Re: [PATCH v3 1/3] net/virtio_user: convert cq descriptor IOVA address to Virtual address

[Jerin Jacob <jerinjacobk@gmail.com>]

On Wed, Jul 3, 2024 at 3:43 PM Srujana Challa <schalla@marvell.com> wrote:
>
> This patch modifies the code to convert descriptor buffer IOVA
> addresses to virtual addresses during the processing of shadow
> control queue when IOVA mode is PA. This change enables Virtio-user
> to operate with IOVA as the descriptor buffer address.
>
> Signed-off-by: Srujana Challa <schalla@marvell.com>
> ---
>  .../net/virtio/virtio_user/virtio_user_dev.c  | 33 ++++++++++++-------
>  1 file changed, 21 insertions(+), 12 deletions(-)
>
> diff --git a/drivers/net/virtio/virtio_user/virtio_user_dev.c b/drivers/net/virtio/virtio_user/virtio_user_dev.c
> index 1365c8a5c8..7f35f4b06b 100644
> --- a/drivers/net/virtio/virtio_user/virtio_user_dev.c
> +++ b/drivers/net/virtio/virtio_user/virtio_user_dev.c
> @@ -896,6 +896,15 @@ virtio_user_handle_mq(struct virtio_user_dev *dev, uint16_t q_pairs)
>
>  #define CVQ_MAX_DATA_DESCS 32
>
> +static inline void *
> +virtio_user_iova2virt(rte_iova_t iova)
> +{
> +       if (rte_eal_iova_mode() == RTE_IOVA_PA)

There is RTE_IOVA_DC as well. So we may put positive logic. i.e
rte_eal_iova_mode() == RTE_IOVA_VA

> +               return rte_mem_iova2virt(iova);
> +       else
> +               return (void *)(uintptr_t)iova;
> +}
> +
>  static uint32_t
>  virtio_user_handle_ctrl_msg_split(struct virtio_user_dev *dev, struct vring *vring,
>                             uint16_t idx_hdr)
> @@ -921,17 +930,18 @@ virtio_user_handle_ctrl_msg_split(struct virtio_user_dev *dev, struct vring *vri
>         idx_status = i;
>         n_descs++;
>
> -       hdr = (void *)(uintptr_t)vring->desc[idx_hdr].addr;
> +       hdr = virtio_user_iova2virt(vring->desc[idx_hdr].addr);
>         if (hdr->class == VIRTIO_NET_CTRL_MQ &&
>             hdr->cmd == VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET) {
> -               uint16_t queues;
> +               uint16_t queues, *addr;
>
> -               queues = *(uint16_t *)(uintptr_t)vring->desc[idx_data].addr;
> +               addr = virtio_user_iova2virt(vring->desc[idx_data].addr);
> +               queues = *addr;
>                 status = virtio_user_handle_mq(dev, queues);
>         } else if (hdr->class == VIRTIO_NET_CTRL_MQ && hdr->cmd == VIRTIO_NET_CTRL_MQ_RSS_CONFIG) {
>                 struct virtio_net_ctrl_rss *rss;
>
> -               rss = (struct virtio_net_ctrl_rss *)(uintptr_t)vring->desc[idx_data].addr;
> +               rss = virtio_user_iova2virt(vring->desc[idx_data].addr);
>                 status = virtio_user_handle_mq(dev, rss->max_tx_vq);
>         } else if (hdr->class == VIRTIO_NET_CTRL_RX  ||
>                    hdr->class == VIRTIO_NET_CTRL_MAC ||
> @@ -944,7 +954,7 @@ virtio_user_handle_ctrl_msg_split(struct virtio_user_dev *dev, struct vring *vri
>                                 (struct virtio_pmd_ctrl *)hdr, dlen, nb_dlen);
>
>         /* Update status */
> -       *(virtio_net_ctrl_ack *)(uintptr_t)vring->desc[idx_status].addr = status;
> +       *(virtio_net_ctrl_ack *)virtio_user_iova2virt(vring->desc[idx_status].addr) = status;
>
>         return n_descs;
>  }
> @@ -986,18 +996,18 @@ virtio_user_handle_ctrl_msg_packed(struct virtio_user_dev *dev,
>                 n_descs++;
>         }
>
> -       hdr = (void *)(uintptr_t)vring->desc[idx_hdr].addr;
> +       hdr = virtio_user_iova2virt(vring->desc[idx_hdr].addr);
>         if (hdr->class == VIRTIO_NET_CTRL_MQ &&
>             hdr->cmd == VIRTIO_NET_CTRL_MQ_VQ_PAIRS_SET) {
> -               uint16_t queues;
> +               uint16_t queues, *addr;
>
> -               queues = *(uint16_t *)(uintptr_t)
> -                               vring->desc[idx_data].addr;
> +               addr = virtio_user_iova2virt(vring->desc[idx_data].addr);
> +               queues = *addr;
>                 status = virtio_user_handle_mq(dev, queues);
>         } else if (hdr->class == VIRTIO_NET_CTRL_MQ && hdr->cmd == VIRTIO_NET_CTRL_MQ_RSS_CONFIG) {
>                 struct virtio_net_ctrl_rss *rss;
>
> -               rss = (struct virtio_net_ctrl_rss *)(uintptr_t)vring->desc[idx_data].addr;
> +               rss = virtio_user_iova2virt(vring->desc[idx_data].addr);
>                 status = virtio_user_handle_mq(dev, rss->max_tx_vq);
>         } else if (hdr->class == VIRTIO_NET_CTRL_RX  ||
>                    hdr->class == VIRTIO_NET_CTRL_MAC ||
> @@ -1010,8 +1020,7 @@ virtio_user_handle_ctrl_msg_packed(struct virtio_user_dev *dev,
>                                 (struct virtio_pmd_ctrl *)hdr, dlen, nb_dlen);
>
>         /* Update status */
> -       *(virtio_net_ctrl_ack *)(uintptr_t)
> -               vring->desc[idx_status].addr = status;
> +       *(virtio_net_ctrl_ack *)virtio_user_iova2virt(vring->desc[idx_status].addr) = status;
>
>         /* Update used descriptor */
>         vring->desc[idx_hdr].id = vring->desc[idx_status].id;
> --
> 2.25.1
>