vhost: support indirect descriptor in non-mergeable Rx

Linux virtio-net kernel driver uses indirect descriptors when
mergeable buffers are not used.

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 3f82643..595f67c 100644 (file)
--- a/lib/librte_vhost/virtio_net.c
+++ b/lib/librte_vhost/virtio_net.c
@@ -186,8 +186,8 @@ copy_virtio_net_hdr(struct virtio_net *dev, uint64_t desc_addr,
 }
 
 static inline int __attribute__((always_inline))
-copy_mbuf_to_desc(struct virtio_net *dev, struct vhost_virtqueue *vq,
-                 struct rte_mbuf *m, uint16_t desc_idx)
+copy_mbuf_to_desc(struct virtio_net *dev, struct vring_desc *descs,
+                 struct rte_mbuf *m, uint16_t desc_idx, uint32_t size)
 {
        uint32_t desc_avail, desc_offset;
        uint32_t mbuf_avail, mbuf_offset;
@@ -196,7 +196,7 @@ copy_mbuf_to_desc(struct virtio_net *dev, struct vhost_virtqueue *vq,
        uint64_t desc_addr;
        struct virtio_net_hdr_mrg_rxbuf virtio_hdr = {{0, 0, 0, 0, 0, 0}, 0};
 
-       desc = &vq->desc[desc_idx];
+       desc = &descs[desc_idx];
        desc_addr = gpa_to_vva(dev, desc->addr);
        /*
         * Checking of 'desc_addr' placed outside of 'unlikely' macro to avoid
@@ -233,10 +233,10 @@ copy_mbuf_to_desc(struct virtio_net *dev, struct vhost_virtqueue *vq,
                                /* Room in vring buffer is not enough */
                                return -1;
                        }
-                       if (unlikely(desc->next >= vq->size))
+                       if (unlikely(desc->next >= size))
                                return -1;
 
-                       desc = &vq->desc[desc->next];
+                       desc = &descs[desc->next];
                        desc_addr = gpa_to_vva(dev, desc->addr);
                        if (unlikely(!desc_addr))
                                return -1;
@@ -276,8 +276,9 @@ virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id,
        struct vhost_virtqueue *vq;
        uint16_t avail_idx, free_entries, start_idx;
        uint16_t desc_indexes[MAX_PKT_BURST];
+       struct vring_desc *descs;
        uint16_t used_idx;
-       uint32_t i;
+       uint32_t i, sz;
 
        LOG_DEBUG(VHOST_DATA, "(%d) %s\n", dev->vid, __func__);
        if (unlikely(!is_valid_virt_queue_idx(queue_id, 0, dev->virt_qp_nb))) {
@@ -319,7 +320,22 @@ virtio_dev_rx(struct virtio_net *dev, uint16_t queue_id,
                uint16_t desc_idx = desc_indexes[i];
                int err;
 
-               err = copy_mbuf_to_desc(dev, vq, pkts[i], desc_idx);
+               if (vq->desc[desc_idx].flags & VRING_DESC_F_INDIRECT) {
+                       descs = (struct vring_desc *)(uintptr_t)gpa_to_vva(dev,
+                                       vq->desc[desc_idx].addr);
+                       if (unlikely(!descs)) {
+                               count = i;
+                               break;
+                       }
+
+                       desc_idx = 0;
+                       sz = vq->desc[desc_idx].len / sizeof(*descs);
+               } else {
+                       descs = vq->desc;
+                       sz = vq->size;
+               }
+
+               err = copy_mbuf_to_desc(dev, descs, pkts[i], desc_idx, sz);
                if (unlikely(err)) {
                        used_idx = (start_idx + i) & (vq->size - 1);
                        vq->used->ring[used_idx].len = dev->vhost_hlen;