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-rw-r--r--hw/virtio-net.c31
1 files changed, 19 insertions, 12 deletions
diff --git a/hw/virtio-net.c b/hw/virtio-net.c
index 59ab674..5206648 100644
--- a/hw/virtio-net.c
+++ b/hw/virtio-net.c
@@ -715,10 +715,10 @@ static int32_t virtio_net_flush_tx(VirtIONet *n, VirtQueue *vq)
}
while (virtqueue_pop(vq, &elem)) {
- ssize_t ret, len = 0;
+ ssize_t ret, len;
unsigned int out_num = elem.out_num;
struct iovec *out_sg = &elem.out_sg[0];
- unsigned hdr_len;
+ struct iovec sg[VIRTQUEUE_MAX_SIZE];
/* hdr_len refers to the header received from the guest */
hdr_len = n->mergeable_rx_bufs ?
@@ -730,18 +730,25 @@ static int32_t virtio_net_flush_tx(VirtIONet *n, VirtQueue *vq)
exit(1);
}
- /* ignore the header if GSO is not supported */
- if (!n->has_vnet_hdr) {
- out_num--;
- out_sg++;
- len += hdr_len;
- } else if (n->mergeable_rx_bufs) {
- /* tapfd expects a struct virtio_net_hdr */
- hdr_len -= sizeof(struct virtio_net_hdr);
- out_sg->iov_len -= hdr_len;
- len += hdr_len;
+ /*
+ * If host wants to see the guest header as is, we can
+ * pass it on unchanged. Otherwise, copy just the parts
+ * that host is interested in.
+ */
+ assert(n->host_hdr_len <= n->guest_hdr_len);
+ if (n->host_hdr_len != n->guest_hdr_len) {
+ unsigned sg_num = iov_copy(sg, ARRAY_SIZE(sg),
+ out_sg, out_num,
+ 0, n->host_hdr_len);
+ sg_num += iov_copy(sg + sg_num, ARRAY_SIZE(sg) - sg_num,
+ out_sg, out_num,
+ n->guest_hdr_len, -1);
+ out_num = sg_num;
+ out_sg = sg;
}
+ len = hdr_len;
+
ret = qemu_sendv_packet_async(&n->nic->nc, out_sg, out_num,
virtio_net_tx_complete);
if (ret == 0) {