On Thu, Jun 29, 2023 at 5:25 PM Hawkins Jiawei <[email protected]> wrote:
>
> According to VirtIO standard, "The driver MUST follow
> the VIRTIO_NET_CTRL_MAC_TABLE_SET command by a le32 number,
> followed by that number of non-multicast MAC addresses,
> followed by another le32 number, followed by that number
> of multicast addresses."
>
> Considering that these data is not stored in contiguous memory,
> this patch refactors vhost_vdpa_net_load_cmd() to accept
> scattered data, eliminating the need for an addtional data copy or
> packing the data into s->cvq_cmd_out_buffer outside of
> vhost_vdpa_net_load_cmd().
>
> Signed-off-by: Hawkins Jiawei <[email protected]>
> ---
> v2:
> - refactor vhost_vdpa_load_cmd() to accept iovec suggested by
> Eugenio
>
> net/vhost-vdpa.c | 42 ++++++++++++++++++++++++++++++++----------
> 1 file changed, 32 insertions(+), 10 deletions(-)
>
> diff --git a/net/vhost-vdpa.c b/net/vhost-vdpa.c
> index 6f6a5c6df6..0bd1c7817c 100644
> --- a/net/vhost-vdpa.c
> +++ b/net/vhost-vdpa.c
> @@ -620,29 +620,43 @@ static ssize_t vhost_vdpa_net_cvq_add(VhostVDPAState
> *s, size_t out_len,
> }
>
> static ssize_t vhost_vdpa_net_load_cmd(VhostVDPAState *s, uint8_t class,
> - uint8_t cmd, const void *data,
> - size_t data_size)
> + uint8_t cmd, const struct iovec *data,
> + size_t data_len)
> {
> const struct virtio_net_ctrl_hdr ctrl = {
> .class = class,
> .cmd = cmd,
> };
> + void *cursor = s->cvq_cmd_out_buffer;
>
> - assert(data_size < vhost_vdpa_net_cvq_cmd_page_len() - sizeof(ctrl));
> + /* pack the CVQ command header */
> + assert(sizeof(ctrl) < vhost_vdpa_net_cvq_cmd_page_len() -
> + (cursor - s->cvq_cmd_out_buffer));
> + memcpy(cursor, &ctrl, sizeof(ctrl));
> + cursor += sizeof(ctrl);
>
> - memcpy(s->cvq_cmd_out_buffer, &ctrl, sizeof(ctrl));
> - memcpy(s->cvq_cmd_out_buffer + sizeof(ctrl), data, data_size);
> + /* pack the CVQ command command-specific-data */
> + for (int i = 0; i < data_len; ++i) {
> + assert(data[i].iov_len < vhost_vdpa_net_cvq_cmd_page_len() -
> + (cursor - s->cvq_cmd_out_buffer));
> + memcpy(cursor, data[i].iov_base, data[i].iov_len);
> + cursor += data[i].iov_len;
> + }
Can we replace all of the above by iov_to_buf?
>
> - return vhost_vdpa_net_cvq_add(s, sizeof(ctrl) + data_size,
> + return vhost_vdpa_net_cvq_add(s, cursor - s->cvq_cmd_out_buffer,
> sizeof(virtio_net_ctrl_ack));
> }
>
> static int vhost_vdpa_net_load_mac(VhostVDPAState *s, const VirtIONet *n)
> {
> if (virtio_vdev_has_feature(&n->parent_obj, VIRTIO_NET_F_CTRL_MAC_ADDR))
> {
> + const struct iovec data = {
> + .iov_base = (void *)n->mac,
> + .iov_len = sizeof(n->mac),
> + };
> ssize_t dev_written = vhost_vdpa_net_load_cmd(s, VIRTIO_NET_CTRL_MAC,
>
> VIRTIO_NET_CTRL_MAC_ADDR_SET,
> - n->mac, sizeof(n->mac));
> + &data, 1);
> if (unlikely(dev_written < 0)) {
> return dev_written;
> }
> @@ -665,9 +679,13 @@ static int vhost_vdpa_net_load_mq(VhostVDPAState *s,
> }
>
> mq.virtqueue_pairs = cpu_to_le16(n->curr_queue_pairs);
> + const struct iovec data = {
> + .iov_base = &mq,
> + .iov_len = sizeof(mq),
> + };
> dev_written = vhost_vdpa_net_load_cmd(s, VIRTIO_NET_CTRL_MQ,
> - VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET,
> &mq,
> - sizeof(mq));
> + VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET,
> + &data, 1);
> if (unlikely(dev_written < 0)) {
> return dev_written;
> }
> @@ -706,9 +724,13 @@ static int vhost_vdpa_net_load_offloads(VhostVDPAState
> *s,
> }
>
> offloads = cpu_to_le64(n->curr_guest_offloads);
> + const struct iovec data = {
> + .iov_base = &offloads,
> + .iov_len = sizeof(offloads),
> + };
> dev_written = vhost_vdpa_net_load_cmd(s, VIRTIO_NET_CTRL_GUEST_OFFLOADS,
> VIRTIO_NET_CTRL_GUEST_OFFLOADS_SET,
> - &offloads, sizeof(offloads));
> + &data, 1);
> if (unlikely(dev_written < 0)) {
> return dev_written;
> }
> --
> 2.25.1
>
