[Minios-devel] [UNIKRAFT PATCH 4/5] plat/drivers: Add 9P transport for virtio 9P

[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 | 84 +++++++++++++++++++++++++++++++++++++++++
 1 file changed, 84 insertions(+)

diff --git a/plat/drivers/virtio/virtio_9p.c b/plat/drivers/virtio/virtio_9p.c
index ab3a1b1679de..08b2eb62a273 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 +59,86 @@ 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;
+       unsigned long flags;
+
+       ukplat_spin_lock_irqsave(&virtio_9p_device_list_lock, flags);
+       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->msize = (NUM_SEGMENTS - 1) * __PAGE_SIZE;
+
+       dev->p9dev = p9dev;
+       p9dev->priv = dev;
+
+out:
+       ukplat_spin_unlock_irqrestore(&virtio_9p_device_list_lock, flags);
+       return rc;
+}
+
+static int virtio_9p_disconnect(struct uk_9pdev *p9dev)
+{
+       struct virtio_9p_device *dev;
+       unsigned long flags;
+
+       UK_ASSERT(p9dev);
+       dev = p9dev->priv;
+
+       ukplat_spin_lock_irqsave(&virtio_9p_device_list_lock, flags);
+       dev->p9dev = NULL;
+       ukplat_spin_unlock_irqrestore(&virtio_9p_device_list_lock, flags);
+
+       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,
+       .is_default     = 1,
+       .a              = NULL /* Set by the driver initialization. */
 };
 
 static int virtio_9p_recv(struct virtqueue *vq __unused, void *priv __unused)
@@ -224,6 +305,9 @@ 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;
 }
-- 
2.11.0


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