 0;
-                                               secure_len += vq->desc[idx].len;
-                                               if (vq->desc[idx].flags &
-                                                       VRING_DESC_F_NEXT) {
-                                                       idx = vq->desc[idx].next;
-                                                       next_desc = 1;
-                                               }
-                                       } while (next_desc);
+                               if (unlikely(res_cur_idx == avail_idx))
+                                       goto merge_rx_exit;
 
-                                       res_cur_idx++;
-                               }
+                               update_secure_len(vq, res_cur_idx,
+                                                 &secure_len, &vec_idx);
+                               res_cur_idx++;
                        } while (pkt_len > secure_len);
 
                        /* vq->last_used_idx_res is atomically updated. */
@@ -465,33 +529,8 @@ virtio_dev_merge_rx(struct virtio_net *dev, struct rte_mbuf **pkts,
                                                        res_cur_idx);
                } while (success == 0);
 
-               id = res_base_idx;
-               need_cnt = res_cur_idx - res_base_idx;
-
-               for (i = 0; i < need_cnt; i++, id++) {
-                       uint16_t wrapped_idx = id & (vq->size - 1);
-                       uint32_t idx = vq->avail->ring[wrapped_idx];
-                       uint8_t next_desc;
-                       do {
-                               next_desc = 0;
-                               vq->buf_vec[vec_idx].buf_addr =
-                                       vq->desc[idx].addr;
-                               vq->buf_vec[vec_idx].buf_len =
-                                       vq->desc[idx].len;
-                               vq->buf_vec[vec_idx].desc_idx = idx;
-                               vec_idx++;
-
-                               if (vq->desc[idx].flags & VRING_DESC_F_NEXT) {
-                                       idx = vq->desc[idx].next;
-                                       next_desc = 1;
-                               }
-                       } while (next_desc);
-               }
-
-               res_end_idx = res_cur_idx;
-
-               entry_success = copy_from_mbuf_to_vring(dev, res_base_idx,
-                       res_end_idx, pkts[pkt_idx]);
+               entry_success = copy_from_mbuf_to_vring(dev, queue_id,
+                       res_base_idx, res_cur_idx, pkts[pkt_idx]);
 
                rte_compiler_barrier();
 
@@ -503,40 +542,157 @@ virtio_dev_merge_rx(struct virtio_net *dev, struct rte_mbuf **pkts,
                        rte_pause();
 
                *(volatile uint16_t *)&vq->used->idx += entry_success;
-               vq->last_used_idx = res_end_idx;
+               vq->last_used_idx = res_cur_idx;
+       }
+
+merge_rx_exit:
+       if (likely(pkt_idx)) {
+               /* flush used->idx update before we read avail->flags. */
+               rte_mb();
 
                /* Kick the guest if necessary. */
                if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT))
-                       eventfd_write((int)vq->kickfd, 1);
+                       eventfd_write(vq->callfd, (eventfd_t)1);
        }
 
-       return count;
+       return pkt_idx;
+}
+
+uint16_t
+rte_vhost_enqueue_burst(struct virtio_net *dev, uint16_t queue_id,
+       struct rte_mbuf **pkts, uint16_t count)
+{
+       if (unlikely(dev->features & (1 << VIRTIO_NET_F_MRG_RXBUF)))
+               return virtio_dev_merge_rx(dev, queue_id, pkts, count);
+       else
+               return virtio_dev_rx(dev, queue_id, pkts, count);
+}
+
+static void
+parse_ethernet(struct rte_mbuf *m, uint16_t *l4_proto, void **l4_hdr)
+{
+       struct ipv4_hdr *ipv4_hdr;
+       struct ipv6_hdr *ipv6_hdr;
+       void *l3_hdr = NULL;
+       struct ether_hdr *eth_hdr;
+       uint16_t ethertype;
+
+       eth_hdr = rte_pktmbuf_mtod(m, struct ether_hdr *);
+
+       m->l2_len = sizeof(struct ether_hdr);
+       ethertype = rte_be_to_cpu_16(eth_hdr->ether_type);
+
+       if (ethertype == ETHER_TYPE_VLAN) {
+               struct vlan_hdr *vlan_hdr = (struct vlan_hdr *)(eth_hdr + 1);
+
+               m->l2_len += sizeof(struct vlan_hdr);
+               ethertype = rte_be_to_cpu_16(vlan_hdr->eth_proto);
+       }
+
+       l3_hdr = (char *)eth_hdr + m->l2_len;
+
+       switch (ethertype) {
+       case ETHER_TYPE_IPv4:
+               ipv4_hdr = (struct ipv4_hdr *)l3_hdr;
+               *l4_proto = ipv4_hdr->next_proto_id;
+               m->l3_len = (ipv4_hdr->version_ihl & 0x0f) * 4;
+               *l4_hdr = (char *)l3_hdr + m->l3_len;
+               m->ol_flags |= PKT_TX_IPV4;
+               break;
+       case ETHER_TYPE_IPv6:
+               ipv6_hdr = (struct ipv6_hdr *)l3_hdr;
+               *l4_proto = ipv6_hdr->proto;
+               m->l3_len = sizeof(struct ipv6_hdr);
+               *l4_hdr = (char *)l3_hdr + m->l3_len;
+               m->ol_flags |= PKT_TX_IPV6;
+               break;
+       default:
+               m->l3_len = 0;
+               *l4_proto = 0;
+               break;
+       }
 }
 
