Re: [Minios-devel] [UNIKRAFT PATCH v2 4/5] plat/drivers: Add 9P transport 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 adds the 9P transport driver skeleton for virtio 9P devices,
> by providing the required connect, disconnect and request callbacks. The
> request callback is left as a stub to be implemented in the following
> patches.
> 
> Signed-off-by: Cristian Banu <cristb@xxxxxxxxx>
> ---
>  plat/drivers/virtio/virtio_9p.c | 86 +++++++++++++++++++++++++++++++--
>  1 file changed, 83 insertions(+), 3 deletions(-)
> 
> diff --git a/plat/drivers/virtio/virtio_9p.c b/plat/drivers/virtio/virtio_9p.c
> index ab3a1b16..8094ec70 100644
> --- a/plat/drivers/virtio/virtio_9p.c
> +++ b/plat/drivers/virtio/virtio_9p.c
> @@ -35,6 +35,7 @@
>  #include <inttypes.h>
>  #include <uk/alloc.h>
>  #include <uk/essentials.h>
> +#include <uk/9pdev_trans.h>
>  #include <virtio/virtio_bus.h>
>  #include <virtio/virtio_9p.h>
>  #include <uk/plat/spinlock.h>
> @@ -58,6 +59,83 @@ struct virtio_9p_device {
>       struct virtqueue *vq;
>       /* Hw queue identifier. */
>       uint16_t hwvq_id;
> +     /* libuk9p associated device (NULL if the device is not in use). */
> +     struct uk_9pdev *p9dev;
> +};
> +
> +static int virtio_9p_connect(struct uk_9pdev *p9dev,
> +                          const char *device_identifier,
> +                          const char *mount_args __unused)
> +{
> +     struct virtio_9p_device *dev = NULL;
> +     int rc = 0;
> +     int found = 0;
> +
> +     ukarch_spin_lock(&virtio_9p_device_list_lock);
> +     uk_list_for_each_entry(dev, &virtio_9p_device_list, _list) {
> +             if (!strcmp(dev->tag, device_identifier)) {
> +                     if (dev->p9dev != NULL) {
> +                             rc = -EBUSY;
> +                             goto out;
> +                     }
> +                     found = 1;
> +                     break;
> +             }
> +     }
> +
> +     if (!found) {
> +             rc = -EINVAL;
> +             goto out;
> +     }
> +
> +     /*
> +      * The maximum message size is given by the number of segments.
> +      *
> +      * For read requests, the reply will be able to make use of the large
> +      * msize, and the request will not exceed one segment.
> +      * Similarly for write requests, but in reverse. Other requests should
> +      * not exceed one page for both recv and xmit fcalls.
> +      */
> +     p9dev->max_msize = (NUM_SEGMENTS - 1) * __PAGE_SIZE;
> +
> +     dev->p9dev = p9dev;
> +     p9dev->priv = dev;
> +
> +out:
> +     ukarch_spin_unlock(&virtio_9p_device_list_lock);
> +     return rc;
> +}
> +
> +static int virtio_9p_disconnect(struct uk_9pdev *p9dev)
> +{
> +     struct virtio_9p_device *dev;
> +
> +     UK_ASSERT(p9dev);
> +     dev = p9dev->priv;
> +
> +     ukarch_spin_lock(&virtio_9p_device_list_lock);
> +     dev->p9dev = NULL;
> +     ukarch_spin_unlock(&virtio_9p_device_list_lock);
> +
> +     return 0;
> +}
> +
> +static int virtio_9p_request(struct uk_9pdev *p9dev __unused,
> +                          struct uk_9preq *req __unused)
> +{
> +     return -EOPNOTSUPP;
> +}
> +
> +static const struct uk_9pdev_trans_ops v9p_trans_ops = {
> +     .connect        = virtio_9p_connect,
> +     .disconnect     = virtio_9p_disconnect,
> +     .request        = virtio_9p_request
> +};
> +
> +static struct uk_9pdev_trans v9p_trans = {
> +     .name           = "virtio",
> +     .ops            = &v9p_trans_ops,
> +     .a              = NULL /* Set by the driver initialization. */
>  };
>  
>  static int virtio_9p_recv(struct virtqueue *vq __unused, void *priv __unused)
> @@ -185,7 +263,6 @@ static int virtio_9p_start(struct virtio_9p_device *d)
>  static int virtio_9p_add_dev(struct virtio_dev *vdev)
>  {
>       struct virtio_9p_device *d;
> -     unsigned long flags;
>       int rc = 0;
>  
>       UK_ASSERT(vdev != NULL);
> @@ -204,9 +281,9 @@ static int virtio_9p_add_dev(struct virtio_dev *vdev)
>       if (rc)
>               goto out_free;
>  
> -     ukplat_spin_lock_irqsave(&virtio_9p_device_list_lock, flags);
> +     ukarch_spin_lock(&virtio_9p_device_list_lock);
>       uk_list_add(&d->_list, &virtio_9p_device_list);
> -     ukplat_spin_unlock_irqrestore(&virtio_9p_device_list_lock, flags);
> +     ukarch_spin_unlock(&virtio_9p_device_list_lock);
>  out:
>       return rc;
>  out_free:
> @@ -224,6 +301,9 @@ static int virtio_9p_drv_init(struct uk_alloc 
> *drv_allocator)
>       }
>  
>       a = drv_allocator;
> +     v9p_trans.a = a;
> +
> +     rc = uk_9pdev_trans_register(&v9p_trans);
>  out:
>       return rc;
>  }
> 

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