virtio: fix to use chained descriptors when missing indirect descriptor
Some vhost-backed missing the VIRTIO_RING_F_INDIRECT_DESC feature.
Previously, vpp doesn't support jumbo frames using chained descriptors.
This patch fixes this issue.
Type: fix
Change-Id: I20487e201e88ea136b556ac84dde058019ab3e78
Signed-off-by: Mohsin Kazmi <sykazmi@cisco.com>
diff --git a/src/vnet/devices/virtio/device.c b/src/vnet/devices/virtio/device.c
index 9d04474..367372f 100644
--- a/src/vnet/devices/virtio/device.c
+++ b/src/vnet/devices/virtio/device.c
@@ -126,6 +126,14 @@
n_left--;
last++;
n_buffers++;
+ struct vring_desc *d = &vring->desc[e->id];
+ u16 next;
+ while (d->flags & VRING_DESC_F_NEXT)
+ {
+ n_buffers++;
+ next = d->next;
+ d = &vring->desc[next];
+ }
if (n_left == 0)
break;
e = &vring->used->ring[last & mask];
@@ -238,8 +246,9 @@
static_always_inline u16
add_buffer_to_slot (vlib_main_t * vm, virtio_if_t * vif,
- virtio_vring_t * vring, u32 bi, u16 avail, u16 next,
- u16 mask, int do_gso, int csum_offload, uword node_index)
+ virtio_vring_t * vring, u32 bi, u16 free_desc_count,
+ u16 avail, u16 next, u16 mask, int do_gso,
+ int csum_offload, uword node_index)
{
u16 n_added = 0;
int hdr_sz = vif->virtio_net_hdr_sz;
@@ -283,7 +292,7 @@
d->len = b->current_length + hdr_sz;
d->flags = 0;
}
- else
+ else if (vif->features & VIRTIO_FEATURE (VIRTIO_RING_F_INDIRECT_DESC))
{
/*
* We are using single vlib_buffer_t for indirect descriptor(s)
@@ -367,6 +376,55 @@
d->len = count * sizeof (struct vring_desc);
d->flags = VRING_DESC_F_INDIRECT;
}
+ else if (vif->type == VIRTIO_IF_TYPE_PCI)
+ {
+ u16 count = next;
+ vlib_buffer_t *b_temp = b;
+ u16 n_buffers_in_chain = 1;
+
+ /*
+ * Check the length of the chain for the required number of
+ * descriptors. Return from here, retry to get more descriptors,
+ * if chain length is greater than available descriptors.
+ */
+ while (b_temp->flags & VLIB_BUFFER_NEXT_PRESENT)
+ {
+ n_buffers_in_chain++;
+ b_temp = vlib_get_buffer (vm, b_temp->next_buffer);
+ }
+
+ if (n_buffers_in_chain > free_desc_count)
+ return n_buffers_in_chain;
+
+ d->addr = vlib_buffer_get_current_pa (vm, b) - hdr_sz;
+ d->len = b->current_length + hdr_sz;
+
+ while (b->flags & VLIB_BUFFER_NEXT_PRESENT)
+ {
+ d->flags = VRING_DESC_F_NEXT;
+ vring->buffers[count] = bi;
+ b->flags &=
+ ~(VLIB_BUFFER_NEXT_PRESENT | VLIB_BUFFER_TOTAL_LENGTH_VALID);
+ bi = b->next_buffer;
+ b->next_buffer = 0;
+ n_added++;
+ count = (count + 1) & mask;
+ d->next = count;
+ d = &vring->desc[count];
+ b = vlib_get_buffer (vm, bi);
+ d->addr = vlib_buffer_get_current_pa (vm, b);
+ d->len = b->current_length;
+ }
+ d->flags = 0;
+ vring->buffers[count] = bi;
+ vring->avail->ring[avail & mask] = next;
+ n_added++;
+ return n_added;
+ }
+ else
+ {
+ ASSERT (0);
+ }
vring->buffers[next] = bi;
vring->avail->ring[avail & mask] = next;
n_added++;
@@ -457,8 +515,9 @@
{
u16 n_added = 0;
n_added =
- add_buffer_to_slot (vm, vif, vring, buffers[0], avail, next, mask,
- do_gso, csum_offload, node->node_index);
+ add_buffer_to_slot (vm, vif, vring, buffers[0], free_desc_count,
+ avail, next, mask, do_gso, csum_offload,
+ node->node_index);
if (PREDICT_FALSE (n_added == 0))
{
@@ -466,13 +525,15 @@
n_left--;
continue;
}
+ else if (PREDICT_FALSE (n_added > free_desc_count))
+ break;
- avail += n_added;
+ avail++;
next = (next + n_added) & mask;
used += n_added;
buffers++;
n_left--;
- free_desc_count--;
+ free_desc_count -= n_added;
}
if (n_left != frame->n_vectors)
diff --git a/src/vnet/devices/virtio/pci.c b/src/vnet/devices/virtio/pci.c
index 5482822..c7398c9 100644
--- a/src/vnet/devices/virtio/pci.c
+++ b/src/vnet/devices/virtio/pci.c
@@ -1052,6 +1052,17 @@
* read device features and negotiate (user) requested features
*/
virtio_pci_read_device_feature (vm, vif);
+ if ((vif->remote_features & VIRTIO_FEATURE (VIRTIO_RING_F_INDIRECT_DESC)) ==
+ 0)
+ {
+ virtio_log_warning (vif, "error encountered: vhost-net backend doesn't "
+ "support VIRTIO_RING_F_INDIRECT_DESC features");
+ }
+ if ((vif->remote_features & VIRTIO_FEATURE (VIRTIO_NET_F_MRG_RXBUF)) == 0)
+ {
+ virtio_log_warning (vif, "error encountered: vhost-net backend doesn't "
+ "support VIRTIO_NET_F_MRG_RXBUF features");
+ }
virtio_negotiate_features (vm, vif, args->features);
/*