-/* This function works for TX packets with mergeable feature enabled. */
 static inline void __attribute__((always_inline))
-virtio_dev_merge_tx(struct virtio_net *dev, struct rte_mempool *mbuf_pool)
+vhost_dequeue_offload(struct virtio_net_hdr *hdr, struct rte_mbuf *m)
+{
+       uint16_t l4_proto = 0;
+       void *l4_hdr = NULL;
+       struct tcp_hdr *tcp_hdr = NULL;
+
+       parse_ethernet(m, &l4_proto, &l4_hdr);
+       if (hdr->flags == VIRTIO_NET_HDR_F_NEEDS_CSUM) {
+               if (hdr->csum_start == (m->l2_len + m->l3_len)) {
+                       switch (hdr->csum_offset) {
+                       case (offsetof(struct tcp_hdr, cksum)):
+                               if (l4_proto == IPPROTO_TCP)
+                                       m->ol_flags |= PKT_TX_TCP_CKSUM;
+                               break;
+                       case (offsetof(struct udp_hdr, dgram_cksum)):
+                               if (l4_proto == IPPROTO_UDP)
+                                       m->ol_flags |= PKT_TX_UDP_CKSUM;
+                               break;
+                       case (offsetof(struct sctp_hdr, cksum)):
+                               if (l4_proto == IPPROTO_SCTP)
+                                       m->ol_flags |= PKT_TX_SCTP_CKSUM;
+                               break;
+                       default:
+                               break;
+                       }
+               }
+       }
+
+       if (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE) {
+               switch (hdr->gso_type & ~VIRTIO_NET_HDR_GSO_ECN) {
+               case VIRTIO_NET_HDR_GSO_TCPV4:
+               case VIRTIO_NET_HDR_GSO_TCPV6:
+                       tcp_hdr = (struct tcp_hdr *)l4_hdr;
+                       m->ol_flags |= PKT_TX_TCP_SEG;
+                       m->tso_segsz = hdr->gso_size;
+                       m->l4_len = (tcp_hdr->data_off & 0xf0) >> 2;
+                       break;
+               default:
+                       RTE_LOG(WARNING, VHOST_DATA,
+                               "unsupported gso type %u.\n", hdr->gso_type);
+                       break;
+               }
+       }
+}
+
+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)
 {
        struct rte_mbuf *m, *prev;
        struct vhost_virtqueue *vq;
        struct vring_desc *desc;
        uint64_t vb_addr = 0;
+       uint64_t vb_net_hdr_addr = 0;
        uint32_t head[MAX_PKT_BURST];
        uint32_t used_idx;
        uint32_t i;
        uint16_t free_entries, entry_success = 0;
        uint16_t avail_idx;
-       uint32_t buf_size = MBUF_SIZE - (sizeof(struct rte_mbuf)
-                       + RTE_PKTMBUF_HEADROOM);
+       struct virtio_net_hdr *hdr = NULL;
+
+       if (unlikely(!is_valid_virt_queue_idx(queue_id, 1, dev->virt_qp_nb))) {
+               RTE_LOG(ERR, VHOST_DATA,
+                       "%s (%"PRIu64"): virtqueue idx:%d invalid.\n",
+                       __func__, dev->device_fh, queue_id);
+               return 0;
+       }
+
+       vq = dev->virtqueue[queue_id];
+       if (unlikely(vq->enabled == 0))
+               return 0;
 
-       vq = dev->virtqueue[VIRTIO_TXQ];
        avail_idx =  *((volatile uint16_t *)&vq->avail->idx);
 
        /* If there are no available buffers then return. */
        if (vq->last_used_idx == avail_idx)
-               return;
+               return 0;
 
-       LOG_DEBUG(VHOST_DATA, "(%"PRIu64") virtio_dev_merge_tx()\n",
+       LOG_DEBUG(VHOST_DATA, "%s (%"PRIu64")\n", __func__,
                dev->device_fh);
 
        /* Prefetch available ring to retrieve head indexes. */
@@ -545,11 +701,12 @@ virtio_dev_merge_tx(struct virtio_net *dev, struct rte_mempool *mbuf_pool)
        /*get the number of free entries in the ring*/
        free_entries = (avail_idx - vq->last_used_idx);
 
