Re: [Minios-devel] [UNIKRAFT PATCH v2 3/5] plat/drivers: Allocate virtqueue for virtio 9P

[Costin Lupu <costin.lup@xxxxxxxxx>]

Reviewed-by: Costin Lupu <costin.lupu@xxxxxxxxx>

On 9/7/19 12:45 PM, Vlad-Andrei BĂDOIU (78692) wrote:
> From: Cristian Banu <cristb@xxxxxxxxx>
> 
> This patch implements virtqueue allocation with a stubbed interrupt
> handler for virtio 9P devices.
> 
> Signed-off-by: Cristian Banu <cristb@xxxxxxxxx>
> ---
>  plat/drivers/virtio/virtio_9p.c | 57 +++++++++++++++++++++++++++++++++
>  1 file changed, 57 insertions(+)
> 
> diff --git a/plat/drivers/virtio/virtio_9p.c b/plat/drivers/virtio/virtio_9p.c
> index 798ebe90..ab3a1b16 100644
> --- a/plat/drivers/virtio/virtio_9p.c
> +++ b/plat/drivers/virtio/virtio_9p.c
> @@ -32,6 +32,7 @@
>   * THIS HEADER MAY NOT BE EXTRACTED OR MODIFIED IN ANY WAY.
>   */
>  
> +#include <inttypes.h>
>  #include <uk/alloc.h>
>  #include <uk/essentials.h>
>  #include <virtio/virtio_bus.h>
> @@ -39,6 +40,7 @@
>  #include <uk/plat/spinlock.h>
>  
>  #define DRIVER_NAME  "virtio-9p"
> +#define NUM_SEGMENTS 128 /** The number of virtqueue descriptors. */
>  static struct uk_alloc *a;
>  
>  /* List of initialized virtio 9p devices. */
> @@ -52,8 +54,56 @@ struct virtio_9p_device {
>       char *tag;
>       /* Entry within the virtio devices' list. */
>       struct uk_list_head _list;
> +     /* Virtqueue reference. */
> +     struct virtqueue *vq;
> +     /* Hw queue identifier. */
> +     uint16_t hwvq_id;
>  };
>  
> +static int virtio_9p_recv(struct virtqueue *vq __unused, void *priv __unused)
> +{
> +     return 0;
> +}
> +
> +static int virtio_9p_vq_alloc(struct virtio_9p_device *d)
> +{
> +     int vq_avail = 0;
> +     int rc = 0;
> +     __u16 qdesc_size;
> +
> +     vq_avail = virtio_find_vqs(d->vdev, 1, &qdesc_size);
> +     if (unlikely(vq_avail != 1)) {
> +             uk_pr_err(DRIVER_NAME": Expected: %d queues, found %d\n",
> +                       1, vq_avail);
> +             rc = -ENOMEM;
> +             goto exit;
> +     }
> +
> +     d->hwvq_id = 0;
> +     if (unlikely(qdesc_size != NUM_SEGMENTS)) {
> +             uk_pr_err(DRIVER_NAME": Expected %d descriptors, found %d 
> (virtqueue %"
> +                       PRIu16")\n", NUM_SEGMENTS, qdesc_size, d->hwvq_id);
> +             rc = -EINVAL;
> +             goto exit;
> +     }
> +
> +     d->vq = virtio_vqueue_setup(d->vdev,
> +                                 d->hwvq_id,
> +                                 qdesc_size,
> +                                 virtio_9p_recv,
> +                                 a);
> +     if (unlikely(PTRISERR(d->vq))) {
> +             uk_pr_err(DRIVER_NAME": Failed to set up virtqueue %"PRIu16"\n",
> +                       d->hwvq_id);
> +             rc = PTR2ERR(d->vq);
> +     }
> +
> +     d->vq->priv = d;
> +
> +exit:
> +     return rc;
> +}
> +
>  static int virtio_9p_feature_negotiate(struct virtio_9p_device *d)
>  {
>       __u64 host_features;
> @@ -107,6 +157,12 @@ static int virtio_9p_configure(struct virtio_9p_device 
> *d)
>               goto out_status_fail;
>       }
>  
> +     rc = virtio_9p_vq_alloc(d);
> +     if (rc) {
> +             uk_pr_err(DRIVER_NAME": Could not allocate virtqueue\n");
> +             goto out_status_fail;
> +     }
> +
>       uk_pr_info(DRIVER_NAME": Configured: features=0x%lx tag=%s\n",
>                       d->vdev->features, d->tag);
>  out:
> @@ -119,6 +175,7 @@ out_status_fail:
>  
>  static int virtio_9p_start(struct virtio_9p_device *d)
>  {
> +     virtqueue_intr_enable(d->vq);
>       virtio_dev_drv_up(d->vdev);
>       uk_pr_info(DRIVER_NAME": %s started\n", d->tag);
>  
> 

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