vhost: support indirect descriptor in mergeable Rx

Windows virtio-net driver uses indirect descriptors with
mergeable buffers.

This patch adds its support, fixing the use of indirect
descriptors with these guests.

Signed-off-by: Maxime Coquelin <maxime.coquelin@redhat.com>
Acked-by: Yuanhan Liu <yuanhan.liu@linux.intel.com>

diff --git a/lib/librte_vhost/virtio_net.c b/lib/librte_vhost/virtio_net.c
index eed0b1c..3f82643 100644 (file)
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -351,29 +351,41 @@ virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id,
 }
 
 static inline int __attribute__((always_inline))
-fill_vec_buf(struct vhost_virtqueue *vq, uint32_t avail_idx,
-            uint32_t *vec_idx, struct buf_vector *buf_vec,
-            uint16_t *desc_chain_head, uint16_t *desc_chain_len)
+fill_vec_buf(struct virtio_net *dev, struct vhost_virtqueue *vq,
+                        uint32_t avail_idx, uint32_t *vec_idx,
+                        struct buf_vector *buf_vec, uint16_t *desc_chain_head,
+                        uint16_t *desc_chain_len)
 {
        uint16_t idx = vq->avail->ring[avail_idx & (vq->size - 1)];
        uint32_t vec_id = *vec_idx;
        uint32_t len    = 0;
+       struct vring_desc *descs = vq->desc;
 
        *desc_chain_head = idx;
+
+       if (vq->desc[idx].flags & VRING_DESC_F_INDIRECT) {
+               descs = (struct vring_desc *)(uintptr_t)
+                                       gpa_to_vva(dev, vq->desc[idx].addr);
+               if (unlikely(!descs))
+                       return -1;
+
+               idx = 0;
+       }
+
        while (1) {
                if (unlikely(vec_id >= BUF_VECTOR_MAX || idx >= vq->size))
                        return -1;
 
-               len += vq->desc[idx].len;
-               buf_vec[vec_id].buf_addr = vq->desc[idx].addr;
-               buf_vec[vec_id].buf_len  = vq->desc[idx].len;
+               len += descs[idx].len;
+               buf_vec[vec_id].buf_addr = descs[idx].addr;
+               buf_vec[vec_id].buf_len  = descs[idx].len;
                buf_vec[vec_id].desc_idx = idx;
                vec_id++;
 
-               if ((vq->desc[idx].flags & VRING_DESC_F_NEXT) == 0)
+               if ((descs[idx].flags & VRING_DESC_F_NEXT) == 0)
                        break;
 
-               idx = vq->desc[idx].next;
+               idx = descs[idx].next;
        }
 
        *desc_chain_len = len;
@@ -386,9 +398,9 @@ fill_vec_buf(struct vhost_virtqueue *vq, uint32_t avail_idx,
  * Returns -1 on fail, 0 on success
  */
 static inline int
-reserve_avail_buf_mergeable(struct vhost_virtqueue *vq, uint32_t size,
-                           struct buf_vector *buf_vec, uint16_t *num_buffers,
-                           uint16_t avail_head)
+reserve_avail_buf_mergeable(struct virtio_net *dev, struct vhost_virtqueue *vq,
+                               uint32_t size, struct buf_vector *buf_vec,
+                               uint16_t *num_buffers, uint16_t avail_head)
 {
        uint16_t cur_idx;
        uint32_t vec_idx = 0;
@@ -404,8 +416,8 @@ reserve_avail_buf_mergeable(struct vhost_virtqueue *vq, uint32_t size,
                if (unlikely(cur_idx == avail_head))
                        return -1;
 
-               if (unlikely(fill_vec_buf(vq, cur_idx, &vec_idx, buf_vec,
-                                         &head_idx, &len) < 0))
+               if (unlikely(fill_vec_buf(dev, vq, cur_idx, &vec_idx, buf_vec,
+                                               &head_idx, &len) < 0))
                        return -1;
                len = RTE_MIN(len, size);
                update_shadow_used_ring(vq, head_idx, len);
@@ -543,8 +555,9 @@ virtio_dev_merge_rx(struct virtio_net *dev, uint16_t queue_id,
        for (pkt_idx = 0; pkt_idx < count; pkt_idx++) {
                uint32_t pkt_len = pkts[pkt_idx]->pkt_len + dev->vhost_hlen;
 
-               if (unlikely(reserve_avail_buf_mergeable(vq, pkt_len, buf_vec,
-                                       &num_buffers, avail_head) < 0)) {
+               if (unlikely(reserve_avail_buf_mergeable(dev, vq,
+                                               pkt_len, buf_vec, &num_buffers,
+                                               avail_head) < 0)) {
                        LOG_DEBUG(VHOST_DATA,
                                "(%d) failed to get enough desc from vring\n",
                                dev->vid);