+       free_entries = RTE_MIN(free_entries, count);
        /* Limit to MAX_PKT_BURST. */
        free_entries = RTE_MIN(free_entries, MAX_PKT_BURST);
 
        LOG_DEBUG(VHOST_DATA, "(%"PRIu64") Buffers available %d\n",
-               dev->device_fh, free_entries);
+                       dev->device_fh, free_entries);
        /* Retrieve all of the head indexes first to avoid caching issues. */
        for (i = 0; i < free_entries; i++)
                head[i] = vq->avail->ring[(vq->last_used_idx + i) & (vq->size - 1)];
@@ -568,8 +725,18 @@ virtio_dev_merge_tx(struct virtio_net *dev, struct rte_mempool *mbuf_pool)
 
                desc = &vq->desc[head[entry_success]];
 
+               vb_net_hdr_addr = gpa_to_vva(dev, desc->addr);
+               hdr = (struct virtio_net_hdr *)((uintptr_t)vb_net_hdr_addr);
+
                /* Discard first buffer as it is the virtio header */
-               desc = &vq->desc[desc->next];
+               if (desc->flags & VRING_DESC_F_NEXT) {
+                       desc = &vq->desc[desc->next];
+                       vb_offset = 0;
+                       vb_avail = desc->len;
+               } else {
+                       vb_offset = vq->vhost_hlen;
+                       vb_avail = desc->len - vb_offset;
+               }
 
                /* Buffer address translation. */
                vb_addr = gpa_to_vva(dev, desc->addr);
@@ -588,27 +755,24 @@ virtio_dev_merge_tx(struct virtio_net *dev, struct rte_mempool *mbuf_pool)
                vq->used->ring[used_idx].id = head[entry_success];
                vq->used->ring[used_idx].len = 0;
 
-               vb_offset = 0;
-               vb_avail = desc->len;
-               seg_offset = 0;
-               seg_avail = buf_size;
-               cpy_len = RTE_MIN(vb_avail, seg_avail);
-
-               PRINT_PACKET(dev, (uintptr_t)vb_addr, desc->len, 0);
-
                /* Allocate an mbuf and populate the structure. */
                m = rte_pktmbuf_alloc(mbuf_pool);
                if (unlikely(m == NULL)) {
                        RTE_LOG(ERR, VHOST_DATA,
                                "Failed to allocate memory for mbuf.\n");
-                       return;
+                       break;
                }
+               seg_offset = 0;
+               seg_avail = m->buf_len - RTE_PKTMBUF_HEADROOM;
+               cpy_len = RTE_MIN(vb_avail, seg_avail);
+
+               PRINT_PACKET(dev, (uintptr_t)vb_addr, desc->len, 0);
 
                seg_num++;
                cur = m;
                prev = m;
                while (cpy_len != 0) {
-                       rte_memcpy((void *)(rte_pktmbuf_mtod(cur, char *) + seg_offset),
+                       rte_memcpy(rte_pktmbuf_mtod_offset(cur, void *, seg_offset),
                                (void *)((uintptr_t)(vb_addr + vb_offset)),
                                cpy_len);
 
@@ -639,7 +803,7 @@ virtio_dev_merge_tx(struct virtio_net *dev, struct rte_mempool *mbuf_pool)
                                prev->next = cur;
                                prev = cur;
                                seg_offset = 0;
-                               seg_avail = buf_size;
+                               seg_avail = cur->buf_len - RTE_PKTMBUF_HEADROOM;
                        } else {
                                if (desc->flags & VRING_DESC_F_NEXT) {
                                        /*
@@ -673,7 +837,7 @@ virtio_dev_merge_tx(struct virtio_net *dev, struct rte_mempool *mbuf_pool)
                                                prev->next = cur;
                                                prev = cur;
                                                seg_offset = 0;
-                                               seg_avail = buf_size;
+                                               seg_avail = cur->buf_len - RTE_PKTMBUF_HEADROOM;
                                        }
 
                                        desc = &vq->desc[desc->next];
@@ -702,16 +866,18 @@ virtio_dev_merge_tx(struct virtio_net *dev, struct rte_mempool *mbuf_pool)
                        break;
 
                m->nb_segs = seg_num;
+               if ((hdr->flags != 0) || (hdr->gso_type != VIRTIO_NET_HDR_GSO_NONE))
+                       vhost_dequeue_offload(hdr, m);
 
+               pkts[entry_success] = m;
                vq->last_used_idx++;
                entry_success++;
-               rte_pktmbuf_free(m);
        }
 
        rte_compiler_barrier();
        vq->used->idx += entry_success;
        /* Kick guest if required. */
        if (!(vq->avail->flags & VRING_AVAIL_F_NO_INTERRUPT))
-               eventfd_write((int)vq->kickfd, 1);
-
+               eventfd_write(vq->callfd, (eventfd_t)1);
+       return entry_success;
 }